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Pirina ile ağır ham petrolün eş-pirolizi
Bu çalışmada, İskenderun ilçesinde faaliyet gösteren zeytinyağı üretim tesislerinden temin edilen pirina ile Batı Raman kökenli ağır ham petrol numunesi sabit yataklı reaktörde bireysel ve eş piroliz çalışmaları gerçekleştirilmiştir. Sıcaklığa bağlı olarak ürünlerin verim değerlerinin değişim eğilimlerini belirlemek ve ayrıca amaç kapsamında uygulanan şartlarda en yüksek verimli sıvı ürün eldesine yönelik optimal piroliz sıcaklık değerini belirlemek amacıyla 10 o C/dakika ısıtma hızı şartları altında ve 400-500 o C arasında 5 farklı sıcaklık değerinde ve aynı şartlar altında 3 tekrarlı bir dizi piroliz işlemi gerçekleştirilmiş elde edilen ürünlere ilişkin ortalama verim değerleri hesaplanması sonucu en yüksek sıvı ürün verim değerlerine 500 o C piroliz sıcaklığında ulaşılmış ve ayrıca bu sıcaklık değeri TG analiz sonuçları ile uyumluluk göstermiştir. Bunun akabinde hem bireysel hem de ağır ham petrol numunesi ile pirinanın eş pirolizi sırasında sinerjik etkinin gerçekleşip gerçekleşmediğini belirlemek amacıyla 500 o C optimal piroliz sıcaklığı ve 10 o C/dak ısıtma hızı şartlarında 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 ve 1 (ağır ham petrol/ pirina, kütlece) karışım oranlarında (ɸ) piroliz işlemi gerçekleştirilmiştir. Yapılan bu çalışmalar neticesinde ürünlere ilişkin olarak yüzde verim (%, kütlece) değerleri ile birlikte ayrıca her bir ürün için belirlenen teorik verim ve deneysel verim farkı hesaplanmıştır. Bu sonuçlar ɸ = 0,7 karışım oran değerinden daha yüksek karışım oran değerlerinde sıvı ürün verimi azalma olurken genel olarak gaz ve katı ürün verimlerinde artış meydana gelmiş ve sıvı ürün verim farkı bakımından en güçlü sinerjik etkinin ɸ = 0,7 karışım oran değerinde gerçekleşmiş olduğunu ortaya çıkarmıştır. Çalışmada ana amaç olan sinerjik etkisinin ürün yapısı ve kalitesi üzerine etkisini değerlendirmek için optimal karışım oranı (ɸ = 0,70) şartlarında elde edilen sıvı ürün ile aynı piroliz şartlarında bireysel piroliz sıvıları üzerinde karakterizasyon çalışmaları (Fizikokimyasal, FT-IR ve GS-MS) yapılmıştır. Fizikokimyasal analiz sonuçları eş piroliz sıvı ürününün, kuru pirinanın bireysel piroliz sıvısına kıyasla daha yüksek malten ve daha düşük asfalten içerikli olduğunu göstermektedir. Ayrıca yapılan hesaplamalar neticesinde eş piroliz sıvı ürünün deneysel olarak elde edilen yüzde malten içerik değeri (%93,68) ile hesaplanan (teorik) malten içerik değeri (%82,55) arasında %11,13'lük bir farkın oluşması eş piroliz işlemi sırasında malten verimi üzerinde pozitif bir sinerjik etkinin oluştuğunu göstermektedir. FT-IR analizi ile eş piroliz esnasında sıvı ürünlerin kimyasal içerik tür dağılımı üzerinde de sinerjik etkinin oluştuğu anlaşılmakla birlikte sıvı ürünlerin, organik bileşik tür ve çeşidi bakımından zengin içerikli oldukları tespit edilmiştir. GS-MS sonucu olarak eş piroliz sıvı ürününün, düşük oksijenat ve yüksek hidrokarbon (alkanlar, alkenler ve benzen türevleri) 5 içerik dağılımına sahip olduğu görülmekte ve ayrıca eş piroliz malteninde polisiklik aromatik bileşik konsantrasyonu (%5,52), ağır ham petrolün pirolitik malten fraksiyonuna kıyasla daha yüksek olarak gerçekleşmiştir. Analiz sonuçlarının birbiriyle uyumlu olduğu görülmüştür. Sonuç olarak, eş piroliz teknolojisi ile elde edilen sıvı ürün, yüksek katma değerli hidrokarbonlarca yüksek fakat istenmeyen unsurlar olan oksijen ve azot içeriği bakımından da düşük içerik dağılımına sahip olmuştur. Bu hususlar, eş piroliz sıvı ürünün bireysel piroliz sıvı ürününe göre daha üstün vasıfsal özellikte olduğunu ortaya koymaktadır. Bu olumlu özellikli eş piroliz sıvı ürün; zengin değerli organik bileşik içeriğinden dolayı çeşitli petrokimyasalların ve kısmen pahalı olan petrol bazlı fenolün hammadde olarak kullanılmasıyla üretilen fenol-formaldehit ya da fenolik reçineler gibi endüstriyel ürünlerin üretimi için maliyet etkili alternatif hammadde yüklemesi olarak değerlendirilebildiği kanaatine varılmıştır.
Perlitin su bazlı sondaj çamurlarında katkı maddesi olarak kullanılmasının araştırılması
Sondaj uygulamalarında başarılı bir operasyon gerçekleştirmek için kullanılan sondaj akışkanının performansı oldukça önemlidir. Son zamanlarda özellikle pahalı teknolojilerin kullanıldığı yatay ve derin deniz sondajlarındaki gelişmelerin yanı sıra sondaj çamuru teknolojisindeki gelişmeler de ekonomik anlam kazanmıştır. Çevre korumaya yönelik yasal düzenlemelerin getirdiği yeni yükümlülüklere çözüm aranırken aynı zamanda da mevcut sorunlara daha etkin çözüm yöntemleri arayışları devam etmektedir. Bahse konu olan bu durum doğrudan veya dolaylı olarak sondaj sıvısı ile ilişkilidir. Sondaj sıvısının temel görevleri; kayaç ve kırıntıların yüzeye taşınması, yer altı basıncını kontrol edilmesi, sondaj kuyusunun denge ve desteğinin sağlanması, kuyu tabanının temizlenmesi, matkap ve sondaj dizisinin soğutulması yağlanması, göçme ve oyuk oluşumuna engel olmak için geçirimsiz bir pastanın oluşturulması, yüksek basınçlı formasyonların kontrol edilmesi, sondaj dizisi ve koruma borularının taşınması, korozyona karşı koruyucu olması olarak ifade edilebilir. Bu çalışmada; hem petrol hem de doğalgaz sondaj işlemlerinin önemli bir maliyet yükünü oluşturan sondaj çamuruna, ham perlit ve genleştirilmiş perlit ayrı ayrı eklenip sondaj çamurunun daha efektif kullanılması amaçlanmıştır. Bu bağlamda su bazlı sondaj çamuruna farklı oranlarda ham perlit (%0,5-5 k/h) ve genleştirilmiş perlit (%0,1-0,6 k/h) eklenerek hazırlanan sondaj çamuru numunelerinin; plastik viskozite, görünür viskozite, kopma (akma) noktası, jel mukavemeti (10 saniye, 10 dakika) gibi reolojik analizlerinin yanı sıra, sıvı kaybı ve kek kalınlığı gibi filtrasyon özellikleri de incelenmiştir. Amerikan Petrol Enstitüsü (API) standartlarına göre gerçekleştirilen bu çalışmayla elde edilen sonuçlar incelendiğinde; ham perlit ve genleştirilmiş perlit ilave edilmiş sondaj çamurunun, spud (ham perlit ve genleştirilmiş perlit katkısız) çamura göre daha iyi reolojik özellik gösterdiği tespit edilmiştir. Dolayısıyla gerek ham perlitin gerekse de genleştirilmiş perlitin sondaj çamuru katkı maddesi olarak kullanılabileceği kanaatine varılmıştır.
Sondaj çamurlarında grafitin kullanılabilirliğinin araştırılması
Bu tez çalışmasında, sondaj çamuruna grafit katılmasının sondaj çamurunun reolojik özelliklerine olan etkisi incelenmiştir. Bu amaçla bentonit, kostik, su karışımından oluşturulmuş su bazlı sondaj çamuruna farklı konsantrasyonlarda (%0,1-%2) toz haldeki grafit eklenerek hazırlanmış sondaj çamurunun; PV, AV, YP, jel mukavemeti, filtrasyon kaybı, kek kalınlığı, pH ve yoğunluk analizleri Amerikan Petrol Enstitüsü (API) standartlarına göre analiz edilmiştir. Çalışmanın sonunda temel haldeki sondaj çamurunun görünür viskozitesi 38 saniye plastik viskozitesi 10 cP, kopma noktası 13, jel mukavemeti 11, filtrasyon kaybı (100bar/ 7,5 dakika) 30 ml, kek kalınlığı (100bar/ 7,5 dakika) 1mm, pH 13, tanecik boyutu 0,1 mm olarak ölçülmüştür. %0.1 ile %2 oran aralığında hazırlanmış sondaj çamurunun reolojik özellikleri incelendiğinde ise pH'ın sabit olarak 13 olduğu, görünür viskozitenin %0,1'den %1,2'ye kadar 38 saniye olduğu, %1,2'den %1,8'e kadar 39 saniye olduğu, %1,8 ile %2 aralığında ise görünür viskozitenin 40 saniye olduğu ölçülmüştür. %0,1 ile %2 oran aralığında toz grafit eklenmiş sondaj çamurunun plastik viskozitesi 10 cP ölçülmüştür. %0,1 ile %2 oran aralığında toz grafit eklenmiş sondaj çamurunda YP, %0,1 ile %1,3 aralığında 13, %1,3 ile %1,8 aralığında 14, %1,8 ile %2 aralığında 15 olarak ölçülmüştür. %0,1 ile %2 oran aralığında toz grafit eklenmiş sondaj çamurunun filtrasyon kaybı(100bar/ 7,5 dakika), 30 ml olarak ölçülmüştür. %0,1 ile %2 oranında toz grafit eklenmiş sondaj çamurunun kek kalınlığı (100bar/ 7,5 dakika) 1mm olarak ölçülmüştür. %0,1-%2 oranında toz grafit eklenmiş sondaj çamurunun tanecik boyutu 0,1 mm olarak ölçülmüştür. %0,1-%2 aralığında yoğunluğa ölçülebilir etkisi tespit edilmemiştir. Yapılan deney sonuçları birbirleriyle benzer sonuçlar vermektedir. Buna göre, görünür viskoziteyi artırması, plastik viskoziteyi arttırması, YP'yi ve jel mukavemeti değerlerini yükseltici etkisi bakımından pozitif etkisi olmaktadır.
Killi formasyonlarda yaşanan sondaj problemleri ve sondaj sıvıları
Petrol arama ve üretimi sırasında, delinmiş formasyonlardaki şeyllerin kararsızlığı ciddi operasyonel sorunlara neden olur. Sondaj kuyusu kararlılığı ve formasyon verimliliği, formasyon kimyası ve sondaj çamuru arasındaki etkileşimlere dayanarak seçilen sondaj sıvısı türüne bağlıdır. Bu tezde şeyl tipleri, kuyu stabilitesi ve takım sıkışmaları açıklanmıştır. Sondaj kuyusu kararsızlığının nedenleri ve mekanizmaları ile ilgili kil mineralleri ve şeyl numune karakterizasyonunu araştırmada kullanılan teknikler tartışılmıştır. Özellikle yeni sondaj sıvısı katkı maddelerinin geliştirilmesiyle, sıvı kararlılığı ve reoloji parametrelerinde dikkate değer iyileştirmeler gözlemlenmiştir, ancak günümüzdeki asıl sorun inhibisyon ve filtrasyon özelliklerini iyileştirmektir. Bu farklı sonuçları etkileyen ana faktörlerin (numune kalitesi, fiziksel veya kimyasal faktörler, kullanılan deneysel yöntem veya kil mineralleri içeriği) hangileri olduğu sorusunu yanıtlanmıştır. Ülkemizde özellikle Güneydoğu Anadolu Bölgesi'nde üretim zonlarına ulaşılmadan önce aktif şeyllerin bulunduğu kalın formasyonlar kesilmektedir. Kuyu stabilitesine bağlı tight hole, kuyu duvarının yıkılması, takım sıkışması gibi problemler bu formasyonların sondajında önemli maddi kayıplara ve gecikmeye sebep olmaktadır. Bu bölgede özellikle aktif şeyllerin suyla etkileşiminin kayacın mekanik özelliklerini değiştirmesiyle öne çıkan tektonik aktiviteye bağlı kuyu stabilitesi problemleri sıklıkla görülmektedir. Söz konusu formasyonlarda sondaj için çoğunlukla düşük maliyeti ve bilinirliği sebebiyle su bazlı, inhibitive olmayan bentonit-lignosülfanat çamurları yaygın olarak kullanılmaktadır. Bununla birlikte stabilite problemlerinin önlenmesi için saha alışkanlıklarıyla gelişmiş, sık aralıklarla uygulanan kısa mesafeli manevralar, gözenek basıncı ve in-situ stresleri dikkate almadan ve önceden planlanmamış çamur ağırlaştırma gibi yöntemler kullanılmaktadır.
Parameter estimation using pressure and temperature transient data from wireline formation tester interval pressure transient tests (IPTT)
Reservoir behavior may be considered as isothermal because changes in temperature are generally small. In the past, use of transient temperature measurements had limitations due to the simplified assumption of isothermal fluid flow. Moreover, owing to poor resolution of temperature devices, small differences in the bottomhole (sandface) temperatures could not be detected. On the other hand, recent enhancement in the resolution of the downhole temperature devices allowed researchers to analyze and interpret transient temperature measurements to estimate near wellbore and reservoir characteristics. Therefore, the use of bottomhole temperature analysis has been expanded due to the development in resolution and accuracy in downhole gauges and the information that temperatures retain. Traditional pressure transient analysis has been used to obtain reservoir characteristics for a long time for conventional well testing and interval pressure transient test (IPTT). Recently, several works showed that near wellbore parameters can be acquired from transient temperature measurements. Previous works on transient temperature analysis performed based on slightly compressible fluid for fully-penetrated vertical or horizontal well in a single or multilayer homogeneous reservoir. Nonetheless, none of the studies analyzed temperature transient measurements acquired from the interval pressure transient test in partially-penetrated well to use in parameter estimation. Temperature data is obtained in IPTT; however, it is never being accounted in interpretation. The main target of this study is to estimate formation and near wellbore characteristics, especially horizontal and vertical permeability in the damaged zone and undamaged zone in a reservoir where damage in the formation is modeled as composite, by analyzing transient temperature measurements from the interval pressure transient test (IPTT). Furthermore, the effect of mud filtrate invasion on transient temperature measurements and parameter estimation is investigated. In this study, one of the commercial multi-purpose nonisothermal CMG-STARS simulator based on the fully-implicit numerical procedure is used. In the course of modeling, well block pressure and temperature in the simulator, some oil physical properties such as density, isothermal compressibility, and formation volume factor are allowed to vary with pressure and temperature. On the other hand, oil, water, and solid matrix specific heat capacities and isobaric thermal expansion coefficients are taken into consideration as constant with temperature. In the model, viscosity is treated as constant, at the initial conditions. To model conduction with oil, water, and rock system, a constant value of thermal conductivity is used. J-T expansion coefficient is accounted implicitly in the simulator through the variation enthalpy with pressure. Dual-packer tool configuration is used in modeling to compute transient temperature data to apply straight-line and nonlinear regression analysis including the effects of damage in the formation and mud filtrate invasion along with anisotropy. Probe configuration is modeled to generate transient temperature data to study nonlinear regression analysis including the effects of damage in the formation together with anisotropy. In this study, a commercial software CMOST AI for assisted history matching is used as an optimization module. A stochastic-based optimization technique that minimizes the difference between the observed data and the simulation responses as quantified with an objective function is used. To begin with, a synthetic model configured with a dual-packer tool is used to compute transient temperature data with constant oil production in a partially-penetrated well for a thin reservoir. Absolute temperature derivative showed that temperature propagates much slower than the pressure in the formation; thus, radial flow regime exhibits at very late times both in the damaged and undamaged zone. Horizontal permeability could be estimated precisely in the case of zero damage. In the presence of damage, horizontal permeability in the damaged zone may be estimated well if damaged zone radius is long enough for the reason that J-T expansion masks intermediate-time IARF for small damaged zone radius. In addition, another synthetic model constructed with the dual-packer tool is used to generate transient temperature data with constant production of oil in a partially-penetrated well for a thick reservoir. Nonlinear regression analysis is applied to only transient temperatures computed from this model. Horizontal permeability in the damaged zone is estimated correctly in both isotropic and anisotropic cases. Moreover, it is assessed precisely under shortened test period and mud filtrate invasion effect. The estimation of horizontal permeability in the undamaged zone is meaningful in case of no damage effect or small damaged zone radius in both isotropic and anisotropic cases. On the other hand, deep damaged zone radius and short test time result in deviation at the true value of horizontal permeability in the undamaged zone. Unfortunately, the estimations of vertical permeability in both damaged and undamaged zone are not close enough to the correct values due to the sensitivity of this parameter to temperature transient. Lastly, a synthetic model created with sink probe tool is used to compute transient temperatures with constant production of oil in a partially-penetrated well for a thick reservoir. Similarly, nonlinear regression analysis is applied to only transient temperatures generated from this model. In the case of isotropy, horizontal permeability in the damaged zone is estimated accurately, and horizontal permeability in the undamaged zone is estimated exactly only in absence of damage. When the reservoir is homogeneous and anisotropic, none of the parameters is estimated precisely. Moreover, the impact of various rock, fluid, and thermal properties on transient drawdown temperature is investigated. It is observed that reservoir thickness, porosity, and rock heat capacity do not have a significant effect on temperatures from IPTT. On the other hand, penetration interval, horizontal permeability, and viscosity may create extensive temperature changes. Also, the presence of skin and anisotropy have a substantial impact on transient temperatures from IPTT.
