Characterization of Geothermal Reservoir in Cibitoke and Rumonge Provinces of Burundi

The geothermal energy sector in Burundi has not yet had any particular attention in term of developing this renewable resource which has the potential as a source for electricity generation and direct use applications. The country has more than 13 geothermal springs spread over different regions. This research is focused on the characterization of geothermal reservoir of Mugara and Ruhwa sites. Geophysical and geochemical methods have been used to collect the data. Thus, geological, electrical resistivity data based to Schlumberger method and chemical elements were analysed in order to investigate the geological structures and the quality of these geothermal reservoirs. The results showed that in Mugara site, the geothermal reservoir is located geologically in the spongoliths, coarse cemented sands, clay-sandstone spongoliths whereas the Ruhwa site is found in the white quartzites with intercalations of phyllite rocks with the presence of schites, psammoshistose, sandstone-silty quartzites. The aquifer in Mugara site is a semi-confined aquifer and the Ruhwa geothermal reservoir is a confined aquifer due to its roof, which is composed of clay. The highest temperature in Ruhwa site is 68°c and underground source temperatures are postulated to be as high as 110-120°c based on the quartz geothermometer in the hot springs from the porous sediments. The chemical analysis results of water from Ruhwa and Mugara indicated that 3 elements which are Fe, Mg and K have a high content of 21.5 mg/l, 10mg/l and 76mg/l respectively.