Hydrocarbon source rock and shale gas potential of the lower carboniferous alacaağzi formation shales

Lower Carboniferous aged Alacaağzı Formation in the northwestern part of Turkey includes the organic carbon rich black shales. Alacaağzı Formation indicates the geological units which represents a global sea-level changes and significant anoxic interval in the Devonian-Carboniferous boundary (D-C). In the Tarlaağzı section, detailed organic geochemical analysis, whole rock and X-Ray diffraction analysis were performed to obtain source rock potential. The TOC contents range from 0,18 to 1,75 wt%. Average Tmax value is 438°C in the Tarlaağzı samples which represents oil window. Illite crystallinity (IC), Weawer index (SR) and sharpness ratio of chlorites (Chc) of all samples are in the Anchizone and Epizon stages declare that clay minerals could be allogenic. Pr/Ph ratio was calculated 1,14 indicates anoxic or sub-oxic depositional environment. The calculated values of the gas chromatography analysis represent that the organic matter was originated from 'Type II / III' kerogen. TRHI average calculated value is (78%) inform that the samples tend to produce gas. The calculated Tmax-based R0% value is (0,73) indicates low shale gas potential. Brittleness of Tarlaağzı samples are the range to less brittle to brittle. Alacaağzı shales can be considered a shale gas formation because of its thickness, contents of brittle minerals, retention of organic matters and more than 78 %TRHI. Oil generation time for the effective source rocks in the region was occurred 145-66 mybp.