The Influence of Several Polymer Oil Displacement Agents on the Stability of Produced Water and the Treatment Performance of Typical Nonionic Water Clarifier

In this paper, first, the effects of four polymers, including partially hydrolyzed polyacrylamide (HPAM), hydrophobically modified polyacrylamide (HMPAM), surface-active polymer (SAP), and heavy oil activator (HOA), on the stability of produced water were studied, and then, the effects of the four polymers on the performance of a nonionic polyether water clarifier AE411 were compared. The results of turbiscan stability index and heart-shaped structure microfluidic chip experiments showed that the four polymers can enhance the stability of oil droplets, ranked as SAP > HMPAM > HOA > HPAM. They can increase the absolute value of oil droplet ζ-potential, the elastic modulus of the oil-water interface, and the repulsion force between oil droplets. SAP and HMPAM significantly increased the absolute value of ζ-potential and the steric repulsion force between oil droplets, respectively, which enhanced the stability of oil droplets in produced water stronger than that of HPAM and HOA. The produced water treatment results presented that these polymers weakened the performance of AE411, and the weakening result was consistent with their impact on the stability of oil droplets. The four polymers would affect the adsorption of AE411 at the oil-water interface, thus affecting its performance of reducing the strength of the oil-water interface and generating attractive force on the oil droplets.