Simulation of cold heavy oil production using an integrated modular approach with emphasis on foamy oil flow and sand production effects

In this paper, the authors extend earlier work on sand production modeling to incorporate the foamy oil effect, and present an integrated modular approach to quantitatively predict volumetric sand production and enhanced oil recovery. This model is based on mixture theory with erosion mechanics, in which multiphase hydrodynamics and geomechanics are coupled in a consistent manner via principal unknowns, such as saturation, pressure, porosity, and formation displacements. Foamy oil is modeled as a dispersion of gas bubbles trapped in the oil, where these gas bubbles maintain a higher reservoir pressure. A modular approach is then adopted to effectively take advantage of the existing advanced standard reservoir and stress-strain codes. The model is implemented into three integrated computational modules, i.e. erosion module, reservoir module, and geomechanics module. The stress, flow and erosion equations are solved separately for each time increment, and the coupling terms (porosity, permeability, plastic shear strain, etc) are passed among them and iterated until certain convergence is achieved on a time step basis. The system is powerful in terms of its capabilities, yet practical in terms of computer requirements and maintenance. Numerical results of field studies are presented to illustrate the capabilities of the model. The effects of foamy oil flow and sand production are also examined to demonstrate their impact on the enhanced hydrocarbon recovery.