Salt induced shear thickening behavior of a hydrophobic association polymer and its potential in enhanced oil recovery

Abstract

Shear thickening solution is rarely encountered but the solution with low concentration and high salinity is really desired in enhanced oil recovery. In this paper, we developed a comb micro-block hydrophobic association polymer (CBHAP). The polymer solution with high salinity showed an obvious shear thickening behavior, even if the polymer concentration was very low (1 g/L). In addition, with the increase in salinity (> 20 g/L) and temperature, shear thickening phenomenon will be more obvious. We analyzed that the unique rheological behavior was influenced by the comb micro-blocked structure and the forces transition from intramolecular to intermolecular when the curled polymer chains were stretched under shearing. In porous media, high permeability and low flow rate were beneficial to achieve the shear thickening flow. The unique property will endow CBHAP better mobility control ability than conventional polymers, especially in high permeability reservoirs or fractured reservoirs.