million hydraulic fracturing jobs have been done in the United States (some wells are hydraulically fractured more than once), and almost 90% of new US onshore oil and gas wells are hydraulically fractured. Typical extraction process The process of extracting shale oil or gas typically has several stages, including some legal preliminaries. First, a company must negotiate the mineral rights with the owners. After a company has leased the mineral rights, it must obtain a permit to drill a well. Permits are regulated by state agencies and the requirements vary. Once it has obtained the permit, the company clears an area of 4–5 acres for a stage bed; it may also construct roads, a waste water site, and a temporary gas storage facility. Next is the drilling and casing of the well. In a process similar to that for constructing water wells, a bore machine drills vertically in the ground, and two or more steel casings are set in the well in a reverse telescope manner. The casing helps keep the well open by providing structural support and preventing fluid and gas flow into the surrounding ground. Once the casing is in place, cement is pumped down inside the casing and back up on the outside of the casing. This is done to cement the casing in the formation and to prevent any leakage or flow of the gas and fluids behind the casing. The next step is the fracturing itself. A mixture of water and chemical additives are pumped down the well at high pressure. This creates fractures in the rock, and a proppant such as sand is injected to keep the fracture open. This allows the natural gas to flow to the well and up to the surface. The fracturing phase takes a few days, and the recovery enhancement success of the fracturing job depends on a number of in-situ and operational parameters. After all this preparation, the well has a few years of production where natural gas is brought to the surface, treated, and carried off. This may be punctuated by workovers during which the well is cleaned and maintained to increase production. When the well has been exhausted, it is plugged. The area around it is restored to the level required by state standards and the agreement with the owner. Economic impact Hydraulic fracturing of tight oil and shale gas deposits has the potential to alter