How an innovative adaptive fine calculation can help in coning simulation

Abstract

Coning phenomenon is an unfavourable experience and should be prevented by the predicting of controlling parameters. The large grid model in conventional reservoir simulation is not able to predict this phenomenon. Large pressure and saturation changes and high velocity near wellbore cause numerical instability and dictate for using fine grid model. Reservoir simulation with fine gridding is not practical because of the need for large CPU time. In this work, we have developed new software using critical region approach to solve this problem. In this approach, for each time step of simulation, the saturation and pressure of each phase are first calculated for all grids globally. Then, in the defined region around the wellbore, each time step is divided to very small time steps and the saturation and pressure of phases will be calculated again with this new small time steps. Our software based on this technique is using triangular irregular grids and finite volume method for the simulation of heterogeneous reservoirs. We used IMPES method for solving the pressure and saturations. The software has been tested by the comparison of water cut between our software and the fine grid model with satisfactory results. © 2010, European Association of Geoscientists and Engineers.