Abstract
Natural gas extraction is a greener solution to world energy resource depletion and water-based hydraulic fracturing is traditionally used to produce gas from deep and tight geological formations. However, since this practice fails to produce a commercially viable amount of gas and raises many environmental issues, better alternatives are being tested in the field, among which the usage of foam-based fluid is a comparatively novel but effective technique. The aim of this review is to understand the current opinion on foam-based fluid fracturing, its merits and demerits and the associated environmental footprint. Foams are made by mixing a gas phase with a liquid phase using a suitable surfactant, and the foam quality is composition-dependent, with high quality foams having higher percentages of gas. The properties of the injecting foam, including its rheology and viscosity, are important for the fracturing process. According to current studies, foams have two separate flow regimes (low and high quality) and a unique multiphase flow pattern. Foam viscosity should be low to enter the ends of the fracture and high to have a good proppant-carrying capacity. Greater proppant-carrying capacity, lower water consumption and chemical usage, quicker and easier fluid flowback and less environmental damage are the advantages of foambased fracturing, and lack of knowledge, high capital cost, and potential damage to the environment from surfactants are the limitations. However, foam-based fracturing has been tested in very few locations to date.