Calculation method and suitability zoning of recoverable geothermal fluid in Guantao Formation of Tianjin City

This paper is the result of geothermal resources survey engineering.

Objective The "14th Five-Year Plan" is a critical period and a window period for carbon peaking. It requires efforts to promote clean energy utilization and low-carbon transformation rationally. Low-carbon and clean geothermal resources in Tianjin are abundant. It is significant to adjust the energy structure and conservation and improve the environment. Tianjin has carried out the compilation of the "Tianjin Mineral Resources Planning (2021-2025)". Among them, to consolidate the foundation of planning and finding geothermal reserves, an evaluation topic is set up to conduct in-depth research on the potential of geothermal resources in Tianjin.

Methods The special topic evaluates and compares the geothermal resource potential of the Tianjin Guantao Formation by using the thermal storage method, statistical analysis method, and numerical simulation method.

Results It is concluded from the research that the recoverable amount of geothermal fluid in the Guantao Formation is 0.94×10⁸m³/a without considering recharge and other constraints; with statistical analysis method in the case of considering recharge, water level depth, and water level drop, the recoverable amount of geothermal fluid in Guantao Formation is 0.28×10⁸m³/a; numerical simulation method in the case of considering recharge, temperature drop and water level drop, the recoverable amount of geothermal fluid in Guantao Formation is 0.296×10⁸m³/a.

Conclusions Through comparative research, it is believed that the statistical analysis method and numerical simulation method are used to calculate the reliability of the results. The GIS-based AHP is used, and the GIS technology and the AHP are combined to carry out comprehensive evaluation and suitability zoning of geothermal resource development and utilization potential in the Guantao Formation.