Foam Mobility Control for Surfactant EOR

Abstract

Abstract Foam generated in situ by surfactant alternated with gas injection is demonstrated as a substitute for polymer drive in the alkaline-surfactant-polymer (ASP) EOR process. Foam is also effective in a similar process for a 266 cp crude oil, even though the system did not have enough polymer for favorable mobility control. Foam is shown to greatly enhance sweep efficiency in a layered sandpack with a 19:1 permeability ratio. Foam diverted surfactant solution from the high-permeability layer to the low-permeability layer. Ahead of the foam front, liquid in the low-permeability layer crossflowed into the high-permeability layer. A layered system with a 19:1 permeability contrast could be completely swept in 1.3 TPV (total pore volume) with foam while waterflooding required 8 PV (pore volume).