Use of Domain Decomposition for Simultaneous Simulation of Reservoir and Surface Facilities

Abstract

Abstract The main purpose of this paper is to describe the advantages of using domain decomposition when surface facilities are coupled to reservoirs in simulators. Full-held reservoir models that can handle both reservoirs and surface facilities are needed for accurate performance predictions and optimization. Use of conventional techniques for such models can be very CPU time intensive. For this reason, full-field models are either rarely used or they are simplified by handling surface facilities explicitly. Domain decomposition is useful either as an acceleration techniques to reduce computer time in implicit methods or, in conjunction with the use of different local timesteps in each domain, to improve accuracy of explicit methods. An example is presented showing a comparison of accuracy and CPU time for explicit and implicit methods, with and without domain decomposition. Small subdomains around wells are used to model the interface between reservoir and production facilities, and the rest of the reservoir is simulated with conventional techniques. This approach improves performance of full-field models. The prediction of reservoir performance accurately and efficiently can be accomplished by full-field models that use the domain decomposition technique presented in this paper. A fast full-field reservoir model is an important tool for the simultaneous optimization of the entire production system. The techniques presented here provide an efficient way to handle the coupling of reservoirs with surface facilities.