Resource Assessment Methods Selection for Geothermal Exploration Project in Indonesia: What Are the Considerations?

Abstract

In developing a geothermal exploration strategy, as mentioned in many scientific publications, the selection of resource assessment methods become very crucial due to the high uncertainty level of this stage. Of the various resource assessment methods available in the industry today, the volumetric method is the most often used in Indonesia during the exploration phase, while numerical modelling is more common for development phase where more sub-surface and production data has been collected. Other than those, there are several other methods such as surface heat flux, planar-fracture, magmatic heat budget, total well flow, mass-in-place, power density, decline analysis, and lumped-parameter. The question that arises is when each of these many resource assessment methods should be used in the exploration stage. This paper aims to review some considerations and limitation of various geothermal resource assessment methods that can be utilised by the decision-making team in designing exploration strategies. The methods used in this study are literature review and direct interviews with geothermal practitioners in Indonesia. The summary of this study is expected to become a simple tool that able to assist new investor or geothermal developer formulating their exploration strategy.