Distribution Of Paleozoic Shale And Geological Conditions Of Shale Gas Accumulation In Southern Enshi?Hubei Province

The research area is located in the south of Enshi state,Hubei Province.The tectonic position belongs to the western Hunan-Hubei thrust fold belt in the middle Yangtze block,which is adjacent to the Sichuan basin in the west,the Qinling-Dabie mountain orogenic belt in the north,and the south-Xuefeng slip-nappe uplift belt in the east,belonging to the middle and upper part of the Yangtze quasi-platform.Through field geological survey and structural section analysis and combined with regional tectonic background data,the results show that complex sedimentary construction are developed in the research area,which can be divided into four tectonic units: from south to west,it can be divided into Sangzhi and Shimen reverse slope fold belts.,Central anticlinorium fold belt,Yidu-Hefeng anticlinorium fold belt,Huaguoping reverse slope fold belt.Tectonical deformation has obvious control effect on the migration of useful components of palaeozoic shale in this area and provides good conditions for shale gas accumulation.The predecessors' work in the area mainly focused on the exploration and exploitation of polymetallic mineral resources,while the degree of geological research on shale gas in the research area was insufficient and the cognition was limited.Therefore,this paper take“ the distribution of shale strata in the paleozoic community and the geological conditions analysis of shale gas accumulation ”for the title,and relies on the project of "exploration of shale gas resources in the southern region of enshi,Hubei province".Based on the field survey and the collection of previous data,this paper analyzes the conditions of shale formation and shale gas accumulation in Enshi state.In the Paleozoic period,the shallow marine sedimentary environment dominated the research area,forming multi-layer black shales.Paleozoic rich organic shale mainly includes the Cambrian niutitang Formation,the Ordovic-Silurian Wufeng-Longmaxi Formation,and the Permian Dalong Formation.The space distribution of the three stratums is large and the thickness is relatively stable.However,the influence of the late tectonic stress had a strong deformation,therefore it resulted the burial depth of the core area of the anticline was smaller and even the surface of the exposed surface was eroded.The organicgeochemical analysis shows that the total organic carbon content in the rich organic shale is high,and the organic matter evolution reaches a mature-over-mature stage and has hydrocarbon potential.At the same time,the content of debris particles in the rich organic shale is also relatively high,and the types of porosity are abundant,which has the conditions for shale gas storage and fracturing development.This paper studies the geological conditions of shale gas accumulationin the research area by analyzing the distribution characteristics,structure characteristics,structure preservation conditions and geochemical characteristics of shale shale in the paleozoic area of Southern Enshi state,.It is necessary to make clear that its shale gas resources have great potential and further research is needed.In addition,the preservation conditions and reservoir space types of shale gas resources are analyzed and compared.To sum up,The research of Paleozoic shale distribution and reservoir forming conditions in the south of Enshi state has theoretical guidance to make up for the gaps in shale gas exploration right and for the subsequent shale gas-related geological work in this area.