Optimization of the Process for Thawing Frozen Ground During Drilling
Proposals for improving the design of rock cutting tool (bit) during drilling in permafrost conditions in areas of the North-East and Arctic regions are considered. The extreme climatic conditions of the regions and thick layers of permafrost rocks bring about special requirements for methods and technology of exploration. Deposits of the permafrost zone have significant differences from deposits located in areas with a temperate climate and positive temperature rocks due to a complex interaction and the influence of geological, mining, permafrost and climatic factors. The basis of the complicated conditions of drilling in permafrost temperature is the temperature factor that determines the efficiency of the process of destruction and transportation of frozen rocks. In the process of destruction of frozen rocks, upon contact of the cutters with rocks in the area of the working surface of incisors the heat dissipation is enhanced. Analytical studies of the regularities of heat formation on the surface of the incisors are carried out and the dependence of heat generated on the wellbore from the radius of the rock cutting tool (bit) cutters location T=f(r) when cutting frozen rocks is revealed. On the basis of the obtained data, we propose an improved version of rock cutting tool (bit), which provides effective destruction of the borehole bottom and minimizes the heating.