Thermo-hydro-mechanical-chemical impacts of high-temperature aquifer thermal energy storage
(English) High Temperature Aquifer Thermal Energy Storage (HT-ATES) involves the injection and extraction of non-isothermal fluids into aquifers and triggers thermo-hydro-mechanical-chemical processes. These processes must be analysed and understood for obtaining safe and efficient HT-ATES systems....
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| Tipo de recurso: | tesis doctoral |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/432850 |
| Acceso en línea: | https://hdl.handle.net/2117/432850 https://dx.doi.org/10.5821/dissertation-2117-432850 |
| Access Level: | acceso abierto |
| Palabra clave: | HT-ATES Thermo-hydro-mechanical-chemical impacts Temperature Analytical solution Modelling 624 - Enginyeria civil i de la construcció en general 55 - Geologia. Meteorologia 620 - Assaig de materials. Material comercials. Economia de l'energia Àrees temàtiques de la UPC::Enginyeria civil Àrees temàtiques de la UPC::Energies |
| Sumario: | (English) High Temperature Aquifer Thermal Energy Storage (HT-ATES) involves the injection and extraction of non-isothermal fluids into aquifers and triggers thermo-hydro-mechanical-chemical processes. These processes must be analysed and understood for obtaining safe and efficient HT-ATES systems. This thesis aims to deepen the understanding of these processes, provide methods and solutions that can be easily and straghtforwardly implemented, for assessing the impact and feasibility of these systems and iii) forecast the system's long-term performance. First, the coupled thermo-hydro-mechanical finite (THM) element code CODE_BRIGHT has been verified against several tests of a benchmark for thermo-hydraulic processes (TH) in geothermal situations. This code has been used in the development of other methods of the thesis. It has been showed that CODE_BRIGHT is competent in performing all these tests. Second, a method that can be used to develop analytical and semi-analytical solutions for calculating reaction rates for non-isothermal cases has been developed. The method assumes that aqueous and mineral reactions are in equilibrium. The chemistry has been decoupled from the TH processes. In the chemical part of the method, batch calculations are performed to obtain dissolution or precipitation of minerals and water chemistry changes due to temperature variations. The TH part consists of calculating temperature and spatial and temporal derivatives of temperature. From this, one can easily calculate both the chemical composition of groundwater and the rates of mineral precipitation or dissolution. The method facilitates comprehension of the dominant reactive transport processes, mineral reaction rates and porosity changes. The application of this method for simulating a HT-ATES system resulted in a reduction of computational costs by a factor of seven compared to a conventional coupled thermo-hydro-chemical numerical code. Third, a dimensional and numerical analysis of the THM behaviour of a pilot HT-ATES system has been proposed. Three dimensionless numbers that could be easily implemented have been obtained: Peclet number and two numbers for the hydraulic and thermal strains. The Peclet number, which has been decomposed in conductive and dispersive terms, is useful to identify the dominant TH flux (advection, dispersion or conduction). Hydraulic and thermal strains numbers relate the strain generated by changes of hydraulic head and temperature, respectively, with respect the initial total strain of the system. This study's findings have revealed information about the main TH fluxes and their domain areas, evolution of the energy efficiency of the system over time and the role of the hydraulic and thermal loads generated by the injection and extraction of hot water in the vertical displacement of the terrain. The study has provided information about the behaviour and efficiency of the system to long term operation. Finally, an analytical solution for calculating ground surface uplift due to point non-isothermal injections which takes into account thermal and hydraulic head changes has been presented. The main advantage of this solution is its easy implementation in a superfast way, in terms of computational cost, in comparison to a standard thermo-hydro-mechanical code. This solution has been verified satisfactorily against results from a coupled THM numerical model and field data (levelling and PS-INSAR) in a leakage case in a geothermal power plant. The results have demonstrated the contribution of hydraulic head and temperature to ground surface displacements and have facilitated an understanding of the effect of the natural geothermal gradient. The solution is useful for forecasting ground displacement resulting from point injections and extractions under various conditions and time scales. |
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