Sandstone Reservoirs Evaluation Of Taiyuan Formation In Qinshui Basin

The study object of this paper is the sandstone reservoir of Taiyuan Formation in Qinshui basin.Consulting the previous research,based on the isopach map of sandstone thickness,sand ratio distribution and carbonate rocks ratio distribution,Qinshui Basin is divided into three sedimentary systems,the northern part of the delta sedimentary system,lagoon depositional system in the center and carbonate platform-lagoon depositional system in the south.Sandstones of Taiyuan Formation is mianly medium-fine graped feldspar lithic sandstone,have extremely low porosity and permeability,and grains are point-linear contact,have better sorting,and psephicity is mainly subangular and sub-rounded,cementation type is pore cementation.The main pore type is dissolution pore,the mainly type of diagenesis are compaction,pressolution,cementation and metasomatism,diagenesis stage mainly in the stage B,a few in the middle diagenetic stage A and late diagenetic stage.This paper choose the grey correlation method to evaluate the reserviors,select the parameters which have great influence on the reservoir,then make a comprehensive quantitative evaluation.According to the industry standard SYT?5717-1995,the reservoirs are divided into three categories,and the better reservoirs have a sedimentary environment of barrier sand dam deposition,mainly located in the south of the basin;the middle level reservoir is the corresponding barrier sand dam edge and tidal sand dam sedimentary environment,located mainly in the southern and central basin;poor level reservoir sedimentary facies as the lagoon,mainly located in the central basin.