渝南-黔北五峰组-龙马溪组页岩气地质特征

Geological Characteristics of Wufeng-Longmaxi Formations in Southern Chongqing-Northern Guizhou Area

康建威 余谦 闫剑飞 孙媛媛 戚明辉

KANGJianwei YUQian YANJianfei SUNYuanyuan QIMinghui

成都地质调查中心, 四川 成都 610081 成都理工大学沉积地质研究院, 四川 成都, 610059 页岩气评价与开采四川省重点实验室, 四川 成都 610091 四川省煤田地质局, 四川 成都 610072

Chengdu Center, China Geological Survey, Chengdu, Sichuan 610081, China Institute of Sedimentary Geology, Chengdu University of Technology, Chengdu, Sichuan 610059, China Sichuan Key Laboratory of Shale Gas Evaluation and Exploitation, Chengdu, Sichuan 610091, China Sichuan Coalfield Geology Bureau, Chengdu, Sichuan 610072, China

通过大量野外露头、钻井岩芯观察，以下古生界五峰组-龙马溪组富有机质泥岩为研究对象，结合有机地化、显微薄片、X-衍射、孔渗、比表面积、扫描电镜等实验测试分析手段，综合分析了五峰组-龙马溪组页岩气基本地质特征。研究表明，在浅水陆棚-深水陆棚的沉积格局控制下，研究区富有机质页岩具有南薄北厚（10~80 m）的分布特征；富有机质页岩总体平均有机碳含量大于2.0%，为腐泥型I型干酪根，有机质成熟度程度高（为0.82%~3.04%）；富有机质泥岩物性特征为低孔-低渗型，发育多种微观孔隙结构。在此基础上，通过页岩气区块优选和评价，认为安场-道真向斜区具备良好的页岩气富集基础地质条件，具有良好的页岩气勘探前景。

Through observation of outcrop, drilling core and the organic-rich mudstone in Wufeng-Longmaxi, and with organic geochemistry, microscopic section, X-ray diffraction, pore permeability, specific surface area, and scanning electron microscope, we analyzed the basic geological characteristics of shale gas reservoir in Wufeng-Longmaxi formation. The analysis shows that the Wufeng-Longmaxi shelf environment is the foun-dation of organic rich mud shale. The sedimentary pattern of shallow shelf and deep water shelf determines the mudstone distribution which is thin in the South(10-80 m). Deepwater mudstone average organic carbon content is greater than 2.0%, and the organic matter is of type I kerogen of sapropel type, with high degree of maturity(=0:82%-3.04%). The reservoir is of low porosity and low permeability, with various micro pore structures.Through shale gas block assessment and selection, we conclude that the Anchang-Daozhensyncline area is of favorable geological conditions for shale gas enrichment and has a good prospect for shale gas exploration.

10.11885/j.issn.1674-5086.2016.06.07.01