Rotary Drilling and Coring in Permafrost. Part III. Deep Core Drilling, Core Analysis and Bore Hole Thermometry at Cape Thompson, Alaska

摘要

Two holes were successfully drilled and cored to depths of 1000 ft and 1200 ft in the frozen mudstone of the Tiglukpuk formation at Cape Thompson, Alaska. Permafrost extends to a depth of approximately 1000 ft. The hole walls were successfully stabilized, even in zones of very weak rock, by the use of refrigerated diesel fuel as a drilling fluid, and frozen cores of good quality were taken with little difficulty. A thermistor cable was inserted in one of the holes and ground temperatures were measured to 1000 ft with a high order of accuracy and stability. Data required to predict accurate equilibrium temperatures were available one month following installation. (Modified author abstract)