Hydraulic fracturing, also referred to as hydrofracking, is a well-drilling technique to fracture rocks. In this process, water is combined with small amounts of chemicals and proppants, then pumped into the well under high pressure to create more fractures in the rock structure along already existing fractures. The hydrofracking process allows natural gas, petroleum and brine to flow more freely.
Once the pressure is released and the water removed, the proppants used in the process, most often sand or aluminum oxide, are left behind to prop open the fractures. A number of estimates claim that in wells where the hydrofracking technique is used, there is more than a 90 percent increase in recovering natural gas and petroleum, which is a high percentage compared to wells where more traditional drilling techniques are used.
Hydrofracking began as an experiment in Kansas in 1947. It was first used successfully in commercial applications in 1949. As of 2012, some 2.5 million hydrofracking operations had been performed worldwide on gas and oil wells.
Though the technique increases gas and oil production, it is highly controversial due to environmental concerns. The major concerns with hydrofracking include the treatment of resulting wastewater and the safety of the chemicals used in the process. Other environmental concerns include the triggering of earthquakes, noise pollution, surface pollution and decreased air quality.