Characteristics And Main Controlling Factors Of Permian Oil And Gas Accumulation In Western Jimusar Sag

This paper addresses the problems of unclear reservoir distribution characteristics and fault characteristics of the Permian Wutonggou Formation and Jingjingzigou Formation in the western Jimusar Sag,Xinjiang,and unclear oil and gas accumulation laws and main control factors for enrichment.Through field,core,seismic,logging,and comprehensive research methods,the distribution of reservoirs in the target layer is clarified,a fault transport control model is established,the main controlling factors of oil and gas enrichment are found,and favorable oil and gas enrichment areas are predicted.The main oil layers in the Permian include the bottom of the Wutonggou Formation(layer 1),the middle of the first member of the Wutonggou Formation(layer 2),and the middle of the Jingjingzigou Formation(layer3).The reservoirs of Jingjingzigou Formation are characterized by fine sandstone,siltstone and migmatite,with relatively fine grain size,mainly from the braided rocks from the southeast to the north into the lake.river delta.The favorable reservoir distribution area of No.1 and No.2 reservoirs is in the northeast,and the thickness of the reservoir can reach 30 meters.The favorable reservoir area of No.3 reservoir is in the southeast,and the thickness of the reservoir is 40 meters.The target layer in the study area generally develops a left-handed strike-slip fault system with F1 as the main fault,and is vertically composed of a left-handed strike-slip fault system of Carboniferous extension-strike-slip inversion and end-Permian-Triassic-Jurassic.The two strike-slip fault systems,broom and oblique,control the tectonic pattern of east-west zoning,north-south zoning,and upper and lower layers in the study area.Strike-slip faults have three zones from the inside to the outside: fault core(fault cavity or mylonite-fault mud zone),slip fracture zone and induced fracture zone.Active disks are generally better than passive disks.The strike-slip fault transport and seal control model of "active disk transport and migration,passive disk block and accumulation" is constructed,and two types of strike-slip faults in active and stationary periods are summarized to control accumulation,specifically controlling fault blocks,lithology,The Jimsar oil and gas accumulation and distribution patterns of the formation and distribution of five types of oil and gas reservoirs in fault bodies,stratigraphic and volcanic rocks.The oil and gas accumulation and enrichment law of "strike-slip faults control the formation and distribution of oil and gas reservoirs,and the physical properties of the reservoirs control the enrichment and high production of oil and gas" is proposed.The lower bound of high production predicts favorable hydrocarbon enrichment areas and exploration targets.