黔东北地区下寒武统牛蹄塘组页岩气特征及主控因素分析*

黔东北地区页岩气资源丰富,其下寒武统牛蹄塘组具有巨大的勘探潜力。在对几口探井分析的基础上,结合露头资料及地球化学特征,认为研究区牛蹄塘组页岩具有厚度大、分布广、有机碳含量高、热演化程度相对较高、储集条件较好等特征。但由于大部分针对牛蹄塘组页岩气的钻井遇到的都是含气量低、甲烷含量低、氮气含量高的页岩,因此对黔东北地区页岩气富集的主控因素进行了系统分析,认为该地区牛蹄塘组页岩气具有沉积控带、断裂控藏的明显特征。

Characteristics and its main enrichment controlling factors of shale gas of the Lower Cambrian Niutitang Formation in northeastern Guizhou Province

The shale gas resource is rich in northeastern Guizhou Province,and especially,the Lower Cambrian Niutitang Formation has great exploration potential. Based on the data of several drilling wells,combined with the data of outcrops and their geochemistry characteristics,we studied the characteristics and main enrichment controlling factors of the shale gas of the Lower Cambrian Niutitang Formation in northeastern Guizhou Province. The shale is characterized by great thickness,wide distribution,high content of organic carbon,higher thermal evolution degree and good reservoir conditions,etc. However,most wells met the phenomena of low gas content,low methane content and high nitrogen content. Upon the system analysis of main enrichment controlling factors,it is considered that the shale gas enrichment of the Niutitang Formation in study area has distinct characteristics of distribution zone controlled by sedimentary facies and reservoir controlled by fault.