Air System and Drilling Fluid Circulation System for Subglacial Bedrock Sampling in Polar Regions: Design and Testing

Abstract. A multi-process drilling system (MPDS), comprising an air system and a drilling-fluid circulation system (DFCS) was developed for sampling the subglacial bedrock in polar regions. The air system can produce dry, cold compressed air in high pressure. The DFCS produced low-temperature drilling liquid and could separate ice or rock cuttings from the drilling liquid for recycling. The two systems were integrated into modified 20 ft containers for easy transportation and assembly. The air system comprised a compressor, receiver, freezing dryer, desiccant dryer and cooler. The DFCS comprised a refrigerating machine, heat exchanger, circulation pump, drilling-fluid pump, vibration sieve, vertical centrifuge, circulation tank, stirring tank, and settling tank. Both systems worked with limitations: the failure of the freezing dryer and desiccant dryer led to the breakage of the air cooler in the field, and several problems were found in the drilling-fluid pump, vibration sieve, vertical centrifuge, and circulation tank. This paper presents in detail, the requirements, principles, and design of the air system and DFCS, in addition to the domestic and Antarctic test results. The experiences and learnings gained in this study will contribute to the development of ice and subglacial bedrock drilling technology.