贵州省主要黑色页岩层页岩气成藏规律及找矿潜力

The Reservoir Forming Law and Prospecting Potential of Shale Gas in the Main Black Shale Layers in Guizhou Province

贵州发育多套黑色页岩层,其中最重要的页岩层为寒武系牛蹄塘组/渣拉沟组、奥陶系五峰组-志留系龙马溪组和石炭系打屋坝组/旧司组,前期实施了多口探井调查其页岩气资源条件,勘查结果显示不同的黑色页岩页岩气富集成藏特征有明显差异。牛蹄塘组/渣拉沟组页岩层在全省分布最广,有机质丰度最高,但热演化程度同样很高,页岩气含量偏低甚至局部地区以氮气为主,受构造破坏影响很大;五峰组—龙马溪组、打屋坝组/旧司组页岩层分布范围和有机质丰度不如牛蹄塘组/渣拉沟组,但生烃演化历程相对要短,热演化程度适中,受构造破坏影响相对较小,页岩气富集受有机质丰度、微观孔隙发育、矿物成分影响明显。三个主要页岩层中,五峰组—龙马溪组和打屋坝组/旧司组页岩气勘查显示较好,资源条件较佳,找矿潜力大,是下一步贵州页岩气勘查开发的重点层位。

There are many black shale layers in Guizhou province,and the most important shale layers are the Cambrian Niutitang formation/Zhalagou formation,Ordovician Wufeng formation-Silurian Longmaxi formation,Carboniferous Dawuba formation/Jiusi formation.The wells have been implemented to investigate their shale gas resource conditions.The exploration showed significant differences in the characteristics of different black shale gas rich reservoirs.The Niutitang formation/Zhalagou formation shale is the most widely distributed in the Guizhou province,with the highest organic matter abundance.However,the degree of thermal evolution is also high,with low shale gas content and even partial areas dominated by nitrogen gas.The enrichment characteristics are complex and greatly affected by structural damage.The distribution range and organic matter abundance of the Wufeng formation-Longmaxi formation,Dawuba formation/Jiusi formation shale formations are not as good as those of the Cambrian Niutitang formation/Zhalagou formation.However,the hydrocarbon generation evolution process is relatively short,the degree of thermal evolution is moderate,and the impact of structural damage is relatively small.Shale gas enrichment is significantly influenced by organic matter abundance,micro pore development,and mineral composition.Among the three main shale formations,the shale gas exploration of the Wufeng formation-Longmaxi formation and the dawuba formation/Jiusi formation are good,with good resource conditions and great exploration potential.They are the key horizons for further shale gas exploration and development in Guizhou Province.