鄂西—渝东北地区五峰组—龙马溪组页岩气成藏地质条件分析

Shale gas reservoir geology of the Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation in western Hubei and northeastern Chongqing

周志 翟刚毅 石砥石 王胜建 郭天旭 刘一珉 王浩

ZHOU Zhi ZHAI Gangyi SHI Dishi WANG Shengjian GUO Tianxu LIU Yimin WANG Hao

1. 中国地质调查局 油气资源调查中心, 北京 100083; 2. 中国地质大学(北京), 北京 100083

1. Oil & Gas Survey, CGS, Beijing 100029, China; 2. China University of Geosciences, Beijing 100083, China

上奥陶统五峰组-下志留统龙马溪组是鄂西-渝东北地区页岩气勘探的重要层位，目前勘探尚未取得突破，页岩气富集成藏的主控因素不清。通过对鄂西建始地区JD1井及其邻区钻井岩心和野外露头资料的测试分析，研究了鄂西-渝东北地区五峰-龙马溪组深水陆棚相优质页岩时空分布、有机地化、储集物性以及含气性等特征。鄂西-渝东北地区五峰-龙马溪组富有机质页岩发育，深水陆棚相富有机质页岩主要分布在凯迪阶、赫南特阶和鲁丹阶3个层段，具有厚度大、有机碳含量高、热成熟度适中、储集条件好、埋藏深度适中等特点，具有良好的页岩气成藏地质条件。凯迪阶、赫南特阶和鲁丹阶3个层段深水陆棚相沉积的富有机质页岩、断裂欠发育的稳定构造、中下三叠统区域盖层发育是鄂西-渝东北地区五峰-龙马溪组页岩气富集成藏的主控因素。

The Upper Ordovician Wufeng Formation and the Lower Silurian Longmaxi Formation are important strata for shale gas exploration in the western Hubei and northeastern Chongqing area. At present, no breakthrough has been made in exploration, and the main factors controlling shale gas enrichment are unclear. The spatial and temporal distribution, geochemical features, reservoir properties and gas-bearing capacities of high-quality shale of deep-water continental shelf facies in the Wufeng-Longmaxi formations were studied based on the analysis of drill core and field outcrop data of well JD1 and its adjacent area in Jianshi area. Organic-rich shale was developed well in the Wufeng-Longmaxi formations. The organic-rich shale of deep-water continental shelf facies was mainly found in the Katian, Hirnantian and Rhuddanian stages, which featured substantial thickness, high TOC content, medium maturity, favorable reservoir conditions and medium burial depth, showing a good potential for shale gas enrichment. The organic-rich shale of deep-water continental shelf facies in the Katian, Hirnantian and Rhuddanian stages had a stable structure with few fractures, and a regional cap rock in the Middle and Lower Triassic and these are the main controls for shale gas enrichment in the Wufeng-Longmaxi formations in the western Hubei and northeastern Chongqing area.

国家科技重大专项项目“页岩气资源评价方法与勘查技术攻关”（2016ZX05034）和中国地质调查项目“鄂西页岩气示范基地拓展区战略调查（DD20189812）”资助。

https://doi.org/10.11781/sysydz201901001