煤矿区煤层气抽采效果检测指标及评价

Detection Indexes of Coalbed Methane Drainage Effect and Evaluation Method in Coal Mine Area

采用实测和数值模拟方法对晋城矿区地面煤层气抽采效果进行了检测,实测法检测地面抽采5年后煤层气含量由21.58 m3/t降到10.74 m3/t,气含量降低率为50.2%;数值模拟法检测地面抽采5年、10年后井群范围内气含量降低率均值分别为43.3%和58.2%。煤矿井下抽采15.6个月和29.6个月后,实测法检测煤层气含量由抽采前20.1 m3/t分别降低到11.24 m3/t和4.76 m3/t,气含量降低率均值为44.0%和76.3%。根据实测的煤层气含量和储层数值模拟结果,并结合我国煤矿区煤层气抽采的实践经验和相关管理规定,综合考虑煤矿区煤层气抽采的安全和资源效益,提出以煤层气含量和气含量降低率(或采收率)作为煤矿区煤层气抽采效果检测和评价指标,分别建立了煤矿区地面和井下煤层气抽采效果评价方法。

The ground drainage effect of coalbed methane （CBM） in Jincheng Coal Mine area was detected by using numerical simulation and measured method. It was measured that the CBM content by ground drainage after 5 years was declined from 21.58 m^3/t to 10.74 m^3/t and the value of declined rate of the CBM content was 50.2%. After being drained by 5 years and 10 years, the average value of the CBM content declined rate within the well group was 43.3% and 58.2% using the numerical sim- ulation method respectively. After 15.6 months and 29.6 months by underground mine drainage, it was measured that the CBM content declined from 20.1 m^3/t to 11.24 m^3/t and 4.76 m^3/t respectively. According to the measured CBM content and the numer- ical simulation results of coal reservoir, combining with the practical experiences of CBM drainage in coal mine areas and the re- lated management stipulations in China, and considering the safety of CBM drainage and the resource benefits in coal mine area comprehensively, it is suggested that the CBM content and the reduced rate （or recovery rate） of CBM content are taken as the detection and evaluation indexes of CBM drainage effect in coal mine area, and the detection and evaluation technical methods of CBM drainage effect in coal mine area are established respectively.