贵州北部龙马溪组页岩特征及页岩气勘探前景

Shale Features and Exploration Prospect of Shale Gas in Longmaxi Formation in Northern Guizhou

利用野外露头观测、岩心观察、薄片观察及相关测试分析结果,对贵州北部地区下古生界龙马溪组页岩沉积特征及页岩气勘探前景进行研究。结果表明:龙马溪组页岩厚度普遍较大,由20 m到200 m不等,主要发育于陆棚环境。页岩矿物成分以碎屑石英和黏土矿物为主,岩石类型主要包括黑色页岩、粉砂质页岩、炭质页岩、钙质页岩和泥质粉砂岩。龙马溪组页岩有机质类型以Ⅰ—Ⅱ型为主,Ro平均为1.87%,大多处于成熟—过成熟阶段,具有高TOC含量和高含气量,且二者具有较好的正相关性。龙马溪组页岩沉积环境稳定,页岩发育厚度大且分布稳定,烃源岩品质好,脆性矿物含量较高,具备页岩气勘探开发的基本参数要求,研究区页岩气具备较大的勘探潜力。

With outcrop,core and section observations and relevant analysis and test results,a study has been made on sedimentary features of shale and exploration prospect of shale gas in Longmaxi Formation of lower Paleozoic,northern Guizhou. Result indicates that,shale in Longmaxi Formation is generally thick,from 20 m to 200 m,mainly developing in continental shelf. Shale minerals are mainly dominated by clastic quartz and clay minerals. The rocks are mainly black shale,silty shale,carbonized shale,calcic shale and muddy siltstone. Longmaxi Formation shale is mainly of Type- I and II organic matters,with average Roof 1. 87%. It is mainly in mature- over mature phase,with high TOC and gas content that have good positive correlation. The shale,deposited under stable settings,is steadily distributed in large thickness. Moreover,the formation contains good source rock,and high content of brittle minerals. It can meet the parameter requirements to explore and develop shale gas. In summary,the study area has great potential of shale gas.