Simulation of geothermal reservoirs with high amount of carbon dioxide

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2018
Küçük, Serhat
Geothermal energy is always attributed as a sustainable and environmentally friendly source of energy. But in some cases, amount of the greenhouse gas emissions from geothermal fields become a big issue. Kızıldere Geothermal Field, one of the most important and large scale geothermal fields of the world, is a subject of these issues, experiencing excess amount of CO2 production rates and a rapid decline in the reservoir pressures. This study aims to construct a numerical model of the Kızıldere Geothermal Field and predict the consequences of potential/possible future operations. Petrasim interface is used for the creation and the visualization of the model, as well as preparation of the simulation input files. EOS2 fluid property module of TOUGH2 simulation codes is used for the numerical simulation of the geothermal model. The natural state model of the field is obtained by running the simulation for a long time until the reservoir parameters are reached to stabilized conditions. In order to test the model, static pressure and temperature data of 53 wells, as well as dynamic pressure data of 15 observation wells are matched with the simulation results, within an error range of 10%, and the model is validated with a great accuracy. Based on the validated model, different reinjection scenarios under two different strategies are carried out. In the first strategy, production rates are kept constant in exchange for the wellhead pressures, while wellhead pressures are kept constant by adjusting the production rates in the second strategy. The results of different scenarios show that the current reinjection plan of the field restricts to have higher impacts on the reservoir pressures by higher reinjection rates. Results also show that Kızıldere Geothermal Field can be used as a sink for greenhouse gases (especially CO2), which have positive effects on the reservoir management purposes beside the environmental benefits.

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Citation Formats
S. Küçük, “Simulation of geothermal reservoirs with high amount of carbon dioxide,” M.S. - Master of Science, Middle East Technical University, 2018.