Summary In preparation for the SPE Applied Technology Workshop (ATW) held in Brugge in June 2008, a unique benchmark project was organized to test the combined use of waterflooding-optimization and history-matching methods in a closed-loop workflow. The benchmark was organized in the form of an interactive competition during the months preceding the ATW. The goal set for the exercise was to create a set of history-matched reservoir models and then to find an optimal waterflooding strategy for an oil field containing 20 producers and 10 injectors that can each be controlled by three inflow-control valves (ICVs). A synthetic data set was made available to the participants by TNO, consisting of well-log data, the structure of the reservoir, 10 years of production data, inverted time-lapse seismic data, and other information necessary for the exercise. The parameters to be estimated during the history match were permeability, porosity, and net-to gross- (NTG) thickness ratio. The optimized production strategy was tested on a synthetic truth model developed by TNO, which was also used to generate the production data and inverted time-lapse seismic. Because of time and practical constraints, a full closed-loop exercise was not possible; however, the participants could obtain the response to their production strategy after 10 years, update their models, and resubmit a revised production strategy for the final 10 years of production. In total, nine groups participated in the exercise. The spread of the net present value (NPV) obtained by the different participants is on the order of 10%. The highest result that was obtained is only 3% below the optimized case determined for the known truth field. Although not an objective of this exercise, it was shown that the increase in NPV as a result of having three control intervals per well instead of one was considerable (approximately 20%). The results also showed that the NPV achieved with the flooding strategy that was updated after additional production data became available was consistently higher than before the data became available.

In preparation for the SPE-ATW held in Brugge in June 2008 a unique benchmark project to test the use of flooding optimization and history-matching methods was organized in the form of an interactive competition during the months preceding the ATW. In total nine different groups participated and presented their results during the workshop. Prior to the Brugge workshop, early 2008, a 3D synthetic dataset was made available to the participants by TNO. The dataset consisted of 104 upscaled realizations of a 3D geological model, well-log data from wells with fixed positions, the first 10 years of the production history of the field (including measurement errors), inverted time-lapse seismic data in terms of (uncertain) pressures and saturations, and economic parameters for oil and water (price and discount rate). Participants were asked to provide a history match (either a single matched "best" model or a matched ensemble) based on the available data, and an optimal production strategy (without infill drilling) for the next period (10–20 years). Their strategy was tested on the "real field" to obtain additional production data over the 10-year period. Using these production data, the participants updated their reservoir model and revised their optimal production strategy for the final period of production (20–30 year). The final objective of the exercise was to optimize, within a time constraint, the NPV of a waterflooded oilfield having smart wells that can be controlled by an inflow control valve per completed layer. The results of the nine participants are compared to an optimization of the "real field" as performed by TNO. This paper gives an overview of the results obtained from this benchmark study. After the Brugge workshop the participants that were not able to finalize the exercise in time were given an additional two months time. The results of this additional exercise are reported in this paper as well.

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