also called fracking, fracing, hydrofracking, fraccing, frac'ing, and hydrofracturing, is a well stimulation technique involving the fracturing of bedrock formations by a pressurized
liquid. The process involves the high-pressure injection of "fracking fluid" (primarily
water, containing sand or other proppants suspended with the aid of thickening agents) into a wellbore to create cracks in the deep-rock formations through which natural gas, petroleum, and brine will
flow more freely. When the hydraulic pressure is removed from the well,
small grains of hydraulic fracturing proppants (either sand or aluminium oxide) hold the fractures open.