| Title | 3D Resistivity Inversion for Geothermal Resource Modeling: Insights from Kiejo-Mbaka Geothermal Prospect, SW Tanzania. |
|---|---|
| Authors | Lucas Tumbu, Mbega Ramadhani Ngata |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | |
| Abstract | The Kiejo-Mbaka geothermal prospect, located in southwestern Tanzania, is part of the East African Rift System and is a fault-controlled geothermal field with active heat sources beneath the surface. Geoscientific investigations including geological, geochemical, and geophysical studies have confirmed its geothermal potential, leading to plans for drilling geothermal wells to assess its viability for energy production. This study presents a comprehensive exploration framework, emphasizing the role of resistivity methods, particularly Magnetotelluric (MT) techniques, in delineating subsurface geothermal reservoirs. Through 3D inversion and modeling, the study enhances well-targeting strategies and improves drilling precision. A geothermal conceptual model integrating geological, geochemical, and geophysical data is developed to support resource assessment. Based on MT interpretations Slim Wells were strategically located to confirm geothermal reservoirs. The findings reveal that the Mbaka fault system is characterized by thick, low-resistivity sedimentary rocks in the west and high-resistivity Pre-Cambrian basement in the east. Additionally, the Kiejo volcanic system exhibits a low-resistivity layer that thickens eastward, likely due to hydrothermal alteration or sedimentary accumulation. Findings from MT surveys identified a high-resistivity zone extending beyond 3 km depth, coinciding with outcropping pre-Cambrian basement rocks. This suggests a distinct separation between the Kiejo and Mbaka systems, potentially governed by impermeable or cold, permeable rock formations. These insights contribute to refining geothermal exploration strategies, optimizing drilling plans, and advancing Tanzania’s geothermal development initiatives. |