Potential of Hydro-thermal Spallation Drilling in Geothermal Scenario

Abstract

The aim of this paper is to compare the different types of drilling technologies with Hydrothermal Spallation Drilling (HSD) based on technical basis and efficiency. These days, HSD method is used over the conventional drilling technologies like cable tool drilling and mud rotary drilling. The HSD is a new, efficient and effective contact-free drilling technology which uses a hydrothermal flame to drill through the rocks. It has been brought in use as it is cheaper than other conventional drilling technologies like Rotary Drilling Technology. This technology creates thermal stress on the upper rock layer which breaks the polycrystalline rock into small disc-like fragments with the help of a highly energetic flame jet. Whereas for drilling of deep geothermal boreholes with kilometres of depth, this technology has to rely on water-based drilling fluid. The maintenance of relatively cooler drilling fluids could lead to the loss of heat before even reaching the rocks and converting them to spalls which is one of the drawbacks of this method. Together, this study discusses the technical aspect and the different processes that are included in this method.