Genesis and resource assessment of Lindian geothermal field, Heilongjiang Province

In order to establish the genesis model of Lindian geothermal field and accurately evaluate the potential of the geothermal resources, geological exploration including geological survey, geophysical exploration, geothermal drilling, geophysical logging and water level monitoring were employed. The results show that the main heat sources in Lindian geothermal field are mantle-derived heat, radioactive decay heat produced by basement granite and friction heat generated by deep faults. The geothermal reservoir is mainly composed of sandstones. The third and fourth members of the Quantou Formation, the Qingshankou Formation and Yaojia Formation of the Cretaceous are the main reservoirs. The burial depth of the main geothermal reservoir are ca.940 ~ 2062 m, and the accumulated thickness of the reservoir is ca.150 ~ 240 m. Three deep faults, namely Lindian fault, Lindian East fault and Western Boundary Fault of Heiyubao Sag are good channels for conduction of the deep heat to the upper strata. Furthermore, the Nenjiang Formation, the Sifangtai Formation and the Mingshui Formation overlaying the reservoir form a good thermal insulation caprock. According to calculation, the base resources of the Lindian geothermal field reaches 6.95×10¹⁹ J, whereas the volume of the geothermal fluid is 9.78×10¹⁰ m³, and the recoverable geothermal fluid is 9.84×10⁷ m³/a, equaling to a capacity of 694.13 MW, which is equivalent to a large scale geothermal field. According to water level monitoring, withdrawal of the thermal water in Lindian town reached the maximum in 2017, and the water level dropped to the lowest point, which exceeded the maximum allowable withdrawal, thus reinjection is necessary. This research provides technical support for the exploration, exploitation and utilization planning and mining right setting of the Lindian geothermal field in the future.