Decline Curve Analysis -- A Useful Reservoir Engineering Tool for Predicting the Performance of Geothermal Wells

Abstract

This paper shows that the theory of decline curve analysis, which has been widely used in the petroleum industry of quite a long time, can be applied for predicting and studying the behavior of both geothermal wells and geothermal reservoirs as a whole. A study was made of several wells of the geothermal field of Cerro Prieto, Mexico; this work includes the results obtained for three of them, which were judged to be the more representative cases. In addition to the application of the decline curve theory, an analysis of the history of flowing well conditions was made by mean of the data of pressure vs. depth and temperature vs. depth taken during the wells productive life. all these data were analyzed together in order to know what the conditions of the wells were after been flowing of some time. Predictions of future production from the wells were made based upon the assumptions of both hyperbolic and exponential declination type.