Controlling Gas Mobility in Water-Alternating Gas Injection by Surfactant Blend Formulations

Controlling the viscous fingering in water-alternating gas injection, addition of foam with injection water is more favorable. The use of foam surfactant is one of the potential solutions for reducing the gas mobility. The main objective of this study is to generate stable foam for gas mobility control using surfactant blend formulations. Surfactant blend synergistically exhibit better foaming properties than those of individual surfactant. The blend contains anionic as primary surfactant and amphoteric as a foam stabilizer. Surfactant blend improves the foam stability and reduces the destabilizing effect of crude oil. Alpha olefin sulfonate (AOSC14-16) is selected as a primary surfactant. Amphoteric surfactant lauryl amido propyl amine oxide (LMDO) is selected as an additive. The foam was generated in the absence of crude oil in porous media by using Berea sandstone core samples at 96 degrees C and 1400 psi. The increase in differential pressure showed reduction in gas mobility. The average mobility reduction factors of surfactant blend 0.6% AOS and 0.6% AOS + 0.6% LMDO at reservoir conditions were resulted as 2.5 and 4.35, respectively. The experimental results showed that the blend formulations play an imperative role in minimizing gas mobility during water-alternating gas injection.