Thoughts About Techniques Applicable in Exploration of Geothermal Resources of Uganda

Abstract

Some thoughts about the most important geophysical techniques used in geothermal exploration are presented. The exploration methods are Passive seismic, Transient Electromagnetic Magnetic (TEM) and Magnetotelluric (MT) and Gas geochemistry. Integrating the models from these techniques with geological and terrain models benefits the exploration strategy to the next step of prefeasibility and feasibility studies of the prospects respectively. In Uganda, only surface exploration of the geothermal resources has been limited in extent and exploration techniques. Over the years, of all the available geothermal surface manifestations sites, only three prospects at Kibiro, Buranga and Katwe-Kikorongo have been studies using the geological and geochemistry methods but geophysical techniques were limited in extent and scope. TEM was used to explore the three prospects above, and covered extensively Katwe- Kikorongo. In Kibiro, fieldwork focused in the south, whereas very few TEM soundings are located in the northern part of the prospect. In Buranga, the TEM field work plan was inadequate and terrain is complex and mountainous. The results from the prospects caused the drilling of shallow wells for temperature gradient measurements in only Katwe-Kikorongo and Kibiro. Buranga was not subjected to temperature gradient measurements because the results from passive seismic and Direct Current resistivity methods alone were insufficient. The geothermal techniques used in exploration of geothermal resources in Uganda are inadequate. The prospects need to be re-investigated using Gravity, TEM and MT.