Hot dry rock resource is clean and renewable energy with abundant reserve. Exploitation of hot dry rock resource requires drilling to the reservoirs and establishing an enhanced geothermal system (EGS). Hot dry rock formations are usually igneous rock with poor drillability and high temperature, which is a huge challenge to the drilling technology, equipment and materials. Based on analysis of the characteristics of and difficulties in hot dry rock drilling, this paper introduces the key technology and development, including high-temperature drilling fluid, downhole motor, well control, igneous rock fracturing and distributed temperature measurement, and discusses the focus and direction of drilling technology research, which may provide references for managers, researchers and engineers.

hot dry rock drilling  /  high-temperature drilling fluid  /  diamond bit  /  high temperature well control  /  temperature measurement  /  igneous rock fracturing