What actually went wrong on Deepwater Horizon?

By Aimee Whitcroft 31/05/2010

With the Deepwater Horizon line still haemorrhaging oil, there has been a great deal of uncertainty about what actually caused the blowout (a subject of great interest not only to the public, but also to the various companies trying to avoid full liability for the catastrophe).

Below, a great infographic from The Times shows exactly what the problem was: a deadly combination of failed cement, insufficiently pressured drilling mud, and a BOP (blowout preventer) that couldn’t handle the strain.

With BP’s latest attempts to stop the spill having failed, it looks like the oil will keep spilling for quite some time – building a permanent relief well*, for example, could take a couple of months.

[click on picture for bigger version]

deepwater horizon failure

*Watch out for an upcoming post on the subject on misc.ience.

0 Responses to “What actually went wrong on Deepwater Horizon?”

  • What actually went wrong on Deepwater Horizon?

    Greed, and the consequent blinkered approach to risk that most corporates usually take.
    This is not a technical problem.

  • Rainman, if you are interested, then I suggest reading a little more. The Oil Drum WWW site ( US, not NZ/Oz ), is a good place to start.

    Yes, it appears there were “early completion” bonuses, which may have caused some important processes to not be diligently followed, however cement failures and well kicks are not uncommon in drilling, and remedial procedures are well defined – provided you know they are happening.

    This was a human error problem, They chose not to monitor the mud flows whilst displacing the mud, so didn’t know the well was kicking until too late. 11 people died.

    The cement failure may be one cause, however the failure to log mud flows meant that any actions would be too late, and may even have compromised the fail-safe systems..

    Mud flow is one of the most critical aspects of well drilling, and they chose not to whilst displacing the mud for future use. The direct transfer presumably worked OK previously, but this well had kicked many times during drilling, so extra care should have been taken.

    The failure of the Blowout Preventer is still to be investigated, but there are many potential causes to investigate, eg there was no requirement to lock down the casing ,so it may have lifted and interfered.

    In my experience from years ago, most drilling decisions are reviewed and confirmed. Somebody made the decision not to log or monitor the mud flows, and somebody else approved, so let’s wait until the inquiry is completed.

  • There’s always the possibility that something bad can happen when drilling, and this well had a history, but such well behavior wasn’t unique, and was managed during drilling. The operators had completed the drilling, and obviously believed the well was sealed.

    That’s why there are procedure and approval processes, and why BP, Transocean, Halliburton, and the MMS are all being investigated. There are always issues, and the inquiry will find out how they were handled.

    For those that want a NZ connection, Transocean ( who owned the rig and Blow Out Preventer ) was previously known as Sedco, and the rig ( Sedco 135F ) that drilled the NZ Maui field was also responsible for the largest blowout and spill to date in the Gulf of Mexico ( Ixtoc I ).

    It’s possible this well will claim that dubious title. If you review both events and mitigation actions, there are several parallels, because the available options are limited.