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  1. #1
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    More on Deepwater Horizon problem

    I found this detailed description of equipment this morning and more importantly to my mind, the discussions by people who know what they are talking about. They raise the same question I had, why didn't they see the kick and respond to it. Nobody knows but you might find the discussions interesting.

    http://www.drillingahead.com/forum/t...ater-horizon-1

  2. #2
    xxl
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    AP had this report:

    http://news.yahoo.com/s/ap/20100508/...gulf_oil_spill

    First the WVA mine, now this: why does methane hate us?

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    Quote Originally Posted by xxl
    AP had this report:

    http://news.yahoo.com/s/ap/20100508/...gulf_oil_spill

    First the WVA mine, now this: why does methane hate us?
    No question that it was a gas bubble but the real question is how it went undetected. The discussions by industry personal with extensive knowledge of deepwater drilling are asking much the same questions. Failure of the BOP caused by the explosion is one scenario but how the hell did they get snuck up on is the one that is unanswered. I wasn't that far off when I wondered if they had sealed the well with cement which is actually the process that they were completing. The well could then be safely abandoned until it was possible to produce it at some later date at which time they would drill through the cememt plug and reopen it. One proposed scenario is that the drill team had relaxed their vigilance because with the cement in place the well was deemed safe, no more direct contact to the reservoir and it's pressures. They were wrong. This makes the most sense to me as the cause of the disaster. There is an added factor in that it sounds to me as if this happened right after a shift change. In the process of going off shift and settling in between two crews, the well deemed safely sealed, people got careless.

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    Quote Originally Posted by Snakebit
    I found this detailed description of equipment this morning and more importantly to my mind, the discussions by people who know what they are talking about. They raise the same question I had, why didn't they see the kick and respond to it. Nobody knows but you might find the discussions interesting.

    http://www.drillingahead.com/forum/t...ater-horizon-1

    Thanks for the link. I've studied the CRB report on the BP Texas City explosion. I wonder if you get to the root of it all if the causes are similar--poor process safety management and training.

    I've designed large scale commercial chemical processes using highly hazardous materials. Even though it's been 10 years since I completed my last project, I still worry that something might go wrong.

    I hope the people who died never saw it coming. Burning to death is one of the worst ways to go.
    Lugged Steel Treks

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    Quote Originally Posted by Reynolds531
    Thanks for the link. I've studied the CRB report on the BP Texas City explosion. I wonder if you get to the root of it all if the causes are similar--poor process safety management and training.

    I've designed large scale commercial chemical processes using highly hazardous materials. Even though it's been 10 years since I completed my last project, I still worry that something might go wrong.

    I hope the people who died never saw it coming. Burning to death is one of the worst ways to go.
    There is no way to insure that people never get complacent and too comfortable and secure in knowledge that they think they have. This sounds like an experienced crew that just didn't suspect there was still a threat. High pressure can kill you so many ways and so damned quick. They will come to understand exactly what happened here and if there is a safety factor that can be engineered into the system for future use it will be done. It will also add another level of training for rig personel and probaby altered procedures. I have no doubt that the people involved really understand what took place at this point but CYA is now the order of the day. Not so much to dodge responsibility as to get their order of battle set up for the coming legal fights which will take years to resolve. I thought the discussions among the industry people and questions they were asking each other were the most illuminating information that I have seen so far. Reporters are such dumb butts. All the news reports are so vague and peripheral because that is the only information the various companies are officially passing on. Necessarily so because of legal restraints.

  6. #6
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    Quote Originally Posted by Snakebit
    I found this detailed description of equipment this morning and more importantly to my mind, the discussions by people who know what they are talking about. They raise the same question I had, why didn't they see the kick and respond to it. Nobody knows but you might find the discussions interesting.
    New York Times has further interesting coverage. Not as much technical detail as your piece, but a useful supplement.

    Basically, when BP was planning the drilling operation they declared that there was a "negligible risk" of high-pressure gas pockets. The government warned BP that they should be worried about the gas and "exercise caution."

    During the drilling, gas burps became a big problem and during the weeks prior to the explosion they had to halt hot work on the platform when big bursts of gas came up.

    Also, Halliburton was plugging the well with a particularly difficult type of cement, aerated with a large fraction of nitrogen. And they were rushing because they'd get a bonus if they finished ahead of deadline.

    The explosion came when they were flushing the drilling mud out of the pipes with seawater, relying on the cement plug in the drilling pipe to contain the oil and gas when the weight of the mud was removed.
    Anything that doesn't take years of your life and drive you to suicide hardly seems worth doing. ---- Cormac McCarthy

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  7. #7
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    swoosh, boom, run

    From this commie rag.


    Bubble Of Methane Triggered Gulf Oil Rig Blast

    SNIP

    Portions of the interviews, two written and one taped, were described in detail to an Associated Press reporter by Robert Bea, a University of California Berkeley engineering professor who serves on a National Academy of Engineering panel on oil pipeline safety and worked for BP PLC as a risk assessment consultant during the 1990s. He received them from industry friends seeking his expert opinion.

