Drilling Technical Difficulties and Solutions in Development of Hot Dry Rock Geothermal Energy

The exploration and development of hot dry rock resources, first of all, needs to address the drilling issues in deep, hot, hard and unstable formations. By studying geological features and storage conditions of hot dry rocks, the key technical difficulties of hot dry rock drilling are presented. The high-temperature resistance performance index of oil and gas drilling technologies at home and abroad are investigated. The applicability of high effective rock breaking tools, MWD instruments, drilling fluid systems, well cementing and completion technologies are analyzed, and feasibility analyses have been conducted on gas drilling, dry wellbore cementing and foam pressurized drilling techniques. On the basis of the above analyses, the developing directions and issues urgently to be addressed about domestic hot dry rock drilling technology are discussed so as to provide references for drilling program optimization and drilling technology research in the development of hot dry rock geothermal energy.