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

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（10～80m）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（Ro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 organicgeochemistry, microscopic section, X-ray diffraction, pore permeability, specific surface area, and scanning electronmicroscope, we analyzed the basic geological characteristics of shale gas reservoir in Wufeng-Longmaxi formation. The analysisshows that the Wufeng-Longmaxi shelf environment is the foun- dation of organic rich mud shale. The sedimentary patternof shallow shelf and deep water shelf determines the mudstone distribution which is thin in the South(10 – 80 m). Deepwatermudstone 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(Ro = 0:82% – 3.04%). The reservoir is of low porosity and low permeability, with various micropore structures.Through shale gas block assessment and selection, we conclude that the Anchang-Daozhensyncline area is offavorable geological conditions for shale gas enrichment and has a good prospect for shale gas exploration.