Batı Raman petrolü kullanılarak buhar- alkali (borax) solüsyon enjeksiyonunun deneysel incelenmesi
An experimental study has been conducted to compare the effect of steam injection and steam-alkali solution injection in improving the recovery of heavy oil. Bati Raman oil is used for the experiments. The API gravity (11.6º) and viscosity are typical of a heavy oil. Steam injection is used to increase the temperature in the reservoir reducing oil viscosity thus increasing the mobility of the oil. On the other hand, the target of alkali flooding is to reduce the residual oil saturation by generating surfactants in situ. Alkali solution is prepared by using Borax which forms weak alkali solutions. Borax mineral resources are abundant in Turkey and it is one of the least studied alkali solutes. Therefore, Borax is chosen in this study for the experiments. A laboratory setup was designed and built for the purpose of steam injection. The experimental setup consisted of four main systems; steam injection system, injection tube, fluid production system, and data measurement and recording system. The steam injection system consists of two reservoirs that hold the water and the alkali solution, an electrical pump, and an electrical steam generator. The injection tube is a stainless steel cylinder with a length of 1 meter and an internal diameter of 7.3 centimeters and a thin wall (1.5 mm) with flanges at both ends. Twenty-one thermocouples are placed at specific distances in the injection tube to record temperature profiles. To represent the reservoir rock and fluids, the injection tube is packed with a mixture of sand, oil, and water. The fluid production system consists of a condenser, a sand trap, and two separators. The produced samples are collected from the bottom of the separators in graduated tubes. Data measurement and recording system consisting of a data logger and computer to record the steam injection temperature and injection tube profile temperatures. Six runs are conducted as follows; water flooding, alkali solution flooding, conventional pure steam injection, cyclic injection of steam and alkali solution (4.0 wt %), cyclic injection of steam and alkali solution (4.0 wt %) with different cyclic injection period, and cyclic injection of steam and alkali solution (8.0 wt %). No oil is produced from water flooding and alkali solution flooding runs. Conventional pure steam injection recovered 8% OOIP. Experimental results show that, using of Borax solution results in a decrease in recovery of oil from 8% (pure steam injection) to 3 % (steam-alkali solution, 4.0 wt %) and 5.5% (steam-alkali solution, 8.0 wt %).
Analysis of interval pressure transient tests conducted by wireline formation testers in oil reservoirs with a connected water aquifer system
Interval Pressure Transient Test (IPTT) is one of the commonly used formation testing methods in the industry to estimate some of the unknown parameters that have vital importance in the characterization of the reservoir. The parameters such as vertical and horizontal permeability can be estimated by applying classical straight line analysis if classical radial and spherical flow regimes are observed. Nevertheless, these estimations may not be accurate when there is a transition zone such as oil reservoirs with connected water aquifer systems. In this case, regression analysis should be performed to estimate the unknown parameters. In this study, basically, parameter estimation is performed in an oil reservoir with connected water aquifer system having a transition zone through the method of history matching using the IPT test data. Before estimating the parameters, two different reservoir models for an oil-water system having a single well in radial coordinates are created by using commercial simulator software CMG-IMEX. One of these models includes a transition zone between oil and water phases while there is a sharp interface for the other. Several IPT tests are run at different depths and in different zones for these two models and water cut ratios are measured in addition to packer and probe pressure data. The vertical and horizontal permeability values are estimated at first from packer-probe pressure data by using a gradient based approach based on maximum likelihood estimation for both models. Then, the same parameters are estimated only for the reservoir model having a transition zone by using CMOST which is an optimization and history matching tool of CMG. Furthermore, relative permeability and capillary pressure curves are estimated from the Modified Brooks-Corey model parameters by using CMOST based on the water cut data obtained from IPT tests performed in the transition zone. Lastly, relative permeability and capillary pressure curves as well as horizontal and vertical permeability are estimated at the same time by using all IPT test data including both packer-probe pressure and water cut measurements in CMOST software. The results show that accurate estimation of horizontal and vertical permeability values of the model where the capillary pressure is zero is possible with gradient based approach whilst having a transition zone gives moderately acceptable results for the same approach. On the other hand, estimated horizontal permeability value and anisotropy ratio is slightly better when CMOST is used in parameter estimation for the model where a transition zone exists. Moreover, relative permeability and capillary pressure curves are estimated accurately when water cut measurements are used in addition to packer-probe pressure data.
Parameter optimization for z-factor correlations to predict Joule-Thomson inversion curve
When a real gas undergoes a volumetric process, a temperature change is usually observed. Temperature change is experienced during production at the perforations, throughout surface and subsurface chokes, at the surface where heavier hydrocarbons are removed at the processing facilities and compression and liquefaction of natural gas. Temperature change accompanying volumetric change is known as Joule-Thomson effect. The sign and magnitude of the temperature change may be determined by using Joule-Thomson coefficient. If Joule-Thomson coefficient is positive, then the gas temperature decreases as a result of expansion. Under the condition where the coefficient is negative, expansion process increases the gas temperature. If Joule-Thomson coefficient is identically zero, no temperature change will be observed as a result of volume change. Projection of the pressure-temperature pairs at which Joule-Thomson coefficient becomes zero creates an envelop on the P-T plane. This envelop is known as Joule-Thomson inversion curve. The inversion curve separates the P-T plane into two regions where the temperature changes have opposite signs. All gases have different inversion conditions. Measurement of inversion condition for gases requires precisely controlled experimental conditions. As a result of experienced difficulties in the experimental setups, the inversion data is limited in the literature. In lack of sufficient experimental data, some correlations, equation based prediction methods and molecular simulation techniques are all used to compute the inversion characteristics of the different gases. None of these methods are able to predict the inversion conditions accurately. The aim of this study is to search the applicability of several z-factor correlations extensively used in petroleum and natural gas engineering in prediction of Joule-Thomson inversion curve. Adjustable parameters of the correlations would be optimized to improve the accuracy of the inversion curve computations. Since these equations are readily programmable, they will be valuable tool in engineering calculations.
Application of kNN-GRNN algorithm for liquid holdup determination in two-phase flow
In some industries, such as chemical industry, nuclear power plants, geothermal energy, petroleum industry, etc. two-phase flow dynamics arise. Especially in oil and gas industry while producing hydrocarbons (oil and gas), starting with production string in the well through pipelines in the surface two-phase flow is transpired. Two phase flow is defined as two distinct phases are flowing simultaneously in the pipe. The dynamics affects the interphase between involved phases thus influences the distribution of both phases through the flowing pipeline. Relative distribution between phases is defined as holdup, generally defined as liquid phase holdup, or more precisely liquid holdup. This holdup is important for flow dynamics. The estimation of liquid holdup in pipelines is very substantial in the oil and gas industry. It affects seperation design equipment and slug catching. For both horizontal, inclined and vertical conditions various models are proposed to find this term in flowing conditions. Most of the proposed studies are for specific conditions and could not be generalized to other conditions. The start of the procedure in those models are identifying the flow pattern first (each flow pattern have its own solution procedure for finding liquid holdup) then finding the liquid holdup for each case. Liquid holdup is used in friction factor calculation and as a result for finding the pressure distribution along the pipeline. Flow pattern dependent models have the difficulty for finding the accurate liquid holdup value across the flow pattern transition boundaries. Those blurred transition region phenomena may result inconsistency as flow conditions differ. Neural Networks are designed by the inspiration of neurons in living organism nervous system. Neural networks are processors for understanding the data and diagnose the relations within them thus consequently find out and solve chaotic patterns related to data. Those systems foster themselves by getting every new data in time and do not need specific problem related programming. Neural networks evolve pertinent specifications and use them as the solution process. In recent years, they are used as solution process in many industries and in many engineering problems. Compared to conventional methods (empirical or mechanistic methods) Neural networks achieve promising results in various engineering applications such as multiphase flow modeling. Flow pattern identification, liquid holdup calculation and pressure distribution calculation can be conducted in multiphase flow modeling. In this study, machine learning algorithms were applied for liquid holdup determination. We tried to find the most important parameters that affect the two phase flow by trying all combinations of parameters used in the experiments. Mathematical correlations and Neural network algorithms were applied to the problem to compare K-nearest neighbours and GRNN combined (kNN-GRNN) algorithm. K-nearest neighbours was used as clustering for GRNN algorithm. Coefficient of determination (R) and average absolute percent relative error (AAPE) are used to compare the performance of all models. Hybrid kNN-GRNN algorithm performed the best with a 0.9573 R value and 18.02% AAPE.
Değirmenköy yeraltı gaz depolama sahasının modellenmesi
The major source of energy essential to life comes from fossil fuels, and the dominant fossil fuels used today by most industrialized and developing countries are oil, coal, and natural gas. Among these fossil fuels, the natural gas is a versatile, clean-burning, and efficient fuel that is used in a wide variety of applications. According to the International Energy Agency (IEA), since the beginning of the 70s, the share of gas in the world energy balance has increased from 16 to 21% in 2008. According to the British Petroleum (BP) Statistical Review of World Energy, this share in 2010-2014 in global energy consumption was even higher - about 24%. BP forecasts that natural gas will be the fastest growing type of fuel in the next 25 years. The experts of IEA believe that the share of gas in the world energy by 2035 will increase to 25%, the gas will be the second energy source after oil, shifting coal into third place. Stable development of the gas industry and its individual factors are related to the capital investment of both new construction and in the maintenance of the achieved level. Improving the reliability of gas supply to consumers is particularly important. Consequently, one way to increase the security of gas supply is the underground gas storage facilities. Underground gas storage is an independent sub-sector of the gas industry. It plays an important role in ensuring the stability of gas supply by creating the reserve volume of gas in case of emergency situations in the gas pipeline system, which require prompt increase in supply. Involvement capacities of underground gas storage allows to balance the work of the gas supply system by increasing the productivity of the gas transportation system, or accumulating excessive amounts of commercial gas in the period of low demand. Gas is stored most commonly in underground storage facilities under pressure. These underground facilities are depleted oil and/or natural gas reservoirs, aquifers, and salt cavern formations. Natural gas is also stored in liquid or gaseous form in aboveground tanks. Gas is the major energy source consumed in Turkey. Today, Turkey needs to import substantial amount of energy since indigenous energy resources are not sufficient to meet increasing in demand. By virtue of this, the main goal of Turkish energy policies has been set as the supplying of required energy in a timely, dependable, cost-effective, environmentally sound and in a high-quality basis to support the development impulse and social progress. Turkey's energy security is closely related with the amount of gas stored. In Turkey there exist surface storage in form of tanks and underground gas storage. However, underground gas storage provides significantly large volume and meets various strategic requirements and delivery rates. At present Turkey does not have significant underground gas storage volumes comparable to other countries, despite the presence of suitable geology of both salt cavern and depleted field storage. One of the depleted underground gas storage of Turkey is the Degirmenkoy field. The Degirmenkoy is one of the two reservoirs of Silivri underground natural gas storage facility. The field is located in the Thrace region of Turkey. It is an onshore gas field located 16 km northern-west of the Northern Marmara field. The feasibility of creating gas storage in the Degirmenkoy field was examined based on process design, geologic factors, and preliminary economical analysis. The purpose of the design for an underground storage reservoir is to obtain the maximum working gas capacity for a given configuration of reservoir and surface properties under the influence of economics. The method of selecting the appropriate number of wells, wellhead pressure and base gas requirements is to fix one of the parameters and determine how the other parameters change depending on each other. In this study, the Degirmenkoy natural gas field is designed for storage purposes using RUBIS simulator. Approaches to designing the Degirmenkoy gas field as underground gas storage are as follows: - To design the current state of field maintaining the working gas capacity of 14.37 bscf for a given number of wells, reservoir and well properties. - To observe the reservoir performance of field with additional wells. The storage cycle for one year in Degirmenkoy UGS field is planned as follows: 180 days of injection period followed by 35 days of shut-in period, then 150 days production period is followed. It is assumed that all wells have the same wellbore and flow characteristics, accordingly simulated data are obtained from well #5. To achieve a desired result, firstly the model is simulated with already existing six wells. By using RUBIS simulator, two approaches for operation of the underground gas storage facility, namely the constant flow rates for both injection and production periods and the constant bottomhole and wellhead pressures are investigated. After that, new six wells are added to maximize the working gas capacity. The capacities of six wells and twelve wells are compared. In addition, the mechanical skin effect is considered. Increasing the skin factor causes to decrease the working gas capacity, which is not desirable. Hence, the efforts to minimize wellbore damage is the cause for concern. The wellhead pressure is the key parameter for defining the quantity of horsepower requirements for compressing the gas to the market. Therefore, the wellhead pressure effect on performance of the underground gas storage reservoir is studied. The result show that decreasing the wellhead pressure leads to an increase in working gas capacity for a fixed number of wells.
Performance behavior of compressed liquid geothermal reservoirs under a constant energy production scheme
A reservoir model is a utility describing the change in reservoir pressure and temperature as a function of time or cumulative fluid production. Pressure and temperature are the main parameters to consider when modelling the geothermal reservoirs. Primary objectives of geothermal reservoir modeling are to estimate production capacity of the geothermal fields, the rate of reservoir pressure decline and the effects of fluid recharge and injection on field performance. There are mainly three methods of modeling available in the literature, which are decline curve analysis, numerical modeling and lumped parameter modeling. Lumped parameter modeling, also known as zero-dimensional modeling, is a commonly used method when there is less data available at the early life of the field. In this model, reservoirs and aquifers are defined as homogeneous tanks and their average properties are used. Pressure and temperature behaviors are obtained by solving mass and energy conservation equations. In the literature, many lumped parameter (tank) models have been proposed for isothermal and non-isothermal geothermal fields. However, most of these models are valid for constant flow rate production scenario. In this study, a new non-isothermal single tank model was developed. Pressure and temperature behaviors are obtained by solving mass and energy conservation equations. With the new model developed, the temperature and pressure behaviors of the reservoir can be predicted for both scenarios, namely constant flow rate production and constant energy production scenarios. The tank system used in the model to represent the geothermal system is a reservoir tank and a recharge source. In the model, the tank is assumed to be recharged from a constant pressure source from the outer edge of the tank. Natural recharge is considered by applying the Schilthuis steady state water influx model between the recharge source and the reservoir. The main objective of this study is to compare reservoir performances under constant-energy and constant-flow production scenarios and to discuss the effects of certain parameters on reservoir performance behavior under constant energy production scenario. From this study, it is concluded that for the assumed reservoir parameters, pressure and temperature at late time for constant energy production scenario stabilize at some value like in the constant flow rate production scenario. When flow rate production is considered under constant energy production scheme, it is observed that mass flow rate is dependent on temperature and and specific heat capacity of the water. While bulk volume affects pressure and temperature at early and middle times, it has no effect on the steady state pressure and temperature under both scenarios. Under constant energy production scheme, required energy value is observed to affect reservoir steady state pressure, however, it has no effect on the steady state temperature for constant energy production scheme. It is also observed that steady state pressure and temperature are not affected by the rock porosity. Since pressure and temperature at late time depend on the injection rate, they will stabilize at different values for each case of reinjection ratio. While recharge constant has no effect on the steady state temperature, it affects steady state pressure under constant energy production scheme.
