Lithofacies and Characteristics of Micro-pore Structure of Permian Shale in Hongxing Area,Sichuan Basin
The Hongxing area of Sichuan Basin is a significant replacement area for the exploration of shale gas in the Permian Formation.Currently,the overall exploration level is low,and the lithofacies types of shale are unclear,and the characteristics of the micropore structure of the reservoir are unknown.Techniques such as thin sections,scanning electron microscopy,X-ray diffraction,total organic carbon analysis,and low-temperature nitrogen adsorption experiments were used to clarify the lithofacies types and micropore structure characteristics of the fourth member of Maokou Formation-Wujiaping formation shale and to explore the main controlling factors of high-quality reservoirs.The results show these as follows.There are five types of lithofacies of the fourth member of Maokou Formation-Wujiaping formation of the Permian shale in Hongxing area,including high carbon-high siliceous shale,high carbon-low siliceous shale,low carbon-high siliceous shale,high clay shale,and carbonate-mixed shale.The high carbon-high siliceous shale lithofacies are mainly characterized by micropores and small pores,high carbon-low siliceous shale lithofacies are mainly characterized by micropores,low carbon-high siliceous shale lithofacies are mainly characterized by small to medium pores,the high clay shale lithofacies are mainly characterized by medium to large pores,and the carbonate-mixed shale lithofacies are mainly characterized by large pores.The lithofacies of High carbon-high siliceous shale have the highest porosity,pore volume,and specific surface area,followed by the high carbon-low siliceous shale,high clay shale,and low carbon-high siliceous shale,while carbonate-mixed shale have the smallest values.The volume of micropores is proportional to the organic matter content,the volume of small pores is positively correlated with the content of siliceous,the volume of medium pores is controlled by the content of clay,and large pores are not well developed.Based on the development proportion of lithofacies and reservoir characteristics,the lithofacies of high carbon-high siliceous shale and High carbon-low siliceous shale are the most favorable lithofacies types,followed by the High clay shale and Low carbon-high siliceous shale,while the lithofacies of Carbonate-mixed shale are relatively the least favorable.
lithofaciesshalereservoir characteristicsthe fourth member of Maokou FormationWujiaping FormationHongxing areaSichuan Basin
万方数据
维普
