Thermal and permeability structure and recharge conditions of the low temperature Paratunsky geothermal reservoirs in Kamchatka, Russia

TOUGH2 modeling of the thermo-hydrodynamic natural state and the history of exploitation (involving pressure, temperature and chemical changes response to utilization) between 1965 and 2014 yield estimates of hot water upflow rates (190 kg/s), the production reservoir compressibility (up to 4 × 10−8 Pa−1) and permeability (up to 1.4 D). Modeling confirmed areal discharge of the thermal water from the production reservoir in the top groundwater aquifer (top Dirichlet boundary conditions). Modeling of the chemical (Cl-) history of exploitation provides an explanation of gradual Cl- accumulation due to the inflow of chloride-containing water through the eastern (open) boundary of the geothermal reservoirs. Modeling of the long-term exploitation until 2040 with an exploitation load of 256 kg/s merely shows a low pressure drop (0.7 bar) and an insignificant drop of temperatures in the production geothermal reservoir of the Paratunsky geothermal field.