Probability based volumetric "heat in-place" methods for predicting power (electricity) generation potential of liquid-dominated geothermal systems
Reserve estimation is the vital part of reservoir engineering to be able to get an idea about the accumulation and the producibility of the reserve. One should make realistic guesses about the areal extension, thickness, resource temperature, porosity, density, isobaric, volumetric specific heat capacity of reservoir rock to be able to make reserve estimations of the geothermal resource. Also recovery factor is an important input parameter having the most uncertainty in estimation of the recoverable portion of the reserve in geothermal field. It is very usual to use a volumetric probabilistic approach for the purpose of getting recoverable reserve estimations because deterministic approaches do not consider uncertainty propagation in estimation. USGS (United States Geologic Survey) and MIT (Massachusetts Institute of Technology) methods are widely used for volumetric probabilistic approaches to reserves with estimated input data distributions of the reservoir parameters (Garg and Combs, 2015), (Başel, 2010). When these methods are associated with probabilistic methods like MC (Monte Carlo) or its simple alternative Analytic Uncertainty Propagation (Onur et al. 2010), they give probabilistic results to assess the uncertainty in the estimation by using commonly used statistical markers of P10 (proved), P50 (probable) and P90 (possible). Clearly it is impossible to have an exact idea for the geothermal in-situ reserves due to the included uncertainties related to reservoir characteristics such as tectonic settlement, fracture networking, porosity, thickness, areal extension, heat flow mechanism or so. That is why researchers often use stochastic approaches instead of deterministic ones. Monte Carlo simulation or analytical based uncertainty propagation methods give results by using statistical markers P10 (proved), P50 (probable) and P90 (possible) to propagate the uncertainty. These markers represent the confidence of the estimated results belong to real geothermal reserve. "P" stands for the percentile of confidence. As an example; If one says; • The estimated P10 value is 200 MWe then that means there is at least a 90% probability (chance of occurance) that the exact, unknown reserves recovered will be equal or exceed the estimated value of 200 MWe. This is equivalent to starting that there is a 10% chance of occurance that the estimated value of 200 MWe will be equal or less than the unknown reserves recorded. • The estimated P50 value is 300 MWe then that means there is at least a 50% probability (chance of occurance) that the exact, unknown reserves recovered will be equal or exceed the estimated value of 300 MWe. This is equivalent to starting that there is a 50% chance of occurance that the estimated value of 300 MWe will be equal or less than the unknown reserves recorded. • The estimated P90 value is 400 MWe then that means there is at least a 10% probability (chance of occurance) that the exact, unknown reserves recovered will be equal or exceed the estimated value of 400 MWe. This is equivalent to starting that there is a 90% chance of occurance that the estimated value of 400 MWe will be equal or less than the unknown reserves recorded. These examples show that the P10 provides a conservative estimate of reserves, while the P90 provides an overoptimistic estimate of reserves. If the distribution of reserves is symmetrical, which is rarely the case, it could be said that P50 value has a more confidence to occur because it is closer or equal to the mean value of the real potential of reserve. However, the distribution of the reserves is usually log-normal and hence, it is usually preferable to consider the tails of the distribution (Capen 1996, 2001). For example, P10 is the value used to solicit financing from banks and these statistical markers are also required by private and government institutions or agencies to classify the potential of the oil, gas or geothermal reservoirs as well as providing finance to the projects proposed by the investors or decision makers (Capen 2001). USGS and MIT methods use arbitrarily chosen reference temperature and thermal power conversion efficiency values for their estimations without taking the second law of thermodynamic and the installed power conversion system into consideration. So this leads to overestimated results of reserve estimations, as shown by Garg and Combs (2015). Garg and Combs (2015) proposed a new method that a geothermal field must be treated with an approximation that relies on the resource temperature of the reservoir. If the reservoir temperature value is higher than 180 oC than this reservoir is proper for single or double flash power conversion system and if the reservoir temperature is between 57-180 oC then a binary power plant should be installed to be able to produce electricity from the resource efficiently. Also the input parameters used for the volumetric probabilistic reserve estimation should be chosen related and accordant to the power conversion system. Monte Carlo simulation method is the widely used method for reserve approximations in a probabilistic way and also analytical uncertainty propagation method presents an alternative analytical way to probabilistic reserve estimations giving very close resultant values in comparison to Monte Carlo simulations. In this thesis, all volumetric estimations of power generation potential based on USGS, MIT and Garg and Combs (2015) have been evaluated by MC simulation and AUP methods. The working equations of AUPM for each of the three methods have been derived in this thesis. Then, the applications of AUP method have been presented and compared with the MC simulation results applied to USGS, MIT and Garg and Combs (2015) methods. The results predicted by the new AUPM equations derived in this work showed an excellent agreement, not requiring extensive MC simulations and a commercial software use. Suggestions were made about the usage of USGS and MIT methods that give overestimated results by the usage of arbirtarily chosen reservoir input parameters. At the last section of this thesis, Garg and Combs (2015) method was applied to 25 geothermal fields of Turkey, which are amenable to power generation, by MCM and AUPM approximations. The same 25 fields were originally considered and studied by Başel in 2010 in her PhD thesis by using the MIT method. In Başel's dissertation, these geothermal fields were all treated by a reference temperature of 100 0C when estimating Turkey's power generation potential. However, today it is well known that binary power conversion plants are designed to generate electricity from resources having reservoir temperature values ranging from 57 to 180 0C. It is shown here that Garg and Combs (2015) method without any usage of arbitrary values and considering the installed power conversion system and thermodynamic properties of the produced water or the secondary fluid of the power conversion system is the best method to eliminate the subjectivity in selecting the reference (or abandonment) temperature and conversion efficiency and hence to estimate or predict the power generation of a geothermal field or country more realistically. In this thesis, it also shown that the AUPM and MC based Garg and Combs (2015) method predict the power generation of of the 25 geothermal fields of Turkey considered in Başel's PhD dissertation as P10 = 661 MWe, P50 = 1165 MWe, and P90 = 1909 MWe, based on arithmetic summation. On the other hand, for the same geothermal fields, Başel (2010) predicted the power generation potential as: P10 = 840 MWe, P50 = 1428 MWe, and P90 = 2371 MWe. As the same data for all 25 geothermal fields provided by Başel, it is clearly the MIT method used by Başel overestimates the power generation potential of Turkey based on these 25 geothermal fields.
Tekirdağ doğal gaz sahasının yer altı gaz depolaması olarak modellenmesi
The Tertiary-age Thrace Basin is the largest gas producing onshore area in Turkey. Thrace region has both large and mostly small size natural gas fields. However, the gas producing fields in Thrace region are only producing less than one percent of the domestic demand. On the other hand, gas interruption in supply due to long-distance pipeline routes as well as political and technical reasons pose a risk to continuous gas demand of the country. Thus, gas storage in emergency situations or during the unexpected short term excess demand plays a key role in security of the country energy needs. As a result, converting of partially or fully depleted gas reservoirs to the underground gas storage is inevitable. Tekirdağ field is one of the biggest shallow gas reservoirs in Thrace region producing from deltaic Osmancik formation. Tekirdağ field was discovered in 1998 and despite of that it is close to fully depletion now, there is no precise and accurate OGIP estimation to date due to lack of data. In this study, firstly original gas in place (OGIP) has been estimated using static and dynamic data for the reservoir Unit-A and Unit-B. As a result of marial balance method, 452 psia and 473 psia of original reservoir pressure has been calculated for Unit-A and Unit-B respectively. Also, OGIP has been calculated as 32.1 bscf (909.0 million sm3) and 17.5 bscf (495.5 million sm3) for the reservoir Unit-A and Unit-B, respectively. Secondly, it has been worked on the modeling for underground gas storage. Thus, Tekirdağ gas field is designed for storage purposes using RUBIS simulator. In the first scenario, Tekirdağ field is simulated as a underground gas storage with already existing twenty two wells for Unit-A and eight wells for Unit-B. Secondly, mechanical skin has been applied to all wells. And finally, one horizontal well for each reservoir has been placed and investigated results of the all scenarios. In order to achieve the results, one year of storage cycle is planned as follows for Unit A and Unit-B; • Five months of injection period keeping the bottom hole injection pressure as original reservoir pressure. • One month of shut-in period. • Five months of production period keeping the surface flowing pressure at 145 psia. • One month of shut-in period.
Modeling bottomhole cooling
Nowadays, the geothermal energy becomes more and more common while the technology and the investments increase. Concordantly, the scientific studies are being interested in geothermal reservoirs, wellbores, and energy plant processes.Although geothermal industry uses the background of oil and gas industry, some of the main differences (such as high temperatures, cracked systems etc) route us to study on particular subjects for geothermal systems. Modeling of bottomhole cooling operations is one of the particular subjects for geothermal since the temperatures in these systems are extremely high in comparison with oil and gas. To be able to perform lots of operations in field such as drilling, cementing, logging, acidizing etc, a cooling operation is needed in geothermal wells. However the tools (even some of temperature measurement tools), chemicals, equipments etc. are not resistant to such high temperatures. Therefore the only way we have in today's technology to estimate the bottomhole temperatures after a cooling operation is the modeling. In this study, the behavior of the bottomhole temperature of a geothermal well is investigated for single phase flow in steady state conditions. For this purpose, numerical and analytical models are developed concordantly. Verification of these two models is performed and interpreted. The numerical model is developed based on solving the energy balance equation for an isobaric geothermal system. The design of the reservoir and wellbore are made by grid block systems. For the verification of the numerical model, an analytical model from the literature is used by designing both models compatible. After verification analyses, a synthetic base case scenario is designed and the temperature distribution through the reservoir, and the bottomhole temperature behavior are investigated. Different synthetic applications are also modeled to be able to observe the effects of various parameters (such as thermal conductivity, injection rate, injection temperature etc) on the temperature behavior during and after the cooling operation. Additionally, two different flow schemes are modeled where in one case the injected fluid enters the reservoir and in the other case the fluid does not enter the reservoir. The effect of the cold injection fluid is also investigated and concluded.
Akış performans eğrilerinin oluşturulmasında kullanılacak bilgisayar programının geliştirilmesi ve petrol saha verileri ile test edilmesi
Petrol üretiminde rezervuar basınç dağılımının, kuyu dibi basıncının ve üretim hızı ile kuyu dip basıncı arasındaki ilişkinin belirlenmesi çok önemlidir. Kuyu dibinden rezervuar sınır yarıçapına kadar olan mesafedeki herhangi bir noktada basınç değerinin hesaplanmasında kullanılacak denklemlerin seçimine, log yaklaşımının belirlenmesinde kullanılan X değeri hesaplanarak karar verilir. X<0,01 durumunda log yaklaşımı geçerli olurken, diğer X değerlerinde log yaklaşımı gerçekleşmemektedir. Bu hesaplamaların bilgisayar destekli yapılabilmesi için eksponansiyel integral verilerinin modellenmesi ve model denklemlerinin türetilmesi gerekmektedir. Bu çalışmada petrol mühendisliği ile ilgili çeşitli bilimsel kaynaklarda verilen eksponansiyel integral verileri Curve Expert Basic 2.2.3 programının deneme sürümü kullanılarak modellenmiş ve farklı veri aralıkları için yüksek korelasyon katsayılarına sahip model denklemleri geliştirilmiştir. -Ei(X) için geliştirilen bu model denklemleri kullanılarak rezervuardaki basınç dağılımı, tek fazlı akış performansı ve kısmi iki fazlı akış performans ilişkisini hesaplamak için C++ programlama dilinde 3 program kodlanmış ve Türkiye saha verileri kullanılarak test edilmiştir. Rezervuar basınç profilini elde etmek için kullanılan denklemler gözeneklilik, geçirgenlik, sınır basıncı, rezervuar alanı ve yüksekliği, oluşum hacim faktörü, viskozite ve zar faktörü gibi birçok parametreyi içerir. Her parametrenin sonucu azaltma veya artırmadaki etkisi, parametreler cinsinden yazılan denklemlerde görülse de, diğer parametrelerin sabit değerlerinde, herhangi bir hesaplama yapmadan bir parametrenin değişen değerlerinin basınç profil eğrisi trendi üzerindeki etkisine doğrudan karar vermek mümkün değildir. Rezervuar basıncı değişiminin belirlendiği bölümde denklemde geçen her bir parametrenin etkisi, belirli bir adım büyüklüğü kullanılarak Türkiye saha parametrelerinin alt sınır ve üst sınır değeri aralığında araştırılmıştır.Petrol üretim hızı ile dip delik akış basıncı arasındaki ilişkiyi hesaplamak için C++ programlama dilinde bir bilgisayar programı daha geliştirilmiştir. Hazırlanan program yardımıyla iç akış performans ilişkisi (IPR) denklemlerindeki her bir parametrenin etkisi araştırılmıştır. Çalışmada yapılan hesaplamalar hem mevcut üretim kuyuları hem de benzer parametre değerlerinde daha sonra üretime alınacak kuyular için üretim planlaması konusunda fikir verecek şekilde düzenlenerek sunulmuştur. Bu çalışmada yapılan örnek hesaplamalar, özellikle yeni keşfedilen petrol sahalarında kapsamlı jeolojik model geliştirilinceye kadar üretimle birlikte kuyu ve çevresindeki basınç değişmelerinin tahmininde faydalı olabilir. Geliştirilen bilgisayar programı aynı zamanda programlardaki kuyu parametrelerini değiştirerek yeni rezervuar ve kuyular için kolaylıkla hesaplama yapma olanağı da sağlamaktadır. Anahtar Kelimeler: Kuyu Dibi Akış Basıncı, Giriş Performans İlişkisi (IPR), Rezervuar Özellikleri, Türkiye Petrol Sahaları, Rezervuar Basınç Dağılımı.
Kil içerikli formasyonların sondaj problemlerinin deneysel olarak araştırılması
Türkiye'nin Güneydoğu Anadolu Bölgesi, ülkenin en büyük petrol rezervlerine sahiptir. Ayrıca en çok petrol üretiminin yapıldığı alandır. Ülkenin bu alanlarından özellikle Batman ve Diyarbakır Bölgeleri formasyon özellikleri bakımından yoğun kil mineralleri içermektedir. Bundan kaynaklı bu bölgelerin petrol sondajlarında meydana gelen stabilite sorunları kuyu problemlerinin yaşanmasına sebebiyet verir. Yaşanacak olan her bir problem maddi ve manevi kayıplara neden olur. Petrol kuyularındaki faaliyetlerin artması ile oluşan veri kaynağındaki artış bu formasyonların farklı sondaj akışkanları ile ıslah edilip daha verimli sondaj operasyonlarının gerçekleşmesine yardımcı olmuştur. Bu çalışmada, Batman ve Diyarbakır Bölgelerinde yer alan A ve B petrol sahalarında bulunan A-1 ile B-1 kuyuları inceleme alanı olarak seçilmiştir. İncelenen bu alanlarda yoğun kil formasyonlarının sondajı ile yaşanmış olan sondaj problemleri ele alınmış ve adım adım ıslah yöntemleri dinamik koşullardaki deneysel çalışmalar ile incelenmiştir. Çalışma alanı olarak seçilen A ve B petrol sahalarında stabilite sorununa karşı uygulanan KCl polimer çamur ile stabilite sorunu minimuma indirilmeye çalışılmıştır. Sondaj boyunca kullanılan KCl polimer çamurun içermiş olduğu özellikle potasyum ile iyonik inhibisyon ve polimerler ile sıvı kaybı kontrolü ve reolojik özellikleri kontrol altında tutulmuştur. Sondaj boyunca devam eden ıslah yöntemleri sondajın sorunsuz devam etmesini sağlamıştır. Bu tez çalışmasında yer alan A-1 ve B-1 kuyularında stabilite sorununa sebebiyet veren kil içerikli Germav-Kastel formasyonlarının sondajı boyunca kullanılan KCl polimer çamurun günlük laboratuvar deneyleri API standartlarına göre yapılmış ve rapor edilmiştir. Deneylerin analizlerine göre ıslah yönetmeleri belirlenmiştir. KCl polimer çamurun dinamik koşullarda killi formasyonlar üzerindeki etkinliği bu çalışmada gösterilmiştir. Belirtilen bu formasyonların bulunduğu A-1 kuyusunda, çamur özellikleri pilot deney sonuçları referans alınarak yapıldığında ve doğru ıslah yöntemleri sağlandığında KCl polimer çamurun etkin ve güvenli sondaj sağladığı sonuçları elde edilmiştir. Fakat B-1 kuyusunda yaşanan lojistik kaynaklı aksaklılar ile B-1 kuyusunun arama kuyusu olmasından kaynaklı KCl polimer çamur etkinliği sağlanamamış ve yıkılma, kaçak gibi sondaj problemlerine sebebiyet vermiştir. Bu çalışmanın ele aldığı her iki kuyu ve pilot deney sonuçları KCl polimer çamurun doğru kullanım şekilleri ile maddi ve manevi kayıpları önlediği göstermiştir.
