Resistivity structure of the Eburru geothermal field, Kenya, depicted through 1D joint inversion of MT and TEM data

Abstract

Eburru is one of the geothermal fields in Kenya, producing 2.5 MWe from one of the six exploratory wells. In order to drill production wells, a total of 36 additional MT and TEM soundings were carried out in 2013 to delineate the geothermal resource field of Eburru. This report discusses and presents the results of earlier soundings and soundings from 2013 which brought the total number to 43 MT and 43 TEM soundings. The TEMTD program was used for joint 1D inversion of MT and TEM data, the program calculates the shift factor. The MT data are, therefore, corrected for static shift. Data used in this report were acquired by the KenGen staff team using a data logger MTU-5A made by Phoenix Ltd. for acquiring MT data and TerraTEM made by Monex GeoScope Ltd. for TEM data. MT data were processed using SSMT2000 and MTEditor before jointly inverted with TEM data. The results discussed in this report present 1D joint inversion, resistivity cross-sections and isoresistivity maps down to a few kilometres. The reservoir in Eburru geothermal field is located at about 2500 m b.g.l. according to the sub-surface resistivity structure.