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

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.