Characteristics of geothermal geology of the Qiabuqia HDR in Gonghe Basin, Qinghai Province

Based on regional geology, geothermal geology and integrated geophysical exploration results, the GR1 hot dry rock exploration well was completed in the central part of Qiabuqia Town in the Gonghe basin. The GR1 well is the highest temperature hot-dry rock exploration well in China, which has laid an important foundation for China's first EGS demonstration project. The temperature measurement results show that the temperature at the depth of 2500 m is 150℃, entering into the hot dry rock section. The temperature of the bottom hole at the depth of 3705 m is 236℃. The average geothermal gradient of 2500-3705 m is 71.4℃/km, which is higher than that of the other 3 hot dry rock exploration wells. At 2800-3705 m of GR1 well the geothermal gradient is higher than 80℃/km. The exploration results show that the depth of the hot dry rock is 2104.31-2500 m, which is oval-shaped in the east-west direction, with an area of 246.90 km². The evaluation results show that the total theoretical resources of the Qiabuqia hot dry rock is 1638.16EJ in the depth of 3-5 km, equivalent to 55.909 billion tons of standard coal.