    A group of BP executives were on board the Deepwater Horizon rig celebrating the project's safety record, according to the transcripts. Meanwhile, far below, the rig was being converted from an exploration well to a production well.

    Based on the interviews, Bea believes that the workers set and then tested a cement seal at the bottom of the well. Then they reduced the pressure in the drill column and attempted to set a second seal below the sea floor. A chemical reaction caused by the setting cement created heat and a gas bubble which destroyed the seal.

    Deep beneath the seafloor, methane is in a slushy, crystalline form. Deep sea oil drillers often encounter pockets of methane crystals as they dig into the earth.

    As the bubble rose up the drill column from the high-pressure environs of the deep to the less pressurized shallows, it intensified and grew, breaking through various safety barriers, Bea said.

    "A small bubble becomes a really big bubble," Bea said. "So the expanding bubble becomes like a cannon shooting the gas into your face."

    Up on the rig, the first thing workers noticed was the sea water in the drill column suddenly shooting back at them, rocketing 240 feet in the air, he said. Then, gas surfaced. Then oil.
    Story continues below

    "What we had learned when I worked as a drill rig laborer was swoosh, boom, run," Bea said. "The swoosh is the gas, boom is the explosion and run is what you better be doing."

    The gas flooded into an adjoining room with exposed ignition sources, he said.

    "That's where the first explosion happened," said Bea, who worked for Shell Oil in the 1960s during the last big northern Gulf of Mexico oil well blowout. "The mud room was next to the quarters where the party was. Then there was a series of explosions that subsequently ignited the oil that was coming from below."

    According to one interview transcript, a gas cloud covered the rig, causing giant engines on the drill floor to run too fast and explode. The engines blew off the rig and set "everything on fire," the account said. Another explosion below blew more equipment overboard.

    SNIP

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    Quote Originally Posted by rocco
    According to one interview transcript, a gas cloud covered the rig, causing giant engines on the drill floor to run too fast and explode. The engines blew off the rig and set "everything on fire," the account said. Another explosion below blew more equipment overboard.
    The details make no sense. How would methane covering the rig affect drill engines? That doesn't compute.

    What happened is methane covered the rig and a spark from some piece of equipment ignited it.

    They had at least one similar giant gas bubble in the week or two before the explosion, but were able to alert the crew to stop all hot work in time to prevent igniting it.
    Anything that doesn't take years of your life and drive you to suicide hardly seems worth doing. ---- Cormac McCarthy

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    Quote Originally Posted by Fredke
    The details make no sense. How would methane covering the rig affect drill engines? That doesn't compute.

    What happened is methane covered the rig and a spark from some piece of equipment ignited it.

    They had at least one similar giant gas bubble in the week or two before the explosion, but were able to alert the crew to stop all hot work in time to prevent igniting it.

    Could make an episode of MythBusters.

    Diesel engines use air compression, not spark as do gasoline engines. Air is initially introduced into the combustion chamber. The air is then compressed which heats the air to 550 °C. At the top of the compression stroke, fuel is injected into the compressed air in the combustion chamber. The heat of the compressed air vaporizes the fuel the vapor is ignited.

    The methane in the air around the rig would have been mixed with the compressed air introduced into the combustion chambers of the engines. It wouldn't surprise me if this cause the drill engines to run faster momentarily before everything ignited.

    On the other hand, we could be looking at mis perceptions/confused recollections of what must have been an overwhelming experience. Imagine all of the extreme stimuli that would have overwhelm all of the senses in the moment.
    Last edited by rocco; 05-08-2010 at 01:13 PM.

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    Quote Originally Posted by Reynolds531
    Thanks for the link. I've studied the CRB report on the BP Texas City explosion. I wonder if you get to the root of it all if the causes are similar--poor process safety management and training.

    Most of the CSB reports I've reviewed tend to have the same basic conclusion- people didn't follow procedures that had been established to prevent exactly the incidents that occurred. I recently finished a couple of PSM reviews ( a loooong process), and found that despite general awareness of the hazard(s), folks were not nearly attentive enough to the formal procedures established in their plans. Part was training, but a bigger part (iMO) was lack of management follow through in ensuring that the plan was followed....

  11. #11
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    Quote Originally Posted by Snakebit
    There is no way to insure that people never get complacent and too comfortable and secure in knowledge that they think they have. This sounds like an experienced crew that just didn't suspect there was still a threat.
    Drills are the way you do this. (drills as in practice, not as in poking holes in the sea-floor).

    Putting pilots into flight simulators and throwing unexpected stuff at them. Holding evacuation drills in buildings. Stuff like that. Aircraft carrier flight decks are incredibly dangerous and have incredibly good safety records in large part because the Navy understands the hell out of drilling sailors on proper procedure.

    But drilling means paying people to do training exercises instead of producing, so employers generally don't like to do this.
    Anything that doesn't take years of your life and drive you to suicide hardly seems worth doing. ---- Cormac McCarthy

    A man can get disouraged many times, but he is not a failure until he begins to blame somebody else and stops trying --- John Burroughs

  12. #12
    xxl
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    Apparently the concrete dome fix isn't fixing: http://news.yahoo.com/s/afp/20100508...ypollutiondome

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    Quote Originally Posted by Fredke
    The details make no sense. How would methane covering the rig affect drill engines? That doesn't compute.

