新疆典型矿区低煤阶煤层气成藏差异对比研究

基于沙尔湖矿区和阜康白杨河矿区两个发育煤层火烧的典型低煤阶含气地区的地质背景和煤储层物性研究,结合两矿区火烧区水文地质条件的差异对比分析,阐明了新疆火烧区低煤阶煤层气成藏差异及主控因素。研究结果表明:两矿区煤层厚度大、构造样式简单、孔隙发育良好,但沙尔湖矿区由于地下水动力条件较弱,且为矿化度极高的原生水,不利于低煤阶煤层气的生成,且矿区东部煤层火烧使得气体发生逸散,导致矿区内含气量偏低;阜康白杨河矿区水源补给充足,在火烧区低洼处形成滞水层,一方面,滞水层为次生生物成因气的生成提供了有利条件,另一方面形成水力封堵利于煤层气的保存。火烧区滞留水对煤层气富集成藏具有指向作用,因此本次研究成果将为新疆低煤阶煤层气勘探提供理论参考。

Comparative research on the difference of low rank CBM accumulation in typical Xinjiang mining area

On the basis of the study about geological setting and reservoir property, Shaerhu (SEH) mining area and Fukang Baiyanghe (BYH) mining area were defined as two typical coalbed methane (CBM) in low rank coal. Some coal seams were burned in this two mining areas. The difference of hydrogeological condition of two mining burning areas were compared and analyzed. The differences about accumulation and main controlling factors of low rank CBM in Xinjiang were clarified. The authors found that the coal seams in the two mining areas are large in thickness, simple in structure and well-developed in porosity. However, due to the weak dynamic conditions of groundwater and the high degree of mineralization of the primary water, the SEH mining area is not conducive to the generation of low-rank CBM, and the coal seam fire in the east of the mining area causes gas to escape, led to the low volume of gas in the mining area. On the contrary, the water supply is adequate in BYH mining area, monimolimnion were formed in the low-lying area. On the one hand, the monimolimnion provides favorable conditions for the generation of secondary biogenic gas, on the other hand it forming hydraulic seal to preserve the gas. The monimolimnion in the burning area can point to the enrichment area of CBM. Therefore, the research will provide theoretical references for the exploration of low rank CBM in Xinjiang.