Commercial compositional reservoir simulators do not consider the kinetic effects in the phase equilibrium calculation. Phase equilibrium is calculated using a conventional flash. Therefore, there is an instantaneous equilibrium between the injected gas and the reservoir fluid. In most cases, this is a reasonable assumption, since the gas will be in contact with the reservoir fluid for a long period of time. There are cases though, where miscibility plays an important role in the total recovery and where the instantaneous equilibrium can be an optimistic assumption.

This work aims at implementing a methodology to incorporate the kinetic effects of the phase equilibrium in a compositional reservoir simulator. The methodology was inspired in the "DRSDT" keyword widely used in black oil simulators. In this methodology, the maximum solubilization ratio is defined by the user and the fugacity equations were modified to guarantee that this target would never be violated.

The implementation was tested for different scenarios using real field data. The main objective of these simulations was to evaluate the importance of the kinetic effects for different fluid models and different injected gas compositions. These analyses demonstrated to be rather challenging, since there is a lack of experimental data in the literature. Therefore, a workflow was developed that isolates the phenomenon analyzed. Using this workflow, we could evaluate three different real fluid models and the importance of phase equilibrium kinetics on the recovery forecast.

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