Drilling for oil is more risky than it used to be

Gulf of Mexico oil slick, April 29
Satellite image of the Gulf of Mexico oil slick, April 29. Source: NASA Earth Observatory.

A post by Chris RowanThe causes of the explosion on the Deepwater Horizon rig that has led to 5000 barrels (210,000 gallons) of oil a day being leaked into the Gulf of Mexico, and an oil slick that can be seen from space, are still murky (Update: but check out a detailed account of the accident, courtesy of mandobob in the comments below). What we do know so far does not reflect particularly well on BP, who apparently understated the magnitude of the leak following the accident. Worse, just today the New York Times has reported claims that they exceeded the remit of their licence by drilling too deeply, and decided against installing a cut-off valve in the well, (in addition to choosing not to install another safety device that could also have shut off the well) although in the latter case I find the fact that BP had a choice in the matter just as disturbing as the fact that they chose incorrectly.

But there is a wider point to be considered here. The offshore drilling industry is currently undergoing a transition. Most easy targets have already been developed, and yet global demand for oil is not abating. In an attempt to quench this thirst, attention is moving into more technically challenging areas, with more complex geology and often in the deeper waters of the outer continental shelf continental slope. The increasing complexity of the equipment required to drill in such areas increases the number of things that can go wrong, and the location of the drilling makes dealing with catastrophic failures much more difficult, as we are seeing all too clearly this week.

Even if you set aside the climatic impacts of using oil to fuel our civilisation, there are environmental risks associated with drilling for it and transporting it. But I’m not sure that many people fully appreciate that for the newer oil fields that are being developed, and proposed for development, these risks are potentially much higher. The fact that current industry practices have, on the whole, not led to major spills in the past couple of decades* is no guarantee that they reduce the risks to acceptable levels at these new, more extreme drilling locations. This is especially true when, in the absence of rigorous regulatory scrutiny, oil companies are tempted to take shortcuts that may not have led to disaster in the past, but could be catastrophic where the margins of safety are lower.

In that context, I have been struck by several parallels between events in the Gulf of Mexico and Lusi , the mud volcano in Indonesia that is widely believed to have been triggered by exploratory drilling. In both cases, drilling was taking place in a difficult drilling environment with low margins of error (in the case of Lusi, the suspect hole was drilled in an area ‘primed’ for mud volcano formation). In both cases, the drilling companies did not follow absolute best practice (in the case of Lusi, they failed to case the well, which would probably have prevented the blow-out). In both cases the environmental and economic consequences for the surrounding area are severe and of long duration.

At the moment, the focus is rightly on trying to seal the Deepwater Horizon well leak and reducing as much as possible the environmental damage in the Gulf of Mexico. But one fact cannot, and should not, be ignored: the demand for oil is not going away any time soon. That demand is driving drilling in places where accidents of this sort – major, hard to stem leaks – are going to be a major risk, and our safety regulations should be evolving to adjust to this new reality. As a start, I’d propose that emergency shut-off valves cease to be an optional extra on drilling rigs.

*this ignores, of course, what has been recently pointed out by Lab Lemming, and Lisa Margonelli in the New York Times: that major spills have been regularly occurring – and largely ignored by the developed world – in places like Nigeria. The fact that oil companies have such a poor record in places unlikely to be touched by Western media and public outrage does not instil much confidence in the idea of self-regulation.

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Comments (20)

  1. CherryBomb says:

    Apparently, this “shut-off valve” is some sort of BOP installed a couple of hundred feet deep in the well. I am not familiar with how it works. Maybe someone who is could explain why it would be more effective than a BOP stack at the wellhead.

  2. Omega Centauri says:

    Cherry bomb, apologies if I get it not entirely correct, I am giving second hand information, but I’ll attempt anyway.
    The BOP is a large structure that in the event of a blowout, was supposed to push a hydraulic ram that cuts through the drill pipe, and effectively caps the well. My understanding is that it is required equipment. The failure is probably that US regs didn’t require a demonstration that it could cut the particular drill pipe being used. Apparently for these deep water drills, they use harder grades of steel than usual, and the BOP simply failed. With hindsight it appears that that oversight could be the culprit. The claim is that other advanced offshore drilling nations require tests, but the US does not. So a case could be made that if we had followed best international practices we could have avaoided this mess.
    The people in the industry do pay significant attention to these issues. Their lives are at stake, as well as the environment.

