川东南包鸾地区五峰组-龙马溪组页岩岩相特征

Lithofacies of Shale of the Wufeng Formation-Longmaxi Formation in the Baoluan Region,Southeast Sichuan

基于岩心、薄片以及分析测试数据,本文对川东南包鸾地区五峰组-龙马溪组页岩岩相进行了研究。宏观上,研究区五峰组-龙马溪组发育5种宏观岩相——凝灰质页岩相、角砾页岩相、块状页岩相、纹层状页岩相、云质灰岩相。定量研究发现:川东南包鸾地区五峰组-龙马溪组发育6大类岩相(硅岩相、硅质页岩相、混合页岩相、粘土质页岩相、粘土岩相以及灰质页岩相),11种小类岩相,其中研究区主要以富粘土硅质页岩相、混合硅质页岩相、粘土质/硅质页岩相以及富硅粘土质页岩相这四类岩相为主;通过TOC、含气量、孔隙度以及渗透率4个参数对不同页岩岩相进行研究发现:硅岩相是研究区页岩气勘探的最有利岩相,其次为硅质页岩类的含粘土硅质页岩相和混合硅质页岩相;粘土质/硅质页岩相和混合页岩相中等,最差的岩相为粘土质页岩相和粘土岩相。

This paper has a discussion on lithofacies of shale of the Wufeng Formation-Longmaxi Formation in the Baoluan region,southeast Sichuan based on drill core,rock thin section observation and test data.Macroscopically,shale of the Wufeng Formation-Longmaxi Formation in the Baoluan region may be divided into 5 lithofacies such as tuffaceous shale facies,breccia shale facies,massive shale facies,laminated shale facies and dolomitic limestone facies.Quantitative study indicates that shale of the Wufeng Formation-Longmaxi Formation in the Baoluan region may be divided into 6 lithofacies such as silica-dominated shale facies,siliceous shale facies,mixed shale facies,argillaceous shale facies,clay-dominated shale facies and lime shale facies among which clay-rich siliceous shale facies,mixed siliceous shale facies,argillaceous/siliceous shale facies and silica-rich argillaceous shale facies dominate.All lithofacies are evaluated by TOC content,total gas content,porosity and permeability.The results show that silica-dominated shale is the most potential shale for shale gas exploration,followed by siliceous shale(clay-rich siliceous shale and mixed siliceous shale),secondly the argillaceous/siliceous shale and mixed shale,the argillaceous shale and clay-dominated shale.