大倾角低阶煤储层含气性分布特征——以准南煤田乌鲁木齐河东矿区西山窑组为例

Gas Distribution Characteristics of Low-rank Coal Reservoir with Large Dip Angle:A Sase Study of Xishanyao Formation in Urumchi Hedong Mining Area, Zhunan Coalfield

新疆准噶尔盆地南缘乌鲁木齐河东矿区勘探开发研究程度较低,为了找出该区煤层含气性分布差异性的原因,以研究区煤层含气量分布特征为基础数据,分析大倾角煤层中埋深、构造条件、封盖层对煤层气含气性特征的影响。结果表明:埋深在400~1152.3m含气性较好,在550~750m含气饱和度含量最高,煤层储气效果最好;在垂向上,整体含气性随埋深的增加呈现出“驼峰”状,表现为先增大,后逐渐减小的趋势;断层对含气性产生了影响,其中含气性受到F2断层影响较小、受f8断层影响明显含气量出现明显下降、受F7-2和F7-3断层影响煤层气出现了明显的富集现象。

The exploration and development degree of the Urumchi Hedong Mining Area in the southern margin of Xinjiang Junggar Basin is relatively low. To find out the reason for the difference in gas content distribution in coal seams of this area, based on the data of the gas content distribution characteristics of coal seams in the study area, the influences of the buried depth, structural conditions, and capping layer on the gas content characteristics of coalbed methane in the large dip angle coal seam were analyzed. The results show that, when the buried depth is 400~1152.3m, the gas content is relatively good, and the gas content is the highest between 550m and 750m, with the best storage effect of the coal seam. In the vertical direction, the overall gas content shows a “hump” shape with the increase of burial depth, which increases first and then decreases gradually. The fault influences the gas content. The gas content is less affected by the F2 fault, the gas content is significantly decreased by the F8 fault, and coalbed methane is enriched by the F7-2and F7-3faults.