我国西北地区中低煤阶煤层气成藏规律及控气因素探讨

Discussion on the Law of Coalbed Methane Accumulation and Gas Control Factors of Middle and Low Coal Rank in Northwest China

我国中低煤阶煤层气资源丰富,其勘探开发一直备受关注。基于中低煤阶煤层气富集成藏自身的特殊性,研究中低煤阶的成藏规律及控气因素是煤层气勘探开发及综合评价的前提和基础。通过系统分析、总结我国西北地区煤层气成藏地质特征、煤层气富集规律,认为我国西北地区中低煤阶煤层气含量的地质控制因素主要表现为煤变质作用、构造演化、沉积特征、岩浆活动等,各种地质因素系统作用控制了煤层气赋存和富集格局,煤变质作用是影响煤层含气量的直接因素。

China is rich in medium and low coal ranks coalbed methane(CBM),and its exploration and development have always been of great concern.Based on the special characteristics of enrichment and storage in medium and low coal ranks,studying the rules of methane generation and the factors controlling gas content is a prerequisite and basis for the exploration,development,and comprehensive assessment of CBM.Through systematic analysis and summary of the geological characteristics of CBM reservoir formation and the law of CBM enrichment in northwest China,it is believed that the geological control factors for the content of CBM in middle and low ranks coal seams in northwest China are mainly coal metamorphism,tectonic evolution,sedimentary characteristics,magmatic activity,etc.The systematic role of various geological factors controls the pattern of coalbed methane occurrence and enrichment,and coal metamorphism is the direct factor affecting the content of CBM.