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Numerical Modeling of Thermo-Hydro-Mechanical Behavior of Deep Geothermal Reservoirs

Bannae Sharifian, Mohammad Reza | 2020

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 53636 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Pak, Ali
  7. Abstract:
  8. All societies need energy to meet the basic needs of the people and to carry out the production processes. From 1850 onwards, the global use of fossil fuels (coal, oil and gas) for energy production increased, leading to a dramatic increase in the emission of carbon dioxide (CO2) into the atmosphere. Rising carbon dioxide and other greenhouse gases in the Earth's atmosphere and seeing adverse effects such as global warming have prompted the international community to replace fossil fuels with clean energy as much as possible. Geothermal energy as one of the clean, sustainable and extensive sources can be one of the available solutions to meet this need.Numerical modeling of geothermal reservoirs is essential for reservoir management in terms of energy production as well as predicting reservoir behavior in the production process. In the present study, two approaches of thermo-hydraulic (TH) and thermo-hydro-mechanical (THM) processes have been used to predict the performance and behavior of geothermal reservoirs. Verification and modeling of problems in the technical literature showed that COMSOL software can be a good tool for investigating geothermal reservoirs with the two approaches mentioned.Examination of the performance of geothermal reservoirs with TH approach showed that the thermal effects of rock buffer around the reservoir on the temperature of the outlet fluid, especially with increasing the thermal conductivity of the rock matrix cannot be ignored. Then the optimal arrangement of the reservoir was studied. It was observed that the two-well arrangement, which is diagonally placed inside the reservoir, has the best thermal performance. Also, comparing the performance of two fluids, water and brine with a concentration of 15%, showed that the performance of thermal energy extraction with water is more optimal.By extending the TH-correlated process to the THM process and considering the changes in the permeability coefficient of the reservoir rock with stress, it was observed that the creation of a flow channel is one of the most important factors in reducing the thermal performance of the reservoir. Changes in the size of the parameters related to thermoelastic stress (elastic modulus and thermal expansion coefficient of rocks) have the greatest impact on the formation of the flow channel. Also, the use of hydraulic heterogeneity of the rock matrix in the proper arrangement of wells reduces the effects of the flow channel and increases the thermal extraction of the reservoir
  9. Keywords:
  10. Thermohydraulics ; Deep Geothermal Reservoir ; Porous Media ; COMSOL Software ; Thermo Hydromechanical Analysis ; Clean Fuel ; Clean Aquatic Energy Harvesting

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