上扬子区下寒武统筇竹寺组页岩气成藏条件

Accumulation conditions of shale gas reservoirs in the Lower Cambrian Qiongzhusi formation,the Upper Yangtze region

页岩气是未来中国天然气储量增长重要的和现实的可接替新领域。利用中国上扬子地区下寒武统筇竹寺组黑色页岩的地质、钻井气显示以及有关地化分析数据,剖析了该区页岩气藏形成地质条件,认为上扬子区下寒武统筇竹寺组黑色页岩发育且区域分布稳定,并呈现出川南、黔北及湘鄂西3个与"海湾体系"密切相关的"优质源岩"分布区,是页岩气成藏最有利的地区;威远及黔西北毕节—大方一带在勘探震旦系灯影组气藏过程中,钻至下寒武统筇竹寺组页岩中普遍见气侵、井涌等不同级别的气显示,部分黑色页岩层段密闭取心测试含有低—中等商业性吸附气含量(0.4～0.83m3/t),尤其是威远地区九老洞组页岩中含气显示分布特点表明其不受气水边界及构造因素控制,而与有效页岩分布密切相关。综合研究后认为川南、黔北可作为中国页岩气藏近期突破的重要选区。

In China,shale gas will be an important,realistic and new alternative energy resource for the growth of natural gas reserves in future.By using of the geological data,gas show in drilling and geochemical information from the Lower Cambrian black shale in Qiongzhusi formation in the Upper Yangtze region,this paper analyzed the accumulation condition of shale gas reservoirs.It is believed that this area is the most favorable for forming shale gas resource because it develops black shale characterized by stable regional distribution and presents three distribution areas of excellent source rocks such as southern Sichuan,northern Guizhou and western Hunan and Hubei closely related to bay environment system;Along Weiyuan and Bijie-Dafang in northwestern Guizhou,there encounters gas show in different level such as gas cut and well kicks when drilling the Lower Cambrian black shale in Qiongzhusi formation during exploring gas reservoir in Sinian Dengyin formation in which parts of black shale contain low-medium commercial adsorption gas ranging from 0.4-0.83 m3/t tested by pressure coring data,especially the shale in Jiulaodong in Weiyuan area shows such distribution characteristics as it is not controlled by gas-water boundary and tectonic factors but closely related to the distribution of efficient shale.It is suggested that the southern China and the northern Guizhou in China should be areas with high priority for exploring shale gas resources after comprehensive study.