Successful 1st Eocene Carbonate Reservoir Steamflood Pilot Mitigates Key Technical Uncertainties for Full Field Development of Wafra Field, PZ Kingdom of Saudi Arabia & Kuwait: Part 2 Simulation Model Validation

Abstract

Abstract This paper describes the key learnings from detailed data analysis and the application of a probabilistic workflow to achieve a validated dynamic simulation model of the large scale pilot (LSP) that was successfully completed in the 1st Eocene reservoir in the Wafra field, PZ. The development of the validated dynamic simulation model was a key success measure identified for the pilot to assist in the broader Wafra full field steamflood development decision making process. The pilot consisted of sixteen 2.5 acre inverted 5 spot patterns (16 injectors and 25 producers) with associated steamflood and production facilities. In the execution of this work, detailed analysis of production, pressure, temperature, oil viscosity and geochemical data was conducted to develop key insights into the pilot behavior. A 1st Eocene LSP steamflood model was successfully validated with production and injection data through the primary and steamflood periods. The validation method took into account uncertainties in static and dynamic properties. A probabilistic methodology using design of experiments on uncertainty parameters, combined with error-filters on multiple responses of rates, pressure and temperature was used in the study. The confidence in the final validated model was high with excellent agreement achieved between pilot and model data. The validated model also captured regional behaviors observed in the production data analysis. The validated model captured both pre-steam and post-steam behavior in the pilot. The successful execution of this work has resulted in an estimate of carbonate steamflood recovery possible in the 1st Eocene reservoir in Wafra.