煤层气储量计算及其参数评价方法

METHODS FOR CBM RESERVE CALCULATION AND PARAMETER EVALUATION

煤层气的储量计算主要考虑到煤层气的特殊性,同时参照流体矿藏(天然气)和固体矿藏(煤炭)储量计算方法。煤层气储量计算中最重要的参数是含气量,其分布随着盖层分布、地层压力及水动力条件的变化而有所不同。煤层气藏的储量计算不同于常规天然气,其含气边界的确定是以煤层含气量等值线确定的。圈定含气面积的最低含气量值根据煤层气藏地质条件、采用煤层储量历史模拟软件进行模拟确定,并参考国外煤层气开发选区的含气量标准。煤层气储量计算方法有体积法和数值模拟法,后者适合于开发中期或者在生产试采资料很丰富的情况下使用。

Calculating the Reserves of coalbed methane(CBM) gives the main consideration to the particularity of CBM by referring the methods of estimating the reserves of the fluid(natural gas) and solid(coal) mineral resources.The coalbed methane content is the most important parameter in estimating coalbed methane reserves and its distribution is different by the change of factors,such as caprock distribution,formation pressure,hydro-dynamic condition,etc.The reserve estimation method of CBM reservoir is different from that of conventional gas reservoir and the boundary of CBM reservoir is determined by methane content contours.The lowest methane content value of enclosing methane-bearing area is based on the geological conditions of CBM reservoir,determined by the use of historical simulation software of CBM reserves and in consideration of the foreign methane content's standard of area-selection of coalbed methane development.The methods of estimating coalbed methane reserves include volumetric method and numerical simulation method,and the latter is suitable for the CBM reservoir in its middle development stage or for the one with a wealth of the production and test data.