云南老厂矿区煤层气储层地质条件及其资源潜力

Geological Conditions and Resource Potential of Coalbed Methane Reservoirs in Laochang Mining Area,Yunnan Province

云南老厂矿区煤层气资源丰富,是近年来我国煤层气资源勘探开发的热点区域。针对煤层厚度、储层物性、含气量等储层基本参数特征进行分析,对区域煤层气资源潜力进行评价。结果表明:云南老厂矿区煤层厚度较大、层数较多,煤层顶底板以泥岩、粉砂岩为主,生储盖配置较好;目标煤层孔隙度相对较高,裂隙较为发育,可为煤层气的富集和产出提供良好的条件;主要煤层压力整体上属于常压储层,煤层解吸速率较高;同时煤储层大多处于欠饱和状态,开发过程中需要较长时间的排水降压;老厂矿区雨汪区块埋藏深度小于1000 m的煤层气资源量为270.93亿m^(3),资源丰度为3.20亿m^(3)/km^(2)。总体而言,研究区煤层气勘探开发条件较好,具有较大的勘探开发的资源潜力。

The Laochang mining area in Yunnan is rich in coalbed methane resource,and is a hot spot for coalbed methane resource exploration and development in China in recent years.Here,the basic reservoir parameter characteristics,such as coal seam thickness,reservoir physical properties and gas content are analyzed,and the potential of regional coalbed methane resources is discussed.Our results show that the coal seams in Laochang mining area are thick and multi-layered,the coal seam roof and floor are mainly mudstone and siltstone,respectively,and the configuration of source-reservoir-cap is good.The target coal seam has relatively high porosity and well-developed fractures,which can provide favorable conditions for the enrichment and output of coalbed methane.The main coal seam pressure belongs to the normal pressure reservoir as a whole,and the desorption rate of coal seam is high.Meanwhile,most of the coal reservoirs are under-saturated,and it took long time to drain and depressurize during their development.The coalbed methane resource with buried depth below 1,000 m in the Yuwang block are 27.093 billion m^(3),and the resource abundance is 320 million m^(3)/km^(2).In general,the local coalbed methane exploration and development conditions are good,and there is great resource potential for exploration and development.