Hydrophobic effect further improves the rheological behaviors and oil recovery of polyacrylamide/nanosilica hybrids at high salinity. (15th March 2021)

• Record Type: Journal Article
• Authors: Xu, Long; Liu, Sen; Qiu, Zhe; Gong, Houjian; Fan, Haiming; Zhu, Teng; Zhang, Huan; Dong, Mingzhe
• Is Part Of: Chemical engineering science. Volume 232(2021)
• Publication Date: 2021-03-15
• Subjects: Hydrophobically associating polyacrylamide -- Hydrophobic modified nanosilica -- Rheology -- Enhanced oil recovery -- Synergy; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; Chemical engineering; Periodicals; Electronic journals; 660
• DOI: 10.1016/j.ces.2020.116369
• Languages: English
• ISSNs: 0009-2509

Abstract

Graphical abstract: Highlights: Hydrophobic functionalized nanosilicas with different alkyl chains were synthesized. Synergy between HAHPAM and CMNP on thickening was found at high salinity. The CMNPs markedly facilitate the cross-links among HAHPAM molecules. The oil displacement mechanisms of the HAHPAM/CMNP hybrid were proposed. The hydrophobic effect effectively improves the salt tolerance of HAHPAM/CMNP hybrids. Abstract: The study aims to improve the rheological behaviors and oil recovery of hydrolyzed polyacrylamide (HPAM) at high salinity by introducing nanosilicas. It was found that the combination of hydrophobically associating polyacrylamide (HAHPAM) and cetyl-modified nanoparticles (CMNPs) has a more substantial synergy for improving rheological behaviors of hybrid dispersions at high salinity, comparing with other HPAM/NP hybrids. The CMNPs markedly facilitate the cross-links among clumpy molecular aggregates of HAHPAM and made the hybrids more elastic. At a given HAHPAM concentration, there exists an optimal CMNP concentration at which the adsorption of nanosilicas on the polymer molecular chains is maximized. Under reservoir conditions, the HAHPAM/CMNP hybrid is more efficient than the HAHPAM/NP hybrid for enhanced oil recovery. The oil displacement mechanism of the HAHPAM/CMNP hybrid is attributed to the synergistic thickening and wettability change. The hydrophobic effect between HAHPAM and the CMNPs effectively improves the salt tolerance of the hybrids.