Çeşitli tarımsal atıkların kayıp önleyici malzeme olarak kullanımının araştırılması
Sirkülasyon kaybı, sondaj operasyonları sırasındaki en büyük sorunlardan biridir ve bir sondaj operasyonu sırasında sondaj çamurun, kuyu cidarından formasyona geçmesi durumunu ifade eder. Sirkülasyon kaybı, sondaj deliğinin çökmesi, ekipman hasarı ve sondaj süresinin uzaması, bileşiminin bozulması ve sirkülasyon çamuru ile birlikte taşınan kesintilerin çökerek birikmesi gibi bir dizi zorluğa neden olabilir. Oluşan tüm bu sorunlar sondaj operasyon maliyetlerini de olumsuz etkilemektedir. Bu nedenlerden dolayı, sondaj operasyonunun, öncesinde dikkatlice planlanması ve sirkülasyon kaybı için gerekli önlemlerin alınması gerekmektedir. Sirkülasyon kaybını önlemek veya azaltmak için çeşitli yöntemler kullanılmaktadır. Kuyu deliği güçlendirme teknikleri, çamur keki özelliklerini iyileştirmek veya sondaj sıvısına kayıp önleyici malzemeler ekleyerek çamur ağırlığını arttırmak iyi bilinen ve çokça karşılaşılan uygulamalardır. Atıkların petrol sektöründe kayıp önleyici malzeme olarak kullanılması ise son yıllarda üzerinde çokça durulmaya başlanan bir konu olmuştur. Bu çalışmada hem maliyet hem de kuyu stabilitesi açısından sorun yaratmayan KCl çamuru kullanıldı. Çeşitli gıda atıkları ve kuru yemiş kabuklarının hazırlanan KCl çamurunda kayıp önleyici malzeme olarak kullanılabilirliği araştırıldı. Gıda atıkları olarak ay çekirdeği, ceviz, Siirt fıstığı, yer fıstığı, fındık gibi çeşitli kuruyemişlerin kabukları, buğday samanı, limon kabuğu ve kereviz sapı tozu kullanıldı. Çamurun fiziksel özelliklerinin belirlenmesi amacıyla deneyler yapılmış, eklenen malzemelerin reolojik özelliklere ve filtrasyon özelliklerine etkileri incelenmiştir. Farklı maddelerin, tanecik çapının, madde miktarının ve çamur tipinin etkileri çalışıldı. Ayrıca çamura farklı miktarlarda XCD, nişasta ve pektin eklemenin çamur özelliklerinde ne tür bir değişim yaptığı da incelendi. Genel olarak eklenen tüm malzemeler çamurun reolojik ve filtrasyon özelliklerinde iyileşmeye sebep olmuştur. İncelenen maddelerin çamura eklenen miktarının artması hem viskoziteleri, kopma noktasını ve jel mukavemetini artırmış hem de sıvı kaybını ve filtre keki kalınlığını artmıştır. İncelenen tüm deney koşullarında jel mukavemet değerlerinde bir miktar değişiklik gözlenmesine rağmen çamurun genel özelliklerinde herhangi bir değişiklik olmamıştır. Siyah ayçiçeği kabuğu, limon kabuğu tozu ve kereviz sapı tozu, çamurun reolojik özelliklerini bu çalışmada kullanılan diğer katkı maddelerine göre daha fazla geliştirmiştir. Başta limon kabuğu tozu olmak üzere buğday samanı ve ceviz kabuğu hem düşük sıvı kaybı hem de ince filtre keki oluşturarak çamurun filtrasyon özelliklerini geliştirici etki yapmıştır. Çamura eklenen XCD, nişasta ve pektin miktarlarının atması hem reolojik özelliklerin hem de filtrasyon özelliklerinin artmasına neden olmuştur. Bu maddeler içinde çamura XCD ilavesinin etkisi çok büyüktür.
Yüksek basınç ve yüksek sıcaklıklı raudhatain sahasında asitle çatlatmanın tasarlanması ve etkisinin araştırılması
Dünya ekonomileri, modern planlama ilkelerine uygun şekilde gelişirken büyük ölçüde fosil yakıt bazlı enerji kaynaklarına bağımlı hale gelmiştir. Ayrıca yenilenemeyen kaynaklara dayalı enerji tüketimi sürekli artmaktadır. Petrol ve doğalgaz sektörü bu enerji arzını karşılayan ilk kaynağıdır ve şimdiye kadar enerjinin dayanım noktası olarak sayılmaktadır. Ancak, petrol ve gazın genel küresel enerji tüketiminin bugünden 2030 yılına kadar % 34 olarak artması beklenmektedir. HPHT kuyuları, ek rezervler için araştırma amacıyla odak noktası haline gelmiştir. Kuveyt'teki Jura rezervlerinde Yeni yapılan projelerle birlikte 40 kuyu sondajını yaparak ve 13 workover operasyonların tamamlanması ile 2024 yılına kadar üretilen ilişkili olmayan gaz miktarı 1 Bcf'e yükseltmesine planlamaktadır. Kuezy Kuveyt'in jura formasyonun bazı kısımları ise sıkı doğası, düşük geçirgenliği, formasyonun heterojenliği ve düşük üretim oranları nedeniyle kazılan kuyulardan optimum üretime ulaşmak için yeni stimülasyon teknolojiler ve asit çalışmalar uygulanmaktadır. Bu çalışmada, Raudhatain sahasında bulunan ve Orta Marrat rezervuarını hedefleyen RA-X kuyusunun asit çatlatma tasarımı irdelenmiştir, bu çalışmanın amacı ise optimum üretimi elde etmek için ve çatlaklar istenilen yönde açılınca formasyonun sıkı doğasına rağmen rezervuarın bir itme mekanizması oluşturmaktadır ve Orta Marrat'ta 180 ft'den daha uzun yarı uzunlukta ve ana rezervuar drenaj alanı içinde etkili bir iletken oluşturmaktır. Bu çalışmada, doğal çatlaklı kuyularda üretimi artırmak için çatlak iletkenliği ve asit penetrasyon mesafesi incelenmiştir. RA-X kuyusunda yapılan asit çatlatma operasyonunda, SRT ve mini-frac testleriyle çatlak ve kapanma basınçları belirlenmiştir. SRT testi ile çatlak genişleme basıncı 8920 psi olarak belirlenmiştir. Bunun yanı sıra, mini-frac testi kapanma basıncının 7262 psi olduğunu ortaya koymuştur Marrat formasyonunun sıkı yapısı nedeniyle yüksek enjeksiyon yüzey basıncı (11.500 psi) ve yüksek sızıntı gözlenmiştir. Asit çatlatma sonrası kuyu verimliliğindeki artış, rezerv hedeflerine ulaşmada önemli katkılar sağlamıştır. Kuyunun simülasyonu için StimPlan ve MEM programları kullanılmıştır ve asit iletkenliği hesaplamalarında Nierode-Kruk korelasyonu uygulanmıştır. Simülasyon sonuçları, 266 ft çatlak uzunluğu, 234.1 ft yükseklik ve 0.24 ft çatlak genişliği göstermiştir. Karbonat rezervuarları asitle temas ettiğinde yüksek reaktivite nedeniyle solucan delikleri oluşmuş ve asit sızma katsayısı artmıştır.
Türkiye'de jeotermal bir sahanın karbondioksit üretiminin matematiksel modellenmesi
Turkey's non-condensable gases production from geothermal fields is very high when compared to other countries' average production values. A big predominance of these gases is generally carbon dioxide (CO2) and the origin of this CO2 is generally meteoric for the studied area as reservoir rocks are carbonate-dominated metamorphic rocks such as dolomitic marbles and marbles.The dissolution of calcite mineral within the reservoir rocks, where it equilibrates with water, results in CO2 release from the system. And this release occurs because of meteoric waters. When a field is put on production, a CO2 decline is observed during the production life time and this decline can be addressed in three different scenarios. First, re-injected brine does not include any CO2 as it is released to the atmosphere after production. When this brine reaches to the production wells due to the strong hydraulic connectivity, a sharp CO2 decline occurs in the reservoir. Second, there might be a weak hydraulic connectivity between the production and re-injection wells and a gradual CO2 decline may be observed with time due to the natural recharging. Last, a CO2 decline may occur as a result of a sharp pressure decline in an excessively producing well because of the water invasion that comes from the upper part/shallow part of the geothermal system and this sub-surface water has less amount of dissolved CO2 in it. This study aims to clarify modelling of CO2 declines for an Alaşehir geothermal field. It has been observed that CO2 declines show the best matches with the hyperbolic decline method introduced by Arp's in 1945. In this study, the reasons of the observed declines in Alaşehir geothermal field showed that a strong hydraulic connectivity between the re-injection and production wells resulted in a sharp CO2decline. On the contrary, a gradual CO2 decline has been observed when there is a weak hydraulic connectivity between the wells.
İzotermal olmayan koşullarda matriks – çatlak transferi
A numerical and experimental study was carried out to investigate matrix-fracture transfer in fractured porous media. Film type heat flux sensors were installed in four different synthetically fractured core plugs to measure the temperature and heat flux in fracture during cold water injection. Experimental values of heat flux were used to calculate convective heat transfer coefficient. Fracture temperatures were used to calibrate numerical model developed using CMG-STARS simulator to evaluate contributing matrix thermal properties. The results show that the temperature decrease in fracture is lower when rock matrix has higher thermal properties. The variations in heat flux and temperature difference along matrix-fracture interface with respect to time necessitates the use of variable convective heat transfer coefficients for accurate analysis of matrix-fracture heat transfer. Moreover, results of tracer experiments where Rhodamine B solution was injected at a flow rate of 1 cc/min and outer temperature of 70 °C was used to determine dispersion coefficients using aforementioned numerical model. Sensitivity analysis of the numerical model indicated that thermal properties of matrix are effective in matrix-fracture mass transfer similar to injection rate. To illustrate, the solute penetration is higher in core plugs with larger matrix thermal properties that provide larger temperature gradient over matrix-fracture interface. This can be explained by the Soret effect that is kind of coupled heat and mass transfer at non-isothermal conditions.
Deneysel koşulların doğal gaz hidrat oluşumuna etkisi
Global request will increase considerably in the following decades as population of the earth proliferates. US DOE 2016 International Energy Outlook, claims that the universal energy consumption will augment from 549 quadrillion BTU in 2012 to 815 quadrillion BTU in 2040, indicating 48% augmentation. As methane hydrates are able to comprise between 150 and 180 v/v at standard temperature and pressure conditions, they provide both gas storage characteristics and transportation characteristics. Stirring procedure is the best way to ameliorate heat and mass transfer in methane hydration procedure: induction time was shortened, formation rates accelerated and storage capacity was augmented when stirring was applied. 24 experiments were conducted by methane with two different impellers such as pitched blade turbine upward (PBTU) and rushton turbine (RT) with mixed and radial flow respectively. The design of the experiments was different by the use of baffles (full baffle, half baffle, surface baffle) or no. The 24 experiments were divided in 8 single experiments and 16 dual experiments with all possible combinations such as PBTU/PBTU, RT/RT. PBTU/RT and RT/PBTU. Calculations such as rate growth, induction time, process of hydrate formation, hydrate productivity and conversion of water to hydrates are included to our research. Furthermore other 24 experiments were conducted by mixture methane (95%)-propane (5%) with PBTU and RT impellers. The design of experiments was the same like methane with thedifference in pressure , temperature and in the number of single and dual experiments. There were 16 single experiments. 8 experiments with same driving force of methane hydrate formation and 8 experiments with driving force almost double. The 8 dual experiments were conducted with the double driving force compared to methane hydrate formation. Calculations such as rate growth, induction time, process of hydrate formation, hydrate productivity, split fraction and separation fraction are comprised in our research. Finally 6 experiments were conducted with 5 different amino acids and with no amino acid (just water), hence to investigate which of these acids behave as prompters or as inhibitors in mixture (methane 95% - propane 5%) hydrate formation. Calculations such as rate growth, induction time, process of hydrate formation were included together with images during hydrate formation. RT experiments have highest rates of hydrate formation compares to PBTU ones in single and dual impellers in both methane and methane-propane hydrate formation. Their main difference is that in single impellers, the rate of hydrate formation is higher for RT experiments also in first 30 minutes while in dual experiments happens the opposite. The RT experiments although they form more quickly and for less time hydrates (smaller induction time compared to PBTU ones), they have higher power consumption values, hence they consume more energy. RT experiments convert more water and methane to hydrates although these values are very small due to high water quantity. In methane-propane hydrate formation, the split fraction of methane has higher values in single experiments with T=8.5C compared to single experiments with T=2C. Final, all amino acids that are used to form methane-propane hydrates in our system behaved like promoters and none of them as inhibitor.
Jeotermal kuyularda yaşanan buru ve kaçak problemlerinin sondaj sıvısı yönünden incelenmesi
Drilling in a lost circulation zone has long been a challenge in geothermal wells due to its strong potential for high torque and wellbore instability. Excessive torque and friction values cause overpull, pipe stuck and severe problems ending up with losing the well in some cases. High temperature-high pressure (HTHP) drilling fluids design; which minimize loss rates and friction values, is critical for the success of these challenging drilling practices. Known fact is that, oil/synthetic based drilling fluids have the best lubricity performance. However, application of these drilling fluid systems is limited because of high cost and environmental constraints. At this point, water-based drilling fluid compositions with high lubricity performance, HTHP resistance and high loss zone plugging performance, are investigated. In this study, HTHP drilling fluid system; frequently used in Turkey and worldwide, is selected for the experiments. Several chemical commercial lubricants are added in this fluid system to find the compositions for the highest lubricity performance closest to oil/synthetic based drilling fluid systems. Also, considering the formation characteristics and drilling limitations; best fluid compositions are formulated to plug the potential seepage and partial loss zones and reduce the differential-sticking tendency by using proper lost circulation materials. Results reveal that lubricity and pore plugging characteristics of the selected compositions are highly innovative and noteworthy to be used in field applications for geothermal drilling industry.
Rota hesaplama yöntemlerinin Türkiye'nin Ege Bölgesi'ndeki jeotermal kuyular üzerinde uygulanması
Productive sections of geothermal wells generally exceed hundreds of meters which is substantially longer than that of the oil and gas reservoirs. This brings a flexibility and cost-effective solutions in the application of directional drilling activities during geothermal drilling. Well trajectory, especially the bottom hole position, is critical for geothermal operators and three parameters (measured depth, inclination, and azimuth) obtained from MWD surveys are used to carry out survey calculations. The minimum curvature method (MCM) is considered the most accurate and the industry standard, although there exist several other calculations. The novelty of this thesis is to find out the geothermal well directional needs, on Aegean part of Turkey, in terms of survey calculation methods; later on, recommend which method(s) should be utilized at what conditions. In order to address this gap, 5 methods were chosen taking into account popularities and complexities; tangential, balanced tangential, average angle, radius of curvature, and minimum curvature methods. Afterwards, these 5 procedures were applied on 9 drilled pre-selected geothermal wells by using Python programming language. As a result, most divergence from MCM was observed with tangential method, having the easiest calculation formulas, on J type wells with increasing dogleg, inclination, and depth; which is around 5-6 m. Under the usual conditions the geothermal wells drilled in Turkey, it will be maximum of 10 m; even though it is quite satisfactory for most of the operators, average angle method, which is the easiest one after tangential, would also be utilized to have better results. This means that the operators, willing to establish their own directional drilling departments to decrease the costs of directional operations, may utilize a basic software or a spreadsheet, for their each well, depending on average angle, or even tangential method, to eliminate complicated formulas, while calculating the positions of each survey or interpolation depths. An only advanced software may be preferred for operator office.
Yapay olarak kırılmış ve jel işlemı görmüş karotlarda akışkan akışının modellenmesı ve sımülasyonu
The dynamics of fluid flow in the matrix and in the fractures are significantly different from each other. Fractures are highly permeable flow pathways and are generally considered as the main flow unit. On the other hand, the matrix occupies most of the porous medium's volume and is considered as the main storage unit. The main objective of this thesis is numerical modeling of water flooding experiments in artificially fractured and gel-treated core plugs. MATLAB Reservoir Simulation Toolbox (MRST) is used to create the numerical models. Three main cases, namely non-fractured core plug, fractured core plug, and polymer gel treated core plugs, were created by using MRST. 2 PV water injection into these core samples simulated by using MRST. Additional 2 PV water was injected after polymer gel treatment operation for artificially fractured core plugs. Hydrocarbon recovery vs. time plots, as well as 3-dimensional fluid saturation profiles, are obtained. Standard Buckley-Leveret solution is used to validate the model, and Embedded Discrete Fracture Network (EDFM) was used to model the fractures. Results of the numerical models were compared with the results of core flooding experiments. During the experiments, results are obtained and recorded after 2 PV water injections, and for the polymer gel treated core plugs, 2 PV additional water was injected after the operation, and results were recorded again. Models and simulations are done to represent the core flooding experiments described. The non-fractured core plug oil recovery after 2 PV water injections was found to be 42.5% and 42.8% experimentally and with an MRST solution. For the artificially fractured core plugs, oil recovery was increased from 28.87% to 42.85% in experiments and from 28.87% to 40.83% in MRST solution after polymer gel operation. Similarly, in experiments, 8.16% and in MRST model 7.07% increase in the mean water saturation observed after polymer gel treatment. Additional oil recovery was observed in both experiments and in the MRST model after the polymer gel operation. In addition, how fracture permeability and aperture affect recovery was also investigated. When the fracture permeability is constant, fracture aperture directly affects the hydrocarbon recovery for the low aperture values. Similarly, when the fracture aperture is constant, fracture permeability directly affects recovery for the high values.
Çatlaklı şeyl rezervuarlarında kararsız akış modellemesi
Oil and gas production from shale reservoirs has been popular in North America for more than two decades. Commercial production from these extremely low permeability reservoirs is only achieved by multi-stage fractured horizontal wells. However, production performance of these wells is quite different than wells drilled in conventional reservoirs. Main distinct behavior seen in these wells is very long period of transient flow due to tightness of such reservoirs. This thesis questions validity of existing dual-porosity reservoir simulation technique for fractured shale reservoirs. In this respect, analytical solutions of pressure diffusion are presented for constant fracture pressure, constant rate and constant fracture pressure followed by linearly declining fracture pressure boundary conditions. According to these solutions, time-dependent shape factors are derived for 3D rectangular anisotropic matrix. Obtained shape factors and proposed simplifications are verified against fine scale single-porosity numerical models. Key finding from this study is that matrix – fracture transfer function (shape factor) is not constant, but rather decreases with time until reaching to a constant value. Therefore, dual-porosity simulation of fractured shale reservoirs using constant shape factor does not capture actual physics of matrix to fracture flow and yields inaccurate performance prediction. Also, proposed simplifications either as an empirical function or reduced form are robust in modeling this phenomenon. In addition to those, common features of decline curve analysis are tested for fractured shale reservoirs. Time dependency of b-parameter used in hyperbolic decline curve analysis is assessed for different reservoir properties by sensitivity analysis. Proposed empirical functions are used to obtain b-parameter for these cases and results are compared with actual ones.
