Investigation of the accuracy and efficiency of the operatorbased linearization through an advanced reservoir simulation framework

Any complex phase behavior computation is a main challenge in reservoir simulation since it introduces high nonlinearities. To overcome this, an operator-based linearization (OBL) has been introduced recently. In OBL, an operator format is applied to represent the mass-based formulations. By computing the values of the operators related to rock and fluid properties on pre-defined status, the values of the operators and their derivatives on any status, which emerges during a simulation run, can be determined by interpolation. Obviously, the accuracy of the results is mainly controlled by the pre-defined status. In this work, we present a detailed investigation of the accuracy and efficiency of the OBL. To guarantee an objective evaluation, a novel advanced parallel framework is applied for reservoir simulation. In this framework, we implement a multipoint linearization method that is capable to provide accurate, robust, and convergent solutions for reservoir simulation. The number of points in the parametric space of each nonlinear known is defined as resolution. By running simulations at different resolutions, we compare the numerical solutions with analytical solutions. It shows that the resolution has a large effect on the accuracy of numerical solutions. We also investigate the robustness of the OBL by running simulations on several models with different complexity of the phase behavior. Besides, by looking into the convergent process, we also study the efficiency of the OBL method. Finally, we test several filed cases to show the performance of the OBL method for general-purpose reservoir simulations.