College of construction engineering, Jilin University, Changchun Jilin 130026, China
Clc Number:
P634
Fund Project:
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Abstract:
Air reverse circulation drilling technology, which has advantages of fast drilling speed, low energy consumption, continuous core sampling without tripping and effective prevention of circulation loss in snow cover, sees great potential application in ice drilling. In view of the characteristics of ice drilling technology, this paper proposes three kinds of air reverse circulation ice drilling techniques, including dual-wall drill pipe, double channel high pressure hose and parasitic high pressure hose; and describes their working principles and characteristics respectively. Analysis is made of the suspension velocity of ice particles in air medium with the suspension and transport equations for both the single ice particle and the particle group established under the guidance of pneumatic transportation and gas drilling theory. Meanwhile, the experimental bench was designed to test the air speed required for ice chips suspension. The calculated values are in good agreement with the measured values with the maximum difference at about 10.91%. The results showed that the ice particle size, ice particle density and air volume are the key factors affecting the suspension and up-hole velocity. The equation for ice chips movement established in this paper can be used to calculate the air volume required to carry ice chips during actual drilling, providing a basis for the subsequent implementation of air reverse circulation ice drilling technology in the polar regions.