Petroleum geological conditions of Carboniferous- Permian in Ejina Banner and its vicinities,western Inner Mongolia, China

Based on preliminary study of distribution, lithologic features and sedimentary environment of Carboniferous- Permian in Ejina Banner and its vicinity, the paper mainly take studies on distribution of source rocks, organic matter abundance and thermal evolution history, combining with the evaluation of reservoir, cap and preservation conditions, then the authors summarize the Carboniferous- Permian petroleum geological conditions of the study area. There is several meters remnant in thickness of Upper Carboniferous-Upper Permian in this area, the lithologic association is clastic rocks- carbonate rock- volcanic rock, which shows the sedimentary characteristics of rift basin. The shale of neritic shelf fades is widely developed in this area, and the shale has good hydrocarbon generation conditions, the Kerogen type is dominated by Ⅱ-Ⅲ type, middle content of organic carbon, general vitrinite reflectance ranging from 0.79% to 1.08%. The evolution level of hydrocarbon source rocks is mature, which of some seismics is overmature, because of the effect of the tectonic dynamics. Controlled by the sedimentary and evolution of basin, there are several types of reservoir, including shoreside glutenite, platform slope bioclastic limestone, pyroclastic rock (volcanic breccia), volcanic lava, and weathering crust. Cretaceous widely distributed is good regional cap, and tectonism after the main hydrocarbon-generating stage were mainly depression-sedimentation, extrusion and uplift, which was benefit for hydrocarbon preservation. And also gain the hydrocarbon occurrence information related with Carboniferous- Permian source socks, this shows that there is good prospects for hydrocarbon resources.