Simply built microfluidics for fast screening of CO₂ foam surfactants and foam model parameters estimation

Surfactant-stabilized CO₂ foam is a promising technique to increase an oil reservoir's sweep efficiency and therefore produce more oil. The development of successful CO₂ foam formulations requires extensive screening and development of commercially available and new chemicals. In this work, we provide a detailed procedure to build a cost-efficient microfluidic device for rapid prescreening of CO₂ foam surfactants. Several surfactant-stabilized CO₂ foams were successfully tested using the device which demonstrated complete foam quality testing to pre-screen a surfactant in less than an hour. Foam measurements successfully differentiated between different surfactant solutions and showed an increase of viscosity in comparison to CO₂ and brine flood alone. The microfluidic device enabled systematic studies of the effect of chip geometry, surfactant type and concentration, injection flow rate, gas fractional flow, and oil fractional flow on CO₂ foam strength. The steady-state foam results from the device were used to estimate the texture implicit foam model parameters. The method provided is not only robust for fast surfactant screening, but also for understanding the foam fluids transport phenomenon and foam modeling using microfluidics.