Efficient gradual deformation using a streamline-based proxy method

The application of state-of-the-art history matching methods to large heterogeneous reservoirs is hampered by two main problems: (1) reservoir models should be constrained jointly to dynamic data and a large variety of geological continuity information, and (2) CPU demand should not be prohibitive for large models. This paper proposes a method contributing to alleviating these two main concerns. By combining three existing ideas, namely gradual deformation, multiple-point geostatistics and a fast streamline-based history matching method, an algorithm is proposed that could honor a large variety of geological scenarios and is obtained with a limited amount of flow simulations. The method expands on the traditional gradual deformation methodology in three ways: (1) multiple-point geostatistics is used to generate models that are geologically more realistic than traditional variogram-based models, (2) a streamline simulator is used to define “zones-of-influence” of producers in order to locally deform an initial model toward jointly matching a large amount of wells and most importantly (3) the number of flow calculations is limited by defining a proxy to the streamline simulator in terms of streamline-based harmonic averages. Using synthetic examples of increasing complexity, the methodʹs efficiency and generality is assessed.