Near-Well & Oil Reservoir Simulation using ANSYS CFD

Marcus Reis, Carlos Fontes, João Aguirre, Clarissa Bergman Fonte

ESSS – Engineering Simulation and Scientific Software, Brazil


Reservoir and well simulations are computational techniques commonly used as part of global reservoir management. In general terms, these simulations are performed by different groups and using a variety of individual tools which do not have a common integrated working environment which leads to an inefficient and sometimes cumbersome workflow between these tools. In the reservoir simulator, a point or a line source represents a well; therefore, reservoir simulators employ a poor representation of the well and its geometry or the type of well completion are not accounted for appropriately. Well completions are important means to optimize well performance throughout the entire well life, especially for challenging and remote environments. On the other hand, there are several well simulators that take into account wellbore characteristics such as hydraulic fractures, open intervals, completions and geometry. While these tools prove sufficient for well design, they are inaccurate for predicting flow in porous media leading to a poor reservoir representation.
The above current scenario reveals a clear need for a common simulation environment which is able to better answer the current O&G industry demands of wellbore design by providing coupled reservoir and well simulation capabilities.
This work presents an integrated approach using CFD simulation that can reduce the existing gap between well and reservoir engineers, and can help predict petroleum engineering issues such as, flow distribution along horizontal wells, optimal length and diameter of a horizontal well, how ICD (Inflow Control Device) can affect the well productivity, the influence of well geometry and completion on the well productivity provided by hydraulic fracture and etc.
In light of the aforementioned scenario, the scope of this work is to present an initiative to bridge part of this gap between well and reservoir simulations by developing an additional Oil Reservoir Module for ANSYS CFD to further enhance its existing capabilities by allowing for the efficient transfer and handling of reservoir simulation data, solving the multiphase flow problem inside porous media by adding a Darcy’s Law equation solver to the existing ANSYS CFD code; and developing additional GUI functionalities to speed up the simulation problem setup. Results presented involve benchmark cases, comparison with standard reservoir codes and preliminary real case scenarios.