煤系水矿化度是影响低煤阶煤层气生成、运移和成藏的重要因素之一.以新疆准噶尔盆地南缘地区为研究区,把研究区划分为8 个水文地质单元,分析了研究区煤系水矿化度的分布特征及其对产甲烷菌生存的影响.以1 000 m 埋深为例,估算了各个水文地质单元内煤系水的甲烷溶解度,据此分析评价了各水文地质单元溶解运移甲烷的能力.通过煤系水的矿化度分布、氯离子浓度和区域地质构造形态分析,综合判断区域内煤系水的大致流向.以准南地区硫磺沟水文地质单元为例,探讨了矿化度与煤层气富集成藏的关系.研究结果表明,研究区矿化度分布具有南北分带、东西分段的特征.后峡水文地质单元、玛纳斯河–呼图壁河水文地质单元的南部、硫磺沟水文地质单元的南端和阜康水文地质单元的西部地区矿化度有利于产甲烷菌的生存和产气.后峡水文地质单元溶解运移甲烷能力最强.地下水的流向大致由南向北,地表水的径流会使地下水流向发生偏转.指出了硫磺沟水文地质单元内高矿化度中心和低水位的汇水洼地是低煤阶煤层气富集成藏的地区.
Groundwater salinity of coal-series is one of important factors affecting the generation, migration and accumulation of low rank coal bed gas. Taking south of Junggar Basin in Xinjiang as the study area, it is divided into eight hydrogeological units. Distribution characteristics of groundwater salinity of coal-series and the influence on methanogen’s living in the study area are researched. Taking 1000 m depth as example, methane solubility of groundwater in coal-series in each hydrogeological unit was estimated. Capacity for transporting methane was analysed and assessed. Through the analysis of distribution of groundwater salinity, the chloride concentration of groundwater in coal-series and regional geological structures, the flow direction of groundwater in coal-series can be found. Taking Liuhuanggou hydrogeological unit as example relationship between salinity and enrichment of coalbed methane is discussed. The Research results show that the salinity distribution has the characteristics of north-south sub-zone and east-west subsection. Houxia hydrogeological unit, south of Manas river-Hutubi River hydrogeological unit, south of Liuhuanggou hydrogeological unit, west of Fukang hydrogeological unit promote the survival and methane generation of methanogens. Capacity for transporting methane of Houxia hydrogeological unit is strong. The runoff of surface water can influence the flow direction of groundwater . The center of high salinity and depression of low water level is the accumulation area of low-rank coal-bed methane in Liuhuanggou hydrogeological unit.