Multi-Criteria Suitability Modelling for Geothermal Exploration Wells Siting--A Case Study of the Silali Geothermal Prospect, North Rift Kenya

Abstract

Models are used in many different ways, from simulations of how the world works, to evaluations of planning scenarios, to the creation of indicators of suitability or vulnerability. In geothermal exploration, GIS based multi criteria suitability modelling was applied in the Silali geothermal prospect and it involved assigning weights to locations relative to each other based on given geoscientific criteria to find favourable locations for new geothermal exploration wells in the prospect. Geothermal well site selection is a spatial problem that involves the evaluation of data samples collected over a prospect area by different geo-scientific teams such as geophysicist, geochemists, geologists, reservoir engineers, environmentalists and geo-information team using varied spatial sampling methods and techniques. This multi-disciplinary approach of geothermal exploration therefore necessitates multi criteria analysis. Weighted linear combination (WLC) model and Boolean integration modes were utilized towards eventual suitability modelling in GIS. This approach has produced priority maps identifying favourable areas for drilling geothermal exploration wells. The results of the weighted linear combination analysis and the Boolean integration model were combined with those of an environmental suitability analysis for final selection of well sites.