川南煤田古叙矿区钻探技术难点与对策

Drilling problem and countermeasures of drilling technology in Guxu Mining Area of South Sichuan Coalfield

川南煤田古叙矿区地质条件复杂,煤系地层厚度大,煤层松散,溶洞裂隙发育,钻探过程中存在孔壁失稳垮塌、钻孔漏失等技术难点。对此,综合考虑地质条件和溶洞发育情况,优化了钻孔结构;根据煤系地层岩石性质,采用聚合物防塌冲洗液钻进,防止泥岩水化膨胀,保持孔壁稳定;根据钻探过程中不同类型的漏失,采用惰性材料封堵孔隙性漏失,采用桥接堵漏浆液封堵裂缝性漏失,采用速凝水泥浆液封堵溶洞性漏失。将上述技术对策在矿区ZK3003孔进行了现场试验,实现了优质、高效、安全钻进,对该矿区的钻探施工具有较强的指导和借鉴作用。

The geological conditions of Guxu Mining Area in Southern Sichuan Coal Field are complicated,such as thick coal measure strata,loose coal seam,fissure development of karst cave,pore wall instability and collapse,hole leakage and low coal seam taking rate exist in the drilling process.Considering the geological conditions,the drilling structure design and coal bit selection are optimized.According to the characteristics of coal measure strata,the polymeric anti-collapsing washing fluid is used to drill to prevent mudstone hydration expansion and keep the hole wall stable.According to the different types of leakage in the drilling process,the porous leakage is blocked,the fissure leakage is blocked by bridging plugging slurry,and the karst cave leakage is blocked by polyacrylamide cement slurry.The above technical countermeasures are tested in ZK3003 hole of the mining area,and good production results are obtained.It has a good guiding and reference role for drilling construction in the mining area.