Study On The Relationship Between Tectonic Features And Shale Gas Enrichment In Northeastern Yunnan

The thesis is based on mineralogical petrology,the relevant disciplines,such as petroleum geology and tectonic geology,are the theoretical basis,combined with the observation of indoor experiments and field profiles,to analyze the regional geologic background and regional tectonic evolution history,and to study the influence of tectonic features on the enrichment and preservation conditions of shale gas through the tectonic style,fracture characteristics and fracture characteristics of the northeastern Finally,according to the structural preservation condition of shale gas,the favorable block is forecasted to provide geological basis for shale gas exploration in northeastern Chongqing.The northeast region of chongqing is located in the leading edge of the anti-thrust belt of daba mountain,which straddles the qinling strata area and the yangzi formation area.In the study area,the formation of the devonian system and the fourth system are absent.The Chengba fault divides the northeastern Chongqing into two primary tectonic units of the North Dabashan thrust nappe tectonic belt and the southern Dabashan foreland fold thrust belt.The fault zone along the Pingba fault and Jimingsi fault is divided into three secondary tectonic units of the fault zone,fault-fold belt and slip-off fold belt.The tectonic zone of the North Dabashan is a double anticline,and the significant development of the fault shows that the area undergoes a strong thrust.The tectonic pattern of the Dabashan fault zone is the "thrust fold combination",which forms the three types of tectonic assemblage of the thrust fault system,the thrust fold system and the slippage fold system.The fractures in the study area are obviously developed,with small cracks and medium scale fractures,and large scale fractures are poorly developed.The types of cracks include structural joints and diagenetic slivers,mainly in the form of structural joints.Crack filling a high degree of filling mainly for calcite and a small amount of quartz and pyrite.The rich organic matter page strata thickness in northeast Chongqing,buried depth in 250m-4000m,the source rock thermal maturity is in high maturity-over maturity,the region cap is better,and the shale gas preservation and enrichment is beneficial to the northeast of Chongqing.According to the analysis of the tectonic characteristics of the northeastern Chongqing,the lower reaches of the Lower Cambrian Shuijingtuo Formation,Lujiaping Formation and the Upper Ordovician Wufeng Formation-the Lower Silurian Longmaxi Formation are the main exploration target layers.The optimal distribution of the shale gas resources in the lower Cambrian shale is the surrounding area of Wuxi and the northwest of Kaixian county.The upper ordovician shale gas resources distribution favorable area is the southwest direction of Wuxi county,and is located in the area of the red rock to the oblique nucleus and the Manyuexiang in kaixian county.