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Thread: Deep Water oil drilling

  1. #1 Deep Water oil drilling 
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    I find it ironic that just a couple weeks after Obama announced that large segments of the coast are to be opened to oil exploration and drilling, that the Deep Horizon accident happens.

    Given the scale of the disaster, which will almost certainly exceed the Exxon Valdez in scope, this could spell the end of the argument for further oil exploration along the US coast.

    To read up on the rig:
    http://en.wikipedia.org/wiki/Deepwater_Horizon

    To monitor the disaster.
    http://www.nasa.gov/topics/earth/fea...oil-creep.html


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    Indeed, and it is troubling that with every piece of mechanical and electronic technology in use something like this can still happen. BP has been involved now in three recent major incidents - the corrosion issues of the North Slope transfer pipelines resulting in spillage on the tundra, the explosion at Texas City (15 deaths) and now this one. You have to wonder whether BP's safety practices are up to industry standards.


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    In addition to the technology, one must also design the system and employ the technology correctly. Disasters like this take multiple overlapping failures along with some random acts working against you. The failure occurred after a poor cement job due to lost circulation during the operation. The cement went somewhere other than intended and then events got away from them. BP's reputation has taken another big hit, and now mud is starting to land on us all.
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    In addition to the technology, one must also design the system and employ the technology correctly. Disasters like this take multiple overlapping failures along with some random acts working against you. The failure occurred after a poor cement job due to lost circulation during the operation. The cement went somewhere other than intended and then events got away from them. BP's reputation has taken another big hit,
    Halliburton was doing the critical work.
    Quote Originally Posted by bunbury
    Indeed, and it is troubling that with every piece of mechanical and electronic technology in use something like this can still happen.
    It is perfectly normal and to be expected, not "troubling". Surely we don't need to create any more of these disasters simply to establish the fact that they are inevitable?
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    Quote Originally Posted by iceaura
    Quote Originally Posted by bunbury
    Indeed, and it is troubling that with every piece of mechanical and electronic technology in use something like this can still happen.
    It is perfectly normal and to be expected, not "troubling". Surely we don't need to create any more of these disasters simply to establish the fact that they are inevitable?
    That some disasters will occur is inevitable but the frequency of disasters associated with one company is unusual and not expected.

    I'm not in favor of increased offshore drilling and can only hope that this disaster helps to turn the poitlical tide in favor of meaningful climate legislation.
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    1) It is very troubling to me this happened when it did, and to a rig with no automatic shut off valve. I cannot help but wonder if this is an act of Eco-Terrorism.

    2) The Haliburton connection has nothing to do with the accident. How can pouring of the concrete be an issue when the pipe is set, concrete set, then the valve turned on once connected? Can we keep unwarranted political inspired blame out of this please?

    3) The rig is owned by Transocean LTD, operated by their personnel, and leased by BP. I wish people would lean the facts before they unnecessarily assess blame, equivalent to slander.

    4) I am most troubled that there was no automatic shut off valve, or if there was, why did it fail?
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    Quote Originally Posted by iceaura
    In addition to the technology, one must also design the system and employ the technology correctly. Disasters like this take multiple overlapping failures along with some random acts working against you. The failure occurred after a poor cement job due to lost circulation during the operation. The cement went somewhere other than intended and then events got away from them. BP's reputation has taken another big hit,
    Halliburton was doing the critical work.
    They will be a scapegoat.... They had the cement contract, they mix it and pump it, they might even have done the design, but they don't approve it and they don't make the decisions when things start going south, like for example when they lost circulation.

    Quote Originally Posted by bunbury
    Indeed, and it is troubling that with every piece of mechanical and electronic technology in use something like this can still happen.
    It is perfectly normal and to be expected, not "troubling". Surely we don't need to create any more of these disasters simply to establish the fact that they are inevitable?[/quote]

    They are not inevitable. They are a result of many things going wrong at once. There were failures and mistakes made.
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    [quote="Wild Cobra"]1) It is very troubling to me this happened when it did, and to a rig with no automatic shut off valve. I cannot help but wonder if this is an act of Eco-Terrorism.

    It was an accident with contributing causes. Though the blowout prevention stack may not have been the best in the industry, it was typical of 98% of wells drilled. There were two BOP's but apparently no measure to flood the drilling riser and kill the well with seawater, though it may not have helped at all since the riser did not seem to fail. A Production casing shutoff valve likely would not have helped since flow was up the backside.

    2) The Haliburton connection has nothing to do with the accident. How can pouring of the concrete be an issue when the pipe is set, concrete set, then the valve turned on once connected? Can we keep unwarranted political inspired blame out of this please?
    The blowout was almost certainly due to leaking up the backside due to a failed cement job. BP manages activity in these circumstances so haliburton personnel were likely just following instructions.

    3) The rig is owned by Transocean LTD, operated by their personnel, and leased by BP. I wish people would lean the facts before they unnecessarily assess blame, equivalent to slander.
    Yes and BP approved the well design and was calling the shots when things started going wrong.

