Extraction of Geothermal Water Using Directed Energy Method of Millimeter-Wave Technology

Drilling of geothermal water well is quite challenging than traditional water well drilling. Geothermal water well drilling deals with high-temperature and pressure conditions. Conventional drilling methods are very mature, but still have difficulty drilling through very deep, very hard, and hot rocks for geothermal water well drilling applications. Physical contact between the tool bit and the rock or surface to be drilled is the major constraint in conventional drilling methods. It is necessary to find cost-effective technologies to improve drilling performance in hard rock formations in order to support the growth of geothermal energy generation from deep deposits. Currently, the costs associated with drilling can make up to 70% of a deep geothermal project's overall investment. Millimeter waves (MMWs) are one of the technologies which overcome the limitations and reduce rock drilling to a fundamental interaction between energy and matter without the need for mechanical contact with the surface to be drilled. This review states a brief history of directed energy drilling, various types of deep drilling methods including plasma-pulse geo-drilling, thermal spallation drilling, flame jet drilling, electropulse boring, and laser drilling. Millimeter-wave technology is discussed in detail with its method of operation, how it is useful in melting rocks at greater depths, the rate of penetration it provides, and its merits are discussed as compared with conventional drilling methods. Moreover, deep drilling using MMW from a geothermal perspective is discussed where penetrating hard rocks encountered at greater depths are a major challenge.