Oil well control is a comprehensive term used to cover a range of techniques and processes related to the drilling of oil wells. It primarily concerns the careful monitoring and maintaining of the pressure of drilling fluid to prevent the crude oil from causing damage to the drilling equipment and causing a blowout or a gusher, which resembles a geyser of oil shooting up from the ground at the well site. Drilling fluid is a liquid that is pumped into the well under pressure in order to balance the pressure of the oil.
The primary function of an oil well control specialist is to prevent the material in the ground from pushing back into the drilling hole, called the wellbore, during the drilling process. In order to create and bring a successful well into production, the oil, which is called formation fluid, must not be allowed to push out of the reservoir into the wellbore until drilling is complete and the machinery to process the oil has been put in place. This is done by using drilling fluid, which is pumped into the wellbore under pressure to counteract the outward pressure of the formation fluid.
Monitoring the pressure of the drilling fluid is key to oil well control. If the drilling fluid pressure is not high enough, the formation fluid can push back into the wellbore and result in an event known as a blowout or gusher, which is essentially an explosion of oil out of the wellbore at the surface. This can be extremely dangerous and can result in damage to equipment, injury to workers and violent explosions or very large fires that can be very difficult to extinguish. As long as the drilling fluid is maintained at a proper pressure, the formation fluid will be prevented from entering the wellbore and causing such a potential disaster.
A specialist who performs oil well control work employs modern technology to monitor well conditions and to change conditions, such as the pressure of the drilling fluid. Sensors help to monitor drill speed and the pressure of both drilling and formation fluids as well as other conditions or events that can signal a potential problem. A knowledge of the geology of the drilling site can help the oil well control specialist make decisions about how to manage the drilling process to prevent a blowout.