N.G. Timofeev, R.M. Skryabin, R.A. Atlasov

Abstract. There are special requirements for optimum boring tools and drilling technologies when drilling of various wells (prospecting, operational, engineering survey) in the regions of the Northeast and the Arctic zone of the country with extreme climatic conditions and with a thick layer of perennially frozen rocks. Deposits of the permafrost zone have significant differences from analogs located in regions with a temperate climate and a positive temperature of rocks. Their specificity is determined by complex interaction and influence of mining-geological, mining, permafrost and climatic factors. The main thing in complicated conditions of rotary drilling of wells in permafrost rocks is a temperature factor determining the efficiency of destruction process of frozen rocks and their transportation. During the process of destruction of a frozen rock, when a rock-cutting tool incisors contact with a rock mass, a heat release intensifies in the area of a working surface of incisors, which promotes frozen rocks melting and freezing of a broken rock to the drilling tool, what leads to various complications and accidents.

Key words: well drilling, cryolithozone, well temperature, heat exchange, mathematical modeling.