Gas Well Blowout: cause of the blowout and rig fire was the failure of two preventive barriers that were intended to be in place to stop a blowout. Those were the primary barrier—hydrostatic pressure in the well, produced by drilling mud—and the secondary barrier—human detection of gas flowing into or expanding in the well and activation of the rig’s blowout preventer. The report explains that unplanned underbalanced drilling and tripping operations allowed a large quantity of gas to enter the w