Synthesis and Oil Displacement Performance of HMPAM-C 18 S/PS-C 18 Nanofluids

In this study, a hydrophobically modified polyacrylamide (HMPAM-C 18 S) and surface-modified polystyrene nanoparticles (PS–C 18 ) were synthesized using sodium 2-acrylamido-octadecanesulfonate (NaAMC 18 S) as the hydrophobic monomer and emulsifier, respectively. A polymer-based nanofluid for enhanced oil recovery (EOR) was developed by blending HMPAM-C 18 S and PS-C 18 . The effect of the NaAMC 18 S content on the water solubility of HMPAM-C 18 S as well as the particle size and emulsion stability of PS-C 18 were investigated. The properties of HMPAM-C 18 S and HMPAM-C 18 S/PS-C 18 nanofluid solutions were compared. Experimental results demonstrated that PS-C 18 -1.0 enhanced the molecular network structure of HMPAM-C 18 S through van der Waals interactions, significantly improving its apparent viscosity, thermal resistance, salt tolerance, and shear stability. Under reservoir conditions (65 °C, 6070 mg/L salinity, and core permeability of 1200 mD), the HMPAM-C 18 S/PS-C 18 -1.0 nanofluid (1500 mg/L HMPAM-C 18 S + 1000 mg/L PS-C 18 ) exhibited a higher resistance factor (RF) and residual resistance factor (RRF) compared to HMPAM-C 18 S. The EOR reached 28.95%, which was 8.95% higher than that achieved by HMPAM-C 18 S.