Karbon dioksitin depolanması ve gelişmiş petrol kurtarımının birlikte uygulanması
The worldwide growth of industry leads to continuous rise of anthropogenic emission amount into the atmosphere, which causes greenhouse effect all over the world, that is heating up the atmosphere and changing the global climate. On the other hand, carbon dioxide injection into oil reservoirs for the purpose of enhancement of oil recovery (CO2-EOR) has been commercially used for nearly 50 years. The operations in petroleum sector are being carried out in a way to maximize the recovered oil while keeping the amount of CO2 injected at its minimum due to the purchase cost of carbon dioxide. To overcome the economic restrictions for CO2 sequestration during EOR, it is necessary to simultaneously maximize economic oil recovery and the volumes of CO2 injected in oil reservoirs using an engineering approach. This process is named as co-optimization. For this purpose, several simulations for different scenarios are being carried out to find the maximum amount of CO2 that can be stored, maximum amount of oil that can be produced, and an optimal point for simultaneous maximization of both numbers. Results show, that using inverted 5 spot pattern and implementing water-alternating-gas (WAG) injection can significantly contribute to the co-optimization, while other parameters, such as pattern area and injection rate need to be evaluated on case by case basis, considering economical factors as well.
Hidrat oluşumunun olası üretim mekanizmalarının deneysel incelenmesi
In this study, temperature, pressure and mole values of methane hydrate formation and dissociation are analyzed using different production methods under laboratory conditions. During the experiments, a cylindrical high-pressure hydrate cell in a constant temperature room was used. In order to provide the real field conditions of the hydrate reservoirs, methane gas was injected at high pressure into the cell filled with sand and water at low temperatures, and the hydrate reservoir was formed in a 21.2 *liter hydrate formation cell by providing necessary thermodynamic conditions. A ¼ inch production line was used for production of methane and water in 3 different experiments. Production phase of the first two experiments were not discussed due to discrepancies arising from the production data. Two different production stages were applied in the third experiment. The first stage was carried out by combination of pressure reduction and thermal recovery method by providing constant temperature water circulation through the spiral pipe inside the cell. The thermal recovery method's effect decreased and disappeared in the second stage. It left its place only to the depressurization method. As a result of the endothermic dissociation process of the production stage, the heat taken from the environment caused pores to be clogged due to reformation of the hydrate. This slowed down the production and made it stop from time to time. Using the depressurization method with the thermal recovery method, hydrate production became more effective and the hydrate dissociation rate increased. Depressurization method alone became less effective and the rate of dissociation decreased.
Şeyl gazı ve petrolü için arama, üretim, rezerv kestirimive araştırma çalışmalarının incelenmesi ve değerlendirilmesi
Shale is a fine-grained sedimentary rock that consists of significant amount of clays, in addition to sand and silt size minerals. During the sedimentation period, depending on the aqueous sedimentation environment, some organic material in the form of the remnants of dead organisms might accumulate along with some inorganic material, such as the organic or inorganic compounds nickel, zinc, vanadium, molybdenum, selenium, etc, among the grains of shale constituents. Shale is formed as the result of compaction of its constituents under the overburden stress (pressure) of overlaying strata that are accumulated later and under the rising temperature with increasing burial depth, throughout the vast geological time periods. During the millions of years of diagenesis, the period in which the sediments go through various physical and chemical alterations and deformations, the in-situ water in between the granules provides the means for the consolidation and cementation of compacting constituents to form a somewhat firm rock of shale, while some part of the in-situ water being expelled out due to compaction. In addition to pressure the increasing temperature and the radiation from the radioactive elements among the constituents cause shale to experience thermal maturity. Contained organic material, if there is any, in shale would eventually be decomposed into hydrocarbons, partially in the form of kerogen and partially in the form of petroleum, until thermal maturity has reached a certain level. Kerogen is the organic material with long and complex molecular chains that was not converted into petroleum. During diagenesis, oil and gas type hydrocarbons may escape out of shale into other adjacent, preferably sedimentary, formations via the pathways, such as pore networks, cracks, fractures, joints, or faults, and form conventional oil and gas reservoirs if they get hydrodynamically trapped. Therefore, shale is a easy-splitting laminated soft rock and such feature makes it different than the rock called mudstone. Economic oil and gas accumulations in shale formations are classified as unconventional reserves, since pore size and permeability levels in such rocks are much below microscopic scale and, hence, the application of conventional production and reserve estimation techniques is invalid. In this study the interest is in the shale formations that contain unconventional reservoirs of oil and gas. A shale formation is considered to have a prospective reservoir if its organic kerogen content is between 2 to 14 percent. The hydrocarbon that can form in shale is determined by the kerogen type and thermal maturity level in shale. Kerogen, as a solid matter, might have pores with size in the range from few nanometers to few hundred nanometers. Production of oil and gas from shale formations was started during the World War II by the U.S.A. to fuel war tanks. After the war, however, it was uneconomical to produce from the shale formations due to unfeasible technology and low price of oil and gas. The adverse effect of significant increase in oil and gas prices, due to Yom Kippur war between Egypt and Israel in 1973, has forced the U.S. to explore new technology for feasable exploitation of oil and gas in shale formations. In the past two decades, many researchers have introduced new and various methods and techniques for classifying shale formations, estimating oil and gas reserves, and drilling, completing, and stimulating wells for producing unconventional shale plays. Substantial investment in research has led to the development and use of horizontal well drilling and hydraulic fracturing technology that has draw a massive interest in the industry and has enormously increased the shale gas and oil production in the U.S., e.g. the U.S. hydrocarbon gas reserves have increased about 35 percent in 2008. Such success has led many countries worldwide to attempt to explore unconventional oil and gas in shale formations in their sedimentary basins. While research is still continuing worldwide for futher improvement in aforementioned methods and techniques to maximize ultimate recovery from shale formations, only Russia and China other than the U.S. had some limited success in shale gas and oil play so far. Among the shale classification methods, real-time classification is based on well logs to estimate the petrophysical, compositional, and elastic properties of shale rocks. Another technique attempts to identify hydrocarbon-bearing shale groups, based on similar compositional properties exhibited on a combination of well logs, and also to minimize the shoulder-bed effects using the inversion of log derived layer properties. Other method integrates core analysis and well log information to classifying shale in terms of porosity, capillary pressure, mineralogy, and TOC. Though, all the methods are found to yield good results, all of them have to be applied on the same formation to ascertain which method is better than the others, since each shale play is unique. Although conventional reserve estimate methods seem not to work in unconventional shale gas and oil reservoirs, a group of researchers tried to use the usual hyperbolic decline curve analysis technique on a production rate versus time plot to estimate the recoverable reserves. They came up with a nine–equation bivariate regression model based on initial test and recovery data to estimate the reserves in the Devonian shale. A new volumetric total-gas-in-place estimation equation that incorporates Langmuir adsorption isotherm was formulated to take the pore space occupied by the sorbed phase into account. Hydrocarbon phase behavior is realized to be quite different in pores and capillaries with characteristic length less than 100 nanometers, since gas density varies under the influence of organic pore walls of kerogen. Interest in drilling and completion of horizontal wells has increased during the last two decades to enhance productivity and ultimate recovery from shale reservoirs. The most commonly used completion method is casing and perforating the horizontal section of wells. In horizontal wells an optimized multi-stage hydraulic fracturing through perforations is the inevitable stimulation technique to create interconnected fracture network for maximizing the flow into wellbore. Various explosive or impact methods of dynamic fracture and fragmentation data on shale rocks has showed that the interaction of transient wave with the local free surfaces in rock generates tension in some regions of rock where fracture and fragmentation is initiated. Studies has also showed that the static strength of a rock can be less than the dynamic fracture strength as much as one order of magnitude. A researcher with the objective of intersecting as many natural fractures as possible with the hydraulic fractures has developed a rationale for stimulation design for the Devonian shale. The MHF (massive hydraulic fracturing) technique has long been used for the same purpose. It has been found that shale thickness and fracture density are important factors in determining the stimulation technology and strategy. A new hydraulic fracturing technique is CHF (channel hydraulic fracturing) that was first applied in Marcellus shale. In CHF technique; which integrates the geomechanical modeling and perforation strategy, fiber-laden fluid is pumped in a unique manner to create high-conductivity stable channels in the proppant pack placed in the created fracture. Hydrocarbon fluids flow through these high conductivity channels rather than being dependent on the permeability within the proppant pack. Appreciable increase in fracture conductivity by these flow channels has been proven in practice. Reliable forecast of production from shale reservoirs has been another requirement in the industry. The methods of analytical simulation, numerical simulation and various decline curve analyses (DCA) have been utilized. Each method has its own particular advantages and disadvantages. Rapidity and extent of accuracy in production forecast are among the factors considered in these methods. Another model, called the Shale Gas Predictive Model (SGPM), was developed with an alternative approach and was proposed to mitigate the challenges associated with shale gas production. Simple and easy to use model focuses essentially on the flow around individual wells while conserving overall mass. The model has the advantage of generating rapid and repetitive results, in situations where quick turnaround is required to estimate the production and reserves from a large number of wells in a single or multiple shale gas plays. Such situations arise frequently if the operating companies plan to drill hundreds of wells year by year on the millions of acres of land. The model can be run in conjunction with a fracture mechanics software for better fracture design. Production forecasting capability of the model was validated against the actual production from various shale gas plays in different regions. Thus, the model can be reliably used for both matching the past production history and the future production forecast. Oil-rich play and multi-phase flow features of the model provides insight to the condensate production. However, the inaccuracies in recovery prediction are highlighted if the presence of condensate is not considered. When the development of Eagle Ford shale in South Texas was started in 2008, there was not any data analysis available on the production from this shale at that time. Linear dual-porosity type-curve analysis technique was employed for modelling the production behavior and for estimating the essential reservoir parameters. The type curves used were constructed based on the transient production rate at constant well pressure and closed-boundary double-porosity stimulated reservoir volume (SRV.) Two different approaches of Bello-and-Nobakht method were employed to account for apparent skin in analyzing the early-time and the late-time production data. The production from Eagle Ford shale exhibited linear flow, bilinear flow, and boundary dominated flow regimes. Based on bilinear flow analysis and the assumption of slab-type fracture model, the fracture permeability was estimated to be about 820 nano Darcy. On the other hand, the matrix permeability was estimated to be in the range of 181 to 255 nano Darcy, based on linear matrix flow analysis. The results were validated by means of numerical simulation, due to the fact that the permeability values obtained from the numerical simulation study were in the range of agreement with those obtained from the type curve analysis. In order to carry out production forecasting for Eagle Ford shale different adsorption isotherms were used. It was deduced from the results of production forecasting that the gas desorption depends on both the reservoir pressure and adsorption isotherm. The gas desorption in early times, when the reservoir pressure is high, was found to be usually not that important. However, based on the laboratory measured adsorption isotherms, long-term production forecasting is needed for desorption to be effective. A genesis of decline curves with the use of a simple hydrodynamic analogy was also provided. Some physical factors that are critical to well productivity were also examined, based on several studies on production decline curves. It was observed that an exponential or hyperbolic decline curve would adequately fit the production decline data for the wells producing from Devonian Shale. An attempt has also been made to characterize the production decline based on open flow, rock pressure, and specific shale production mechanisms. An analytical tri-linear-flow solution was presented to simulate the transient pressure behavior and production behavior in fractured horizontal wells in unconventional shale reservoirs. Though the model is simple, it is versatile enough to incorporate the fundamental petrophysical characteristics including the intrinsic properties of both matrix and natural fractures of a shale reservoir. Various reservoir components in addition to the special characteristics of fluid exchange may also be considered. A practical analytical model is presented and discussed in this study for the analysis of pressure transient responses in multiple fractured horizontal wells in unconventional shale reservoirs. Oil and gas production from unconventional shale reserves in the U.S. has become feasible both technically and economically, after the remarkable rise of oil and gas prices. Among the mature shale plays in the U.S., and in the World, Barnett shale near Forth Worth, Texas, is the one for which there is satisfactory production history. Therefore, the examination of the economics of exploitation of Barnett shale, as the field had been developed with more than 6000 producing wells, can be considered as the role model for establishing an idea of how shale plays can become commercial. For the costs and prices during this thesis work is conducted, an ultimate recovery of about 550 to 900 million standard cubic feet of gas has to be produced to pay out for one well. In oil production from shales, for a mature field with 100 000 barrels per day oil production the minimum oil price should be at least 43 USD per barrel.
Destek vektör regresyonu yöntemi ile ilerleme hızı optimizasyonu
Drilling operations constitute the major part of the exploration costs. During operations, drill bits are the primary part needs to be changed frequently due to its quick wearing nature. In order to reduce the drilling cost, the optimum bit pulling time must be determined. To determine the optimum bit pulling time, either rate of penetration or the tooth wearing parameter must be estimated. The most common method that developed for estimating the optimum time for bit change is "Bourgoyne and Young" method. In this method, eight parameter coefficients are needed. To obtain these coefficients, thirty different data which can be taken from either different shale zones inside thirty different wells in a field or thirty different shale points from one well is needed. However, when there is not enough data taken from thirty different shale sections, the accuracy of "Bourgoyne and Young" method decreases. To construct the functional relationship with the data and parameter coefficients, a regression analysis must be performed. In this study, two kind of regression technique is used and the results are compared to each other. First technique is the multiple regression analysis, which is also used in "Bourgoyne and Young" method. This analysis applies least-squares-principled-regression to the data and calculates the parameter coefficients in order to estimate the target function. The second technique is one of different types of machine learning algorithms, called Support Vector Regression. In this technique, first, the data is divided into train and test datasets. Then, the regression model is constructed by using train datasets. At last, the model is applied to test datasets in order to predict the target values for the function. For the calculations, the selection of training and testing data sets are divided into cases with different scenarios. The results of different predictor methods for each scenario are compared with each other in the corresponding case. The results show the significant effect of data selection on the accuracy of penetration rate prediction. One of the most powerful methods in machine learning, Support Vector Regression, is used for rate of penetration optimization for the first time in the literature with this thesis study. In this way, the chance for further investigations and studies on the practicability of Support Vector Regression on penetration rate optimization is created.
Ağır petrol sahalarında sagd uygulamalarında kuyu testleri
Thermal Recovery is one of the common EOR recovery methods. Thermal recovery methods are used worldwide to recover heavy oil and bitumen. Thin layer of water between the quartz and the bitumen makes the oil sands water-wet, this plays an important role in the separation of bitumen from the quartz by use of a hot-water extraction technique. High oil prices are pushing the application of horizontal wells in thermal recovery methods. The possibility of horizontal drilling has created a pathway for SAGD (Steam Assisted Gravity Drainage), which is the most preferred heavy oil and bitumen recovery method. Oil recovery by steam injection requires knowledge of the steam-swept pore volume. The determination of the swept volume in a thermal oil recovery process makes it possibile to do early economic evaluation; it means rapid measurement of the fuel concentration for an in-situ combustion operation, and the heat loss from a steam zone. In field operations, the swept volume has been determined by coring and/or temperature observations made at wells during passage of the displacement front. Well testing evaluates the steam-swept volume by inexpensive and a relatively quick way. The aim of the thesis will be to estimate swept volume and steam chamber mobility by using pressure falloff tests of vertical well. Satman, Eggenschwiler and Ramey (1980) presented a method to estimate the steam zone mobility and swept volume using pressure falloff test; assuming two regions of highly contrasting fluid mobility and an impermeable boundary interface in a composite reservoir. Consequently, for a short duration, the swept zone acts as a closed reservoir, during which the pressure response shows the pseudo steady state behavior. Falloff tests are simulated by shutting-in the injector and recording the wellbore pressure with time. The MDH (Miller-Dyes-Hutchinson) method for the analysis of falloff data is used because the shut-in time is much less than the injection time in practical steam injection falloff tests. The pseudosteady state (PSS) method is used to estimate the swept volume, from pressure fall off testing of vertical wells. A homogeneous square box reservoir, in CMG (STARS) simulator, is used to model steam chamber profile. Injection rate, injection time, steam injection quality and gas (steam) mobility relations with time are investigated by using simulator and comparison with PSS method. The simulation and application of case model is described and finally, comprehensive discussion of the analyses, results and conclusions are given. The results obtained in this study yields reliable results when the swept volume is sufficiently large, so that a proper Cartesian straight line behavior exist.
