潞安目标区煤层气赋存和生产的地质因素分析
Analysis on geological factors of coalbed methane distribution and production in Lu'an area
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摘要: 分析了影响潞安目标区煤层气赋存和生产的主要地质因素,提出了本区煤层气井产气量低、产水量高的原因。潞安目标区与晋城目标区相比较,张性断层发育,3号煤顶板砂岩条带发育。地下水从浅部接受大气降水补给,部分在文王山和二岗山断裂带排泄,煤层顶板砂岩含水层与煤层不仅构成了一个统一的地下水系统,又由于与断层的沟通作用形成了一个完整的地下水补径排系统,使得地层能量被释放,煤层气大量运移逸散,煤储层压力降低,煤层气井产能降低。Abstract: The dominant geological factors influencing the target coal seam's gas occurrence and production in Lu′an area are analyzed. Based on that the causes of low gas productivity and high water productivity in the study area are revealed. The reason for that is caused by lots of extensional faults and sandstone belts above No. 3 coal seam. On the whole, with underground water recharging from outcrops at the east of the area and discharging to Wenwangshan and Ergangshan fault zones, as well as the sandstone aquifer above No. 3 coal seam and No. 3 coal seam itself, a complete underground water system was formed, which communicates with the faults. Consequently, reservoir energy was released and coalbed methane was transformed and escaped, which resulted in the low reservoir pressure and the low coalbed methane productivity.