Characteristics and potential evaluation of geothermal resources in Anhui of Yangtze River Economic Zone

This paper is the result of geothermal resource survey engineering.

Objective The geothermal resources in Anhui of Yangtze River Economic Zone are abundant, which has good prospects for city development and utilization. The evalution of geothermal resources can provide a scientific basis for the optimization of energy structure, sustainable development and utilization of geothermal resources in this area.

Methods Through analyzing the geological and hydrogeological conditions, e.g., geological structure, formation lithology, and hydrochemical composition of geothermal fluids, this study reveals the distribution characteristics of geothermal resources in Anhui of Yangtze River Econmic Zone, discusses the storage feature of geothermal resources in uplift mountain convective area and conductive-type sedimentary basins, and evaluates its reserves, development, and utilization potential.

Results The geothermal resources mainly occurred in the uplift mountain including the Chaohu-Hexian bedrock, the Dabie mountain, the bedrock along the Yangtze River, the Jiangnan, and at the sedimentary basin including the Dingyuan, the Feidong, the Huoshan-Jijing, the Luzong, the Anqing, and the Xuancheng, etc. The thermal storage of the former uplift mountain is zonal-type, dominated by granite in the fractured zone of the area. The thermal storage of the latter sedimentary basin is layered and layered-zonal type, dominated by lithologic sandstones and carbonate rocks. The thermal storage is mainly metasilicic acid-fluorine thermal mineral water. The hydrochemical type of the geothermal fluid in uplift-mountain type are mainly SO₄ and HCO₃ type. The hydrochemical type of geothermal fluid in sedimentary-basin type is mainly HCO₃ type. According to the potential evaluation results, the utilization potential of geothermal resources in uplift mountain type is relatively small and is basically in over-exploitation situation while that in sedimentary-basin type is relatively large. There are 4, 6, and 10 basins with big, medium, and small potential in sedimentary-basin type geothermal resources.

Conclusions The potential distribution of geothermal resources in Anhui of Yangtze River Economic Zone is uneven, and the geothermal resources need to be planned and utilized in different zones. It is necessary to consider the surface water pollution caused by the utilization of high fluoride and high salinity hot mineral water.