Hershel-Bulkley modeli kullanılarak surge basınçlarının tahmini ve sonuçların analitik ve yazılım karşılaştırılması
In drilling hydraulics, the estimation of surge and swab pressures is important due to the fact that, the excessive surge pressures generated by pipe movement in tripping operations may result in serious consequences such as blowout and formation damage. Tripping operation can be performed due to several reasons such as adding pipe stand to drillstring, changing worn bit, removing fallen parts from borehole (fishing) or running logging tools. The time spent in tripping operation is a significant portion of the total time spent during overall drilling operations. During the drilling of offshore wells in deep waters, extended reach drilling (ERD) wells and highly deviated wells, small margins are encountered between pore pressure and formation fracture pressure. In such cases, the proper prediction of surge and swab pressure may exhibit paramount importance in order to ensure trouble free and cost effective drilling operations. In this work, the method for estimating surge pressures by analytical calculations using Herschel-Bulkley rheological model is presented and the results are compared with those obtained from Paradigm Sysdrill software, version 10. In calculating the frictional pressure losses for Herschel-Bulkley model the equations introduced by Merlo, et al. (1995) are employed. The barite-weighted and unweighted fresh water sepiolite muds are used in this study. The results estimated with Sysdrill software shows discrepancy, and the surge pressures are lower as compare to the results taken from analytical model. The surge pressures are also estimated using Bingham Plastic and Power Law model, and results are compared with Herschel-Bulkley rheological model. Additionally, a sensitivity analysis is performed to investigate the major parameters that affect surge pressures. The effect of tripping speed and fluid density exhibits the direct relationship, while the effect of borehole clearance exhibits the inverse relationship to the surge pressures. The study shows that, upto the certain degree of temperature, the surge pressures decrease with the increase in formation temperature, and then afterwards the surge pressures display an increment. For better understanding of formation temperature effect on mud rheology and surge pressures, the rheological constants for the mentioned mud samples are taken, using both Fann35A rotational viscometer and Fann50SL high temperature and high pressure (HTHP) rheometer. It is also determined that at the formation temperature up to 350°F, the use of both weighted and unweighted sepiolite muds allow to fasten the tripping speed of the drillstring.
Bir jeotermal rezervuarın birimleştirilmiş ve rekabetçi yararlanma koşulları altındaki performansı
Population growth and rising living standards remain as two of the key drivers for the increase of energy demand. Towards meeting such demand, as the technological advancements are crucial for diversifying energy sources, the adoptation of proper management strategies might be necessary for the efficient capacity development in existing sources. Geothermal energy, classified as a renewable energy resource is playing a vital role in this pursuit because the production system is able to sustain production levels over long periods. The longevity of production can be secured and sustainable production can be achieved, by using moderate withdrawal rates, while considering the local resource characteristics. A geothermal reservoir is indivisible by nature and so unregulated development of straddled leases overlying a reservoir, results in physical waste and under-utilization of resource, economic waste, environmental hazards, and inefficient resource management. The solution put forward to tackle this problem is unitization, which is defined as the voluntary or involuntary agreement by working interest owners of separate leases overlying the same reservoir to exploit and operate the resource as a cooperative and coordinated joint body under a designated operator. This concept delivers sustainable and efficient resource management, economic opportunities, and environmental benefits. The objective of this thesis concerns reservoir behaviour under production with time, where two leases of different reservoir temperatures are operated under competitive and cooperative development strategies, and coming out with the optimum development design to generate 20 MWe power. The study incorporates two stages. The first stage dwells on the comparison of reservoir behaviour under production with respect to time for competitive and cooperative utilization schemes. Reservoir pressure and reservoir temperature are the benchmarks for the analysis. The second stage is about the design of the appropriate development approach for a reservoir shared by two leases, assuming a constant electricity generation capacity throughout the project life. The lumped parameter modelling is an analytical technique used for projecting the pressure response of a geothermal system to extraction. Non-isothermal tank model is selected as the tool to account for significant temperature changes associated with marked differences between recharge temperature and reservoir temperature, variations resulting from injection operations, and decrease in reservoir temperature due to production of fluids. Three hypothetical cases of one-tank and two-tank models are proposed and analysed to study reservoir pressure and reservoir temperature behaviour relative to fluid production and time, with reinjection, under competitive and cooperative management of the two leases for constant electricity generation. The cases are set as, (a) Case 1: competitive approach with two leases, (b) Case 2: cooperative approach with unitized two leases, (c) Case 3: cooperative approach with unitized two leases (production in one lease and reinjection in other lease). The assumptions made in this study are, (i) arbitrarily chosen reservoir rock and fluid properties in both leases, (ii) constant electricity generation from binary power plants, (iii) a binary power plant with 10 MWe electricity generation capacity is installed on each competitive geothermal lease of different reservoir temperatures; or a binary power plant with 20 MWe electricity generation capacity is installed on the unitized leases, (iv) temperature of the recharge (aquifer) and its connected Lease 1 are equal at 180°C in all cases, (v) reservoir temperature in Lease 2 is 160°C, and (vi) project design life is limited to 10,000 days for all cases. The significance of this thesis is emphasized on selection of the most suitable development approach for a reservoir utilized by two straddled leases of different working interest owners. All the cases are evaluated in terms of the variation in average reservoir pressure, average reservoir temperature, net heat produced, and thermal efficiency of the power plant. Out of the three cases investigated the unitized approach, in which production is from Lease 1 and reinjection in Lease 2, is found to be the desired mode of operation to feed the 20 MWe capacity binary plant for the purpose of electricity generation. This case works best, because of well coordinated and informed technical decisions on appropriate well planning, based on extensive integrated data. Hot fluid zones are identified for production and are well separated from cooler regions, in which reinjection wells are to be located. The purpose of proper location of wells is to achieve the most efficient and sustainable energy production. As the reservoir section under Lease 1 is directly connected to the recharge source, from which the reinjection well is located far away in Lease 2, replenishment of produced fluids is at an adequate rate ensuring high average reservoir pressure. Locating the reinjection wells at a safe distance from the production wells in Lease 2, the temperature of the hot water zone is kept under control. Thus, the net heat produced would be very favourable, since the reinjected fluid is channelled through the reservoir section under Lease 2 to ensure minimal drop in temperature of the reservoir section under Lease 1, which enjoys hot liquid influx from the infinite size recharge source (aquifer). Case 3 also experiences the least drop in thermal efficiency of the binary power plant by the end of the design life. It can be concluded that the owners of straddled leases should be encouraged or imposed on to act in a cooperative strategy for an unitized management of land, geothermal energy, any heat or energy source surrounding the geothermal waters, and ecosystem to derive maximum benefits for all stakeholders and safeguard public interests.
Batı Raman petrolü kullanılarak buhar- alkali (borax) solüsyon enjeksiyonunun deneysel incelenmesi
An experimental study has been conducted to compare the effect of steam injection and steam-alkali solution injection in improving the recovery of heavy oil. Bati Raman oil is used for the experiments. The API gravity (11.6º) and viscosity are typical of a heavy oil. Steam injection is used to increase the temperature in the reservoir reducing oil viscosity thus increasing the mobility of the oil. On the other hand, the target of alkali flooding is to reduce the residual oil saturation by generating surfactants in situ. Alkali solution is prepared by using Borax which forms weak alkali solutions. Borax mineral resources are abundant in Turkey and it is one of the least studied alkali solutes. Therefore, Borax is chosen in this study for the experiments. A laboratory setup was designed and built for the purpose of steam injection. The experimental setup consisted of four main systems; steam injection system, injection tube, fluid production system, and data measurement and recording system. The steam injection system consists of two reservoirs that hold the water and the alkali solution, an electrical pump, and an electrical steam generator. The injection tube is a stainless steel cylinder with a length of 1 meter and an internal diameter of 7.3 centimeters and a thin wall (1.5 mm) with flanges at both ends. Twenty-one thermocouples are placed at specific distances in the injection tube to record temperature profiles. To represent the reservoir rock and fluids, the injection tube is packed with a mixture of sand, oil, and water. The fluid production system consists of a condenser, a sand trap, and two separators. The produced samples are collected from the bottom of the separators in graduated tubes. Data measurement and recording system consisting of a data logger and computer to record the steam injection temperature and injection tube profile temperatures. Six runs are conducted as follows; water flooding, alkali solution flooding, conventional pure steam injection, cyclic injection of steam and alkali solution (4.0 wt %), cyclic injection of steam and alkali solution (4.0 wt %) with different cyclic injection period, and cyclic injection of steam and alkali solution (8.0 wt %). No oil is produced from water flooding and alkali solution flooding runs. Conventional pure steam injection recovered 8% OOIP. Experimental results show that, using of Borax solution results in a decrease in recovery of oil from 8% (pure steam injection) to 3 % (steam-alkali solution, 4.0 wt %) and 5.5% (steam-alkali solution, 8.0 wt %).
Parameter estimation using pressure and temperature transient data from wireline formation tester interval pressure transient tests (IPTT)
Reservoir behavior may be considered as isothermal because changes in temperature are generally small. In the past, use of transient temperature measurements had limitations due to the simplified assumption of isothermal fluid flow. Moreover, owing to poor resolution of temperature devices, small differences in the bottomhole (sandface) temperatures could not be detected. On the other hand, recent enhancement in the resolution of the downhole temperature devices allowed researchers to analyze and interpret transient temperature measurements to estimate near wellbore and reservoir characteristics. Therefore, the use of bottomhole temperature analysis has been expanded due to the development in resolution and accuracy in downhole gauges and the information that temperatures retain. Traditional pressure transient analysis has been used to obtain reservoir characteristics for a long time for conventional well testing and interval pressure transient test (IPTT). Recently, several works showed that near wellbore parameters can be acquired from transient temperature measurements. Previous works on transient temperature analysis performed based on slightly compressible fluid for fully-penetrated vertical or horizontal well in a single or multilayer homogeneous reservoir. Nonetheless, none of the studies analyzed temperature transient measurements acquired from the interval pressure transient test in partially-penetrated well to use in parameter estimation. Temperature data is obtained in IPTT; however, it is never being accounted in interpretation. The main target of this study is to estimate formation and near wellbore characteristics, especially horizontal and vertical permeability in the damaged zone and undamaged zone in a reservoir where damage in the formation is modeled as composite, by analyzing transient temperature measurements from the interval pressure transient test (IPTT). Furthermore, the effect of mud filtrate invasion on transient temperature measurements and parameter estimation is investigated. In this study, one of the commercial multi-purpose nonisothermal CMG-STARS simulator based on the fully-implicit numerical procedure is used. In the course of modeling, well block pressure and temperature in the simulator, some oil physical properties such as density, isothermal compressibility, and formation volume factor are allowed to vary with pressure and temperature. On the other hand, oil, water, and solid matrix specific heat capacities and isobaric thermal expansion coefficients are taken into consideration as constant with temperature. In the model, viscosity is treated as constant, at the initial conditions. To model conduction with oil, water, and rock system, a constant value of thermal conductivity is used. J-T expansion coefficient is accounted implicitly in the simulator through the variation enthalpy with pressure. Dual-packer tool configuration is used in modeling to compute transient temperature data to apply straight-line and nonlinear regression analysis including the effects of damage in the formation and mud filtrate invasion along with anisotropy. Probe configuration is modeled to generate transient temperature data to study nonlinear regression analysis including the effects of damage in the formation together with anisotropy. In this study, a commercial software CMOST AI for assisted history matching is used as an optimization module. A stochastic-based optimization technique that minimizes the difference between the observed data and the simulation responses as quantified with an objective function is used. To begin with, a synthetic model configured with a dual-packer tool is used to compute transient temperature data with constant oil production in a partially-penetrated well for a thin reservoir. Absolute temperature derivative showed that temperature propagates much slower than the pressure in the formation; thus, radial flow regime exhibits at very late times both in the damaged and undamaged zone. Horizontal permeability could be estimated precisely in the case of zero damage. In the presence of damage, horizontal permeability in the damaged zone may be estimated well if damaged zone radius is long enough for the reason that J-T expansion masks intermediate-time IARF for small damaged zone radius. In addition, another synthetic model constructed with the dual-packer tool is used to generate transient temperature data with constant production of oil in a partially-penetrated well for a thick reservoir. Nonlinear regression analysis is applied to only transient temperatures computed from this model. Horizontal permeability in the damaged zone is estimated correctly in both isotropic and anisotropic cases. Moreover, it is assessed precisely under shortened test period and mud filtrate invasion effect. The estimation of horizontal permeability in the undamaged zone is meaningful in case of no damage effect or small damaged zone radius in both isotropic and anisotropic cases. On the other hand, deep damaged zone radius and short test time result in deviation at the true value of horizontal permeability in the undamaged zone. Unfortunately, the estimations of vertical permeability in both damaged and undamaged zone are not close enough to the correct values due to the sensitivity of this parameter to temperature transient. Lastly, a synthetic model created with sink probe tool is used to compute transient temperatures with constant production of oil in a partially-penetrated well for a thick reservoir. Similarly, nonlinear regression analysis is applied to only transient temperatures generated from this model. In the case of isotropy, horizontal permeability in the damaged zone is estimated accurately, and horizontal permeability in the undamaged zone is estimated exactly only in absence of damage. When the reservoir is homogeneous and anisotropic, none of the parameters is estimated precisely. Moreover, the impact of various rock, fluid, and thermal properties on transient drawdown temperature is investigated. It is observed that reservoir thickness, porosity, and rock heat capacity do not have a significant effect on temperatures from IPTT. On the other hand, penetration interval, horizontal permeability, and viscosity may create extensive temperature changes. Also, the presence of skin and anisotropy have a substantial impact on transient temperatures from IPTT.
Modeling and interpreting transient wellbore temperature behaviors in wellbores under nonisothermal single-phase liquid flow conditions in oil reservoirs
Currently, the transient temperature data can be useful to predict reservoir and wellbore parameters. With developing technology, temperature sensors can recognize small temperature changes like 0.01 K or less; thus, resarchers use transient temperature data for parameter estimation in reservoir or wellbore. Near wellbore zone, parameter estimation from the transient pressure data is difficult because the pressure changes hastily near wellbore zone. Generally, it is assumed that fluid flow is isothermal in the reservoir although it is nonisothermal. There are some factors which cause thermal changes in reservoir as J-T coefficient, adiabatic expansion or compression, convection and conduction. So, the heat flow model should be used to model and interprete wellbore temperature data. In this work, the transient wellbore temperature distrubitions in wellbores are modeled and interpreted under nonisothermal single-phase liquid flow conditions for oil reservoirs. By using mass, momentum and energy balance equations, the temperature behaviors are obtained for transient and steady state conditions in drawdown and buildup periods. Then, the analytical solutions are coupled with sandface pressure and temperature solutions derived by Kocak (2017) in Laplace space. Derived equations in the solution of analytical model are conventional wellbore storage (WBS) model equation by using mass balance, momentum equation, and heat flow model equation. These equations provide transient and steady state wellbore temperature distrubitions in drawdown and buildup. With these distrubitions, the effects of various parameters on sandface and wellbore temperature can be investigated. Also, the parameters such as permeability, skin, J-T coefficient, earth thermal conductivity can be estimated from transient wellbore temperatures along with transient wellbore pressure data. All of equations derived in this work provide transient temperature data for single phase and slightly compressible fluid for a vertical wellbore in drawdown and buildup periods, for nonisothermal conditions. These data can be used to estimate reservoir and fluid properties, but drawdown temperature data is more crucial due to exhibiting discernable flow regimes. Also, we can not see any distinguishable flow regimes in buildup temperature behaviors.
An experimental investigation of in situ combustion in fractured heavy oil systems
In situ combustion (ISC) is one of the thermal oil recovery processes, which has been applied successfully in a variety of reservoirs. The energy is generated within the reservoir by series of multistep reactions that provide heat to reduce oil viscosity, increase reservoir pressure and upgrade heavy oil in situ by reducing the heaviest fractions of crude oil. Within the scope of this study, in situ combustion in fractured systems is investigated by both conducting kinetic reactor and combustion tube tests using Batı Raman crude oil. The combustion characteristics of the crude were analyzed first to understand reaction kinetics of the oil. Thus, ramped temperature oxidation (RTO) experiments with effluent gas analysis (EGA) were conducted with different sand particle sizes and heating rates. 50 kinetic reactor tests were conducted throughout the study and 25 of them were used in the analyses. The results were analyzed using isoconversional kinetic approach based on the produced effluent gas and temperature data obtained from experiments. A reaction model was proposed for each pair and effective activation energy, atomic hydrogen – carbon (H/C), combustion reaction stoichiometric coefficients and ignition temperature were estimated for the sample with different sand particle sizes. Kinetic reactor tests were used to determine the combustion characteristics of the oil sample and define the particle size that would later be used as fractures for tube tests with sand. In addition to RTO tests, 35 combustion tube tests were performed. During the tests, the temperature was measured along the tube and the produced effluent gas composition was recorded to be used for the analyses. Initially, 12 combustion tube tests were conducted with homogeneous sandpacks to understand the effect of the sand particle size on combustion behavior. Later, 2 tests were performed with heterogeneous sandpacks to investigate the combustion characteristics in the transition region of different porous media with various particle size. Later, 9 fracture tests with sandpack were conducted to obtain a better understanding of the effect of horizontal (perpendicular to air flow), vertical (parallel to air flow), and combined (both vertical and horizontal) fractures on combustion front behavior and determine the conditions that are required for a self-sustained front propagation. Finally, 12 fracture tests with core were performed to investigate the effect of direction, width, spacing, and network of fractures on the combustion front behavior. In 5 tests with sandpack and core, dry air (21% oxygen) was used as the feed gas whereas oxygen – enriched air (39% oxygen) was used in 9 tests with core samples to investigate the effect of oxygen concentration on the front behavior. After the tests, density and the amount of the produced oil were measured for comparison. The temperature and the produced effluent gas data were used to estimate the average front temperature and velocity, H/C ratio, air/fuel ratio, and oxygen utilization. It was concluded that the oxygen diffusion into the matrix and oil availability in the matrix during the process are the main factors for self-sustained front propagation in fractured systems. The failure of the unfractured core tests was related to heat losses, the mass of the core sample and energy generated during combustion reactions. Furthermore, vertical fractures may help to sustain the combustion front in heavy oil system due to the improvement of the available oxygen for the reactions. The horizontal fractures perpendicular to the flow direction have almost no effect on the sustainability of the combustion front whereas the vertical fractures have a significant impact on the front propagation since injected air almost exclusively flows through the vertical fractures. Two different fronts were observed regarding the vertical fracture dominated systems. The first front propagates through the matrix and it is continuous similar to homogeneous packs. The second front is observed in the fracture and it is not continuous; depending on the oil availability the front is intermittent; dies out and rejuvenates. The front in the matrix feeds the front in the fracture by displacing oil into the fracture and oil goes through the combustion process multiple times. The front in the fracture thermally feeds the front in the matrix by providing additional energy to sustain the combustion. It was observed that the duration of the test increases for vertical fracture dominated systems due to the low oxygen diffusion into the matrix and higher amount of oil combusted during these tests. The recovery factor was lower for the vertical fracture dominated systems since the oil combusted more than one time due to the displacement of oil from the matrix into the fracture and because of that the API gravity of the produced oil increased for these tests. An increase in effluent gas methane concentration was observed while the front was moving from higher surface area to lower one. Furthermore, more methane released for the horizontal and combined fractured systems compared to homogeneous packs. The oxygen – enriched air promoted the combustion characteristics in porous media.
