Appraising the impact of metal-oxide nanoparticles on rheological properties of HPAM in different electrolyte solutions for enhanced oil recovery

Abstract

Polymer has been employed as a valuable chemical to increase mobility ratio and subsequently to improve sweep efficiency of water flooding. However, its sensitivity to harsh reservoir conditions which are high formation brine salinity with high temperature has degraded its thickening characteristics and lowered its performance in oil reservoirs. Recently, the application of nanoparticles (NPs) has shown a magnificent impact on chemical performance and eventually boosted chemical flooding recovery under reservoir condition. It has been observed that the role of NPs type as rheology control agents in modification of the polymer performance in reservoir condition has not earned enough attention. The aim of this study is to develop NPs-HPAM hybrid dispersions by employing aluminium oxide, silicon dioxide and titanium oxide NPs to partially hydrolyzed polyacrylamide (HPAM) solutions. The rheological properties of NPs-HPAM hybrid dispersions were examined in the presence of mono- and divalent ions at different shear rates and NPs concentrations. The results revealed that increasing the salt concentration decreases viscosity of the polymer solutions. NPs-HPAM hybrid dispersions exhibit higher viscosity than that of HPAM solutions at the same salinity which contributed to the NPs shield against cations present in the salt. In addition, the Fourier transform infrared spectral data established the presence of hydrogen bonds between NPs and carbonyl groups in HPAM solutions which confirmed improve performance of HPAM solutions by NPs under saline condition. Moreover, NPs-HPAM hybrid dispersions showed higher viscosity than polymer solution at low and medium shear rates, while the reversed trend was detected at higher shear rate due to the adsorption interaction of polymer molecules on NPs surface. Furthermore, the efficiency of NPs-HPAM hybrid dispersions as innovative tertiary recovery technique was put to the test through a water-wet sand pack saturated with intermediate oil. The results indicated that alumina-, silica- and titanium-polymers dispersions have ultimate oil recoveries of 15%, 10% and 6% higher than polymer flooding. Results of these researches prove that application of NPs-HPAM hybrid dispersions is the innovative and advanced method since NPs improve the HPAM solution thickening behaviour and rheological properties in the high salinity reservoir conditions.