黔西地区上二叠统龙潭组页岩气成藏条件研究

Study on shale gas accumulation conditions for Longtan formation of Upper Permia in western Guizhou

为理清贵州省富有机质页岩的成藏规律及成藏模式,以黔西地区上二叠统龙潭组页岩为研究对象,结合研究区10口参数井,分析了龙潭组页岩气源岩、有机地球化学、岩石学及矿物学、含气性及保存条件等成藏条件。研究结果表明:龙潭组地层泥页岩沉积厚度>30 m的区域主要位于晴隆-普安一带;有机质页岩有机质类型以Ⅲ型为主;TOC高值区位于水城-普安、兴仁及威宁地区;有机质成熟度高值区主要分布在普安-贞丰一带;储层整体上为特低孔、特低渗储层;有机质页岩孔隙类型以溶蚀孔、晶内孔、粒间孔为主;泥页岩总含量介于0.82 m^3/t^2.46 m^3/t,平均为1.38 m^3/t,整体含气量较高。有利区主要位于普安-晴隆一带。

Combining with the parameter wells already constructed in the study area, taking the Longtan formation shale of Upper Permian in western Guizhou as the research object,this paper analyses the gas source rocks,organic geochemistry, petrology and mineralogy,gas-bearing and preservation conditions of the Longtan formation shale. The results show that the area with mudstone sedimentary thickness greater than 30 m in Longtan formation is mainly located in Qinglong-Puan area. The organic matter type of organic shale is mainly type III.The TOC high value area is located in Shuicheng-Puan, Xingren and Weining areas.The high value area of organic matter maturity is mainly located in Puan-Zhenfeng area.The shale reservoir of Longtan formation is a very low porosity and permeability reservoir as a whole.The main pore types of organic shale are dissolution pore, intragranular pore and intergranular pore.Organic shale clay has higher mineral content, lower brittle mineral content and general fracture potential. The total content of shale in Longtan formation of Upper Permian in western Guizhou is between 0.82 m3/t^2.46 m3/t, with an average of 1.38 m3/t, and the overall gas content is high. The favorable areas delineated according to organic carbon,maturity and shale thickness are mainly located in Puan-Qinglong area.