Post Macondo Negative Pressure Testing For Offshore Drilling

BP's Macondo blowout was the largest environmental catastrophe that America has ever faced. Multiple factors contributed to the blowout, but the final barrier check – the negative pressure test – was misinterpreted. Proper interpretation of this test might have alerted the rig crew of failed barriers and ultimately prevented the blowout. Due to this blowout, the negative pressure test is now required by the Bureau of Safety and Environmental Enforcement. There is no industry standard, however, on how the negative pressure test should be defined, conducted or interpreted. This paper proposes that a proper negative test requires underbalancing the well with a packer system and monitoring for pressure on the drill pipe. A successful test is only when pressure remains at zero psi. In light of the Macondo well blowout, the proposed procedure includes considerations such as proper spacer fluid selection, reservoir pore pressure and well control measures to decrease operator risk. With these considerations, the procedure can be adopted for any well. Better understanding and definition of the negative pressure test will decrease the operator's exposure to risk and will mitigate the likelihood of future blowouts.