  3. Lab Lemming says:

    If you look at the historical accident reports, there is a potential sampling bias that is even bigger than the developed world issue.
    Russia/USSR has been a major oil producer since the second world war, but there are no accounts of major spills there. one possibility is that their best practices far exceed those of the western world. Another is that they underreport.
    Assuming the second case, When comparing offshore to onshore safety, this large gap in the (mostly onshore) record may lead to significant bias.
    If a rig blows up in the taiga, and everyone who sees it gets sent to the gulag, does it make a sound?

  4. Alex Besogonov says:

    Lab Lemming: Russia has very little (if any) off-shore drilling platforms.
    As for land spills – they happen a lot. And quite often are dealt with an ‘emergency oxidation’ (aka ‘burning it at night when no-one is looking’).

  5. Thanks Chris for the geological perspective. Drilling a well 5,000 feet below the surface of the Gulf of Mexico into the Mississippi Delta sediment wedge is rife with … err … potential problems. The drill probly penetrated the ceiling of a halite diapir where the oil was under immense pressure and now it is flowing inexorably upward. I’d be interested in what the exact geologic formation they punctured. Is it a salt dome/diapir? Unconsolidated sediment?

  6. Robert S. says:

    That additional safety device wouldn’t have done much in this particular case. The acoustical link is simply a backup remote trigger for the cutoff. They activated the direct cutoff controls from an ROV and it didn’t change the leak status, suggesting either the cutoff suffered a critical failure and didn’t work at all (unlikely as the volume of oil would probably be higher) or did trigger, and failed to complete the seal. In either case an acoustical link trigger wouldn’t have helped. If the cutoff didn’t trigger, and the ROV activation worked, then not having an acoustical tertiary activation option would be something to bring up. As it is however nothing I know of points towards the triggering system being at fault.

  7. CherryBomb says:

    Thanks, Omega, but I know all the background. Trust me, I know how BOP’s work. I was wondering whether there is really some advantage to putting one a hundred meters deep in the hole, or is this just lawyer babble? It is something I had never run across before, but I have not been involved in the oil business for 20 years, so I honestly dunno.

  8. BrianR says:

    It’s really tough to know what happened w/ this rig until there can be some investigation (which is obviously not the priority right now). I think we’ll be hearing about this for many months to come so I’m not going to speculate too much right now.
    The deep play these companies are going after is called the Wilcox (Paleocene-Eocene). You sometimes see it referred to as the ‘Lower Tertiary Wilcox’ in industry literature (if you google that you can find a lot of general information about it). If you want to learn a bit more about the geology and paleogeography go to Google Scholar and search ‘Galloway Wilcox Gulf of Mexico’. Bill Galloway and colleagues have published quite a bit about these strata for many years.
    There are numerous wells (I don’t have a number at my fingertips unfortunately) that are in even deeper water — up to 8,000 ft (2,500 m) — further offshore and towards the base of the continental slope.
    Chris, I think you are generally right in that the easier plays/prospects have been exploited. There are, of course, caveats and exceptions but that’s the general situation.
    I think Margonelli’s column in NYT you mention is the smartest commentary I’ve read about this. She makes the very important point that if Americans don’t allow domestic drilling but still use oil, all we are doing is exporting environmental damage to other parts of the world. Maybe this event is a chance to have a reasoned and adult conversation about just how much oil we consume.
    One tiny little nit to pick, you say: “…attention is moving into more technically challenging areas, with more complex geology and often in the deeper waters of the outer continental shelf.”
    Although these areas are called the Outer Continental Shelf by authorities like the Minerals Management Service and the media all these deep-water wells are techincally (i.e. physiographically) on the continental slope. The current shelf edge is a few hundred meters of water depth.

  9. Kristen says:

    Interesting point about Lusi – thanks for this coverage.

  10. Roland says:

    http://en.wikipedia.org/wiki/Blowout_preventer
    The BOP is bolted to the top of the well casing. The casing is a long large pipe fastened in the hole by pumping grout between the pipe and the area outside it. If grouting is done poorly, oil can escape around the outside of the casing. That happened at Ixtoc. A BOP stack normally has multiple rams/closing units. The BOP rams are closed by powerful springs. They can close around, or even shear, drillstring pipe still in the hole. They are kept open by hydraulic pressure (veg.oil) so closing them *should* be as easy as cutting the hose. BOPs are not usually downhole, but stick up from the bottom. After completion, a cage is lowered to protect them from trawls.

