Effects of Porous Media on Foam Properties

Foam flooding is an important pathway for enhanced oil recovery. However, the evaluation of foam properties is usually carried out in free space, which can not accurately reflect the performance of foam in porous oil formation. In the present work, by investigating the foamability and stability of foam systems in sand-pack models with average pore throat radius from 1.24 mu m to 4.28 mu m, the effects of porous media on foam properties are studied. Compared with foam systems in free space, foam systems in porous media have longer foam half-life, longer drainage half-life, and higher foam comprehensive index. The foam volume of foam systems in porous media could be higher or lower than that in free space, depending on the average pore throat radius of the porous media. Generally, in porous media, with the decreasing of pore throat radius, the foamability of the foam systems gradually decreases while the foam stability gradually increases. Moreover, the bubble size and liquid film thickness also decrease with the decreasing of pore throat radius of the porous media. Above all, the behaviors of foams are significantly affected by porous media. When investigating a foam system to evaluate its performance for foam flooding in oil recovery or other applications in porous media, porous models which could reflect the target conditions should be considered to obtain more trustable results.