In the subsurface environment, petroleum-based products are commonly released due to widespread use, improper disposal, accidental spills and through leakage of underground storage tanks. This can serve as a long-term source of contamination of soil and groundwater, which poses significant challenges to the human health, agriculture, and water quality. To avoid adverse environmental effects, it is a necessity to invest more in soil remediation and create tailored guidelines for remediation practices depending on the properties of soil and the contaminating hydrocarbons.

Foam injection in porous media proved to be a promising approach to mobilize the trapped oil thanks to its unique physicochemical properties. Foam is a dispersed gaseous phase within a continuous aqueous phase comprised mainly of thin films known as lamellae. The use of foam compared to other approaches used for oil mobilisation offers the following advantages: a significantly reduced (by one order of magnitude) volume of liquid required for injection, a better sweep of the defending fluid due to relative immobility of foam and a diversion mechanism that the foam tends first to occupy regions with large permeability causing later flow to sweep low-permeability regions. Foam flow in porous media is influenced by the pore geometry, heterogeneity and connectivity of the porous media as well as foam stability in the presence of hydrocarbons. We employ a wide range of theoretical and experimental tools to investigate foam-assisted oil displacement in porous media. This knowledge is important for soil remediation as well as enhanced oil recovery from underground oil reservoirs.  

Figure caption. Foam bubble size distribution in a horizontal Hele-Shaw cell with the colour representing the bubble size (see more details in Osei-Bonsu et al (2015), Colloids and Surfaces A: Physicochem. Eng. Aspects, 481, 514–526).

Figure caption. (a) Top view of the model manufactured by a 3D printer in our work to investigate flowing foam dynamics in porous media. (b) Magnified image of the pores to better illustrate the patterns of pores/grains in the printed porous medium. (c) Pore throat size distribution of the printed porous medium. (d) Typical image recorded during oil displacement by foam. Dark gray represents the oil. (e) Corresponding segmented image of the phase distributions presented in (d) with white, black, and red representing the foam (or escaping gas and surfactant), oil, and grain, respectively (see more details in Shojaei et al. (2018), Ind. Eng. Chem. Res. 2018, 57, 7275−7281).