Clay mineralogy, inorganic and organic geochemical characteristics of Dadaş formation of Çeltikli and Derindere area (The east of Bismil, Diyarbakir)

In this study, mineralogy, clay mineralogy, inorganic and organic geochemical characteristics and the hydrocarbon source rock characteristics for shale gas or rock gas of Dadaş Formation are examined. The study area is located at Derindere and Çeltikli area which is the border of Diyarbakır city, and closer Batman. A lot of units in the study area is available, range from the Ordovician-Oligocene, which covered by Upper Miocene aged Şelmo Formation. Lower Silurian-Lower Devonian aged Dadaş Formation which composed the study subject is formed by shallow marine sandy-silty carbonate and marl sheyl alternation with high organic material. The samples which were taken along sections were analysed by X-ray analysis method and whole rock and clay fraction minerals were determined. According to whole rock analysis results, feldispar, dolomite, calcite, quartz, clays are the common minerals in the studying area. In clay fraction analysis, illite is found as a dominant mineral, and it is companied by the other clay minerals kaolinite, serpantine, and smectite-illite. Illite crystallinity values indicate diagenetic zone in the two area. İnorganic geochemical data from analyzed samples of Derindere-1 and Çeltikli-1 areas of Dadaş Formation show that each borehole is a continuation of each other. Major oxide, rare earth elements and trace elements in some of the levels of Çeltikli-1 and Derindere-1 drilling holes are similar with a 250-300 m code difference. The normalized diagram of rare earths to the North American Shales (NASC) is also showed this similarity. Each of the two areas, Dadaş Formation shale samples are 'middle rich' according to the value of organic matter TOK, which is the most abundant amount increased amount of organic matter reaches the end of the sequence, and at the upper levels decreased and the minimum is observed. S2-TOC, and HI-Tmax of HI-OI kerogen classification charts show that the majority of the samples are in Type III, at least one part is at the Type II kerogen in the each of the two areas. Average rate of S2/S3 Kerogen Type for shale samples was calculated and showed that in general, oil and gas (mixed) kerogen characteristics were pointed out. In drilling holes, the general increase as U, V, Ni, Cu, Ag, Mo, Sb, Cd and Se were enriched with the enriched of TOC values. Considering the higher amount of quartz + calcite minerals, Tmax (maturation), and Total Organic Carbon (TOC), between 3020 and 3050. meters levels could be crack in Derindere-1 borehole, 2760 and 2790 meters levels could be crack in Çeltikli-1 borehole compared to the other levels.