Factors influencing the mobility control ability of diutan gum‐enhanced foam in porous media

Abstract

Diutan gum (DG) is an anionic polysaccharide produced by Sphingomonas sp. ATCC 53159. The DG‐enhanced foam (DGEF) formed by the DG and foam has great application potential in enhanced oil recovery. In this research, the influence of injection parameters on DGEF was studied by conducting orthogonal experiment, with residual resistance coefficient (Rff) as the main evaluation index. The micro‐state of the foam was observed using an etching model and scanning electron microscope. The mechanism of different factors on the mobility control ability of the foam was discussed based on the apparent viscosity and surfactant depletion. The results show that the Rff of foam is correlated with the apparent viscosity, and the foam with high apparent viscosity had a good flow control ability. The calculation of the surfactant depletion shows that the bubble stability decreased significantly when the concentration of Sodium alpha‐olefin sulfonate (AOS) cannot meet the minimum stabilization concentration, thus weakening the mobility control ability. Based on the study of crude oils, the presence of oil phase will seriously weaken the mobility control ability of DGEF, but the effect of oil with higher content of resin and asphaltene will be relatively weak.