Print Email Facebook Twitter Robust ensemble-based multi-objective optimization Title Robust ensemble-based multi-objective optimization Author Fonseca, R.M. Stordahl, A. Leeuwenburgh, O. Van den Hof, P.M.J. Jansen, J.D. Faculty Civil Engineering and Geosciences Department Geoscience and Engineering Date 2014-09-08 Abstract We consider robust ensemble-based multi-objective optimization using a hierarchical switching algorithm for combined long-term and short term water flooding optimization. We apply a modified formulation of the ensemble gradient which results in improved performance compared to earlier formulations. We also apply multi-dimensional scaling to visualize projections of the high-dimensional search space, to aid in understanding the complex nature of the objective function surface and the performance of the optimization algorithm. This provides insights into the quality of the gradient, and confirms the presence of ridges in the objective function surface which can be exploited for multi-objective optimization. We used a 18553-gridblock reservoir model of a channelized reservoir with 4 producers and 8 injectors. The controls were the flow rates in the injectors, and the long-term and short-term objective functions were undiscounted net present value (NPV) and highly discounted (25%) NPV respectively. We achieved an increase of 15.2% in the secondary objective for a decrease of 0.5% in the primary objective, averaged over 100 geological realizations. The total number of reservoir simulations was around 20000, which indicates the potential to use the ensemble optimization method for robust multi-objective optimization of medium-sized reservoir models. Subject EnOptrobust optimizationproduction optimizationoil and gasenergy To reference this document use: http://resolver.tudelft.nl/uuid:5c0b81d2-34f6-4daf-bfe3-eb65c6069104 Publisher EAGE Source ECMOR XIV: Proceedings 14th European Conference on Mathematics in Oil Recovery, Catania, Italy, 8-11 September 2014 Part of collection Institutional Repository Document type conference paper Rights (c) 2014 The Author(s) Files PDF FonsecaEtAl2014_ECMOR_Rob ... zation.pdf 852.4 KB Close viewer /islandora/object/uuid:5c0b81d2-34f6-4daf-bfe3-eb65c6069104/datastream/OBJ/view