    4) I am most troubled that there was no automatic shut off valve, or if there was, why did it fail?
    The Ram BlowOut Preventer deployed but did not close. It is likely that the blowout jammed the poorly cemented casing back up through it and prevented it from closing. Better well design or perhaps more caution when they lost circulation might have saved this. Who knows.
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    Quote Originally Posted by cypress
    The Ram BlowOut Preventer deployed but did not close. It is likely that the blowout jammed the poorly cemented casing back up through it and prevented it from closing. Better well design or perhaps more caution when they lost circulation might have saved this. Who knows.
    Correct me if I'm wrong, but doesn't the valve first have to be closed when doing this work, and opened later?

    How about design. If they are remotely controlled, are they sealed, or could silt have covered it?

    How would a bad concrete job keep such a device from functioning anyway?
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    Quote Originally Posted by Wild Cobra
    Quote Originally Posted by cypress
    The Ram BlowOut Preventer deployed but did not close. It is likely that the blowout jammed the poorly cemented casing back up through it and prevented it from closing. Better well design or perhaps more caution when they lost circulation might have saved this. Who knows.
    Correct me if I'm wrong, but doesn't the valve first have to be closed when doing this work, and opened later?

    How about design. If they are remotely controlled, are they sealed, or could silt have covered it?

    How would a bad concrete job keep such a device from functioning anyway?
    The BOP is bolted to the casing flange on the seafloor. There is a stack of three of them and for this well the stack is about 70 feet total. The bottom is a hydraulic ram with knife edges designed to sheer through the drill pipe and cut it clean, and shut tight. The one in the middle is massive dual gate valve that shuts tight if nothing is in the way, the top one is a massive annular squeeze that closes around any drill pipe. The top one cannot hold back the full pressure of the well and must be deployed at the first sign of a "gas kick" before too much of the mud is lost. If that fails the Ram deploys and sheers off the drill pipe. In this case it did not .....
    Some speculate that the production casing was pushed up through the BOP before it could deploy. Others think the BOP failed.

    They are designed to be filled with mud... They are massive and can cut through 5 inch diameter high pressure pipe.. They cannot reliably cut through 9 5/8 production casing. The rams are hydraulically operated. They are sealed. They are tested regularly. Would love to know when it was last tested.

    Cement is squeezed up the backside of the casing to fill the hole between the rock formation and the outside of the casing. The cement did not get squeezed into this spot and that allowed the oil and gas to "kick" up through the space and get to surface. Worse it allowed the mud and completion fluids to escape into the formation further defeating well control. Finally the cement is supposed to hold the casing in place. It may have failed on all three counts.
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    I'm not sure how aware you guys are of the fact that cement is a product that is often mixed down by dealers to increase profits.

    One of the problems with mixing down cement is increased drying times.

    Id investigate Haliburtons cement supplies used for the well construction to check for any tampering.
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    The problem with the cement was not that it didn't set. The problem was that it did not go where it was supposed to go. It was BP calling the shots, doing the design, specifying the mix, and what happened is they made some sort of error and it may have been too dense so it went off into a washout or something... In any case they may have known the cement job was messed up 30 minutes before the gas kick. They didn't get any returns back to surface when they were pumping so they knew they had an issue. Guess they didn't realize how serious the issue was.
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    Little item from wiki, mentioning some relevant government regulatory agency doings of recent years:

    Quote Originally Posted by wiki
    Atlantis Oil Field safety practices

    The Deepwater Horizon disaster has given new impetus to an effort by Rep. Raúl M. Grijalva (D-AZ) and 18 fellow Democrats to pressure the Minerals Management Service to investigate safety practices on the BP offshore platform in the Atlantis Oil Field. According to Common Dreams NewsCenter, a whistleblower report to MMS in March 2009 that was confirmed by an independent expert, said that "a BP database showed that over 85 percent of the Atlantis Project's Piping and Instrument drawings lacked final engineer-approval, and that the project should be immediately shut down until those documents could be accounted for and are independently verified."[97] According to Grijalva, "MMS and congressional staff have suggested that while the company by law must maintain 'as-built' documents, there is no requirement that such documents be complete or accurate."[98] BP and other oil industry groups wrote letters objecting to a proposed MMS rule last year that would have required stricter safety measures.[99] The MMS changed rules in April 2008 to exempt certain projects in the central Gulf region, allowing BP to operate in the Macondo Prospect without filing a "blowout" plan.[100]
    Far from being a scapegoat, btw, Halliburton seems to have receded into the background - the wiki article, for example, counts the number of employees of BP and Transocean on the the rig, and refers to the rest (more than 40) as "contractors", employer unnamed.
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    Quote Originally Posted by iceaura
    Little item from wiki, mentioning some relevant government regulatory agency doings of recent years:

