| Title | Effects of Carbon Dioxide Dissolved in Geothermal Water on Reservoir Production Performance |
|---|---|
| Authors | Fatma Bahar HOSGOR, Omer Inanc TUREYEN, Abdurrahman SATMAN, Murat CINAR |
| Year | 2015 |
| Conference | World Geothermal Congress |
| Keywords | carbondioxide, production performance |
| Abstract | Geothermal reservoirs often contain carbon dioxide that has considerable role on the reservoir performance and energy production. Even small amounts of carbon dioxide have profound effects on the behavior of reservoir pressure. Carbon dioxide has the tendency to shift the flashing point of the reservoir fluid to a considerably higher value and causes a gas phase to form in the reservoir. Due to the gas phase formed during production, reservoir pressure can be maintained better. When modeling such reservoirs, it is crucial to include the effects of carbon dioxide in the model. In this study, a new non-isothermal lumped parameter (tank) model is developed to examine and predict the behavior of mass and heat production of geothermal fluids with the consideration of the effects of carbon dioxide. Components of the geothermal system such as the reservoir, the aquifer and the heating source are represented by using a tank so the pressure and temperature behavior of any component of the geothermal system can be modelled. This way the behavior of multiple reservoirs (for example shallow and deep reservoirs with different properties such as different carbondioxide concentrations) can be modelled. The model is based on three conservation equations; mass balances on water and carbon dioxide and an overall energy balance. With this model, the change of pressure and temperature that occurs from production, reinjection and natural recharge, the change of carbondioxide concentration both in the liquid and gas phases with production and also the variation of gas saturation in the geothermal reservoir can be examined. On various synthetic examples we study the effects of various parameters on the performance of pressure and temperature of geothermal systems. We especially look at cases where the mass fraction of carbondioxide can change with time and its effects on the performance. |