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.