Foam generation in homogeneous porous media

• Published in: Chemical engineering science 2002-10, Vol.57 (19), p.4037-4052
• Main Authors: A. Gauglitz, P, Friedmann, F, I. Kam, S, R. Rossen, W
• Format: Article
• Language: English
• Subjects: 02 PETROLEUM; Aerosols and foams; CARBON DIOXIDE INJECTION; Chemistry; Colloidal state and disperse state; Emulsions. Microemulsions. Foams; Exact sciences and technology; FLOW RATE; Flows through porous media; Fluid dynamics; Foam; Foam generation; FOAMS; Fundamental areas of phenomenology (including applications); GAS INJECTION; General and physical chemistry; Hysteresis; NITROGEN; Nonhomogeneous flows; Packed bed; PERMEABILITY; Physics; POROUS MATERIALS; Porous media; PRESSURE DROP; Surfactant; SURFACTANTS; SYNTHESIS
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/S0009-2509(02)00340-8

In steady gas–liquid flow in homogeneous porous media with surfactant present, there is often observed a critical injection velocity or pressure gradient ∇ p min at which “weak” or “coarse” foam is abruptly converted into “strong foam”, with a reduction of one to two orders of magnitude in total mobility: i.e., “foam generation”. Earlier research on foam generation is extended here with extensive data for a variety of porous media, permeabilities, gases (N 2 and CO 2), and surfactants. For bead and sandpacks, ∇ p min scales like (1/ k), where k is permeability, over 2 1 2 orders of magnitude in k; for consolidated media, the relation is more complex. For dense-CO 2 foam, ∇ p min exists but can be less than 23 KPa/m (1 psi/ft). If pressure drop, rather than flow rates, is fixed, one observes an unstable regime between stable “strong” and “coarse” foam regimes; in the unstable regime ∇ p is nonuniform in space or variable in time. Results are interpreted in terms of the theory of foam mobilization at a critical pressure gradient.