Geothermal Well Design for the Future 4 Wells in the Lava Lake Area in Caldera Fiale in Djibouti

Authors: Abdirasak Omar MOUMIN
Keywords: Well design, casing design, wellhead pressure estimate, cementing, burst and collapse pressure, Tension load
Conference: World Geothermal Congress Session: Drilling and Completion Technology
Year: 2015 Language: English
Abstract: This abstract describes the geothermal well design for the future 4 wells (wells AA, AB, AC and AD) in the Lava Lake area in Caldera Fiale in Djibouti. Various geophysical studies in the framework of different projects have confirmed the presence of a magmatic heat source potentially useful for the production of geothermal energy. The present work includes: The casing design, the wellhead pressure estimate and cementing of the casings to prevent contamination of fresh water and to maintain well integrity during the exploitation. One excel based programme was developed for the casing design. Also, Viking engineering programme calculates the reduced collapse resistance and assists the first programme. The criteria for casing design are as follows: preliminary selection based on burst and collapse pressure, selection based on tension and finally the biaxial and correction. For the design of the casing string in this case, as reservoir pressures and temperatures (wells AA, AB, AC and AD) are not known, the reservoir pressure and temperature of Asal 5 will be used to design the 4 wells and will be expected to having the same casing design. The lithology from Asal 5 is better than what is expected for the Lava Lake in Fiale area. Asal 5 was drilled in the Inner Rift, about 1 km west of Lava Lake. The drilling of well Asal 5 started on 7th January 1988 and finished on March 3, 1988. The final depth is 2,105 m and the temperature at the bottom is 350°C.
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