Surprisingly, recent experimental and field observations indicate that the addition of viscoelastic polymers improve oil recovery by an additional 20%, contrary to the conventional wisdom that polymers should have no impact on residual oil saturation.
My research group has performed computational fluid dynamics (CFD) simulations of viscoelastic flow around static oil droplets in geometries representative of pore throats. We show that normal forces are significant for viscoelastic fluids and increase with De and the total force imposed on the droplet may be larger than an equivalent Newtonian fluid with the same viscosity. Results indicate that normal forces could dominate, and the total, effective force would be enough to mobilize trapped oil. My research group is currently performing additional CFD simulations for dynamic multiphase flow and developing a multiphase pore-network model; the results have led to a new fundamental understanding of the forces involved in mobilization of trapped oil by elastic polymers and potentially applied to billions of barrels of currently unrecoverable oil.
PhD student: Ali Afsharpoor
Postdoc: Dr. Peixi Zhu
Afsharpoor, A., Balhoff, M.T., Bonnecaze, R. and Huh, C., “CFD modeling of the effect of polymer elasticity on residual oil saturation at the pore-scale,” Journal of Petroleum Science and Engineering, Volume 94-95, pages 79-88, September 2012, published online June 26, 2012, doi: 10.1016/j.petrol.2012.06.027.