Evolution of the Miravalles Geothermal Field in Costa Rica after Ten Years of Exploitation

Abstract

The Miravalles Geothermal Field has been producing since 1994, and its installed capacity has now reached 163 MW. The field is a high-temperature liquid-dominated reservoir with temperatures reaching 230-255?C. Since exploitation began, the reservoir's chemical, hydraulic and thermal parameters have been carefully monitored to assess the changes produced by commercial exploitation. The reservoir response over a ten-year exploitation period has evolved notably due to massive production and injection in some sectors of the field. Further monitoring and modeling studies must address critical questions such as the proper design of production and injection policies, the strategies to be carried out and the future impact on the reservoir from commissioning a new power plant (Unit 5) in early 2004 and other possible developments.