The effect of rock microheterogeneity on steam foam rheology

Supercritical CO2 Foam Stabilized by a Viscoelastic Surfactant in Fractured Porous Media: The Effect of Fracture Surface Roughness

“…Brame et al also noticed a shear-thickening behavior in their heterogeneous pore-size sand pack since the higher flow rates are prone to force the foam bubbles to enter the small pore throats. 46 Also, it is worthy to note that we agree with Brame et al, who believe that the foam will start to show shearthinning behavior once the flow rate is high enough to let the foam bubbles get access to all open and connected pore throats and the maximum lamellae per unit flow rate are reached as foam bubbles enter and evolve in the system. Hence, the observed shear-thickening behavior in the fractured system results from heterogeneity in porous media.…”

“…The surfactant sensitivity of this effect of fracture surface roughness on foam performance was not evaluated in this study. However, we believe that this observation is surfactant-independent since several studies with various surfactant foams performed in the micromodel, Hele–Shaw model, and sand pack obtained similar results. In our previous study, the surfactant with moderate viscoelasticity and low viscosity could generate the foam with a high mobility reduction factor (MRF) in the porous media .…”

“…Shojaei et al 23 noticed the existence of spatially correlated low-and high-aperture areas in an unsmooth fracture surface in their Hele−Shaw-type model, which caused an increase in flow tortuosity and the velocity contrast between preferential flow channels and stagnant zones. Brame et al 46 highlighted that the microheterogeneity promotes the apparent foam viscosity in their wider grain-sizedistribution sand packs. It seems that as the fracture surface roughness R s distribution widens and the mean R s increases, the flow diversion promotes better foam generation in the fracture, elongates the foam "lifetime" in the porous media, facilitates the lamella invasion into the matrix, and hence increases the apparent foam viscosity.…”

CO2 Foam Behavior in Carbonate Rock: Effect of Surfactant Type and Concentration

“…Unexpectedly, then, in this case, the foam scans for both the betaine and the sultaine (Figure ) showed no effect of varying core permeability, with the curves lying together in the low-quality regime. However, as Brame et al also discuss, the heterogeneity of the rock can have an effect on the foaming behavior, with a higher degree of heterogeneity reducing the effect of the different bulk permeabilities.…”

“…It is expected that higher permeability cores give higher measured apparent viscosities over the whole range of foam qualities. Brame et al 44 discuss the relationship between the permeability and the shear rate experienced by the flow in a rock, with the shear rate scaling with k −1/2 . Foams in higher permeability rocks therefore experience lower shear rates and less shear thinning and hence give higher measured viscosities.…”