Synthesis of well test data and modelling of Olkaria South East production field

Abstract

Well data was analysed and reservoir parameters were interpreted, then the two were unified, incorporating the entirety of the known knowledge and information into a single simplified conceptual model. The analysed wells are highly permeable with convective zones appearing below 1 km depth in the zone immediately adjacent to Ololbutot lava flow. No independent magmatic heat sources were interpreted for the system, rather NW-SE and NNE-SSE trending faults act as fluid conduits, allowing the fluid to percolate into the deep reservoir rock where it collects heat, and upwells where localized upflow zones, in the vicinity of Well OW-802, appear along permeable structures. The HOLA well bore simulator is used to predict well output curves for deep wells in the field. Most of the wells are fed by a single phase liquid reservoir; therefore, low outputs are expected. A resource assessment was carried out using the Monte Carlo simulation which showed average power output was likely to be produced in the area, about 42 MWe, and the maximum possible output was shown to be in the region of 73 MWe, using conventional flash power plant cycles. A natural state model for the field was constructed using TOUGH2. The model places plausible resource prospect areas along known structures in the area.