Accumulation characteristics and exploration development revelation on shale gas in Jiusi Formation of Carboniferous in Qianxi

In order to comprehensively evaluate the development potential of the shale gas in the major shale strata in Guizhou Province and to discover the key control factors and enrichment law of the shale gas enrichment accumulation,based on the shale in Jiusi Formation of Weining-Shuicheng Lower Carboniferous as the study object,with the information of two survey wells and two discovered wells within the regional analysis,the enrichment accumulation mode of the shale gas was analyzed and provided in combination of the regional geology and from the structure features. The study results showed that the shale in Jiusi Formation of Qianxi Lower Carboniferous had an average thickness of 400 m,a gas content of 1.5～3.0 m3/t,an organic matter maturity of 2.67 % in average,a brittle mineral content over 60 % and at least three sections of the shale with development potentials vertically deposited. The exploration and development idea of the shale gas was changed from the traditional basin enrichment to the second fractured controlled sunken accumulation and from the negative structure to positive structure. The combined accumulation mode of the “sunken-heave-fracture-slope” shale gas was a favorable unit of the optimization in dessert area of shale gas. "A reverse fault- anticline combined accumulation mode" would have the guide significance to the exploration and development of the shale gas in South China complicated structure area.