黔北地区牛蹄塘组页岩气成藏条件及有利区评价

Reservoir-forming conditions and evaluation of favorabl area of shale gas in Niutitang Formation in northern Guizhou

为评估黔北地区下寒武统牛蹄塘组页岩气资源潜力，根据井下岩心和露头岩样的地球化学实验分析结果，对黔北地区牛蹄塘组页岩气成藏条件进行了研究，并评价了该区页岩气成藏的有利区。研究表明：黔北地区牛蹄塘组页岩主要形成于深水陆棚相沉积，页岩埋深适中（3.0%），有机质类型主要为Ⅰ型，热演化程度高（Ro〉2.0%，为过成熟），页岩储层物性为低孔渗，发育大量的微米-纳米级孔裂隙，富含石英等脆性矿物（平均含量〉40%），页岩含气量较高（平均1.5 m3/t），具备良好的页岩气成藏条件。在上述基础上，提出东南部的石阡–余庆–施秉一带为黔北地区牛蹄塘组页岩气成藏有利区。

In order to investigate the potential of shale gas from the Lower Cambrian Niutitang Formation in northern Guizhou, a study on the reservoir-forming conditions of shale gas in Niutitang Formation was conducted, and the favorable accumulation area for shale gas in northern Guizhou was evaluated according to the geochemical analysis data of the core and outcrop samples in this paper. The result shows that Niutitang Formation shale in northern Guizhou was mainly formed in the deep water shelf sedimentary facies, which features moderate buried depth （3.0%）, mainly type I organic matter, high thermal evolution level （Ro〉2.0%, being over-mature）, low porosity and perme-ability, abundant micro-nanometer pores and fissures, rich brittle mineral （average content 〉40%）, and relatively high gas content （average 1.5 m3/t）. It is indicated that Niutitang Formation in northern Guizhou has good reser-voir-forming conditions for shale gas. On the basis of above studies, it is proposed that the southeastern Shiqian-Yuqing-Shibing zone in northern Guizhou is the favorable accumulation area for shale gas.