By Staff Reporters

Sinopec's Fushen-1 well in Hainan province, south China, has set a new record as the deepest geothermal exploration well in China. It drilled into a 250-million-year-old granite formation in a hot dry rock reservoir to reach a depth of 5,200 meters, the company said.

The well began drilling in August 2023, targeting the tapping into granite formations dated 250 million years ago within the hot dry rock reservoirs.

The drilling started in August 2023, using the company’s self-developed “dual-drive drilling plus high-pressure injection” method. The innovation facilitated successful drilling to a depth of 3,900 meters, obtaining geothermal energy at 150°C,which met the standards for high-temperature geothermal resources.It also led to drilling to a greater depth of 5,000 meters, accessing a greater depth of 5000 meters, accessing?geothermal energy at 180°C, meeting the dry rock temperature limit stipulated by national energy industry standards.

Fushen-1 is a remarkable milestone as geothermal exploration wells rarely go beyond 4 km. In the past, geothermal resource exploitation and utilization in China primarily focused on hydrothermal resources in shallow and moderately deep areas. However, despite the breakthrough, the exploration of deep geothermal resources below 3,000 meters, particularly dry hot rock resources, still remains in the early stages.

The achievements will provide valuable information on the potential of hot dry rock geothermal resources in south China.

According to Chen Hongsheng,chief engineer in the Department of Natural Resources and Planning of Hainan Province,preliminary exploration assessments indicate that the current estimated dry hot rock resources in the province equal approximately 38.6 billion tons of standard coal.

"Calculated at a resource utilization rate of five to eight percent, the exploitable quantity is estimated to be around two billion tons of standard coal. The total electricity generation is projected to range from 60 trillion to 70 trillion kWh," the chief engineer said.