Abstract
In the design of an optimum enhanced oil recovery operation an accurate areal and vertical mapping and analysis of the simulation results plays a fundamental role. In this type of analysis not only should the finer details of the reservoir be considered, but also the grid system superimposed over the domain of interest should exhibit compatibility and consistency with the actual physics of the problem. This will help in accurate characterization of the reservoir and the ongoing physical processes within the domain of interest.
The implications of the aforementioned statements are investigated with the aid of developing a 3-D fieldscale steam injection simulator. The multi-phase mass and energy transport equations are based on compositional balances. In the model the gravitational and capillary forces are accounted together with the viscous flow phenomenon. A fully implicit treatment is used at the multi-block production and injection wells to couple the wellbore to the reservoir. A fully implicit technique is utilized in the solution of the nonlinear system of equations. The model is capable to solve (nhc+5) primary variables simultaneously where "nhc" represents the number of hydrocarbon components that can be considered.
A systematic analysis of the areal and vertical distribution of parameters such as pressure, temperature, phase saturations and composition is conducted. Through this detailed analysis the ever-changing relative effects of the various dominant forces on the establishment of production mechanisms and ultimately on the oil recovery are studied.
The fully implicit formulation, which assumes all the reservoir parameters and operational parameters to be functions of all primary variables identified, makes it possible to focus on any parameter and investigate its effects on oil production. Both qualitative and quantitative implications of capillary pressure on the oil production are observed to be strong functions of the size and uniform nature of the grid constructed over the computational domain.
The proposed model provides some significant insight into the displacement mechanisms and aids us in developing a comprehensive understanding of the nature and magnitude of the forces and controlling parameters. Such an understanding will help in the design of specifics of a recovery operation.
