Oil And Gas Distribution Law Of Chang 6 Extra-Ultra-Low Permeability Reservoirs In Zoumaliang District

This article is based on the development results of oilfields in the block,uses well logging,experimental testing and production performance data to conduct fine geological research through large area,large scale and dense well pattern to analyze the oil and gas distribution law of Chang 6 ultra-low permeability reservoir in Zoumaliang District.According to the characteristics of regional and auxiliary marker layers,sedimentary cycles and lithologic combinations,the destination layers are finely compared and divided,and clarified the top structural characteristics of each sublayer in Chang 6.analyzed the distribution characteristics of sedimentary microfacies in each sublayer of Chang 6,comprehensively analyzed reservoir characteristics and their heterogeneity.calculated the oil saturation and effective thickness of each layer and clarified the distribution characte ristics of oil and gas in space,Finally combined with the top structure,sedimentary microfacies,reservoir physical properties,reservoir heterogeneity and reservoir-cap assemblage characteristics,Comprehensively analyze the distribution of oil and gas in the reservoir.The research results shows: the sedimentary thickness of the Chang 6 sublayers in the Zoumaliang area is relatively stable,and there is no stratigraphic discontinuity,the overall stratum shows a distribution trend of low in the west and high in the east,showing the development of low-amplitude structures.Chang 6 period develops delta front subfacies deposition,with poor reservoir physical properties and strong heterogeneity,which are low porosity and ultra-low permeability reservoirs.The study area has a large distribution area of oil and gas,and the enrichment of oil and gas is controlled by many factors,the areas with high oil saturation are mainly developed in the main parts of river channels and estuary bars;the nose-shaped low amplitude structural area has a good correspondence with the oil saturation high value area,and the structural high position is conducive to the migration and accumulation of oil and gas;reservoir heterogeneity has a strong control effect on the effective thickness of the oil layer,and the effective thickness of the oil layer is relatively larger in areas with weak heterogeneity;areas with better reservoir physical properties have higher oil saturation.The structure and sedimentary facies distribution are the main controlling factors for oil and gas accumulation.Reservoir heterogeneity is the main controlling factor for the effective thickness distribution of the oil layer.In general,oil and gas are enriched and accumulated due to the advantages of various factors such as structure,sedimentation and reservoir characteristics.