High-molar mass acrylamide-co-diacetoneacrylamide graft copolymers as viscosity enhancer for polymer flooding oil recovery

Abstract One of the most widely applied enhanced oil recovery processes is the polymer flooding, in which aqueous solution of polymer viscosifier is introduced in oil reservoirs to increase the recuperation of the remaining oil. From the current challenges of this process, it can be referred to a high cost of materials regarding their substantially required amount and the low impact on the mobility ratio during the process due to the reduction of solution viscosity at high temperatures and high salinity environments. The purpose of this study is to investigate the concept of acrylamide-based thermosassociating copolymer (TAP), with a specific morphology and chemistry (hydrophilic main backbone made of polyacrylamide with grafted amide functionalized pending chains) as viscosity enhancer at harsh conditions of high temperature and salinity. For that aim, a specific TAP microstructure was targeted (very high molar mass linear polymer chains with improved copolymer homogeneity). It is achieved in this study throughout applying the reaction engineering approach, such as synthesis in semi-batch mode or/and in heterogeneous dispersed media. As a result, the synthesized TAP presented excellent behavior as viscosity enhancer especially under high temperature and salinity conditions with improved performance in comparison to TAP synthesized by a conventional solution polymerization approach and to actual commercial high molar mass acrylamide-based polymer.