中国煤系“三气”成藏特征及共采可能性

煤系地层中的非常规天然气资源是非常规天然气的主要组成部分。目前,对煤系地层煤层气、页岩气、致密砂岩气等非常规天然气资源的认识还较薄弱,资源勘探开发程度也都比较低。根据气藏合层开采经验,把煤系地层视作一个整体,综合勘探开发煤系煤层气、页岩气、致密砂岩气不仅可以减少勘探开发成本,增大非常规天然气总储量和技术可采资源量,还可以提高气井使用效率和单井利润。将煤系地层中的煤层气、页岩气、致密砂岩气称为"煤系三气",从煤系地层岩性分布特征、煤系气体成藏机理、不同类型含气储层特征和开采特征等方面分析煤系"三气"共采可能性及共采急需解决的难点。

Reservoir forming characteristics of “the three gases” in coal measure and the possibility of commingling in China

The unconventional gas resource in coal measures strata is the main part of unconventional gas.At present,the understanding of coalbed methane,shale gas and tight sandstone gas in the coal measures strata is relatively limited.Also,the degrees of resources exploration and development are relatively low.According to the experiences of gas reservoir combined mining,the coal measure strata can be considered as a whole,then the cost of exploration and development on coalbed methane,shale gas and tight sandstone gas in the coal measures strata could be reduced.In addition,the efficiency and single well profit of gas well could be improved.In this paper,the coalbed methane,the shale gas and the tight sandstone gas in coal measures strata are referred to as “the three coal gases”.The commingling possibility of “the three coal gases” and the difficulties that commingling urgently needs were analyzed from the formation lithology distribution characteristics of coal measures strata lithology,accumulation mechanisms,reservoir characteristics,exploitation characteristics,etc.