Maintenance of the Production in the Miravalles Geothermal Field, Costa Rica: New Productive Zones

Abstract

The Miravalles Geothermal Field has operated continually since 1994 when a 55 MWe power plant was commissioned, and has raised its installed capacity up to 163 MWe in the present time. As any other aquifer under exploitation, the sustainability of the resource depends on the exploitation policies and if they are able to let the aquifer to reach a steady state that allows the extraction rates being similar to the recharge rates, without showing a significant reservoir pressure and temperature decrease; at the same time these policies allow to control the derived adverse secondary effects of the chemical complexity of the fluids which in fact affect the production capacity.
The exploitation régime of which the reservoir has been operated affects its future performance and sustainability and it is showing indications of decline. If the reservoir continues to be exploited in the actual régime it could suffer an abrupt decline in its productivity. To assure a continuous production in the current levels, different productive zones and aquifers in the field have been studied. These new productive areas would contribute with new reserves (fluid) and distribute the production in a more extensive area, alleviating the pressure drop and improving the mass and energy extraction processes in the field.