试论煤层气系统

煤层气是煤层自生自储的非常规天然气,它的生成、赋存及产出有其自身的特点.在煤层气勘探中引入含油气系统的概念,提出与应用煤层气系统,给煤层气勘探工作者提供了新的思路和研究方法、综合分析煤层空间分布、生储盖组合、煤岩煤质和含气量等静态因素及构造埋藏史、水动力场、古应力场等动态因素,运用系统论的观点,将煤层气勘探目标区煤层作为一个整体进行研究,具体分析煤层气的生成、聚集子系统,全面认识煤层气富集高产的影响因素,有利于对煤层气的勘探.

ON COALBED METHANE SYSTEM

Coalbed methane (CBM) is a kind of inconventional gas,in which the coal seams are both the source rock and the reservoir. The enrichment of CBM is contributed by distribution of coal seams,coal rank,evolution of structure and heat ,and hydrology. Recently,petroleum system has been used in the exploration of conventional oil and gas,the introduction of it in the CBM exploration will give the explorers a new approach. There are two kinds of factors which are the decisive factors in the enrichment of CBM. One kind of them is of static factors, which include distribution of the coal seams, grade and rank of coal, gas content, and layers of maintainance etc. These factors supply the substance and space of the generation and reservation of CBM. The other kind of them is of active factors,which include the evolution of structure and heat of the coalbeds,fields of stress and hydrology of the coal field. These factors affect the evolution of the coal and formation of cleats and fissures in the coal,and contribute to the preservation and enrichment of the CBM. In the exploration of CBM,both the static and the active factors must be studied systematically. This has been demonstrated by the exploration of CBM in Liulin area,Shanxi province.