祁连山区永冻地层钻探工程施工方法

Construction Technology of Drilling Engineering in Permanent Frozen Soil of Qilian Montains

摘要:

通过对高海拔地区永久冻土层的冻结因素和岩心钻探孔内复杂问题的技术分析，从钻孔结构和钻进方法的选择、低温耐寒聚合物冲洗液的选型和配制等方面探讨了在永冻地层钻探施工预防孔内冻结事故和由于孔壁岩石吸热融冻而发生坍塌、缩径、漏失事故等必须解决的关键问题。

关键词:永冻地层;冻结因素;钻孔结构;钻进方法;冲洗介质;选型配制

Abstract:

According to the technical analysis on freezing factors of permanent frozen soil and complex problems in coring borehole, the paper discussed the selection of borehole structure and drilling technology as well as model selection and preparation of cold-tolerance polymer circulation fluid in order to avoid freezing accident in borehole, prevent collapsing, hole shrinkage and leakage caused by thawing from borehole wall endothermic.

Key words:permanent frozen soil; freezing factors; borehole structure; drilling technology; circulation medium; model selection and preparation