Use of Leapfrog Geothermal Software in Data Integration and 3D Visualization Case Study of Olkaria Domes Geothermal System

Abstract

Olkaria Domes is one of the seven (7) geothermal sub-sectors of Greater Olkaria Geothermal area (GOGA). It is still under development with current generation capacity of about 197.8 MWe from Olkaria IV Power plant and well head generating units. This figure is expected to increase when construction of Olkaria V with an installed capacity of 150 MWe is completed by 2018. Over 100 geothermal wells have been drilled that includes production and reinjection/injection wells. Various surface and subsurface data types have been used to generate a model. This paper demonstrates the capabilities of Leapfrog Geothermal Software© which has been used to creSate a 3D model of Olkaria Domes using the data from the drilled geothermal wells. The software has allowed creation of 3D model from integration of geological (borehole lithology logs and hydrothermal alteration minerals), geophysics (resistivity), discharge geochemistry (chloride, sulphate and bicarbonate concentration), geographic information systems (GIS) (maps, images and well locations) and reservoir data (formation temperature, enthalpy). The 3D model resulting from the data integration shows that up flow zones are not localized but rather widespread and occurs in a few localities such as within OW-914, OW-915 and OW-916, OW-921A, and OW-901. Downflow/outflow zones occur within vicinities of OW-907, OW-904, OW-905 and OW-902B. The location of the upflow, downflow/outflow zones are influenced by permeability ensuing from mapped geological structures and deep intrusion. The 3D model is a useful tool for visualization thereby creating an understanding of Olkaria Domes geothermal system for better management.