四川盆地石柱地区自流井组页岩气成藏条件与勘探前景

为研究四川盆地石柱地区自流井组页岩气的成藏条件，开展了野外地质露头调查、岩心观察、有机地球化学分析、X射线衍射测试、物性分析和扫描电镜观察等工作。结果表明：①石柱地区自流井组东岳庙段形成于半深湖相，岩性以泥页岩为主，厚度为30～95 m。②目的层泥页岩具有“有机质丰度高、热演化程度适中”等特征，TOC质量分数多为0.49%～2.02%，R_o平均为1.27%，脆性矿物质量分数平均为58.8%。③岩石中吸附气含量较高，质量体积平均为2.78 m³/t，且埋深适中，具有良好的勘探前景。④采用叠合法预测出石柱地区桥头坝—建南—上水坝一带为页岩气勘探的有利区，通过计算可以获得研究区页岩气地质资源量约为3 905亿m³。该研究成果可为四川盆地石柱地区自流井组页岩气勘探提供借鉴。

Accumulation conditions and exploration potential of shale gas of Ziliujing Formation in Shizhu area,Sichuan Basin

In order to study the shale gas accumulation conditions of Ziliujing Formation in Shizhu area of Sichuan Basin,field geological outcrop survey,core observation,organic geochemical analysis,X-ray diffraction test, physical property analysis and scanning electron microscopy observation were carried out. The results show that:(1)The Dongyuemiao member of Ziliujing Formation in Shizhu area was formed in semi-deep lake facies,and the lithology was dominated by shale with a thickness of 30-95 m.(2)The mudstone of the target zone was characterized by high abundance of organic matter and moderate thermal evolution. The TOC mass fraction is 0.49%-2.02%,the R_o average is 1.27%,and the brittle mineral average is 58.8%.(3)The content of adsorbed gas in rocks is high,the average mass volume is 2.78 m³/t,and the burial depth is moderate,so it has good exploration prospects.(4)The Qiaotouba-Jiannan-Shangshuiba area in Shizhu area was predicted to be a favorable area for shale gas exploration by superimposition method,and the geological resource of shale gas was estimated to be about 390.5 billion m³. The research results can provide reference for shale gas exploration of Ziliujing Formation in Shizhu area,Sichuan Basin.