    Quote Originally Posted by wiki
    Atlantis Oil Field safety practices

    The Deepwater Horizon disaster has given new impetus to an effort by Rep. Raúl M. Grijalva (D-AZ) and 18 fellow Democrats to pressure the Minerals Management Service to investigate safety practices on the BP offshore platform in the Atlantis Oil Field. According to Common Dreams NewsCenter, a whistleblower report to MMS in March 2009 that was confirmed by an independent expert, said that "a BP database showed that over 85 percent of the Atlantis Project's Piping and Instrument drawings lacked final engineer-approval, and that the project should be immediately shut down until those documents could be accounted for and are independently verified."[97] According to Grijalva, "MMS and congressional staff have suggested that while the company by law must maintain 'as-built' documents, there is no requirement that such documents be complete or accurate."[98] BP and other oil industry groups wrote letters objecting to a proposed MMS rule last year that would have required stricter safety measures.[99] The MMS changed rules in April 2008 to exempt certain projects in the central Gulf region, allowing BP to operate in the Macondo Prospect without filing a "blowout" plan.[100]
    Far from being a scapegoat, btw, Halliburton seems to have receded into the background - the wiki article, for example, counts the number of employees of BP and Transocean on the the rig, and refers to the rest (more than 40) as "contractors", employer unnamed.
    "Final engineer approval" of P&IDs is a bit misleading without some additional context. P&IDs do get updated (redlined) as changes occur during construction and final checkout. If Construction says "we can't build it the way it's shown on the drawings" this would precipitate a meeting among all parties including the owner to decide how to proceed. The meeting minutes would record the decision, with a note that the P&IDs need to be updated if the change affected them. Construction could proceed on the basis of the approved minutes without the revised P&IDs necessarily being signed off. I'm not saying this is what happened in this case, but I wouldn't jump to conclusions based on this context-less claim.

    The blowout plan is a separate issue.
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    Even for a story like this one it's hard to find meaningful well integrate information.

    Anyhow the link below is a good consolidation of the new surrounding the gusher and includes a model forecast of the sea surface oil that's updated a couple times a day.

    http://www.northescambia.com/?p=16808
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    I'm wondering if the shutoff failed because the engineers designing the shutoff failed to consider ocean pressures. I've seen my share of engineering designs that never considered one or more factors of physics in play. Cypress mentioned the Hydraulics Ram Blowout Preventor failed. Anyone with a decent background can see the tremendous pressure difference between sea water and hydraulic fluid at 5000 feet of water pressure. The pressures on any hydraulic cylinder and lines are tremendous at 5000 ft. and require even more pressure to operate in a 1.028 SG environment.

    Pressure of a 5000 ft. colum of 1.0 SG water is about 2200 psi.

    Specific gravity of sea water ~ 1.028.
    1.028 x 2200 = 2262.

    Specific gravity of hydraulic fluid ~ 0.87 (assumed, vary allot.)
    0.87 x 2200 = 1914.

    2262 - 1914 = 348 psi difference. Any necessary pressure to operate the Ram will effectively be reduced by about 348 PSI.

    I wonder if anyone in the industry considers this? I know they use pretty high pressures, but could this make the difference? I wonder what the minor deformation of the cylinder can be with such delta pressures too. I would hope that a heavy hydraulic fluid is used, but knowing regulations, I'll bet they are banned for content. I'll bet just the lighter ones are used.
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    I wonder if anyone in the industry considers this?
    Of course they don't. They all just fell off the strawberry truck and forgot their slide rules.

    knowing regulations, I'll bet they are banned for content.
    Covering all the bases, if it wasn't the stupid engineers it must be the gummint and their stupid regulations.
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  19. #18  
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    Quote Originally Posted by Bunbury
    knowing regulations, I'll bet they are banned for content.
    Covering all the bases, if it wasn't the stupid engineers it must be the gummint and their stupid regulations.
    Wow...

    You always try to read into someone's thought?

    Engineering is a difficult field. Even the best overlook things. I am in no way assuming stupidity by them. I just recognize they are not God's, seeing all contingencies.

    As for the regulations... I have seen real lame ones for the silliest of reasons. Hydraulic fluids are normally based on light hydrocarbon molecules, but have additives. All the ones I am aware of that approach the specific gravity of sea water are very toxic.

    Are you aware of all the engineering challenges to such a shutoff device? I know I'm not, but when you make a large hydraulic cylinder, it isn't perfect. Let's get past the seals and math for applied force. Materials warp, distort, etc. At a small scale, this is generally not an issue. This is not small scale. This is a near zero C environment, and you also have materials with different thermal expansion coefficients. One thing I would say is necessary is that a pressure should always be maintained on the hydraulic oil to equalize the pressure at the depth installed. In this case, and my assumed SG of the fluid, it would be somewhere in the neighborhood of 350 psi.
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    I agree that even the more obvious questions should be asked and answered. The subsea hydraulic lines and control systems do figure in density differences and therefore static pressure. Your estimate is reasonable for typical hydraulic fluid. We generally use fluid that is more dense for the reason you indicate. They include location specific transducers for feedback and the hydraulic pumps are sized for up to 8,000 feet water depth on that series of drilling rig. It is possible that the system was not configured correctly but that would have normally been identified during testing. Not sure how often BP requires the drilling contractor to test the BOP assembly.
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