Renewable Capacity of Karst Geothermal Water and ProductionReinjection Balanced Resources Evaluation: A Case Study of Heze Buried Uplift Geothermal Fields

The renewable capacity of geothermal water and production-reinjection balanced resources evaluation of karst geothermal fields are the key issues of sustainable exploitation of geothermal energy. In order to evaluate the research more scientifically, this paper takes the Heze buried uplift geothermal field as an example, and takes the cycle enrichment, development dynamics, hydro-chemical and isotope characteristics of geothermal water as the controlling factors to establish an evaluation index system to comprehensively evaluate the renewable capacity of karst reservoir geothermal resources. The calculation method of sustainable yield of geothermal water is put forward under the prerequisite of production-reinjection balance, i. e. under the condition of geothermal water equilibrium and heat energy equilibrium. Then, the sustainable yield of geothermal water in the concentrated exploitation area of the geothermal field is evaluated. The renewability of geothermal water in the Heze buried uplift geothermal field is divided into four districts: strong, relatively strong, medium and poor. The strong region is distributed in the recharge area in the northeastern part of the geothermal field near the Liang mountain and Jiaxiang; the poor region is distributed in the discharge area around Dingtao-Heze urban area in the central and southern part of the geothermal field. In the recharge area and near the fault zones, the fissures and karstifications are developed strongly, and the water abundance of the geothermal reservoir is rich. On the contrary, far away from the recharge area and the fault zones, the fissures and karstifications are developed weakly, and the water abundance is poor. Under the production-reinjection balanced condition, the sustainable yield of geothermal resources is evaluated to be 122 600 m3/d in the concentrated exploitation area, which is 2.49 times as much as under the natural condition. © 2023 China University of Geosciences. All rights reserved.