中国页岩气勘探新思路

New ideas of shale gas exploration in China

页岩气具有自生自储、低孔低渗的特点,它的成藏机理与常规气藏相似,对产量贡献最大的是游离气。高产页岩气藏需要具备以下四个基本条件:具有持续生气能力的页岩,网状微裂缝发育,气藏发育在构造封闭的宽缓背斜中顶底板岩层致密,形成岩性圈闭。盆地内构造运动影响较小、成藏诸要素具备,是国内重点页岩气勘探区域,尤其是四川盆地下志留统龙马溪组及下寒武统牛蹄塘组黑色页岩,应作为我国页岩气勘探的重点目标。

As a kind of unconventional natural gas,shale gas owns the characteristics of self-generation,self-preservation,low-porosity and low-permeability.The accumulation mechanism of shale gas is similar to conventional gas,and free gas makes the largest contribution to the production.High yield shale gas reservoir needs to have the following four basic conditions:(1)Shale layers with continuous and powerful hydrocarbon generation ability;(2)Highly developed mesh micro fractures;(3)A closed gentle anticline which is benefit for gas preservation;(4)A lithological trap,in order to reduce gas from escaping.The tectonic movement effect is less and all key elements of shale gas accumulation satisfied the area,especially the black shale of lower Silurian Longmaxi formation and lower Cambrian Niutitang formation in Sichuan basin is the main research object and should be regarded as the key target of exploration.