Fluid dynamics simulations of pressure and flow control devices in polymer flooding selective use in enhanced oil recovery.

Abstract

The flow rate in each sand of reservoirs on polymer flooding applications is regulated with flow regulator valves (FRV). Different valves are used depending on their permeability characteristics and reservoir pressure, among other reservoir parameters. However, synthetic polymer solutions generally used in oil recovery processes, like HPAM (Partially Hydrolyzed Polyacrylamide), present high viscosity losses as they flow through regulating valves. Mainly, these viscosity losses happen because commercial water valves designed for waterflooding are used to regulate polymer solutions. To minimize viscosity losses caused by the shear rate in valves, a new flow regulator helicoidal device for polymer flooding was designed and evaluated using computational fluid dynamics (CFD) and experimental tests in a laboratory and a testing bank. Following the energy dissipation principle, this helicoidal valve has a conical reduction and expansion toward the central spiral, creating a smooth flow area reduction. CFD results were compared to laboratory tests, obtaining less than a 15% error for six of the eight cases studied and less than 20% for two. The proposed helicoidal valve of 5 mm presented a reduction of 23 percentage points in the polymeric solution mechanical degradation compared to a commercial water valve. For a 6 mm valve, a reduction of 18 percentage points was achieved with a pressure drop of 500 psi and a polymer concentration of 300 ppm.