Shear rheology and porous media flow of wormlike micelle solutions formed by mixtures of surfactants of opposite charge

Sweep enhancers for oil recovery

“…A solution containing a cationic and anionic surfactant which has nonmonotonic rheological behavior was studied when flowing through a cylinder with mono-disperse glass spheres (Rojas et al 2008(Rojas et al , 2009). It was found that the elongational component of the flow promotes further interaction between worm-like micelles resulting in an enhanced apparent viscosity.…”

“…This reduction in the difference in flow rates has thus created a more uniform flow through these two different permeable cores. The effect of selective viscosifying can be investigated by introducing a resistance factor K (Golombok and van der Wijst 2013; Rojas et al 2008), which is defined as:…”

Wellbore to fracture proppant-placement-fluid rheology

“…There is no estimation of extra stress terms. Although pure Darcy flow strictly speaking, only applies to Newtonian fluids, the non-Newtonian application here is nevertheless a pressure difference driven flow and in such circumstances the application of effective viscosities or equivalently, resistance factors, is an accepted way of quantifying these effects (Rojas et al, 2008). This is particularly useful when it comes to application for flow in a model fracture which we now describe.…”

Reservoir resilience of viscoelastic surfactants

“…RF = l ves /l bf ) where the viscosity of the VES fluid is an average bulk viscosity across the aperture (also called ''apparent'' viscosity) (Gonzalez et al 2005;Rojas et al 2008). The retardation factor depends on the fracture aperture size and is higher in larger fractures.…”