Adsorption mechanism of polymers at the oil-water interfacial film and its effect on interfacial stability

Abstract

The efficient treatment of oilfield produced water is a key link to realize the green and sustainable development of oilfields, so it is of great significance to study the stability mechanism of oilfield produced water to realize the efficient treatment of oilfield produced water. In this paper, the stability of “fracturing return fluids”(i.e., multi-polymer emulsion systems) is used as a background for the study. Molecular dynamics simulation by constructing a sandwich model of oil/intermediate/aqueous phases with different components by varying the concentration ratio between polymers. Study on the effect of changing the concentration ratio between polymers on the stability of oil-water interfaces under polymerization system and the principle of its effect. The results showed that a clear oil-water interface was formed after the system was stabilized, and the thickness, structure, strength and hydrophilic adsorption layer fullness of the interfacial film were related to the concentration ratio between the polymers. The adsorption of Hydroxypropyl guar gum (HPG) and partially hydrolyzed polyacrylamide (HPAM) at the oil-water interface would form a double-layer membrane structure. The interfacial stability was the strongest when the ratio of the concentration of HPG and HPAM reached 2:1.The different polymer concentrations altered the thickness, structure, strength, and hydrophilic adsorbent layer fullness of the interfacial, which in turn affected the stability of the system.