沿煤层顶板钻进煤层气U型井二次贯通技术探讨

摘要

The U-shaped wells are applied progressively in the CBM resource exploitation in recent years, but the U-shaped penetra-tion drilling along the coal roof still the first time in China. Owing to the long distance of casing lowering depth apart from cave thus formed too long cement plug, too long cementing curing time and too large cement strength brought on the first time failure of the sec-ondary penetration. In allusion to the situation, three staged reaming is used on vertical part of the cave and realized secondary penetra-tion finally. The paper comprehensively introduced technical measures in reaming, and corresponding precautionary measures ad-vanced for later operations.%U型井在煤层气资源开发中逐渐得到应用，但沿煤层顶板钻进的U型连通井在国内尚属首例。该在进行二次贯通时，由于套管下深距洞穴太远而形成过长水泥塞、固井候凝时间过长而水泥强度太大的原因造成了第一次二次贯通失败。针对这种情况，现场采取在洞穴直井处三级扩孔方法，最终实现了二次贯通，对在扩孔时技术措施进行了较为全面的介绍，并对以后施工提出了相应预防措施。