BP crews are set to begin drilling a relief well in the Gulf of Mexico (GoM) to stem the flow from the MC252 well.
A drilling rig drills a relief well or second well to intersect the original, flowing well as deeply as possible. A specialized heavy liquid is then pumped into the flowing well to bring it under control.
This liquid is denser than oil and so exerts pressure (known as hydrostatic pressure) to stem the flow of oil. Once the flow is stopped, the well can be returned to a safe condition.
A relief well should be faster to drill than the original well thanks to the knowledge already gained about the geology and pressure in the reservoir.
However, drilling a well of this nature presents many technical challenges to ensure that the flowing well is intersected in the right position and that the fluid pumping operations are effective.
BP has assembled a world-class team of experts from within the company and key specialists in the industry to ensure that the relief well operations are conducted safely and successfully.
A second relief well could form part of the contingency plans in case the first well encounters any delays. This means that progress can still be made to stem a flowing well should one drilling operation encounter a problem.