Nonlinear Simulation of Viscoelastic Fingering Instability in Miscible Displacement through Homogeneous and Heterogeneous Porous Media

The miscible displacement of a Newtonian fluid pushed by a nonlinear viscoelastic fluid (viscous fingering instability) has been investigated via a pseudospectral method and Hartley transform. The results of the present study could be useful for enhanced oil recovery (EOR) using chemical flooding technique. Here, the Giesekus model is applied as the constitutive equation of viscoelastic fluid. In addition to the homogeneous media, the simulations are performed for a horizontal layered heterogeneous medium and the results are presented as concentration contours, transversely averaged concentration profiles, mixing length, and sweep efficiency. It is concluded that the heterogeneity of the medium has a great effect on the flow structure. The channeling regime is observed in these media. Higher layers in the heterogeneous medium reduces the intensity of instability while permeability variance acts on the contrary. This is the first attempt in simulation of the viscoelastic-Newtonian displacement (polymer flooding) in heterogeneous media. (C) 2019 American Society of Civil Engineers.