复杂地层钻孔失稳原因分析及措施

Analysis and Measures of Borehole Instability in Complex Formation

地质钻探向深部发展是必然趋势,孔内复杂情况以及孔壁失稳造成孔内事故越来越频繁。从化学以及力学方面寻找孔壁失稳的原因,通常冲洗液的失水量过大造成孔壁粘土的水化膨胀,孔壁的结构稳定以及力学平衡被破坏,这时就需要通过制定相应的技术措施,优化钻头以及取心工具,并对不同复杂地层配置相应的钻孔冲洗液。通过在一些项目上技术工艺的改进同时配合强抑制性的钻孔冲洗液,在一定程度上提高钻孔稳定性,提高了钻探效率。

The drilling accidents caused by the complicated conditions in the hole and the instability of the hole wall are very common.The hole-wall clay hydration swelling resulting from the excess water loss of the flushing fluid is responsible for hole wall instability.Optimize bit and coring tool and the corresponding drilling flushing fluid arranged for different complex formations can improve the borehole stability to a certain extent.