基于主地质参数的煤层气有利开发区优选及应用

煤层气有利开发区既是煤层气富集区、高渗区，又是煤层气高产区，因此寻找能表征煤层气富集区、高渗区和高产区的主地质参数，是解决煤层气有利区优选问题的关键。基于区块尺度的煤层气有利区优选，建立了一种定量化的综合评价方法：(1)以含气量、储层压力、临界解吸压和试井渗透率为主地质参数并作为评价指标，以煤层气井稳产阶段平均日产气量作为衡量指标，采用灰色关联度分析法定量地确定各评价指标的权重系数以及评价值函数；(2)借助于MapInfo professional软件，计算煤层气区任意位置的综合评价值；(3)用产气量对综合评价值进行标定，确定煤层气开发区类型及分布范围。将该方法应用于沁水盆地南部勘探程度较高的郑庄区块，预测出煤层气有利开发区(产气量＞2 000 m³/d)的分布范围，研究结果对于下一步的煤层气钻井部署具有一定的参考意义。

A Method for Targeting Favorable Coalbed Methane Development Area Based on Primary Geological Parameters and Its Application

Favorable coalbed methane (CBM) development area is characterized by high CBM content, high coal reservoir permeability and high gas productivity. Finding out the primary geological parameter representative of the three high properties is a key to comprehensively evaluate CBM-bearing reservoirs. In this paper, a quantitative method was proposed to target favorable CBM area for a CBM development block. Coalbed gas content, reservoir pressure, critical desorption pressure and coal permeability obtained by injection/falloff well test were selected to be as primary geological parameters used for comprehensively evaluating favorable CBM area. Their weight coefficients and evaluation value functions were obtained by analyzing correlation degree of the geological parameters with the mean gas production rate at stable production period. Based on the soft of MapInfo professional, comprehensive evaluation values for the arbitrary locations of the study area were calculated, and then were calibrated by the mean gas production rate so as to divide different CBM development areas. This method was successfully applied to Zhengzhuang block in southern Qinshui Basin, and favorable CBM areas with the gas-production value larger than 2,000 m³/d were predicated; the result is significant to guide the CBM well drilling in the next stage.