Rig blowouts are some of the most devastating and costly events in oil and gas industry.
Land rig blowouts are incredibly destructive, shooting tons of rock, mud, sand, flammable fluids, and fire across drilling sites with extreme force. Offshore blowouts are equally dangerous. The 2010 subsea Deepwater Horizon MC-252 blowout left 11 platform workers dead, injured another 17, and spilled an estimated 4.9 million barrels of oil into the Gulf of Mexico - considered the largest marine oil spill in the petroleum industry’s history.
Despite 100 years of advances in technology - blowouts continue to take lives.
Hydrocarbon reserves located thousands of feet under the earth’s surface are under immense pressure. Over the years, the oil and gas industry has developed numerous tactics to help maintain control of the various fluids and gas which uncontrolled can led to blowouts. Pressure is a key component of drilling and producing oil and gas. Uncontrolled pressure can lead to blowouts or other well control problems.
In order to properly to prevent pressure issues oil and gas operators chose special equipment to handle the different pressures that can occur on a well. The first line of defense is properly monitoring the pressure and having effect kill weight fluid available should the well need to be shut in. Kill weight fluid can be in the form of brine like weighted water or in the form of mud which is pumped down the well in order to balance and circulate out any unwanted pressure.
A well’s bottom hole pressure (“BHP”) must equal the formation pressure of the underground reservoir to prevent kicks. Pressure differences can occur when tripping out a hole, running tubular, swabbing during tripping operations, logging, losing circulation, changing fluid densities, killing the well after a stem test, or other scenarios where formation fluid is exposed to the wellbore. Operators use drilling mud to make up for any differences in pressure. (Note: in some instances operators choose to drill under balanced: meaning the pressure may exceed the equilibrium point- proper precautions must be taken in all oil and gas exploration no matter the well conditions given the unpredictable nature of oil and gas operations)
If the quest to prevent pressure differences fails – for example, by using the wrong mud weight – a blowout preventer can then intervene to try and stop fluid or gas from ejecting out of the well. A BOP is a large valve which can close the well bore off from the well head not allowing fluid or gas to escape.
The ability to detect and quickly adapt to sudden increases in drilling rates, flow rates, pit volumes, and pump speed is vital to preventing kick. Uncontrolled kicks can lead to blowouts. If signs of a kick are present, operators must perform well shut-in procedures to lessen the kick volume and then kill the well – moving out any remaining fluid from the wellbore and filling it with the right amount of weighted fluid or mud.
Unfortunately, there is no failsafe automated system for preventing kicks and blowouts. Avoiding these hazards is still mostly reliant on the oil and gas operators who have engineers watching these wells and tracking changing conditions. Prudent operators don’t gamble with workers lives and ensure all pressure spikes or deviations are handled with extreme caution.
Currently, the leading causes of kicks and blowouts are failures by the operator to take proper precautions to deal with pressure. Operators are the own the well and receive all the monetary benefits of the oil and gas production. Operators oversee the well and are the only company with the authority to kill the well in most instances. Operators employee engineers who have Petroleum Engineering degrees to watch over and direct operations on wells. The following are just some instances which can lead to blowouts:
- Failure to interpret test results
- Failure to deal with Pressure
- Failure to detect signs of kick
- Faulty decision-making
- Faulty well plan designs
- Faulty well shut-in procedures
- Inadequate reaction to kick
- Poor communication between operator and contractors
Many tragic blowouts are the result of a combination of errors at several levels. For example, BP, Mitsui, and Anadarko approved a shoddy well plan on Deepwater Horizon that didn’t use enough cement to seal off subsea casings. The companies failed to run a cement bond log to measure the seal’s integrity. In addition, poor design and inadequate maintenance and inspection of the BOP may have contributed to the Deepwater Horizon blowout.
No amount of regulations can improve conditions when the safety of oil rig workers relies upon the responsible actions of oil and gas companies, equipment designers, engineers, and other parties. These parties have a legal duty to keep rig workers safe.
Only by continuing to hold negligent companies accountable for worker injuries and environmental damage are we truly able to impact oil and gas industry safety practices and prevent future catastrophic, costly rig blowout events.