  11. doug l says:

    It ain’t pretty, that’s for sure. It was lookin’ pretty insulted even before the blow-out.
    Listened to Dr Sylvia Earle on this evenings PBS News Hour and was heartened to hear her put the oil extraction situation into realistic perspective. Oil drilling’s become pretty safe…the rest of our routinely ignored impacts on the ocean such as overfishing, run-off pollution, bio-pollution are looming if not exactly ‘in our faces’.
    Don’t have a link but it’s worth visiting News Hours web site to find it. cheers.

  12. MadScientist says:

    @Omega Centauri:
    Generally a BOP will not cut through the drill (they’re awfully expensive!). The BOP is meant to create a seal on the bore – whether there is a drill in it or not. If there is a drill there it’s still meant to work and not damage the drill. With the ones used onshore, you generally do something like inject a more dense ‘kill fluid’, then reopen the BOP’s valves and go on with the drilling – or pull your drill out if you decided to stop. The ‘kill fluid’ just has to be dense enough that it can prevent the well fluid (oil or gas) from pushing itself up to the surface. Of course in principle you may not have a dense enough fluid on hand … but you’ll have to ask the drilling people if they’ve encountered such conditions.

  13. MadScientist says:

    @CherryBomb: I suspect the talk about downwell cutoffs is an urban legend. Maybe people are confusing plugs with BOPs? I can’t imagine anything as huge as a BOP going down that hole and I can’t imagine why you’d put a restriction down the well either – how would you hold it in place? Well, I guess you could make a really thick patch … or a valve held in with a packer. I can imagine a few hydraulically or pneumatically actuated valves which can be put in a well, but I still can’t think of a good reason to do it.

  14. MadScientist says:

    @Chris: Regulations differ all over the place. I’m told there are places where the BOPs are not optional, and I suspect that may be true since I know someone who wanted to drill (onshore) into a depleted formation (pressure and history well known, in addition to 1 existing and accessible well) and yet he had to have a BOP while drilling that second well.

  15. David Marjanović says:

    Russia/USSR has been a major oil producer since the second world war, but there are no accounts of major spills there.

    Much of the north coast is soaked in oil (unless they burn it these days — that was news to me). Footage has been shown in documentaries on Western TV.
    Much of the coast of Nigeria looks the same, only it’s full of people.

  16. mandobob says:

