Geothermal well design

Abstract

This report describes the geothermal well design for the future 4 wells in the Lava Lake area in Fiale Caldera 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 maintain well integrity during exploitation. An Excel based programme was developed for the casing design. Also, the Viking engineering programme calculated the reduced collapse resistance and assisted the Excel programme. The criteria for the casing design were as follows: preliminary selection based on burst and collapse pressure, selection based on tension, and finally the biaxial correction. Since the reservoir pressures and temperatures of Wells AA, AB, AC and AD are not known, the reservoir pressure and temperature of Well Asal 5 were used to design the 4 wells and it is expected that the same casing string design will be used.