Impact of polyacrylamide adsorption on flow through porous siliceous materials: State of the art, discussion and industrial concern

Hypothesis: Adsorption of high molar mass polymers impacts flow in porous media. In the industrially crucial case of acrylamide-based polymers in porous silicates, the very occurrence of adsorption is still debated. Thus, the present work aimed at establishing a clear correlation between adsorption of acrylamide-based polymers and injectivity loss in porous silica. Experiments: A review of the literature revealed apparent discrepancies regarding the affinity of acrylamide-based polymers for siliceous materials having ostensibly the same chemical composition. Through a deeper analysis of the reported literature and new experimental measurements on well-defined polymers and surfaces, we investigated the relation between the silica surface properties and the acrylamide-based polymer adsorption. Our observations were confronted with water injection experiments in porous media of different surface compositions previously put in contact with polymers. Findings: The polymer affinity towards the silica surface depended on the density of hydroxyl groups at the surface of the oxide, its thermal treatment, storage condition and purity. This demonstrated that the impact of adsorption on acrylamide-based polymer flow within porous silicates heavily depends on the silicate surface composition and must be carefully evaluated. In view of the continually expanding use of acrylamide-based polymers, notably in enhanced oil recovery, such considerations provide interesting insights into the effect of adsorption on their flow into porous materials. (C) 2018 Elsevier Inc. All rights reserved.