This paper is result of geothermal geological survey engineering[Objective] Geothermal resource in Huaiyang area belongs typical medium- low temperature geothermal resource of subsidence basin. Evaluation of geothermal resources in the Huaiyang area can provide insights into its exploitation and scientific management.[Methods]In this paper, we analyzed the geochemical and isotopes characteristics of geothermal fluids to explore their local geothermal field features and genesis.[Results] The results show that the deep thermal reservoirs are significantly affected by basement structure and faults characteristics. The geothermal gradient is higher (e.g., 3.75℃/100m in the Suzhuang area) along the boundary of faults than the other areas (e.g., 3.5℃/100m). The type of the geothermal fluids are dominated by Cl · HCO₃ · SO₄-Na, Cl·SO₄·HCO₃－Na and Cl·SO₄-Na. The main cation of the geothermal fluid is Na⁺ while the anions variou in types. The geothermal fluids were probably derived from the atmospheric "ancient water" of the Funiu Mountain in the western Henan province before 1952, with relatively weak rock-fluid reaction.[Conclusions]The major exploited geothermal reservoirs are placed at the Neogene Minghuazhen and Guantao Formations. The geothermal resources are mainly used for heating feeding, etc., which has greatly improved the local economy, Contribute to the realization of the "dual carbon" goal in the region.
Highlights: The relationship between geothermal gradient and geological structure in Huaiyang is analyzed; The sources of different ions in Huaiyang geothermal fluid and the main sources of geothermal fluid are discussed.