湖北京山地区孤峰组页岩气地质条件及远景区划分

Geological Conditions and Prospecting Area Delineation of Gufeng Formation Shale Gas in the Jingshan Area,Hubei Province

为研究湖北省京山地区孤峰组页岩气地质条件及资源潜力,从岩石组合、有机地化、储层特征等方面对孤峰组样品进行了测试分析。研究区孤峰组泥页岩厚度为55.2-58.3 m;有机碳含量(TOC)为1.75%-6.39%;干酪根类型为Ⅰ型,镜质体反射率(Ro)为1.23%-1.72%;平均值为1.58%,处于过成熟生气阶段;多种孔裂隙发育,孔隙度平均为4.29%;矿物组成以石英和碳酸盐矿物为主,少量粘土矿物;孤峰组拟合含气量平均为2.21 m^(3)/t。研究结果表明:(1)京山地区孤峰组泥页岩厚度大,生烃能力良好,具备形成页岩气藏的物质基础;(2)孤峰组脆性矿物含量高,有利于压裂改造;(3)采用叠合法预测,研究区存在永隆-长滩地区和钱场-渔薪地区两个远景区。

The rock samples of the Gufeng Formation are tested in their rock assemblage,organic geochem-istry,and reservoir characteristics to evaluate the geological conditions and resource potential of shale gas in the Jingshan area,Hubei Province.The thickness and organic carbon contents(TOC)of the Gufeng Formation shales in the study area are between 55.2-58.3 m and 1.75%-6.39% respectively.Their kerogen is type Ⅰ,and the vitrinite reflectance(Ro)is 1.23%-1.72% with the average value of 1.58%,which indicates that the shales are in the stage of over-mature gas generation.They develop a variety of pores and fissures with the average porosity of 4.29%.The samples consist of mainly quartz and carbonate and minor clay minerals.The average fitted gas content of the Gufeng Formation is 2.21 m^(3)/t.The research results show that:(1)the mud shale of the Gufeng Formation in the study area is thick,and has potential for shale gas reservoir with good hydrocarbon generation ability;(2)The Gufeng Formation has high content of brittle minerals,which is con-ducive to fracturing reformation;(3)According to the superposition method to predict,the study area can be subdivided into two prospective,such as the Yonglong-Long Beach area and Qianchang-Yuxin area.