The major benefits provided by hydraulic fracturing exist due to the ability to fill the fractures with "proppant".

The major benefits provided by hydraulic fracturing exist due to the ability to fill the fractures with "proppant". Proppants are composed of solid granular materials that are injected along with fracturing fluid and enter the open fracture during propagation. Following the creation of a hydraulic fracture the fracturing fluid dissipates into the formation or is pumped back out through the well casing. The solids are left behind and serve to permanently "prop" the fracture open. Quartz sand has traditionally been used as proppant during enhanced flow applications, however, just about any fine- to medium-grained granular material can be used. (i.e. oxidative chemicals, reductive chemicals, nutrients).