İskenderun siyahı (Alexandrette Black) mermer tozlarının sondaj katkı malzemesi olarak kullanılabilirliği ve işletme sahasının iş güvenliği açısından değerlendirilmesi
Bu tez çalışmasında Hatay ili İskenderun ilçesi sınırlarında yer alan özel bir firmanın işlettiği ve İskenderun Siyahi (Alexandrette Black) olarak adlandırılan bir mermer ocağında blok üretimi esnasında açığa çıkan atık mermer tozlarının değerlendirilebilmesi amacıyla sondaj çamurlarında ağırlaştırıcı katkı malzemesi olarak kullanılabilirliği incelenmiştir. Ayrıca açık ocak işletmesinin iş güvenliği açısından değerlendirilmiş ve Fine Kinney metodu ile risk analizi yapılmıştır. Elde edilen veriler neticesinde atık mermer tozunun sondaj çamurunun reolojik özelliklerine etkisi deneysel olarak incelenmiş, risk analizi sonucunda da üretim yapılan işletmenin risk faktörleri belirlenerek önlem ve tedbir çalışmaları yapılmıştır.
Arsuz-İskenderun (Hatay) yöresinde gözlemlenen kumtaşlarının matriks asitleme ile mikroporozite değişimleri
Bu çalışma Arsuz-İskenderun (Hatay) yöresinde gözlemlenen kumtaşlarının saha ve petrografik özelliklerini belirlemek ve asitleme aşamalarında mikro boyutta porozite değişimlerini saptamak amacıyla yapılmıştır. Sahada kumtaşları kiltaşları ile ardışımlı olarak gözlemlenmektedir. Aktepe formasyonunda kiltaşları ve kumtaşları orta tabakalıdırlar. Kiltaşlarının kalınlığı 20 cm ile 33 cm arasında değişirken, kum taşlarının kalınlığı 25 cm ile 40 cm arasındadır. Kızıldere formasyonunda ise kumtaşı ve kiltaşı ardışımları yaygın olarak gözlemlenmekte, gri-sarı renkli kumtaşlarının kalınlıkları 10-50 cm arasında, gri renkli kiltaşları ise 2-30 cm kalınlığındadırlar. Her iki formasyonda da tektonik çatlaklar ve oksidasyon izleri gözlemlenmektedir. Çok ince taneli kumtaşı özellikleri gösteren Aktepe formasyonu kumtaşlarında kuvars taneleri değer bileşenlere göre daha fazladır ve bağlayıcı malzeme matrikstir. Kızıldere formasyonunda ise kayaç kırıntıları kuvars ve feldspat tanelerine nispeten fazla gözlemlenmektedir. Kayaç kırıntıları, fosil kavkıları, kireçtaşı taneleri ve magmatik kayaç parçalarından oluşmaktadır. Bağlayıcı malzeme kalsit çimentodur ve litik arenit olarak isimlendirilmiştir. Rezervuar kayaç asitleme işleminin ilk aşaması olan HCl asitleme işlemi deneysel olarak kapilarite yoluyla sağlanmıştır. Seyreltme oranları %7,5-%15-%30 olan HCl asit çözeltilerinin 100 dk sonrasında etki mesafeleri sırasıyla 0,6-0,8-1,1 cm ve çözülmüş kayaç miktarları sırasıyla 32,82-34,02-35,54 gramdır. Asitlenme işleminde pratikte en çok uygulanan % 15 seyreltilmiş asit ve asitlenmemiş örneklerin Micro-CT ile porozite ortalamaları % 39,6'dır. Kuyu logları ile ölçülen porozite değerleri ile eşdeğer sonuçlar elde edilmiştir. Asitleme işlemiyle porozitede yaklaşık % 16 oranında artış söz konusudur. Asitleme ile boşluklar birbirine bağlanmış ve boyutları yaklaşık % 20 oranında artmıştır. Boşluk boğazı uzunluğunda asitleme ile değişim ise % 51 oranındadır. Micro-CT ve görüntü işleme yöntemleri ile kayaçların porozitelerinin hesaplanması diğer yöntemlere göre daha hızlı yapılabilmektedir. Kızıldere formasyonuna ait kumtaşlarının da hesaplanan porozite değerleri hazne kaya olabileceğini göstermektedir.
Pirina bazlı çeşitli katkıların su bazlı sondaj çamurunun reolojik ve filtrasyon özellikleri üzerine etkileri
Bu çalışmada, Hatay yöresi zeytinyağı işletmelerinden temin edilmiş pirina hammaddesi, piroliz, öğütme ve çürük asit ile muamele gibi işlemlerden geçirilerek sırasıyla; pirolitik yağ, öğütülmüş pirina ve modifiye pirina olmak üzere üç farklı katkı maddesi elde edilmiştir. Bu katkı maddeleri tek başına su bazlı sondaj çamuruna ilave edilerek çamurun reolojik ve filtrasyon özellikleri üzerine etkileri incelenmiştir. Ayrıca, sıcaklığın su bazlı sondaj çamurunun reolojik özellikleri üzerine etkisini araştırmak üzere kapsamlı bir çalışma yürütülmüştür. Katkılı ve katkısız su bazlı sondaj çamurlarının reolojik ve filtrasyon özelliklerini incelerken, çamur ağırlığı, viskozite, kopma noktası, jel mukavemeti, sıvı kaybı, kek kalınlığı ve pH gibi parametreler üzerinde çalışmalar yapılmıştır. Sıcaklığın sondaj çamurunun reolojisine etkisini incelemek için 25 ºC, 35 ºC, 49 ºC ve 66 ºC sıcaklıklarda hazırlanan çamurlar kullanılmıştır. Yapılan bu çalışmalar neticesinde, pirina bazlı katkı maddelerinin sondaj çamurunun reolojik ve filtrasyon özellikleri üzerine etkisinin genel olarak olumlu olduğu görülmüştür. Katkı miktarı arttıkça, katkı miktarı belli bir seviyeyi aştıktan sonra çamurun ağırlığının arttığı, viskozite ve kopma noktası değerlerinin genel olarak azaldığı, daha iyi bir jel yapısı oluştuğu, düşük bir sıvı kaybı meydana geldiği, ince ve geçirimsiz bir kek oluştuğu ve pH değerinin azaldığı görülmüştür. Sıcaklık arttıkça, çamurun viskozitesi, kopma noktası ve jel mukavemeti bazı sıcaklıklarda azalırken, bazı sıcaklıklarda artış göstermiştir. Sıcaklığın pH'a etkisi incelendiğinde ise, tüm katkılı ve katkısız çamurlarda sıcaklığın arttırılmasıyla pH değerinin azaldığı gözlenmiştir.
Arsuz (Hatay) yöresi Kızıldere formasyonunun hidrokarbon potansiyelinin araştırılması
İnceleme alanı Arsuz – HATAY yöresini kapsamaktadır. Yörede bulunan Kızıldere Formasyonunun (Orta – Üst Miyosen) kiltaşlarının ana kaya olma niteliklerini ve formasyon çökelme ortamı incelenmiştir. Petrol ümitli bölgeler Miyosen döneminde oluşmuştur ve formasyonlar; çakıltaşlarından oluşan Kalecik Formasyonu (Orta Miyosen), resifal kireçtaşlarından oluşan Horu Formasyonu (Orta Miyosen) ve Kızıldere Formasyonudur. Bu birimler arasında rezervuar kaya olma özelliği ile Horu Formasyonu ve petrol rezervuar kaya kaynak kaya ve örtü kaya niteliklerini sağlayan Kızıldere Formasyonu önem taşımaktadır. Orta-Geç Miyosen yaşlı formasyon genellikle Konacık (Arsuz) yöresinde tipik olarak gözlemlenmektedir. Kum ve kil ardışımlarının yaygın olduğu formasyonda gri-sarı renkli kumtaşlarının kalınlıkları 10-50 cm arasında orta-kalın tabakalı, gri renkli kiltaşları ise 2-30 cm arasında ince-orta tabakalıdırlar. Kumtaşı ve kiltaşı ardışımının üstünde yer yer tabakalı jibs seviyeleri gözlemlenmektedir ve katman kalınlıkları 5-15 cm arasındadır. Derinlere inildikçe kiltaşı tabakaları 102 cm'ye kadar kalınlaşmaktadır. Orta Miyosen sonrası tektonizmanın etkin olmasından dolayı formasyonda tektonik çatlaklar yaygın olarak gözlemlenmektedir. Jibsler ile birlikte ardışımlı marnlar içerisinde bitki kalıntıları gözle görülebilmektedir. Kiltaşlarında ortalama Toplam Organik Karbon (TOC) değerlerinin 0,56 olması birimin petrol üretim potansiyelinin olduğunu göstermektedir. Ana elementlerden İz elementlerin konsantrasyonlarının ortalaması sırasıyla V-1180,65 ppm, Ni-219,83 ppm, Cr-149,26 ppm, Co-19,45 ppm, Cu-22,63 ppm, Rb-42,96 ppm, As-8,40 ppm, Zn-54,47 ppm, Sb- 0,61 ppm, Mo-1,28 ppm, Cd-(-0,71) ppm, Pb- 5,68 ppm, U-1,35 ppm, Ba-171,15 ppm, Li-24,64 ppm, Cs-3,06 ppm, S-325,48 ppm'dir. İz elementlerden Vanadyum konsantrasyonlarında artışlar ve V/Ni, Ni/Co, V(V+Ni), V/Cr oranları organik maddenin korunumu için uygun olan denizel ve anoksik ortamda kiltaşlarının çökeldiğini göstermektedir. Bölgede iz elementler ve TOC değerlerine göre yapılan sınıflamada ve organik madde korunumunun arttığı ortam geçişleri belirlenmiştir.
Na- bentonitten nanobentonit eldesi ve spud çamurlarında kullanılabilirliği
Bu tez çalışmasının konusu, "Sodyum Bentonitten Nanobentonit Eldesi Ve Spud Tip Sondaj Çamurlarında Kullanılabilirliği" üzerinedir. Çalışma kapsamında Tokat- Reşadiye bölgesine ait farklı boyutlara indirgenmiş TSE EN ISO 13500 standardına uygun sondaj çamurlarında kullanılan sodyum bentonit kilinin sondaj çamurunda oluşturduğu etkiler incelenmiştir. Sodyum bentonit kili öğütme işlemine tabi tutularak ve üç farklı boyutta sodyum bentonit öğütülmüştür. Yapılan işlemler sonucunda sodyum bentonit 75 mikron altı, 25 mikron altı ve 1 mikron altı olarak 3 farklı boyutta öğütülmüştür. Üretilen farklı boyutlardaki bentonit kullanılarak İskenderun Teknik Üniversitesi Petrol ve Doğalgaz Mühendisliği Bölümü Sondaj Laboratuvarında sondaj çamur numuneleri hazırlanmıştır. Hazırlanan sondaj çamurlarının reolojik, filtrasyon ve kimyasal analizleri yapılarak tane boyutunun sondaj çamurunun özellikleri üzerindeki etkileri incelenmiştir.
Jeotermal kuyularda sirkülasyonla eşzamanlı sıcaklık dağılım modellenmesi
Jeotermal kuyularda sıcaklık dağılımının bilinmesi, sondaj operasyonunun tasarımı ve yönetilmesi açısından önem arz etmektedir. Yüksek sıcaklık sondaj sıvısının performansını azaltmakta bu durum ise birçok sondaj problemini beraberinde getirmektedir. Ayrıca, sondaj sıvısındaki ısıl genleşmelerden dolayı yüksek pompa güçlerine ihtiyaç duyulmakta, böylelikle diğer tüm ekipmanlarda istenmeyen arızalar ortaya çıkmaktadır. Bu durum jeotermal kaynak içeren kuyuda kaçınılmaz olmaktadır. Dolayısıyla, oluşabilecek risklere karşı önlem almak ve kuyunun enerji fizibilitesini doğru bir tahminle çıkarabilmek için kuyu derinliği boyunca sıcaklık dağılımının bilinmesi önemlidir. Bu çalışmada, delme anında çamur giriş-çıkış sıcaklıklarından faydalanılarak kuyu dibi sıcaklığını doğru tahmin etmek için ısı transferi prensiplerine dayanan MATLAB programlama dilinde bir yazılım geliştirilmiştir. Kuyu içi sıcaklık dağılımının bulunması için Delphi programlama dilinde bir yazılım geliştirilmiş ve iki yazılım birbirlerini destekleyecek şekilde koordine edilmiştir. Formülasyon ve yazılımların akışı açıklanmıştır. Gerçek bir kuyudan alınan çamur sıcaklık verileri kullanılarak delme işlemi simüle edilmiş ilerlenen derinliklerde ki kuyu dibi sıcaklıkları tahmin edilmiştir. Tahminler ve gerçek değerlerin karşılaştırması ile bir takım ısı transferi yaklaşımlarında bulunulmuştur. Elde edilen sonuçlara göre kuyu içerisinde radyal yönde düzgün bir sıcaklık dağılımı olduğu gözlenmiştir. Kuyu girişinde belli bir derinlikten sonra sıcaklık artışının kararlı bir hal aldığı gözlenmiştir. Ayrıca Peclet (Pe) sayısının ısı transferinde önemli bir rol oynadığı tespit edilmiştir. Akış karmaşıklıklarından dolayı sıcaklık dağılımında bir değişiklik olup olmadığının belirlenebilmesi için ANSYS programı kullanılarak bir akış durumu tasarlanmış ve incelenmiştir. Kuyu uzunluk ölçeğine göre akış karmaşası oluşturan geometrilerin uzunluk ölçeklerinin çok küçük olmasından dolayı akış kaynaklı sıcaklık dağılımının çok fazla değişmediği ve dolayısıyla ısı transferi hesabına dayanan sıcaklık dağılımı hesabı yaklaşımının kabul edilebilir olduğu sonucuna varılmıştır. Çalışma içerisinde ilgili literatürden çok sayıda çalışma incelenmiş ve özetlenmiştir. İlgili tekniğin teorisine değinilmiş ve gelecek çalışmalara yönelik öneri ve düşüncelere yer verilmiştir. Gelecekte çok fazlı Newtonian olmayan akışlar ve farklı toprak sıcaklık değişim senaryoları için daha detaylı sayısal analizler gerçekleştirilebilir.
