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准确确定藏储量是煤层气资源及气藏评价的一个重要因素。不同的气藏特性分析方法可产生不同的煤层气资源及储量值。本文介绍由普遍采用的气藏特性分析方法所得出的准确评估结果。已发现常用的分析方法都有其内在的缺点,主要是对储量值低估误差很大(50％或更大)。6个主要的误差原因是:(1)将气藏面积建立在假设气藏横向连续性是恒定的基础上;(2)为确定总的气藏厚度,采用1.75g/cm~3作为最大的测井密度值;(3)把1.32～1.36g/cm~3作为气藏的原地密度值;(4)将原地气含量建立在通过周围温度条件获得的气体解吸数据基础上;(5)将原地气含量建立在通过钻屑获得的气体解吸数据基础上;(6)将原地气含量建立在假定残余气含量可忽略的基础上。由于上述6种误差的分析方法在过去曾得到广泛应用,所以对许多现有的煤层气田的储量评估具有极大的潜力。
Accurate determination of reservoir reserves is an important factor in CBM resources and gas reservoir evaluation. Different gas reservoir property analysis methods can produce different CBM resources and reserves. This article presents an accurate assessment of the commonly used methods of reservoir characterization. It has been found that the commonly used analytical methods have their inherent disadvantages, mainly because of the large (50% or more) underestimation of reserve values. The six main causes of the error are: (1) the area of the gas reservoir is established on the assumption that the horizontal continuity of the gas reservoir is constant; (2) 1.75 g / cm ~ 3 is used as the maximum for determining the total gas reservoir thickness (3) 1.32 ~ 1.36g / cm ~ 3 as the in-situ density value of the gas reservoir; (4) based on the desorption data of the gas obtained by ambient temperature conditions; (5) Based on the gas desorption data obtained from drill cuttings; (6) Based on the assumption that the residual gas content is negligible. Since these six error analysis methods have been widely used in the past, they have great potential for the evaluation of reserves of many existing CBM fields.