Evaluation Of Surface Investigation Results In Baringo Prospect

Leonard Wamalwa and Levi Shako
Geothermal Development Company Ltd
P.o.Box 1770 Nakuru
E-mail: wwafula@gdc.co.ke lshako@gdc.co.ke
Geographical Information System (GIS) is a technology that was used to determine the spatial
association between geophysical, geochemical and geological evidence and reservoir zones in
Baringo geothermal prospect. Surface observations in lake baringo prospect were used to
determine the geothermal potential by mapping areas with low resistivities at depth that could be
related to alteration zones(reservoir) and heat sources , high values in CO2 corresponding to the
deep buried faults and fractures, high hydrothermal activity manifested by extensive occurrence
of fumaroles, hot springs, altered grounds and thermally anomalous ground-water boreholes. The
chemistry of the discharged fluids indicated possible input from a geothermal reservoir.
The paper also presents the use of GIS tools to manage and analyze geo-scientific data with the
aim of producing a priority map for drilling exploration wells. Spatial distribution of data from
scientific investigation was co-related and visualized using GIS. Several evidence layers were
generated using ArcGIS, and these factors were combined into a map identifying the most
favorable zones for drilling. Multi-criteria evaluation of these evidence layers was done in a
knowledge-driven GIS model where the layers are assigned weights based on a judgment of their
importance to geothermal suitability. Finally exploration well sites were proposed.
Keywords: Geochemistry, Geophysics, hydrothermal, GIS, Model, Geology