湘中邵阳凹陷煤系气成藏基础及其共生组合特征

在系统收集整理邵阳凹陷煤系矿产勘查与评价资料及样品分析测试结果的基础上,将研究区煤系地层中的非常规天然气作为一个整体进行研究,查明了测水组煤层-煤系页岩-煤系砂岩的展布特征,分析了研究区测水组煤系气成藏的可能性,总结了测水组地层垂向发育的岩相组合特征及其对应的煤系气组合模式,通过典型钻孔分析,确定了煤系气发育的有利层段及其气藏类型。结果显示,研究区测水组主要发育以泥页岩为主的岩相组合和以页岩气-煤层气为主的煤系气藏,泥页岩对邵阳凹陷煤系气成藏起关键作用;但在聚煤中心附近的局部区域内,煤储层是煤系气成藏的关键因素。

Accumulation and combination characteristics of coal measure gas of Shaoyang depression in the central Hunan

Based on the comprehensive experimental results incorporated with drilling data in Shaoyang depression,the coal-bearing strata were studied as a whole.The coal measure gas in lateral extension and vertical sequences and its accumulation and combination characteristics were investigated.Based on the study of representative wells in the study area,the favorable segment of unconventional gas and the gas types in the coal measure had been identified.It shows that shale plays a key role on coal measure reservoir in the study area,and Ceshui Formation primarily developed shale-related lithological association and shale gas-coalbed methane.It should be recognized that the distribution of Ceshui Formation is unstable in Shaoyang depression,which leads to the different combination characteristics of coal measure gas in different areas.For example,coal plays a decisive role in the area of coal accumulation center.