Solution Properties and Displacement Characteristics of Core–Shell Hyperbranched Associative Polyacrylamide for Enhanced Oil Recovery

Polymer flooding that is prepared with produced water has been a potential enhanced oil recovery technology in mature reservoir. In this paper, the solution properties, water solubility, flow behaviors, and displacement characteristics of core–shell hyperbranched associative polyacrylamides (HDPAMs) were studied under Xinjiang oilfield reservoir condition. The water solubility tests illustrated that HDPAMs could be completely dissolved in produced water within 130 min. Meanwhile, HDPAMs had favorable thickening ability, antishearing performance, salt resistance, alkali resistance, temperature tolerance, antiaging performance, and viscoelasticity. The injectivity tests and flow behaviors tests illustrated that HDPAMs had favorable injectivity, and HDPAMs could build high resistance (Rf) and residual resistance factor (Rff) to expand sweep efficiency. The core flooding tests were carried out to investigate the effect of permeability, injection rate, slug size, and the viscoelasticity on oil recovery, and the results showed that HDPAMs could obtain high oil recovery owning to high apparent viscosity and favorable viscoelasticity. All of the experiments showed that HDPAMs solution is feasible to be prepared with produced water, and it has great potential for enhanced oil recovery.