A numerical simulation model of the Ribeira Grande geothermal reservoir, São Miguel Island, Azores, has been developed to support the ongoing development and management of the resource for generating electric power. This model has been calibrated using data obtained since startup, including the results of new deep wells drilled during 2005, operations of the Ribeira Grande and Pico Vermelho power plants, logging, testing and sampling of the various wells, and the results of a tracer test conducted during 2007-2008.

The numerical model of the reservoir has been calibrated first by matching the initial subsurface temperature distribution interpreted from temperature-profile measurements in the deep wells. With iterations back to the initial state, the model was then calibrated to the historical production/injection data and to the new tracer data. Following calibration, the model was used to forecast field performance under various operating conditions.

Technical Paper from GRC Transactions, Vol. 33, 2009