The Reservoir Characteristics Of The Wufeng-Longmaxi Formation Shale Of Shizhu Area In The Eastern Sichuan Basin

Sichuan Basin is the main sedimentary area of marine Paleozoic shale in southern China.A series of organic shale has been deposited in the Sichuan Basin.The Wufeng-Longmaxi Formation shale is the focus of shale gas exploration and development.In this paper,shale of Wufeng-Longmaxi formation in Shizhu area is selected as the object of study.By means of microscopic observation,scanning electron microscopy,energy spectrum analysis,X-ray diffraction,particle size analysis and geochemical methods,the characteristics of shale reservoirs in the study area are studied,and the following main results are obtained:1.The Wufeng-Longmaxi formation in Shizhu area consists of ten litho-logic sections,the silty shale,silty mudstone and black mudstone thickness.There are more silty components at the bottom of the profile.2.The mineral compositions of the Wufeng-Longmaxi Formation shale in Shizhu area are quartz,albite,calcite,dolomite,illite and chlorite.The content of brittle minerals such as quartz is higher,and clay minerals and carbonate minerals are less.The mineral composition histogram of Shizhu section is well established.3.The content of organic matter is higher of the Wufeng-Longmaxi Formation shale in Shizhu area.The contents of organic matter in the bottom of the Wufeng-Longmaxi Formation shale were obviously higher,and gradually decreased and tended to be stable.4.There are many causes of quartz of the Wufeng-Longmaxi Formation shale in Shizhu area,and siliceous biogenic origin is the main reason.There is a correlation between the content of quartz and the content of TOC,total gas content.The high quartz content affects the fragility of the shale and is favorable for the fracturing of shale.Siliceous biogenic quartz is very important for the increase of TOC and gas bearing property,and it also increases the heterogeneity of shale reservoirs.