What can tell, what's uncertain? In depth decline curve analysis

DCA (Decline curve analysis) is one of the most powerful tools used in defining well/reservoir worth. DCA aims at estimating reservoir production performance at any time (of production) post plateau period providing realistic and well documented production data. DCA helps in developing production-rate/reservoir-pressure distributions to determine well/reservoir productivity scheme. Forecasting well/reservoir production rate, estimating remaining reserves, monitoring GOR & WC behaviors, deciding on reservoir pressure support and determining economic limits are among the many befits of DCA as well. In this study the AOR (Actual Oil Rate) method has been implemented utilizing the DCA, FASTRTA™ and Ecrin packages to calculate remaining and recoverable reserves in particular. The remaining reserves depend on the production data that are selected to represent the actual well/reservoir behavior. This technique allows eliminating misrepresenting production data due to human error, imposed production rates caused by internal company policy or external factors (politics, natural disasters, etc.) during production life of the field. A case study has been used as a pilot for the proposed method. Analyses have been performed on both well and whole reservoir scale. The outcome yielded more realistic results using AOR and generated very useful development recommendations. The proposed AOR-DCA adopted technique can assist in accurate decisive parameters estimate of both mature and under-development oil reservoirs worldwide.