The Study On Fine Geological Characteristics And Reservoir Evaluation Of Chang8Reservoir Of Yanchang Formation In Fu-xian Exploration District, Ordos Basin

Chang8reservoir of Yanchang Formation in Fu-xian exploration distirct, Ordos basin istypical low-porosity and low-permeability reservoir. At present，with the breakthrough of oilexploration of Chang8reservoir and the continuous accumulation of recognition and data ofrolling construction, the problems of petroleum geological knowledge and development of thestudy area become increasingly prominent. And the overall development effect andconstruction of the oilifeld is always haunted by these problems. Therefore, the ilnc geologicalcharacteirstics and reservoir classification evaluation of the study area should be intimatelyresearch, and its exploration potential should be made clear. It provides reference for thedev elopment pattern and technical research of the study area.The research objcct of this paper is Chang8reservoir of Yanchang Formation in Fu-xian explorationdistrict，Ordos basin. Based on the geological data，core data^logging data and the production dynamic dataof the study area, the reseacrh of stratigraphic fine classiifcation and correlation, sand top micro-structuralfeatures and sand thickness distribution characteirstics, sedimentary micro-facies, reservoir heterogeneity,four characters relationship and sccond well log interpretation, reservoir parameters distributioncharacteirstics and reservoir classification evaluation of its target layer is carrien out.The study has shown that charig8reservoir can be divided into two layers: chang8] and chang8>;thcall structures are simple, showing high in notrheast and low in Southwest, and develop small nose upliftwith a certain inheritance. The sand bodies in chang Si and chang82develop well in the research area. In thestudy area, there is shallow-water delta front deposits, including underwater distributaries channel, leveeand bay sedimentary microface.The river presents northeast to southwest direction and disappears whenaway from ihe source area. The chang81reservoir show strong helerogeneity and chang8> medium；theporosity is between10%and14%and permeability is distributed in (0.8?1.2) X10w2m。Electric features can be used to analysis and show liiho logy property, physical property and oil bearingproperty in research area. The reservoir physical property has a good correlation with the sand bodythickness, deposition micro phase and heterogeneity. The reservoir can be divided into four categories, fromwhich I and II category are deposited in underwater distributaries channcl(good in physical property). Ill and IV category are deposited in underwater distributaries channel and levee (poor relatively inphysical property). Chang81and chang82reservoir are mainly I category,about50%of the all area.This study can greatly promote oil and gas exploration and development in the study area and is of greattheoretical and practical significance.