Challenges in the Design and Management of a 20-MW Geothermal Field: the Maibarara Geothermal Field (Philippines) Experience

Abstract

The Maibarara Geothermal Field is located approximately 70 kms south of the capital city of Manila, within the volcanic zone associated with the Macolod Corridor. The proven reservoir area, about 2.5 km2, is a liquid-dominated system with neutral-pH fluids and temperatures of more than 300oC. The field is expected to be put in commercial operation in February 2014. To date, two production wells supply steam to the power plant and two reinjection wells are used for reinjecting brine and condensate back into the reservoir. Based on the initial behavior of the reservoir, additional capacity can still be tapped to add another 10 or 20 MW to the existing power plant. Continuous production data will be collected to verify this initial behavior. The paper describes the design and operation of the Maibarara geothermal field including challenges to its reinjection and production schemes. Measures to ensure judicious use of the small reservoir and the surface facilities are also described.