ABSTRACT
There are many applications where it is necessary to penetrate rocks and/or the ground that are at very high temperature. These applications include drilling holes in very deep oil and gas reservoirs, drilling geothermal or enhanced geothermal wells, and exploration of hot planets such as Venus and Mercury. In geothermal drilling, for example, the temperature of formations can reach 300°C and more. Because of the relatively small market share, equipment manufactures do not have an incentive to develop geothermal-specific technologies or products. Most of the techniques or tools have been adopted from the oil and gas industry and do not work well past 300°C (GTP, 2010).
