Innovative Approach to Drilling of Geothermal Deep Wells Using the Heat Factor

Abstract

Using of sources of clean alternative energy is among the top priority challenges both in Europe and worldwide. Geothermal energy seems to be among the prospective energy sources. The challenge of developing of geothermal energy resources is caused by its complex nature and high cost of deep (up to 3–8 km) geothermal wells drilling. No traditional drilling methods are effective in this case. The present paper is aimed at estimation of innovative drilling technology using a thermal factor to rock disintegration. Decomposition process is intensified by using the pulse (interrupted) jet flushing mode which impacts the drilling bit / mining rock junction contact temperature and controls the heat exchange processes of the bottom-hole area. The theoretical basis and some experimental results of development such technologies are presented. The presented results show that it is possible to increase the drilling velocity of hard rocks up to 2.6 times due to the use of the heat factor. It is expected to offer new insights into the mechanics of mining rock disintegration by heat impact drilling and relation between mechanical and thermal fields in mining rock and drilling parameters. The proposed method ensures the efficient drilling of hard mining rocks at deep depths as required in the course of geothermal wells boring.