Study On Sedimentary And Reservoir Characteristics Of Chang2Formation In Dongxigou Area Of Qingpingchuan

The Chang2reservoir of theYanchang Formation is rich in oil resources in Dongxigouarea of Qingpingchuan, but the whole exploration maturity and research levels of the reservoiris still in a low level.This paper take full advantage of well logging, mud logging, core,Laboratory analysis and other basic information, and more than300Wells in the study areasmall layer of fine division and correlation, identification of sedimentary microfacies types,analysis of sedimentary microfacies and sand body distribution rule.Research shows that:Chang2reservoir formation thickness change is not big, can besubdivided into Chang21,Chang22and Chang23. Because most of the drilled wells did notreach the bottom of Chang23, so the study of this paper only focuses on Chang21, Chang22,and it is further divided into Chang211,Chang212,Chang213,Chang221, Chang222andChang223.And use the core of the thin section identification, physical property analysis,high-pressure mercury injection and scanning electron microscopy analysis assay data,research on the characteristics of the reservoir,to establish a reservoir classification evaluationstandard,for the study on reservoir classification evaluation of small layer.Chang2reservoirbelongs to the delta sedimentary system, which are mainly developed delta plain subfaciesdistributary channel, natural levee and interdistributary bay microfacies, and delta plaindistributary channel microfacies subject on controlling the range of high quality reservoirdevelopment. Reservoir sandsandstonesare mainly feldspathic sandstone,Development ofintergranular pore, dissolved pores is relatively small,mainly feldspar dissolved pore,chang2reservoir has the characteristics of low porosity and permeability,heterogeneity stronger;Reservoir physical property is dominated by both sedimentary and diagenesis, and the targetformation of researched area has bad physical property;Based primarily on sandstone reservoirporosity, permeability, reservoir thickness,oil saturation of four parameters,the Chang2reservoir is divided into three categories in the study area.Statistics show that each small layerof chang2reservoir class II and class III reservoir proportion bigger, I kind of reservoir in211,221and223small long long long layer, among them, the long221relative to other five smalllayer, I kind of reservoir. I kind of reservoir are restricted to211,221and223small long longlong layer, among them, the long221relative to other small layers, I kind of reservoir.