陇东地区地下水对煤层气开发的影响

Influence of Groundwater in Longdong Region on CBM Development

陇东地区主要含煤地层为延安组,可采煤层主要为5号、6号和8号煤层,煤层瓦斯含量高,煤层气资源丰富。在煤层气勘探的过程中发现,该区下白垩统志丹群洛河组、宜君组裂隙承压含水层为中等富水含水层,且地下水矿化度高,构成煤5和煤8层顶板间接充水含水层,导致煤层气井排采过程中产水量大,动液面下降困难,且油管、油杆等设备腐蚀严重,影响了煤层气井的连续排采。本文通过对该区煤层气井排出水进行测试化验,根据化验结果找出设备腐蚀的原因,并针对该水文地质条件提出煤层气井改进措施。

Yan＇an formation is the main coal bearing stratum in Longdong region. The main mineable coal seams are No. 5,No. 6,No. 8 coal seam. The Coalbed gas content is high,and the resource is rich. It finds that in the process of coalbed methane exploration,the fracture confined aquifer of Zhidan and Yijun formation of lower cretaceous is medium water- rich,and the degree of mineralization of underground water is high. It forms the indirect water filling aquifers of No. 5 and No. 8 coal layer roof,leads to water rate of CBM well is big,working fluid level drawdown is difficult,and equipment such as tubing,rod is serious corrosion,affects the continuous drainage of CBM wells. The discharge water of coalbed methane well in this area is tested,according to the test results find out the cause of equipment corrosion,CBM well improvement measures are put forward based on the hydrogeological conditions in this region.