Surfactants are chemicals containing hydrophilic and hydrophobic groups (water and oil soluble groups respectively) and primarily reduce the interfacial tensions between two fluids, a fluid and a gas, or a fluid and a mineral surface. Depending on the ionic charge of the water-soluble group, surfactants have a wide variety of applications. They are an essential part of drilling, cementing, completion, and stimulation fluids. In fracture fluid systems, surfactants may leave the formation (and fines) water wet as opposed to oil wet, which will aid in hydrocarbon recovery. Furthermore, surfactants are commonly used in lower pressured reservoirs to promote well clean-up operations after a treatment, or as foaming agents in foamed fracturing fluids.