The Analysis of Bio-Precursor Organic Matter Compositions and Its Significance for Gas Shale Reservoir of Wufeng–Longmaxi Formation from Dingshan Area, Sichuan Basin

In order to analyze the organic matter (OM) composition, this study carefully identified OM types of 66 samples from Well A in Dingshan area under microscope, and made an effort obtain semi-quantitative statistics contents different bio-precursor derived OM. The results content obtained microscope showed a strong positive relationship (R2 = 0.85) with TOC analyzed by carbon–sulfur analyzer. contained bethic algae debris, phytoplankton amorphous (AOM), acritarch, vitrinite-like particles, zooplankton (including graptolite, chitinozoa others) solid bitumen which was secondary formation AOM, graptolite were dominated interval. Solid (8%~11%) filled at bottom Wufeng Formation, could be one reason for high shale gas production lower part N2 adsorption that micropores mesopores predominant system, while pore volumes illustrated better relationships than minerals, especially AOM content. Thus, both kerogen main sources generation system.