Shanxi Shale Sedimentary Facies And Reservoirs Characteristics Of The Ordos Basin Region Suiteh

According to the geological characteristics of continental and transitional faciesshale,which had poor distribution continuity,small thickness of single layer,low brittleness of rock and unclear cognition of gas-bearing properties.Based on investigating the status of research on shale gas accumulation conditions and evaluation parameters,this paper selected the shale of Shanxi formation in the Suide area as the target of study,field outcrop,laboratory microscopic observation sampling and testing were carried out.Under the constraint of sedimentary and tectonic background,studying the sedimentary micro-facies of the shale of Shanxi formation systematically,clarifying the horizontal distribution and vertical evolution law of sedimentary micro-facies in Suide area of Ordos basin,establishing the sedimentary model of this area.This paper discusses the geo-chemical features of organic matter type,abundance,maturity,and the reservoir characteristics of reservoir space type,size,structure,gas-bearing properties through the goe-chemical and reservoir test of samples in 261 work area.Shan 1 member of Shanxi formation of the study area are the meandering fluvial facies,and river bed lag deposits,point bar,crevasse splay,natural levee,rich graft swamp,poor graft swamp,peat flat and interfluvial lowlands sedimentary facies can be founded.Shan 2 belong to delta plain deposits,and distributary channel,crevasse splay,natural levee,rich graft swamp,poor graft swamp,interfluvial lowlands and peat flat sedimentary facies can be founded.Rich graft swamp enriching with the highest TOC in the Shan 2 member is the best sedimentary facies for shale,the secondly for poor graft swamp,which is developed in Shan1 and Shan 2 member,but distributary channels are the poorest position.The shale organic matters of Shan formation are dominated by kerogens of type-?₂and?.The maturity is relatively high.The average TOC content of 4%;high degree of organic evolution,Ro mean 1.54%,are mature-mature stage too,favor organic pyrolysis angry.Reservoir clay mineral content between 29%⁹6%,the average content of 50.7%.Class brittle quartz mineral content is relatively low content of 2%⁷0%of secondary importance.Shale porosity of from 1%³%,an average of 1.7%;permeability of 0.01⁰.05mD,average 0.04 mD;.Intergranular pore and intragranular pore are the main pore types.Micropores are relatively developed,while organic pores are not common.The pore size is between 5¹00nm,with an average of 50nm.The main reservoir pore microporous pore throat combination relationship micro pore throat combinations.In view of the work area of Shanxi set of high TOC content and low mineral content brittle,apertures development and other specific circumstances,should now be the main selection shale organic matter abundance,type,maturity and other parameters studied,found among the factors for the exploration and development of the work area good relationship matching,the system determines the evaluation criteria in the area.Through in-depth study of the work area,clear Suiteh Late Paleozoic shale gas reservoir distribution and characteristics of the Ordos Basin,geological favorable area for shale gas exploration and development in the Ordos Basin,providing scientific and effective basis.