下扬子地区页岩气勘探新认识

New Acquirement of Shale Gas Exploration and Development in the Lower Yangtze Region

近几年扬子地区开展的页岩气资源调查表明,下寒武统幕府山组(南部也称荷塘组)、下志留统高家边组底部–奥陶统五峰组、二叠系龙潭组和三叠统青龙组地层具有页岩气勘探潜力,但潜力最大的当属沉积厚度大、分布广、热演化程度适中的志留统高家边组。另外应该注意两点:(1)因页岩气与油气是同源物质,故应在油气发育区上下就近优先寻找页岩气;(2)下扬子地区地层中断层发育,且多为拉张性的正断层,地层中不整合面也发育,这些都是潜在的高渗流通道,钻井和压裂开发时要注意避开和远离,当然更要做好地下水环境保护。

In recent years, shale gas resources in Yangtze area have been investigated. The results show that the lower Cambrian Mufushan Formation (also known as Hetang Formation in the south), the lower Silurian Gaojiabian Formation-Ordovician Wufeng Formation, Permian Longtan Formation and Triassic Qinglong Formation have shale gas exploration potential, but the greatest potential belongs to the Silurian Gaojiabian Formation which is widely distributed with sedimentary thickness and moderate thermal evolution. In addition, two points should be noted:(1) Since shale gas and oil and gas are homologous substances, the priority should be given to shale gas in the development area of oil and gas;(2) Faults developed in the lower Yangtze region and which are mostly tensile normal faults, and the unconformity surface in the stratum is also developed, all of which are potential high seepage channels, drilling and fracturing development should pay attention to avoid and stay away from those high seepage channels, and certainly, we should to protect the groundwater segregate from the drilling fluids to obey the local environment policy.