重庆武隆地区五峰组—龙马溪组页岩气地质条件分析——以黄莺乡剖面为例

Analysis of shale gas geological conditions of Wufeng Formation-Longmaxi Formation in Wulong Area,Chongqing:Take Huangying Township profile as an example

依托于涪陵页岩气田大规模商业开发取得的成功,对涪陵周缘地区页岩气地质条件的研究也不断深入。为了厘清武隆地区上奥陶统五峰组—下志留统龙马溪组页岩气地质特征,对重庆武隆地区野外剖面观测点进行考察与筛选,选定武隆地区黄莺乡野外露头进行观测和取样,通过剖面精细描述和露头样品分析测试,开展地层沉积特征及页岩非均质性研究。分析认为,武隆地区五峰组—龙马溪组沉积环境为滨外陆棚相深水陆棚亚相,以碳质和硅质泥页岩为主,含少量粉砂质泥页岩;有机碳平均含量为3.98%,有机质类型为Ⅱ2型干酪根,镜质体反射率为1.99%~2.23%,平均孔隙度为4.61%,平均脆性指数为70.73%;具有较好的页岩品质和可改造性,证实武隆地区五峰组—龙马溪组具备较好的页岩气地质条件。

Relying on the success of large-scale commercial development of Fuling shale gas field,the geological conditions of shale gas in Fuling peripheral area have been studied deeply.In order to clarify the geological characteristics of shale gas in Upper Ordovician Wufeng Formation Lower Silurian Longmaxi Formation in Wulong Area,the field profile observation points in Wulong Area of Chongqing were investigated and screened,the field outcrop in Huangying Township,Wulong Area was selected for observation and sampling,through detailed profile description and outcrop sample analysis and testing,the study on the sedimentary characteristics and shale heterogeneity is carried out.It is concluded that the sedimentary environment of Wufeng Formation-Longmaxi Formation in Wulong Area is offshore shelf facies deep watre shelf subfacies,mainly composed of carbonaceous and siliceous shale,with a small amount of silty shale;The average content of organic carbon is 3.98%,the organic matter type is typeⅡ2 kerogen,the vitrinite reflectance is 1.99%~2.23%,the average porosity is 4.61%,good brittleness and the average brittleness index is 70.73%.It has good shale quality and remouldability,which proves that Wufeng Formation-Longmaxi Formation in Wulong Area has good shale gas geological conditions.