Hydraulic fracturing, (also known as hydrofracturing, “fracking”, or “fracing”) is the process of creating small cracks, or fractures, in underground geological formations to allow oil or natural gas to flow into the wellbore and thereby increase production. Prior to initiating hydraulic fracturing, engineers and geologists study and model the physical characteristics of the hydrocarbon bearing rock formations, including the formation
porosity, and thickness. Using this information, the well operator designs the process to keep the resulting fractures within the target formation.
To fracture the formation, fracturing fluids are injected down the wellbore and into the formation. These fluids typically consist of water, sand (proppant), and chemical additives. The pressure created by injecting the fluid opens the fractures. In some applications, sand (proppant) is transported into the fractures by a gel-based fluid that keeps the fractures open to increase the flow of oil or natural gas to the wellbore. The chemical additives serve a variety of purposes, including increasing viscosity, reducing friction, controlling bacteria, and decreasing corrosion.
During 2014, 652, or 97.46%, of the well stimulation treatments in California were conducted using hydraulic fracturing.
More information about hydraulic fracturing in California is available on the Division’s website located at: