Evaluation of the preservation conditions of marine shale gas in Wufeng-Longmaxi formations in eastern Sichuan Basin and peripheral areas
Preservation conditions are the key factors affecting the enrichment and high yield of marine shale gas in southern China.Taking the marine shales of the Lower Paleozoic Ordovician Wufeng Formation-Silurian Longmaxi Formation in eastern Sichuan Basin and its periphery as the research object,this paper discusses the influence on the preservation of shale gas from three aspects:tectonic,capping conditions and fluid characteristics,and establishes an index system for evaluating the preservation of marine shale gas in eastern Sichuan Basin and its periphery in combination with the practice of exploration and development.The study concluded that tectonic movement is the root cause of shale gas destruction and dispersion,which is mainly reflected in the intensity of tectonic deformation,the scale of faults and the degree of fracture development,and the degree of uplift and denudation of strata;the capping conditions are the basic guarantee for the enrichment of shale gas reservoirs,and the conditions of top and bottom plates with large thickness,stable spreading,and dense petrography,as well as the closure of thick shale rocks,are the macroscopic geological conditions conducive to the preservation of shale gas.The pressure coefficient has a logarithmic positive correlation with the gas content of shale gas,which is an important index for shale gas preservation evaluation.
万方数据
维普
