The Application of Polymers to Enhance Foam Stability

Most of the oil initially present in an oil reservoir is left after primary and secondary recovery. Primary recovery uses the natural pressure of the reservoir, and secondary recovery uses gas injection or water flooding as the driving force to produce oil. The remaining oil target provides an economic incentive to use tertiary recovery or Enhanced Oil Recovery (EOR), which is oil recovery by the injection of materials not normally present in the reservoir (Lake, 1989). Foam, which is a dispersion of gas in liquid with surfactant present, is a promising tool in various processes in oil and gas production, including mobility control in EOR, acid diversion in well stimulation, and waste recovery in environmental remediation. Although foam is widely used in EOR methods, it has a limited lifetime (Hirasaki, 1989). A possible solution to increase foam stability is the use of polymer in conjunction with surfactant to improve foam properties. Polymer increases liquid viscosity and slows the rate of liquid drainage from bulk foam and improves the foam stability.