The Study On Sedimentary Microfacies And Reservoirs Characteristics Of The1^st And2^nd Member Of Shehejie Formation Of Gaoyang Oilfield In Lixian Slope

Nowadays, the exploration direction of Gaoyang oilfield has turned from structurereservoirs to lithologic reservoirs. The study of micro-facies and reservoir characteristics ofthe oilfield, especially done to single sand bodies, is the prerequisite, which can enhance theunderstanding of the origin and superimposed relationship of sand bodies, and it is alsovaluable for micro-facies distribution definition on basis of recovering lithofaciespaleogeography.On basis of core, thin section observation, logging, laboratory testing and productiondata, under the direction of three-phase unifying, this paper did micro-facies judgments andmicro-facies analysis on unit of fine single sand body, establishing facies models. And on thisbasis, the paper analyzed the reservoir characteristics and did comprehensive assessmentfocusing on Sha1and Sha2formation.According to the micro-facies study of Sha1and Sha2formation in Gaoyang oilfield, wesummed up and improved the micro-facies identification scale of terrigenous clastic rock andcarbonate rock in research area, which has also been applied to carbonate calibration. Theputting forward of carbonate calibration and solving, can direct other researches in the BohaiBay which possess similar problems of carbonate rock lithology combination. The resultshows that in the study area, delta plain sediments developed, in Sha2formation and theupper Sha1formation. In lower Sha1formation, sediments accumulated, formingshore-shallow lacustrine beach bars, which include sandy bars and carbonate bars. Thecarbonate bars developed into grain beaches on high position underwater, and formed intodolomitic limestone lake-bays in lower places. After depicting the transverse and longitudinaldistribution of sedimentary microfacies on the basis of single sand body, we find that in the same channel or beach bar, the superimposing ways of the sand bodys can be divided intomulti-layer type and multilateral type, presenting a panto-communicated way. And thesuperimposing way of sand bodies in different channels and beach bars is the independenttype, becoming different oil-water unit. This explained the problems of oil and water in thepractical oil and gas development through sedimentary aspect.After the analysis of thin sections and physical data, it can be concluded that thereservoir space in research area is mainly secondary pores, which are primarily dissolutionpores between particles and pores inside. The physical property of reservoirs is absolutelycontrolled by sedimentation and diagenesis, and reservoirs in the Sha1formation have a betterreservoir physical property. The reservoirs would be divided into four types, of which type Ireservoirs distribute in the body of shore-shallow lacustrine bars and central underwaterdistributary channels. Type II distribute in underwater distributary channels, centraldistributary channels and lateral margin of sand bars, type III and type IV distribute in edge ofdistributary channels, margin area of sand bars and sand beaches.