Comparison of Asphaltene Models in Two Commercial Compositional Simulators

The many challenges that engineers face during production from hydrocarbon reserviors due to asphaltene deposition show the importance of addressing this phenomenon in the management of reservoirs and adopting production policies. Simulation, as one of the most economic ways of reservoir studies could be done using various software packages. It is clear that each of these simulators has its own strengths and limitations that should be carefully examined and recognized. This study addresses the differences between the asphaltene models of two commercially used compositional simulators and the challenges thereof. It is done using a 3D sector model built on real data from one of the Iranian South oil reservoirs so that the final results resemble the reality of the reservoir. In addition, the simple scenario of natural depletion is considered for production from an undersaturated oil reservoir. The fluid model which is used in both simulators is the solid model implemented in WinProp and in-house software (PVT-Pro). Moreover, the same thermodynamic model has been deployed in both asphaltene models (PR-EOS). Different cases were run to demonstrate the extent of influencing the reservoir by how each simulator models the asphaltene phenomenon. As a result, porosity/permeability reduction, viscosity change, and wettability alteration were described in both simulators. Finally, both simulators are compared regarding whether can describe the final changes caused by asphaltene precipitation and deposition. In the end, the speed of each simulation run is also investigated.