    For anyone who is interested in the facts about what may have happened to cause the Deepwater Horizon explosion off of Louisiana – this was sent to me by an area operator who had a friend who worked on the rig (and was not on it during the explosion).
    Subject: fwd: Horizon Explosion explanation
    Date: Wednesday, May 5, 2010, 9:55 AM
    FYI,
    My buddy sent this from an interview, I believe from the OTC yesterday. is a long time friend of mine that was working on the Rig as a directional MWD hand for Halliburton, but was safe at home when the accident happened.
    —– Forwarded Message —-
    Sent: Tue, May 4, 2010 7:57:18 PM
    Subject: Horizon Explosion explanation
    >>Subject: Horizon Incident
    >>
    >>Good description of what happened from an interview….
    This well had been giving some problems all the way down and was a big discovery. Big pressure, 16ppg+ mud weight. They ran a long string of 7″ production casing – not a liner, the confusion arising from the fact that all casing strings on a floating rig are run on drill pipe and hung off on the wellhead on the sea floor, like a “liner”. They cemented this casing with lightweight cement containing nitrogen because they were having lost circulation in between the well kicking all the way down.
    The calculations and the execution of this kind of a cement job are complex, in order that you neither let the well flow from too little hydrostatic pressure nor break it down and lose the fluid and cement from too much hydrostatic. But you gotta believe BP had 8 or 10 of their best double and triple checking everything.
    On the outside of the top joint of casing is a seal assembly – “packoff” – that sets inside the subsea wellhead and seals. This was set and tested to 10,000 psi, OK. Remember they are doing all this from the surface 5,000 feet away. The technology is fascinating, like going to the moon or fishing out the Russian sub, or killing all the fires in Kuwait in 14 months instead of 5 years. We never have had an accident like this before so hubris, the folie d’grandeur, sort of takes over. BP were the leaders in all this stretching the envelope all over the world in deep water.
    This was the end of the well until testing was to begin at a later time, so a temporary “bridge plug” was run in on drill pipe to set somewhere near the top of the well below 5,000 ft. This is the second barrier, you always have to have 2, and the casing was the first one. It is not known if this was actually set or not. At the same time they took the 16+ ppg mud out of the riser and replaced it with sea water so that they could pull the riser, lay it down, and move off.
    When they did this, they of course took away all the hydrostatic on the well. But this was OK, normal, since the well was plugged both on the inside with the casing and on the outside with the tested packoff. But something turned loose all of a sudden, and the conventional wisdom would be the packoff on the outside of the casing.
    Gas and oil rushed up the riser; there was little wind, and a gas cloud got all over the rig. When the main inductions of the engines got a whiff, they ran away and exploded. Blew them right off the rig. This set everything on fire. A similar explosion in the mud pit / mud pump room blew the mud pumps overboard. Another in the mud sack storage room, sited most unfortunately right next to the living quarters, took out all the interior walls where everyone was hanging out having – I am not making this up – a party to celebrate 7 years of accident free work on this rig. 7 BP bigwigs were there visiting from town.
    In this sense they were lucky that the only ones lost were the 9 rig crew on the rig floor and 2 mud engineers down on the pits. The furniture and walls trapped some and broke some bones but they all managed to get in the lifeboats with assistance from the others.
    The safety shut ins on the BOP were tripped but it is not clear why they did not work. This system has 4 way redundancy; 2 separate hydraulic systems and 2 separate electric systems should be able to operate any of the functions on the stack. They are tested every 14 days, all of them. (there is also a stab on the stack so that an ROV can plug in and operate it, but now it is too late because things are damaged).
    The well is flowing through the BOP stack, probably around the outside of the 7″ casing. As reported elsewhere, none of the “rams”, those being the valves that are suppose to close around the drill pipe and / or shear it right in two and seal on the open hole, are sealing. Up the riser and out some holes in it where it is kinked. A little is coming out of the drill pipe too which is sticking out of the top of the riser and laid out on the ocean floor. The volumes as reported by the media are not correct but who knows exactly how much is coming?
    2 relief wells will be drilled but it will take at least 60 days to kill it that way. There is a “deep sea intervention vessel” on the way, I don’t know if that means a submarine or not, one would think this is too deep for subs, and it will have special cutting tools to try to cut off the very bottom of the riser on top of the BOP. The area is remarkably free from debris. The rig “Enterprise” is standing by with another BOP stack and a special connector to set down on top of the original one and then close. You saw this sort of thing in Red Adair movies and in Kuwait, a new stack dangling from a crane is just dropped down on the well after all the junk is removed. But that is not 5,000 ft underwater.
    One unknown is if they get a new stack on it and close it, will the bitch broach around the outside of all the casing??
    In order for a disaster of this magnitude to happen, more than one thing has to go wrong, or fail. First, a shitty cement job. The wellhead packoff / seal assembly, while designed to hold the pressure, is just a backup. And finally, the ability to close the well in with the BOP somehow went away.

  17. Matt M says:

    Wow, mandobob, that is way more information than I have had from any other source. Thank you for that. This increases my understanding of the situation by three-fold.
    My interest in the well problem is in two areas. I live in Houston, where there is a lot of petroleum related activity, of course. I also have a beach house just off of the Gulf, in Alabama. I am aware of the impact that oil drilling has on the lives of people, and the profits of companies. Also, the impact that is has on wildlife, property, and great places to kick back and relax.
    I hope that this works out to be less of a calamity than Katrina or Ivan.

  18. Passerby says:

    US DOD issued a short newsbrief/warning last week of impending shortages in oil demand, expected as soon as 2013-14. China’s fuel demand has surged by a record 21% in just a few years, as Asian consumer wealth, manufacturing and auto sales response has grown (surpassing peak production in Detroit) in the past decade.
    Global oil demand hasn’t diminished; if anything, petroleum product consumption rate is increasing, markedly. As the pseudo-economy in Europe and the US picks up steam (back to old spendthrift ways after a 2-year lull), automotive fuel and petrochemical demand is rising again in the West.
    Proof is in the pudding, when you pull up to a stop-light at any intersection: the majority of vehicles are still large, expensive gas-guzzling SUVs.
    Answer me this: where are we going to get the refinery bottoms (raw asphalt) product in the future – not just for making new roadways, but for maintaining mega-millions of miles of extant road surfaces here in the US?
    If you can solve that one, you got yourself a golden egg solution. Sure as Sam Hell, you ain’t gonna grow asphaltene complexes in algae or engineered E coli.

  19. kokpilau says:

    And guess who did the cementing job hours before the leak/explosion? Halliburton. Cui bono?

  20. Mary says:

    Great. I bet Bushes hands is in this one too. Nostradamus did not mention a third Evil, but they just could not come to a decision who this is? For me it is obvious….