Development of the Maibarara Geothermal Field, Philippines

Maria Victoria M. Olivar1, Miguel B. Esberto2, Lea Carmelia D. Fernandez1

1PetroEnergy Resources Corp., Pasig City, Metro Manila, Philippines
2Maibarara Geothermal Inc., Pasig City, Metro Manila, Philippines


The Maibarara Geothermal Field is the newest geothermal field to be developed in the Philippines. Exploration was started by Philippine Geothermal Inc. (PGI) in the 1970’s and this led to the drilling of 12 wells from 1977-1983. The potential of the field was realized after testing of these wells; however due to various reasons, development of the field did not materialize. Only after the Philippines’ Renewable Energy Law was enacted in 2008 that field development was initiated by Petroenergy Resources Corp. when it won the bid for the service contract. Maibarara Geothermal Inc (MGI) was subsequently established to develop the field. To date, preparations are underway for the commercial operation of the 20 MW power plant on 4th Qtr of 2013.

The Maibarara Geothermal Field is within a northeast-trending zone of active faulting and intense and young volcanism in South-Central Luzon. The field is associated with Mt. Makiling, as it lies on the volcano’s northwest flank. The permeability of the reservoir is correlated with structures and lithologic contacts. The wells which delineated the center of the resource indicate neutral-pH fluid residing in the reservoir with temperatures as high as 320°C. A highly two-phase zone occurs at mean sea level down to ~-1200 mrsl. Based on stored heat calculation and Monte Carlo estimates, the field has the potential to produce 12-51 MW (P90-P10) in 25 years.

Development plan for the field is compact, as both the fluid conveyance system and the power plant lie approximately 100 meters apart. The power plant is designed and optimized for a single-flash, condensing steam power cycle based on the enthalpy and fluid flow characteristics of the production wells. Three production wells will be utilized for steam supply while two wells will be used for injection of hot brine and cold power plant condensates.

Measures are in place to minimize the environmental impacts of development and future production. Strict adherence to environmental regulations is being followed. Steps are also undertaken to partner with the project stakeholders in our corporate social responsibility and community assistance programs.

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Geological Society of the Philippines

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