煤层气资源储量评估基础参数研究

Research on Coal-Bed Methane Reserves Estimating Parameters

煤层甲烷在煤层中有3种赋存状态,即游离态、吸附态和溶解态。煤层甲烷以自由状态存在于煤的割理和其他裂缝孔隙中,可以自由运移,运移的动力是地层水压力和气体浮力。煤层甲烷绝大多数是以吸附状态存在于煤层中,一般可占煤层甲烷总量的70%～95%。天然气在煤层中的储集主要依赖吸附作用,而不依赖于是否有储集气体的常规圈闭存在。煤层中还有一小部分气体以溶解的方式存在于煤层地层水中。这3部分气体构成了煤层气中全部气体总量,理论上计算煤层气储量,应该分别计算相应的气体量。根据煤层气的赋存状态,提出了煤层气资源储量计算参数的确定原则及要求。通过对3种气体富集方式的实际测算,提出了我国目前煤层气资源储量评估的优化方法。

The occurrence of coal-bed methane (CBM) is expressed in free state,absorbed state,and dissolved state.CBM exists freely in the coal cleat and other fracture pore.It can migrate freely powered by the pressure of formation water and the gas buoyancy.The occurrence of most CBM is expressed in free state,which may account for 70% and 95% in the total amount.The accumulation of natural gas in the coal bed mainly depends on absorption rather than the normal traps.A small part of gas taking the form of dissolutio...