A generalized entering coefficient to characterize foam stability against oil in porous media
- Univ. of California, Berkeley, CA (United States)
Foam is a promising mobility-control fluid for improving oil recovery from porous media. Unfortunately, foams stabilized by most currently employed surfactants do not remain stable in the presence of crude oils. This work establishes that the standard criterion of a negative classical entering coefficient for oil penetration into a water/gas interface (i.e., a nonentering oil) is not pertinent for foam stability in oil-saturated porous media. This paper introduces a generalized entering coefficient that accounts for thin-film forces and capillary-suction pressure. For the first time, disjoining pressure isotherms of pseudoemulsion and foam films, surface and interfacial tensions, and steady-state pressure gradients of flowing foam in glass beadpacks with and without residual oil are measured and compared. The authors find that those surfactants which exhibit highly repulsive disjoining pressures in oil-water-gas thin films (i.e., pseudoemulision films) exhibit high negative generalized entering coefficients. These same surfactants produce foams that are insensitive to residual oil in porous media. Thus, it is the negative value of the generalized entering coefficient, as defined by the integrated disjoining pressure isotherm at the appropriate capillary pressure, and not the classical entering coefficient, that characterizes foam stability against oil.
- OSTI ID:
- 141343
- Report Number(s):
- CONF-930304-; TRN: 93:003688-1020
- Resource Relation:
- Conference: 205. American Chemical Society national meeting, Denver, CO (United States), 28 Mar - 2 Apr 1993; Other Information: PBD: 1993; Related Information: Is Part Of 205th ACS national meeting; PB: 1951 p.
- Country of Publication:
- United States
- Language:
- English
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Generalized entering coefficients: A criterion for foam stability against oil in porous media
Generalized entering coefficients: A criterion for foam stability against oil in porous media