Natural gas is brought above ground using a drilling process called hydraulic fracturing, which has been used since the 1930s.
Hydraulic fracturing works by drilling approximately 2 to 3 kilometers underground and then turning a drill horizontally so it can keep drilling along the horizontal layers of rock where the gas is trapped. The drill can turn in several different directions so only one hole needs to be
drilled on the surface to reach numerous areas underground.
To release the natural gas that is trapped in the rock, hydraulic fracturing fluid is forced into the hole made by the drill (called the well bore) at high pressure. This creates tiny cracks in the horizontal layers of rock and holds them open so the gas can travel into the well bore and up to the surface.
Hydraulic fracturing fluids are typically 99% water and sand. A small amount of chemicals are also added to reduce friction, help the fluid flow into cracks, prevent rust in the drill pipes and prevent bacteria from growing. In BC and Alberta, chemicals used in hydraulic fracturing are reported to provincial regulators and posted at www.fracfocus.ca.
To isolate natural gas wells from water sources and make sure no underground gases escape into the air or shallower rock formations, the steel well bore (drill hole) is contained within multiple barriers of steel casing, including four casings cemented in place. The multiple barriers of steel casings are cemented within each other and are set well down into the well bore to provide an impermeable seal through which hydraulic fracturing and well fluids cannot pass.