Geology and Development of Geothermal Field in Bao-Quanling Formation in Fangzheng County

By taking the Baoquanling Formation geothermal field in Fangzheng County as the research object, this study conducted a detailed investigation of the geothermal resource geological conditions, reservoir characteristics, and geothermal resource potential in the study area, and conducted research on geothermal water extraction and injection balance technology based on geothermal geological conditions. The study shows that the average burial depth of the developed strata in Fangzheng County is 1600–2300 m, the average thickness of the reservoir is 300–500 m, the rock type is mainly sandstone, the average porosity is 18–25%, the permeability is 100–2000 mD, the geothermal resources is 2.5 billion GJ, equivalent to about 21 million tons of standard coal; the geothermal water resources is 5.8 billion cubic meters, and the exploitable geothermal water resources is 1.5 billion cubic meters. By using a large amount of oil and gas exploration well data, a numerical simulation study was conducted on the Baosan section of Fangzheng County, and the optimal well spacing was determined to be 350 m. The predicted single-well production rate is 135 m3/h, the injection rate is 100 m3/h, according to the principle of “determining production based on reinjection”, the five-point regular well pattern is optimized and deployed to meet the heating demand of 2.8 million square meters. The formation water in the study area is of weak alkaline NaHCO3 type, which is non-corrosive, but the total amount of boiler scale exceeds the standard, showing low scaling characteristics. It is suggested to carry out timely scale monitoring in the later production.