Jeotermal sularla hazırlanmış çamurların sondaj performansına etkisi
Jeotermal sondajlar genellikle bol kırık ve çatlaklı volkanik sahalardaki yüksek sıcaklık koşullarında yapılmaktadır. Çamur kaçaklarını ve bozulmalarını beraberinde getiren bu durum ise sürekli çamur yapımı gerektirdiğinden önemli miktarda da su ihtiyacı söz konusu olmaktadır. Çamur yapımında kullanılacak olan tatlı su fayda/maliyet açısından sondaj mahaline en yakın yerden temin edilmek istenir. Bu durumun her zaman mümkün olmadığı durumlarda ise sondaj mühendisleri jeotermal havzalarda yer alan diğer kuyu ve/veya yüzey kaynaklarından mineralli sıcak suları çamur yapımında kullanmaktadırlar. Literatürde tatlı sularla hazırlanmış sondaj çamurlarının reolojik özellikleri üzerine birçok çalışma mevcut olmasına rağmen, farklı mineral içerikli sıcak jeotermal kaynak suları ile hazırlanmış sondaj çamurlarının reolojik özellikleri ve sondaj performansı üzerine etkileri henüz incelenmemiştir. Bu çerçevede, bu çalışma ile literatürdeki boşluğu doldurmak hedeflenmiştir. Çalışma kapsamında öncelikle 1 adet saf su, 8 adet jeoermal kaynak suyu kullanılarak API standartlarına göre çamur numuneleri hazırlanmıştır. Daha sonra bu numunelerin hem ortam koşulları hem de sıcaklık artışına bağlı olarak viskozite, filtrasyon, jel mukavemeti, kek kalınlığı, pH ve çamur yoğunluğu ölçülmüştür. Bu çalışmada ayrıca, formüle edilen çamurların reolojik davranışlarının tahmininde kullanılacak reolojik model ortam koşullarında ve sıcaklık artışına bağlı olarak istatistiksel olarak değerlendirilmiş ve kesinti taşıma indeksleri ile etkin kuyu temizliği için gerekli minimum anülüs hızları yine ortam koşullarında ve sıcaklık artışına bağlı olarak hesaplanarak sondaj performansları değerlendirilmiştir. Yapılan değerlendirmelerde mineralli jeotermal kaynak suları ile hazırlanmış çamurların saf su içerikli çamurlara göre viskozitesinin ve akma noktasının daha düşük olduğu, su kaybının ise daha yüksek olduğu görülmüştür. Diğer yandan numunelerin 6 farklı sıcaklık koşulunda (77, 122, 167, 212, 257 ve 302 (°F) kayma gerilmesiyle kayma hızı arasındaki ilişkiler (reogram) grafiklendiğinde, akışkanın nispeten düşük sıcaklıklarda (77-212 (°F) aralığı) kopma gerilmesinin aşılmasından sonra kayma gerilmesi ile kayma hızı arasındaki ilişki Bingham plastik ve power law modellerinin bir kombinazonu olan Herschel-Bulkley modeli ile ifade edilebilecek akış davranışını gösterdiği, daha yüksek sıcaklıklarda ise bazı su numuneleri için akışkanın kopma gerilmesiz non-Newtoniyen akışkan gibi davrandığı görülmüştür. Kesinti taşıma indeksleri açısından yapılan değerlendirmeye göre ise, jeotermal kaynak suları ile hazırlanmış saf su içerikli çamurlardan daha düşük taşıma kapasitesine sahip olduğu görülmüştür. Etkin kuyu temizliği açısından ise daha yüksek anülüs hızına ihtiyaç duyacağı bulunmuştur. Sonuç olarak jeortamal kaynak suları ile hazırlanan çamurların tatlı su kaynaklarına oranla daha düşük sondaj performansı sergileyeceği kanatine varılmıştır.
Karaçukur havzasının (Abşeron Yarımadası-Azerbaycan) petrol potansiyeli
Dünya'nın en eski petrol üreticisi ve ihracatçısı olan Azerbaycan, yeraltı kaynakları bakımından çok zengin bir ülkedir ve en büyük yeraltı zenginliği petrol olup, ülke arazisinin %70'i petrol yönünden yüksek potansiyele sahiptir. Özellikle Abşeron Yarımadası'nda 1800'lü yıllardan itibaren tespit edilen petrol havzalarından büyük ölçüde petrol çıkarılmaktadır. Abşeron Yarımadası'nın en zengin petrol havzalarından biri olan Karaçukur havzasının jeolojik yapısında Neojen ve Pliyosen yaşlı çökeller yer almaktadır. Fakat, yüzeyde Pleistosen çökelleri de görülmektedir. Güncel (Holosen) sedimanlar ise nispeten derin çökellerden ve tuz katmanlarından oluşan alanlarda yayılmıştır. Karaçukur kıvrımı tektonik açıdan nispeten derin gömülmüş kırıklı antiklinal yapıya sahip olup, Sarıkayabaşı-Şahdeniz antiklinal bölgesi içerisinde yerleşmektedir. Havzanın petrol ve gaz potansiyeli esasen Mehsuldar Kat formasyonu çökelleri ile ilgilidir. Petrol potansiyeli havzanın Surahanı formasyonundan aşağıda tüm kumlu ve kumlu-siltli zonlarda tespit edilmiştir. Havzada gaz potansiyeli diğer formasyonlara nisbeten Kırmeki formasyonunda daha yüksek oranda görülmektedir. Havza, endüstriyel öneme sahip kaliteli bir petrol potansiyeline sahiptir. Karaçukur havzasında bulunan petrolün yoğunluğu düşük olduğu için hafif petrol sınıflamasına dahil edilmektedir .
Geothermal energy integrated resource management in turkey and importance of reinjection
Countries steps to change their energy habits while are willing to fight against the problem of global warming, one of the most important hazards our world faces, which is the result of the greenhouse effect created by a large of quantities carbon dioxide gas emission from heavy fossil fuel use. Geothermal energy has important role in Increasing Renewable Energy using that the most important way. In this study, Integrated Resource Management has been proposed for using geothermal energy resources more efficient and sustainable. Try to explain, which processes can be done on both country and field basis, negative sides, current legal situation and regulations according to Integrated Resources Management. Some examples in literature are presented. Details of Big Data and Data Mining explained as a part of technologic harmony in Integrated Resource Management. Other parts include detailed information about reinjection process as one of the main parts of Integrated Resource Management. Application part of this study contains production and reinjection projection model which is made with Data of Nevada Geothermal Power Plants by artificial neural networks. In this application, future predictions about production and reinjection are presented. As a conclusion, general assessment has been made and findings are presented.
Metil alkol yakıt hücrelerinde kullanılacak karbon temelli kompozitlerin üretimi ve petrol mühendisliğinde kullanımı
Tez.çalışmasında, metanol yakıt hücresinde katalizör olarak kullanılmak üzere grafen kuantum noktacıkları (GKN)/fonksiyonelleştirilmiş çok duvarlı karbon nanotüp (f-ÇDKN) kompoziti sentezlenmiştir. Söz konusu katalizörün optik, elektronik ve petrol mühendisliğinde uygulamalarında yararlı olması beklenilen özellikleri literatür araştırmasıyla tespit edilmiş ve yapılan çalışmalarla etkinliği desteklenmiştir. Kompozit malzemelerin yapıları taramalı elektron mikroskobu (SEM), raman spektroskopisi, x-ışını kırınımı (XRD), UV-Vis spektroskopisi, fourier dönüşümlü kızılötesi spektroskopisi (FTIR) ve elektrokimyasal empedans spektroskopisi (EIS) teknikleri kullanılarak aydınlatılmıştır. Elde edilen kompozit malzemenin karakterizasyon çalışmaları gerçekleştirildikten sonra dönüşümlü voltametri (CV) ve kronoamperometri (CA) teknikleri kullanılarak yakıt olarak kullanılan metil alkole olan elektrokatalik aktivitesi incelenmiştir. GKN, f-ÇDKN ve GKN/f-ÇDKN nanomalzemeler ile modifiye edilmiş camsı karbon elektrotlar (GCE) hazırlandıktan sonra elektrotların spesifik yüzey alanları (SSA) hesaplanmıştır. SSA değerlerine göre hazırlanan kompozit malzemenin yüzey alanı GKN ve f-ÇDKN nanomalzemelerin yüzey alanlarından 2,34 ve 2,84 kat daha yüksek olduğu bulunmuştur. Son olarak CA deneyleri ışığında tez çalışması kapsamında hazırlanan karbon temelli kompozit malzemenin metil alkol oksidasyonu sırasında literatür de kullanılan diğer katalizörlere göre daha verimli olduğu bulunmuştur.
Nanopartiküller ile fonksiyonelleştirilmiş çok katmanlı karbon nanotüplerin su bazlı sondaj çamurlarına etkisi
Sondaj operasyonlarında sirkülasyon işleminin önemli bir parçası olan sondaj akışkanları diğer adıyla sondaj çamurları; sondaj işleminin maliyeti, verimi ve başarısı için kritik bir öneme sahiptir. Son zamanlarda araştırmacılar sondaj akışkanlarına çeşitli boyut ve konsantrasyonlarda katkı maddeleri ekleyerek sondaj akışkanlarının reolojik ve filtrasyon özelliklerini iyileştirmeyi hedeflemiştirler. Bu tez çalışmasında; Al2O3, TiO2 ve ZnO nanopartikül (NP) maddeleri ile fonksiyonelleştirilmiş çok katmanlı karbon nanotüplerin (ÇKKNT), su bazlı sondaj çamuruna (Na-bentonit bazlı) farklı oranlarda (0,001-0,005-0,01 % k/h) ayrı ayrı eklenmesiyle, sondaj çamurunun reolojik ve filtrasyon özelliklerine olası etkisi incelenmiştir. Kimyasal buhar biriktirme (CVD) yöntemi ile üretilen fonksiyonelleştirilmiş çok katmanlı karbon nanotüpler (Al2O3NP/ÇKKNT, TiO2NP/ÇKKNT ve ZnONP/ÇKKNT), taramalı elektron mikroskopu (SEM) ve X-ışını fotoelektron spektroskopisi (XPS) cihazı ile karakterize edilmiştir. Al2O3NP/ÇKKNT, TiO2NP/ÇKKNT ve ZnONP/ÇKKNT'lerin 0,001-0,005-0,01 (% k/h) oranlarında ilave edilmesiyle hazırlanan su bazlı sondaj çamurlarının; plastik viskozite (PV), görünür viskozite (AV), kopma noktası (YP), jel mukavemeti (10 saniye ve 10 dakika) gibi reolojik analizleri FANN 35 viskozimetresiyle, sıvı (filtrasyon) kaybı ve sondaj çamuru kek kalınlığı analizleri de Amerikan Petrol Enstitüsü (API) sıvı kaybı test ekipmanları ile API standartlarına uygun şekilde yapılmıştır. Çalışma sonucunda elde edilen verilere göre Al2O3NP/ÇKKNT, TiO2NP/ÇKKNT ve ZnONP/ÇKKNT ilavesinin su bazlı sondaj çamurunun reolojik özelliklerini olumlu yönde etkilediği görülmüştür. Ayrıca katkısız (spud) su bazlı sondaj çamuru ile kıyaslandığında; Al2O3NP/ÇKKNT, TiO2NP/ÇKKNT ve ZnONP/ÇKKNT ilavesinin sondaj çamurlarının PV değerini sırasıyla %85,7; %71,4; %42,8 oranında arttırdığı, AV değerini sırasıyla %41,8; %41,8; %31,6 oranında arttırdığı, YP değerini sırasıyla %20; %28; %28 oranında arttırdığı, 10 saniye değerini sırasıyla %16,6; %8,3; %25 oranında arttırdığı, 10 dakika değerini sırasıyla %11; %5,6; %38,9 oranında arttırdığı, filtrasyon kaybı değerini sırasıyla %13,8; %8,6; %13,8 oranında azalttığı, aynı zamanda kek kalınlığı değerini de sırasıyla %18,5; %11; %22 oranında arttığı görülmüştür.
Bor türevleri katkılanmış sondaj çamurunun reolojik ve filtrasyon özelliklerinin incelenmesi
BOR TÜREVLERİ KATKILANMIŞ SONDAJ ÇAMURUNUN REOLOJİK VE FİLTRASYON ÖZELLİKLERİNİN İNCELENMESİ (Yüksek Lisans Tezi) Behlül Merve SEBÜKTEKİN İSKENDERUN TEKNİK ÜNİVERSİTESİ MÜHENDİSLİK VE FEN BİLİMLERİ ENSTİTÜSÜ Mayıs 2019 ÖZET Sondaj çamuru petrol aramalarının en büyük maliyet kalemini oluşturduğu için sürekli olarak üzerinde çalışılan konu olmuştur. Çeşitli katkı maddeleri eklenerek sondaj çamurunun reolojik ve filtrasyon özelliklerinin iyileştirilmeye yönelik çalışmalar her geçen gün artarak devam etmektedir. Bu çalışmada, petrol aramalarında en çok kullanılan sondaj çamuru türü olan, su bazlı sondaj çamuru hazırlanmış ve hazırlanan sondaj çamuruna; 45 μm tanecik boyutuna sahip sodyum borat grubu minerali boraks (Na2B4O7.10H2O), 75 μm tanecik boyutuna sahip sodyum-kalsiyum borat grubu minerali üleksit (NaCaB5O9.8H2O) ve 100 μm tanecik boyutuna sahip kalsiyum borat grubu minerali kolemanit (Ca2B6O11.5H2O) farklı konsantrasyonlarda (1-5 % w/v) ilave edilmiştir. Daha sonra bor mineralleri eklenerek hazırlanmış olan sondaj çamuru numunelerinin plastik viskozite (PV), görünür viskozite (AV), jel mukavemeti gibi reolojik özellikleri FANN 35 Viskometre, su kaybı ve kek kalınlığı gibi filtrasyon özellikleri ise Amerikan Petrol Enstitüsü (API) sıvı kaybı test aletleri kullanılarak detaylı bir şekilde analiz edilmiştir. Tüm ölçümler, Amerikan Petrol Enstitüsü (API) standartlarına göre gerçekleştirilmiştir. Ayrıca, hazırlanan sondaj çamuru numunelerinin kimyasal ve morfolojik özellikleri X ışını floresans spektrometresi (XRF) ve taramalı elektron mikroskobu (SEM) cihazlarıyla belirlenmiştir. Boraks, üleksit ve kolemanit minerallerinin ayrı ayrı eklenmesi (% 1-5 w/v) ile hazırlanan sondaj çamurlarının reolojik ve filtrasyon özellikleri kendi içlerinde, daha sonra birbirleri ile ve son olarakta katkısız su bazlı sondaj çamuru ile karşılaştırılmıştır. Bor minerallerinin sondaj çamurunun reolojik özelliklerine olumlu yönde katkı sağladığı tespit edilmiştir. Boraks ve kolemanitin, üleksite oranla daha iyi bir etkiye sahip olduğu görülmüştür. Katkısız su bazlı sondaj çamuruna kıyasla, çamura bor mineralleri eklenmesinin çamurun filtrasyon kaybı ve kek kalınlığını attırdığı görülse de sonuçların referans değer aralığında olduğu tespit edilmiştir.
Bir petrol sondaj sahasının anket yöntemiyle risk değerlendirmesi
Sondaj sektörü çalışma koşulları nedeni ile birçok tehlikeyi içermektedir. Dolayısıyla sondaj sahalarında tehlikelerin belirlenmesi ve gerekli önlemlerin alınabilmesi için mutlaka detaylı risk analizlerinin yapılması gerekmektedir. Bu çalışma ile TPAO Batman Bölge Müdürlüğüne ait bir petrol sondaj lokasyonunun risk analizinin yapılması sondaj lokasyonunda risk oluşturan durumların tespit edilmesi, risklerin en aza indirilmesi ve var olan risklerin ortadan kaldırılması hedeflenmiştir. Bu amaçla petrol sondaj sahasında anket yöntemi kullanılarak riskler tespit edilip risklerin giderilmesine dair önleyici öneriler tez içerisinde sunulmuştur. Çalışma yapılan petrol sondaj sahasında otuz adet çalışana otuz beş farklı anket sorusu sorulmuş ve elde edilen sonuçlara bağlı olarak yapılan risk analizleri sonucunda meydana gelen iş kazalarının çoğunun olumsuz hava koşulları, montaj ve demontaj, tecrübe eksikliği, vardiya değişim saatleri ve uykunun ağır olduğu saatlerde meydana geldiği tespit edilmiştir. Bu kazaların daha aza indirgenmesi için gerekli önlem ve tedbirler tez içerisinde verilmiştir.
Jeolojik formasyonlarda matkap seçimi
Sondaj matkapları, dönme hareketinin ve yukarıdan aşağı uygulanan ağırlığın gücüyle kayaları kırarak ya da sıyırarak kuyu kazmak için kullanılır. Sondaj dizisinin en altına bağlanarak, diziyle birlikte yüzeyden rotary table, top drive veya sondaj çamurunun hidrolik gücüyle dönme hareketi sağlayan bir motorla döndürülür. Genel olarak bir sondaj matkabı, sondaj dizisine bağlantıyı sağlayan shank, ana gövde ve sondaj işini yapan kazıcı yapı olmak üzere üç ana kısımdan meydana gelmektedir. Sondaj sahasına ulaşmadan önce, matkabı oluşturan bu kısımlarının üretimi ve birleşim prosesleri maliyet olarak, astronomik seviyelere ulaşmaktadır. Bu sebeple, sondaj faaliyeti esnasında bir matkaptan üstün performans göstermesi beklenir. Bu koşulun sağlanabilmesi için de litolojiye uygun matkap seçimi büyük önem taşımaktadır. Oluşumu itibariyle, litoloji bantları açısından heterojen yapıya sahip ardalanmalı-karmaşık formasyonların sondajında, formasyona uygun matkap seçimi ve bu doğrultuda öngörü sunabilmekte zorlaşmaktadır. Bu tez çalışmasında, Güneydoğu Anadolu Bölgesinde bulunan, içerisinde karmaşık litolojileri barındıran ve hangi metrajdan ne tür litoloji geleceği tahmin edilemeyen allokton yapılardan oluşmuş Karadut Karmaşığı ele alınmıştır. Çalışmada, Karadut Karmaşığı'nın bulunduğu 2 kuyunun, 12 ¼" kuyu sondajında kullanılan 3 adet PDC, 6 adet Döner Konlu (Roller Cone) ve 3 adet Hibrit matkabın sondaj parametreleri grafikler haline getirilmiştir. 12 adet matkabın saha verileri, İlerleme Hızı (ROP) temelinde değerlendirilerek Karadut Karmaşığına uygun, optimum matkap seçimi yapılmaya çalışılmıştır. Çalışma sonucunda ise, sertliği ve aşındırma kabiliyeti açısından karmaşık litolojiye sahip Karadut Karmaşığı gibi formasyonlarda, sondaj faaliyetleri için Hibrit (Melez) matkapların kullanılması ilerleme hızı yönünden daha uygun olduğu anlaşılmıştır.