3D Simulation of Viscous Fingering and WAG Schemes

Water-alternating-gas (WAG) injection has been suggested as a way to reduce viscous-fingering. This paper presents 3D simulations to assess the combined effects of gravity segregation in the vertical plane and areal viscous fingering for miscible displacements with substantial viscous fingering and for WAG injection. The simulations illustrate variations in recovery with WAG ratio and viscous-to-gravity ratio. A procedure to recalibrate the Todd and Longstaff parameter for WAG schemes in which buoyancy forces have little effect is described. Use of this recalibration provided excellent agreement with results from detailed simulation. Where gravity is important, recalibration of the parameter is required; examples of recalibration coarse-grid calculations are presented