Influence of Surfactant Concentration and Counterion to Surfactant Ratio on Rheology of Wormlike Micelles

Onion-Like Structure of Viscoelastic Surfactant Solution Flow Induced by 4-Blade Paddle Impeller in a Vessel

“…e viscosities at shear rates below 1 s −1 were constant and not a ected by the surfactant concentration. For the surfactantcounterion system used in this study, it has previously been reported that for ξ=1, the zero shear viscosity increases and then decreases, while for ξ=2.5, decreases and then increases with an increase in the surfactant concentration (Lin et al, 2001). For ξ=2, the constant viscosities at small shear rates are conceivable and are probably the result of a balance between the density and size of micellar networks.…”

“…Since the connecting points of micelles change from entanglement to molecular binding upon the addition of excess counterions (Lin et al, 2001), bound micellar network behaves as a single rigid object. us, with increasing shear rate, weakly occulated bound structures are dispersed.…”

“…is is the well-known drag-reducing e ect. e mechanism and e ciency of drag reduction have been intensively studied (Rose and Foster, 1989;Hu and Matthys, 1995;Lu et al, 1998;Lin et al, 2001;Usui et al, 2004;Suzuki et al, 2005). e viscoelasticity of the surfactant solution disappears and recovers depending on the applied shear rate and shearing time because the entangled micellar structure or rod-like micelles are destroyed in a strong shear ow and rebuilt by removing the applied shear stress, while once degraded polymer molecules are not restored .…”

“…e mechanism of viscoelastic change has not been clari ed but viscoelastic changes are presumably caused by structural changes in rod-like micelles, such as branches, bundles, saturation of entanglement (Lin et al, 2001). Nevertheless, it is true that the rheological properties of a viscoelastic surfactant solution are strongly a ected by the concentration of counterions, and interestingly, the viscoelasticity does not monotonously change with an increase in the counterion concentration.…”

A systematic rheological study of alkyl amine surfactants for fluid mobility control in hydrocarbon reservoirs

“…In addition, shear thinning at higher salt concentrations suggests disentanglement of the system and alignment of the wormlike micelles under shear flow (Acharya and Kunieda 2006;Shchipunov and Hoffmann 2000;Trickett and Eastoe 2008). This alignment causes viscosity degradation since the micellar structure orients in a way that minimizes resistance to flow, causing the solution to move as a single object (Lin et al 2001). Furthermore, a slight degree of shear thickening occurs at lower salt concentrations and/or dilute solutions, leading to a fractional viscosity increase of 0.2 mPa s from 1 to 100 s -1 .…”