Study On Lithofacies Paleogeography And Source Rock Of The Middle Permian Xiaojiangbian Formation In Ping Le Depression

This paper is on the basis of previous research results,combine the data of field outcrops,the regional structure of the study area to summarize and analyze,Then the sedimentary petrology,sedimentary facies and paleogeographic characteristics of Ping Le depression in Middle Permian and the edge of Triassic Xiaojiangbian studied lithofacies palaeogeography theory.Combining with the plane characteristics and organic geochemical characteristics of source rocks,analyze the oil and gas prospect.The Middle Permian Xiaojiangbian Formation in Ping Le depression is a set of black calcareous shale and carbonaceous shale sedimentary limestone lenses.In late Middle Permian,the rapid sea-level rise,sea water deepened significantly,the study area mainly developed mixed continental shelf facies,can be further divided into shallow and deep-water outershelf inner shelf subfacies and shelf mud and mud mound facies.In the study area,the source rocks of the small riverside group are mainly dark shale,its distribution in the plane has a considerable size distribution,the range of the floor area ratio is 64.72%-81.77%.The experiment shows that the organic geochemistry,organic carbon content in the study area were generally reached the lower edge of the Xiaojiang source rocks,source rocks of middle part to reach the standard,the majority reached the standards of good hydrocarbon source rock.The type of organic matter is mainly gas type,the second is oil generation type.The study on the thermal evolution of source rocks shows that the maturity of the source rocks in the study area is mainly in the late stage of high maturity and partly in the over mature stage.The study area of Xiaojiangbian formation hydrocarbon generating depression mainly in southwestern Pingxiang,Yichun,Wanzai deep-water outershelf sedimentary area,the abundance of organic matter and organic matter maturity are ideal,is a good source rock area.In addition,Pingle depression in Middle Permian of Triassic Xiaojiangbian of unconventional oil and gas,especially shale gas resource potential is huge,the favorable areas are mainly concentrated in the Qingjiang basin,Jinjiang basin and southern Poyang depression,this area is also an important area of oil-gas.