Oil can accumulate and be trapped around these salt domes. Drilling a conventional, vertical well through a salt dome increases the possibility of drilling problems, such as washouts, lost circulation, and corrosion. Directional wells help avoid trouble spots. 7. Relief-well drilling When the Deepwater Horizon offshore drill rig exploded in 2010, killing 11 workers and spilling an unchecked flow of oil into the Gulf of Mexico, well-operator BP ordered a “relief well” to be drilled immediately. When an existing well becomes damaged – or “goes wild,” as we say in the industry – a relief well uses directional drilling to intersect with the damaged wellbore, plug the hole withmud and water, and redirect the excess liquid. In the case of Deepwater Horizon, the relief well needed to plug a pipe that was gushing oil three miles underwater. That’s a daunting task. Typically, relief wells are dug into solid ground at a safe distance from the original drill site.
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