Aqueous Foams Stabilized with Particles and Surfactants

Abstract

AbstractFoam is a proven method for decreasing gas mobility in both homogeneous and heterogeneous reservoirs. A new foam system, called multi-phase foam system composed of gas, liquid, and particles has been studied in China recently since it has better performance than general gas-liquid foam system in profile control.The aqueous foams prepared by mixtures of pre-performed particles and surfactants were studied in detail. In this article a new method focusing on liquid drainage velocity was used to estimate the stability of multi-phase foam system compared with classical foam stability studies that record foam height variation versus time. A synergistic effect on foam stability occurs and becomes more obvious with increasing surfactant concentration. The synergistic effect mainly comes from the adsorption of particles on the bubble surface and the formation of a three-dimensional network in the coherent phase. In addition, particle size is a significant factor affecting foam formation and stability. Foam prepared by 3 different size particles indicates that foam formability and stability decrease with increasing of particle size. It is hypothesized that the decrease in the foam formation and stability is related to the particle gravity. Finally, experiments about reservoir conditions like high temperature and salinity were also conducted. It shows that increasing temperature will accelerate the velocity of foam decay and the increase of calcium chloride concentration help to stabilize foam while sodium chloride has an optimum concentration for foam stability.