Modeling of the Dachny Site Mutnovsky Geothermal Field (Kamchatka, Russia) in Connection with the Problem of Steam Supply for 50 MWe Power Plant

Abstract

The Mutnovsky geothermal field modeling study (TOUGH2) previously made by the author (Kiryukhin, 1992, 1996, 2002) has shown that total steam production of the wells existing in 1991 will yield not less than 44 MWe x 20 years. In October 2002 Mutnovsky 50 MWe PP was put into operation in Dachny site. The problem of steam supply to Mutnovsky 50 MWe PP (Dachny) trigged the new reservoir model study. Current conceptual model of the Dachny site based on mapping of active fracture zones, circulation losses and production zones distribution data, gas and fluid chemistry data, secondary minerals distributions, recent results of drilling and geothermal analog data reveals "single fault" nature of reservoir (the Main production zone in Dachny site strikes north-north-east and dip east-east-south at the angle 60?. The old model (1992, 1996, 2002) has been revised and the new one based on "well-by-well" generated mesh (A-Mesh grid generator) strongly related to the particular wells and production zones has been used. The following data are used for the new model calibration: (1) pre-exploitation flowtests from wells ?4, 016, 26, 029W and 24, (2) additional wells ?1 - ?4 drilling data, (3) pressure monitoring data (well 012) and (4) exploitation wells ?4, 016, 26, 029W, A2, E5 (2002-2003 year) output data. Modeling results show that total steam production of the operating wells (?4, 016, 26, 029W, E5) will decline from 60-70 kg/s to 30 kg/s during the period of 10 year exploitation due to overload of the north part of the Main production zone. Modeling of the various exploitation scenarios show necessity of drilling of the seven additional wells in the south-eastern part of the Dachny site to maintain 50 MWe PP.