Theoretical and experimental research to remove hot water out of drill hose of deep hot-water drilling system

To date, hot-water drilling with its fast penetration rate is the most advanced technology to access rapidly subglacial environments through the thick ice in the Antarctica and Greenland. During deep hot-water drilling, it is important to remove the residual hot water from the drill hose when drilling stops; otherwise, the residual hot water in the hose will quickly cool down and be frozen in less than 1 h at −20 °C if no mitigation measures taken. The frost heaving force generated during the freezing will expand the hose and easily cause the hose to rupture. Based on prior experience and practice of water removal systems for deep hot water drilling, this study makes method choice and system design of removing hot-water from the drill hose, and theoretically calculates the minimum pressure of air pumping system needed to overcome pressure loss in the drill hose. Moreover, the indoor and outdoor tests are made to verify the calculations and provide a robust drill hose dewatering procedure.