煤层气井井喷机理分析

CBM Well Blowout Mechanism Analysis

山西省某矿在地面施工煤层气井正常钻进至峰峰组进发生了井喷,开始钻孔喷出物为气水混合物,慢慢水量减少,后来喷出物以煤层气为主。为了寻找煤层气井发生井喷的原因,保证煤矿安全生产。在井喷区域进行了补充勘探和地面物探,并收集了以往地质资料。分析表明:煤层气井发生井喷的水源为太原组灰岩水和峰峰组灰岩水的混合水,通道为裂隙断层带和岩溶陷落柱,动力为地应力、水压和气压的共同作用。

A CBM well in a Shanxi coalmine had a blowout during the drilling down to the Fengfeng Formation. At the beginning, the ejecta are mixture of gas and water; gradually water reduced, then transition to mainly coalbed methane. To find out the causation of blowout, ensure coalmine safety in production carried out supplementary exploration and surface geophysical prospecting, collected previous geological data. The analysis has shown that the blowout water source is a mixture of Taiyuan and Fengfeng formations limestone water; channels have fissures, faults and karst subsided columns; driving force is combined action of ground stress, water pressure and gas pressure.