| Abstract |
In order to explore the sandstone reservoir genetic mechanism of Guantao Formation of the Kaifeng depression in southern north China basin. Based on the regional geological structure characteristics, combined with geothermal drilling data, the distribution law of thermal storage, geothermal field and hydrochemical characteristics in the study area were analyzed, and a conceptual model of geothermal system genesis was constructed. On this basis, the geothermal resources were finely evaluated. The results show that the distribution of thermal reservoirs in the Guantao Formation is relatively stable in the area, the floor depth is between 1750-2200m, the thickness of the reservoir is between 133-329m, the porosity is between 16%-32%, and the reservoir-thickness ratio can reach up to 67%. The water temperature of the sandstone geothermal well in the Guantao Formation is 53-70 °C, and the water chemical type is mainly Cl-Na. The upper Quaternary and Minghuazhen Formation strata constitute a good cap layer in the area. The heat source comes from the high geothermal value background of the Cenozoic rift basin, about 56-60mW/m2. The Xinxiang-Shangqiu deep fault in the north is a favorable channels for the upward transportation of deep heat flow. The thermal storage as a whole is recharged by atmospheric precipitation replenishment from the western and southwestern mountainous areas, and is laterally recharged to the thermal storage after deep heat conduction and warming. The evaluation results of the geothermal resources in the Kaifeng Depression show that the sandstone geothermal resources of the Guantao Formation are about 3.14×1011GJ, and the annual exploitable geothermal resources are 7.86×108GJ equivalent to 2.68×107t of standard coal. The annual exploitation of geothermal resources can meet the heating area of about 9.49×108m2, and the development potential is huge. |