The emulsions stabilized by Dodecylbenzenesulfonic acid/asphaltene/hydrolyzed polyacrylamide: Emulsion morphology, stability, and rheology

Aqueous mixtures of dodecylbenzene sulfonic acid (DBSA) and hydrolyzed polyacrylamide (HPAM) are commonly used to enhance oilfield recovery. These two components coupled with asphaltenes (ASP) in crude oil, play a key role in stabilizing the emulsions produced during oil recovery. In this study, the stability of emulsions made with ASP, DBSA, and HPAM as emulsifiers was examined. We discovered that the three ingredients were synergistically adsorbed at the oil-water interface with a synergistic index of 1.075 for interfacial tension (IFT). HPAM enhanced the viscosity and increased the anion content of the dispersed system in the emulsion. DBSA acted as the main anionic surfactant, benefiting to form and stabilize the emulsion droplets. ASP was adsorbed at the oil-water interface to form a rigid interfacial film. When the three ingredients co-existed, they formed a complex adsorption unit with synergistic adsorption, in which DBSA dominated. As the concentration of the three ingredients increased, the emulsion stability showed a trend of enhancing first and then decreasing. This study is dedicated to providing a theoretical basis for the elucidation of the stability of the oil-water system in oil sludge containing polymers.