西部软岩全深冻结泥浆置换技术应用研究

Research on the application of mud displacement technology in total depth freeze of western soft rock

针对西部白垩系、侏罗系软岩地层的冻结井筒,采用泥浆置换技术封堵环形空间漏水通道已成为全深冻结的一个必要工序。为防止因导水淹井事故发生,封堵冻结管与围岩间的环形空间,做到既不影响冻结管下放,又能使环形空间不透水,实验室应根据现场的条件进行试验,根据设计进行计算泥浆置换量和泥浆泵运转时间,确保缓凝水泥浆全部注入到钻孔孔底。实践证明泥浆置换施工过程中,严格按照设计程序进行,能够达到封水的效果,适用于西部白垩系、侏罗系地层封堵冻结钻孔环形空间的漏水通道。

Aimed at the western soft rock strata of Jurassic system and cretaceous system in freezing shaft, using the mud displacement technology to block off water leakage gallery of annular space had become a necessary process of total depth freeze. In order to prevent the flooding shaft accident caused by water diversion and block off the annular space between freezing pipe and surrounding rock, neither influence the placement of freezing pipes, nor make the annular space permeable, some experiments should be conducted in laboratory according to field conditions, which could calculate the mud replacement quantity and the running time of slime pump, ensure that the retarding cement paste could inject completely to the bottom of borehole. The practice proved that in the mud replacement progress, in strict with the design procedure, this technology could seal the water. It was suitable for blocking off the water leakage gallery of annular apace in freezing borehole in western cretaceous system and Jurassic system stratum.