Development of a Toolbox for Simulation of Integrated Reservoir-Production System

The simulation of an integrated reservoir-production system is often suggested or even required to develop offshore oil fields. The pressure drop in the production system is a significant factor to consider in well placement and the selection of production strategy. The simulation of the coupled system can improve accuracy and help optimize the production strategy for higher production and financial outcomes. Methods to couple the production system with the reservoir system fall into three categories: explicit coupling, partially implicit coupling, and implicit coupling method. The implicit coupling method solves both systems in one simulator providing high stability but suffers from high computational cost. The explicit coupling method is flexible in terms of the choices of different simulators. The explicit coupling method has the least computational cost but suffers from unstable results (oscillations). In this study, the MATLAB Reservoir Simulation Toolbox (MRST) is an open-source reservoir simulator used for coupling with the surface network. A surface network modeling module and a reservoir-production system explicitly coupling module are developed to couple with MRST. A new method of obtaining average drainage area pressure for calculating the IPR (Inflow Performance Relationship) curve is developed. The new method is also evaluated on its effectiveness in reducing the instabilities. The new method is ineffective in lowering oscillations for simulations with a large size of time steps but may be useful for smaller time steps. The application of this toolbox is demonstrated with two models, a simplistic, "shoe-box" like model, and a complex model, UNISIM-I-D. UNISIM-I-D is a synthetic numerical model based on the Namorado field, an offshore field in Brazil