Synthesis of a novel reverse demulsifier with the characteristics of polyacrylate and polycation and its demulsification performance

Abstract As the development of oilfield exploitation, more and more oil in water (O/W) emulsion was produced, thus efficient reverse demulsifier becomes increasingly important. In this paper, a series of novel reverse demulsifiers (R‐PED1 ~ 4) with the characteristics of polyacrylate and polycation were prepared. The structure of the product was verified by IR specter and 1H NMR. The thermal stability was studied with TGA and the molecular weight was obtained by GPC. Field evaluation results showed that the oil content in produced liquid after R‐PED4 treatment can be reduced from 1550 to 81 mg/L at R‐PED4 dosage was 50 mg/L. Furthermore, the demulsification mechanism of R‐PED was discussed. The R‐PED has good surface/interfacial activity. It can effectively reduce the oil–water interfacial film strength and reduce the zeta potential of oil droplets, which is beneficial for the coalescence of oil droplets. Especially, the interaction force between oil droplets was measured by the optical tweezers. R‐PED4 can increase the attraction force between oil droplets. Consequently, the contact time of oil droplets during the demulsification process can be prolonged and the coalescence of oil droplets also can be effectively promoted. The novel reverse demulsifier offers a new option for the oilfield produced liquid treatment.