*4.1.4 Foam-based fracturing fluid*

Another type of fracturing fluid is a foam-based fracturing fluid which is generated from the combination of two phases of liquid and gas as well as addition of surfactant to ensure stability [51]. The main advantages of this type of fracturing fluid is its efficiency in water-sensitive areas and its relatively better proppant carrying capacity compared to water-based fracturing fluids [62]. High cost and risk of flammability are the main disadvantages of foam-based fracturing fluids.
