A systematic approach to alkaline-surfactant-foam flooding of heavy oil: microfluidic assessment with a novel phase-behavior viscosity map

Abstract

The apparent viscosity of viscous heavy oil emulsions in water can be less than that of the bulk oil. Microfluidic flooding experiments were conducted to evaluate how alkali-surfactant-foam enhanced oil recovery (ASF EOR) of heavy oil is affected by emulsion formation. A novel phase-behavior viscosity map—a plot of added salinity vs. soap fraction combining phase behavior and bulk apparent viscosity information—is proposed as a rapid and convenient method for identifying suitable injection compositions. The characteristic soap fraction, , is shown to be an effective benchmark for relating information from the phase-viscosity map to expected ASF flood test performance in micromodels. Characteristically more hydrophilic cases were found to be favorable for recovering oil, despite greater interfacial tensions, due to wettability alteration towards water-wet conditions and the formation of low apparent-viscosity oil-in-water (O/W) macroemulsions. Wettability alteration and bubble-oil pinch-off were identified as contributing mechanisms to the formation of these macroemulsions. Conversely, characteristically less hydrophilic cases were accompanied by a large increase in apparent viscosity due to the formation of water-in-oil (W/O) macroemulsions.

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

“…The formation of the emulsion may also overshadow the destructive impact of crude oil on foam performance and cause an increase in apparent viscosity of the injected fluids. This behavior has been reported previously for other oil–foam systems . These findings illustrate the importance of discussing the surfactant–oil–gas interaction on a case-by-case basis.…”

“…This behavior has been reported previously for other oil−foam systems. 51 These findings illustrate the importance of discussing the surfactant−oil−gas interaction on a case-by-case basis. Therefore, these phenomena need to be carefully studied for field foam-EOR operations.…”

Screening High-Temperature Foams with Microfluidics for Thermal Recovery Processes

“…Foam mobility control and oil displacement mechanisms were also observed in a polydimethylsiloxane (PDMS) microfluidic system containing two interconnected parallel porous media, providing insight into the foam conformance in reservoirs with multipermeability zones. , In addition, the stability and pore-scale recovery effectiveness of nanoparticle-stabilized CO 2 foam for light, intermediate, and heavy oils have been evaluated using a microfluidic porous medium . A microfluidic platform was also utilized to assess the impact of emulsion formation on the efficacy of alkaline-surfactant-foam flooding for heavy oil recovery . Furthermore, the mobility reduction factor of thermal and supercritical CO 2 foam surfactants have been evaluated using a microfluidic system. , Pore-scale foam diversion for heavy oil displacement have been also studied using a simple 2-D visualized model .…”

“…42 A microfluidic platform was also utilized to assess the impact of emulsion formation on the efficacy of alkaline-surfactant-foam flooding for heavy oil recovery. 43 Furthermore, the mobility reduction factor of thermal and supercritical CO 2 foam surfactants have been evaluated using a microfluidic system. 44,45 Pore-scale foam diversion for heavy oil displacement have been also studied using a simple 2-D visualized model.…”

A microfluidic study of oil displacement in porous media at elevated temperature and pressure

“…With the quicker performance, it can be considered a preliminary, alternative, or complementary method to core flooding studies. Examples of microfluidic EOR visualization studies include polymer 13 , 14 , surfactant 15 , alkaline surfactant polymer or foam 16 , 17 , nanocellulose 18 , low salinity surfactant 19 , 20 , and low salinity water flooding 21 – 23 . However, only a few studies have considered the effect of temperature on fluid displacement.…”