Effects of Electrolytes on the Stability and Dynamic Rheological Properties of an Oil-in-Water Pickering Emulsion Stabilized by a Nanoparticle–Surfactant–Polymer System

Abstract

Information on the effect of electrolytes on the stability and rheological properties of Pickering emulsion is required for their application in enhanced oil recovery for deep offshore and onshore crude oil reservoirs. In this study, the dynamic rheological properties (viscosity, yield stress, and dynamic moduli) of nanoparticle−surfactant−polymer−salt (NSPS) stabilized Pickering emulsions are investigated at varying pressure (0.1 and 30 MPa) and temperature (298 to 371 K) and compared with those of an NSP stabilized emulsion system. We used nanoparticles (SiO 2 and clay of size ∼15 nm and <80 nm in diameter, respectively), surfactant (sodium dodecyl sulfate, SDS), polymer (polyacrylamide, PAM), and sodium chloride (NaCl) for the formulation of the emulsion. The presence of salt of an appropriate concentration of 1.0 wt % in a NSP emulsion system is observed to improve droplet packing with uniform distribution as observed from microscopic characterization. The interfacial tension of the NSPS emulsion system is observed to reduce significantly in the presence of salt as compared to that of the NSP emulsion system. Dynamic rheological properties of the NSPS emulsion system showed that the presence of salt marginally affected the viscosity and yield stress as compared to those of the NSP emulsion system. The presence of salt affected the elastic modulus, G′, and viscous modulus, G″ providing a stable viscous behavior at elevated pressure (30 MPa) and temperature (371 K) conditions. G″ is observed to be higher than G′ for measured frequency ranges indicating a viscous-like behavior of NSPS emulsion system. With reference to the phase angle (δ), the values of δ for the NSPS emulsion system remains around 90°b ecause of negligible G′ indicating viscous behavior that concurs with literature observations. The results indicated the suitability of a NSPS emulsion system for high pressure high temperature (HPHT) applications such as enhanced oil recovery or drilling fluid design for a saline environment.

Recent Advances in Nanoparticles Enhanced Oil Recovery: Rheology, Interfacial Tension, Oil Recovery, and Wettability Alteration

“…However, there were no significant changes in the viscosity of the Pickering emulsion with the increase in temperature. Another similar study by Sharma and Sangwai reported the effect of NaCl on the rheological properties of Pickering emulsion stabilized by silica/clay nanoparticles-SP system at different pressures and temperature (25 to 98 ∘ C) [45]. Their findings in the dynamic rheological properties measurements revealed that the addition of salts slightly affected the viscosity of NPs-SP emulsions.…”

Effects of the reagent molar ratio on the phase separation and properties of waterborne polyurethane for application in a water‐based ink binder

“…An aqueous solution of 2 M NaCl was slowly dropped into the beaker with a burette until coagulation was obtained. The volume of NaCl necessary to coagulate the WPU dispersions represented the electrolytic stability . The values of the three prepared samples were taken as the average of three replicates.…”

Effects of Divalent Salts on the Interfacial Activity of the Mixed Surfactants at the Water/Model Oil Interface

“…Many reports focused on the effects of salts on the interfacial activity of surfactants (Anachkov et al, 2015;Cao et al, 2012;Gandomkar and Rahimpour, 2017;Johnson et al, 2017;Lashkarbolooki et al, 2016;Lashkarbolooki and Ayatollahi, 2018;Liu et al, 2013Liu et al, , 2014Robertson et al, 2013;Sharma and Sangwai, 2015;Tichelkamp et al, 2014Tichelkamp et al, , 2015Tummons et al, 2017). The addition of salts can affect surfactants in the following ways (Cayias et al, 1976;Eftekhardadkhah and ye, 2013): First, the electrostatic attraction between the counterions and the charged heads of ionic surfactants compresses the occupied area of surfactant head groups at the interface and increases their effective concentrations.…”

“…The salinity is one of the vital factors for the interfacial activity of surfactants (Gandomkar and Rahimpour, 2017;Robertson et al, 2013;Sharma and Sangwai, 2015;Tummons et al, 2017). The salt type (Na + , Ca 2+ , and Mg 2+ ), the salt concentration, and even the ratio of different cations may dominate the salinity effects on the IFT (Anachkov et al, 2015;Cao et al, 2012;Johnson et al, 2017;Lashkarbolooki et al, 2016;Lashkarbolooki and Ayatollahi, 2018;Liu et al, 2013Liu et al, , 2014Tichelkamp et al, 2014Tichelkamp et al, , 2015.…”