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以淮南矿区远程卸压煤层气地面井抽采工程实践为依托,通过工程试验和系统分析,探讨了远程卸压煤层气地面井的产能特点及其影响因素。研究结果表明,远程卸压煤层气地面井的产能曲线可分为两个阶段,在较短时间内顺利完成第Ⅰ阶段的井才能有较高产能。研究还显示,煤层气地面井产能受地层结构和采动影响较大。在研究区,当地层结构为松散层厚度<406 m,基岩与松散层厚度比值>0.74,下保护层与被保护层间距为66~70 m,且平均采高≤2.2 m,平均产煤低于3 898 t/d时,利于远程卸压煤层气地面井抽采;当松散层厚度>430 m,11-2煤和13-1煤层间距>74 m,基岩与松散层厚度比值<0.7时,卸压煤层气地面直井成功率较低,此时,可通过改变井位和优化井身结构来适应地层结构的变化,提高地面井抽采成功率。
Based on the practice of deep well drilling and surface drainage in Huainan mining area, through engineering test and system analysis, the productivity characteristics and the influencing factors of the surface well in the remote relief CBM are discussed. The results show that the production curve of the ground well in the remote relief CBM can be divided into two stages, and the first stage well can be successfully completed in a relatively short period of time to achieve higher productivity. The study also shows that the productivity of coalbed methane ground wells is greatly affected by the stratum structure and mining. In the study area, the structure of the local strata is as follows: the thickness of loose layer <406 m, the ratio of bedrock to loose layer thickness> 0.74, the distance between the lower protective layer and the protected layer is 66-70 m, and the average mining height is less than 2.2 m, When the depth is less than 3 898 t / d, it is favorable for the drainage of the surface wells by the remote relief CBM. When the loose layer thickness is> 430 m, the interval between 11-2 coal and 13-1 coal seam is> 74 m, the ratio of bedrock to loose layer thickness < 0.7, the success rate of ground vertical well in CBM relief is low. At this time, the well structure can be adapted to the changes of the well structure by changing the well location and optimizing the structure of the wellbore to improve the success rate of surface well pumping.