四川省乌蒙山片区白果湾组页岩气地质条件研究

Study on Geological Conditions of Shale Gas of Baiguowan Formation in Wumengshan Area,Sichuan Province

乌蒙山片区是全国新一轮扶贫攻坚的六大片区之一,以四川凉山州东部为主,包含13个县市。在区域地质调查的基础上,分析白果湾组页岩气勘探潜力,认为白果湾组在西昌盆地内广泛发育,厚度500~1000 m,形成于湖泊及三角洲沉积环境,其中分流间洼地、水下分流间湾和半深湖都是有机质泥页岩形成的有利场所;三叠世末,研究区属被动大陆边缘,拉伸环境有利于泥页岩富集。有机质镜质体反射率在2~3;大部分地区生烃强度大于20亿m^(3)/km^(2),为高生烃强度区;邛海—喜德一线以西地区,构造变形极弱,具有较好的封闭性,具备良好的构造保存条件。

Wumengshan area is one of the six areas in the new round of poverty alleviation in China.It is mainly in the east of Liangshan prefecture in Sichuan province,including 13 counties and cities.Based on the regional geological survey,analyzes the shale gas exploration potential of Baiguowan formation.It is considered that Baiguowan formation is widely developed in Xichang basin,with a thickness of 500 to 1000 m.It is formed in lake and delta sedimentary environment.Among them,inter distributary depression,underwater inter distributary bay and semi deep lake are favorable places for the formation of organic shale.At the end of triassic,the study area belongs to passive continental margin,and the tensile environment is conducive to the enrichment of shale.The thermal evolution degree of organic matter and vitrinite reflectance are between 2 and 3;the intensity of hydrocarbon generation in most areas is greater than 2×10^(9)m^(3)/km^(2),which is an area with high hydrocarbon generation intensity;in the west of Qionghai Xide line,the tectonic deformation is very weak and has good sealing,and structural preservation conditions.