Definition - What does Blowout mean?
A Blowout is a situation of uncontrolled flow of gas, oil or water from a reservoir to the surface at a drilling or production site. This condition usually occurs when oil well control techniques are not able to control the pressure of the surge from a well. When a blowout is not controlled or the blowout control techniques fail, then the situation can lead to a disastrous fire due to the leakage of oil or gas from the high-pressure reservoir.
Petropedia explains Blowout
Hydrocarbons are trapped in a reservoir bed under high amounts of pressure and temperature. Due to pressure variance between the earth's surface and the reservoir, the hydrocarbons tend to rise to a low-pressure zone at high speeds which if not handled properly may create a high amount of internal pressure and back pressure kick on the oil well. Such back pressure kick and development of high amount of internal pressure if not handled properly can lead to catastrophic blowouts.
In order to avoid any such situations and secure the life, environment and cost intensive asset, Blowout preventers are used at the top of producing oil wells to control the kicks and release the pressure developing inside an oil well so as to avoid any blowouts.