The continental shale of member 7 of Yanchang Formation in Ordos Basin is rich in oil and gas resources and has great potential for exploration and development.Through core observation,well logging and logging data analysis,geochemical data,X-ray diffraction analysis and on-site analytical gas and other specific test data,in-depth analysis of the shale oil and gas source-reservoir characteristics of the three sub-member of Chang 7 member,and establish the source-reservoir division standard,compare and analyze the relationship between different source-reservoir combination characteristics and oil and gas enrichment rules.The results show that:(1)The organic matter types of Chang 7 member of Yanchang Formation of Triassic in Yan'an area of Ordos Basin are mainly type Ⅱ,and type Ⅱ2,followed by type Ⅰ;the average organic carbon content(TOC)of the three substrata are 3.39％,4.35％and 5.57％,respectively.And value of vitrinite reflectance(Ro)are 0.69％,0.97％and 1.31％.Chang 71、Chang 72 and Chang 73 sub-members are poorly developed,medium source rocks and high quality source rocks,respectively.(2)The shale mineral composition of Chang 73 sub-member of Yanchang Formation in the study area is rich in clay,and the clay mineral content of Chang 72 sub-member is better than that of Chang 71 sub-member.The pore space types of Chang 71,Chang 72 and Chang 73 sub-members are dissolution pore,intergranular pore-solution pore and intergranular pore fracture,respectively,and the developed reservoir characteristics are type Ⅲ(poor),type Ⅱ(medium)and type Ⅰ(excellent),respectively.(3)Six kinds of source reservoir characteristics are mainly developed in the study area,such as high quality hydrocarbon source rock high quality reservoir,medium hydrocarbon source rock medium reservoir,poor source rock medium reservoir,high quality source rock medium reservoir,poor source rock poor reservoir and so on.The enrichment degree of high quality source rock is the highest,which is mainly distributed in Chang 73 sub-member.The second is medium source rock high-quality reservoir,medium source rock medium reservoir,high-quality source rock medium reservoir,mainly developed in Chang 72 sub-member,Chang 71sub-member with poor distribution and other poor source rock reservoirs,which is not conducive to shale oil and gas accumu-lation.(4)Shale with high organic matter abundance and high organic matter maturity has better hydrocarbon generation potential.High clay mineral content and good pore connectivity are conducive to oil and gas migration and accumulation.Source and reservoir characteristics control the enrichment position of shale oil and gas in this area.
维普
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