Geophysical Exploration and Drilling for Thermal Gradient Distribution Study: Joint Project at Bugarama Geothermal Graben Located Between Rwanda, R. D Congo and Burundi

Abstract

Our geoscientific observations in Bugarama Geothermal Graben show that Low Geothermal temperatures can yield significant potentials in direct uses or small to medium geothermal power plants. Geothermal manifestations that appear at surface in that part of the Western Rift, among other geological features, are a signature of what the Earth underneath holds and that there is a geothermal resource to be tapped whether for direct uses (i.e. rice drying, fish farming, geothermal spas for tourism etc.) or small-scale power generation. This paper describes the work done in Bugarama Graben so far since 2016 and potentiality of these geothermal resources. In conjunction with three countries, Rwanda, DRC and Burundi, a joint exploration project was conducted at Bugarama Graben, a continuation of the Western Geothermal Rift System. The graben has got geothermal manifestations at the surface such as hot springs, normal faults and several other geological indications of past tectonic activities. Surface Geophysical exploration were conducted such as TEM (transient Electromagnetic), Magnetics, of which a detailed report has been done, followed by shallow drilling activities to map the temperature gradients distributions. Descrption of retrieved geological core samples were studied and analyzed as well for clear geological settings of the drilled area. The project is set to enlighten scientists and decision makers of energy authorities of the three countries on the geothermal potential and possible future geothermal energy development at Bugarama Geothermal Graben. The analysis from these surveys showed a relatively low to medium temperature geothermal system of which a heat source is yet to be identified. Temperatures were ranging between sixty-three and seventy-five degrees at a depth of one hundred and two meters with an increasing trend as we drill down; in one of the wells. Temperature gradients can build up from surface down deep and future shallow drilling are recommended in Bugarama Graben for delineating the geothermal potential underneath and of which three countries Rwanda, DRC and Burundi can tap together for their energy or geothermal direct uses needs.