    What happened is methane covered the rig and a spark from some piece of equipment ignited it.

    They had at least one similar giant gas bubble in the week or two before the explosion, but were able to alert the crew to stop all hot work in time to prevent igniting it.
    Engines speeding up just prior to explosions is common. In this case methane gas was probably pulled into the engine through the air intakes. If so, it's daja vu for BP. A sign of an impending explosion at Texas City was a diesel truck engine racing. From the CRB report:

    "At least one witness saw a pickup truck parked just north of the Blowdown Drum & Stack with its engine racing and exhaust glowing, but it is not known if this was the source of ignition."
    Lugged Steel Treks

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    Quote Originally Posted by Reynolds531
    Engines speeding up just prior to explosions is common. In this case methane gas was probably pulled into the engine through the air intakes. If so, it's daja vu for BP. A sign of an impending explosion at Texas City was a diesel truck engine racing. From the CRB report:

    "At least one witness saw a pickup truck parked just north of the Blowdown Drum & Stack with its engine racing and exhaust glowing, but it is not known if this was the source of ignition."
    Sounds like a diesel motor could be the equivalent of a canary in these matters. Why not have a running diesel motor where the methane gas would show up and have it triggered to an alarm/kill switch if the RPM's get above a certain number.

    While a diesel motor is not as likely to be a source of ignition as a gasoline motor, I can still seeing it become a source of ignition if it runs too fast. Essentially, it would get way, way too hot and could possibly cause a flash fire, just like a gasoline motor can experience detonation inside the motor without the spark plug even igniting (i.e., detonation occurs when parts on a gasoline motor get way too hot and they set off the air/gas charge way before the spark plug ignites and while the piston is still trying to reach the top of its stroke. This usually leads to blown head gaskets, or worse yet, blown pistons or rods).
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    Quote Originally Posted by fabsroman
    Sounds like a diesel motor could be the equivalent of a canary in these matters. Why not have a running diesel motor where the methane gas would show up and have it triggered to an alarm/kill switch if the RPM's get above a certain number.

    ....

    From what I've gathered they were immediately aware that a methane bubble had shot up the pipe.

    Assuming the air and methane mixture is enough to keep the engine running, how do you immediately kill a diesel engine when you can't cut off all of the fuel sources?

  16. #16
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    Quote Originally Posted by Fredke
    Drills are the way you do this. (drills as in practice, not as in poking holes in the sea-floor).

    Putting pilots into flight simulators and throwing unexpected stuff at them. Holding evacuation drills in buildings. Stuff like that. Aircraft carrier flight decks are incredibly dangerous and have incredibly good safety records in large part because the Navy understands the hell out of drilling sailors on proper procedure.

    But drilling means paying people to do training exercises instead of producing, so employers generally don't like to do this.
    What I think happened here was equivalant to the SWAT team standing around talking about the raid after they believe all the targets to be down, in custody or otherwise neutralized. These guys thought the beast was tamed and took their eyes off of the indicators. They new the drill, just thought there was no threat at the time. They have training courses and regular revue of procedures. The Navy still has accidents on their flight decks.

  17. #17
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    Quote Originally Posted by Snakebit
    The Navy still has accidents on their flight decks.

    Sucks when that happens.


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    Quote Originally Posted by rocco
    From what I've gathered they were immediately aware that a methane bubble had shot up the pipe.

    Assuming the air and methane mixture is enough to keep the engine running, how do you immediately kill a diesel engine when you can't cut off all of the fuel sources?
    Why wouldn't you be able to cut off all the fuel sources? Cut off the diesel fuel and cut off the air intake with an airproof throttle plate. Plus, you can kill the glow plugs. It doesn't seem that hard to me if the motor is air proof other than at the throttle body.
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  19. #19
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    Quote Originally Posted by fabsroman
    Why wouldn't you be able to cut off all the fuel sources? Cut off the diesel fuel and cut off the air intake with an airproof throttle plate. Plus, you can kill the glow plugs. It doesn't seem that hard to me if the motor is air proof other than at the throttle body.
    Big diesels (bigger than car engines) don't have glow plugs. But they'd quickly aspirate a buttload of methane that was shooting out of the ocean like it was carebureted, to ill effect. I imagine even the friction of the running engine might generate enough static discharge to ignite the gas, but I'm no expert on that.

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    Quote Originally Posted by fabsroman
    Why wouldn't you be able to cut off all the fuel sources? Cut off the diesel fuel and cut off the air intake with an airproof throttle plate. Plus, you can kill the glow plugs. It doesn't seem that hard to me if the motor is air proof other than at the throttle body.

    Makes sense. This isn't something that is a typical/standard feature on diesel engines, right?

    A couple of years ago the ignition switch on my folk's boat failed and the only way they could kill the engine was to shut off the main line from the fuel tanks.

    Anyway, as the for the canary application, where could you put the diesel such that it would be useful for deep water drilling?

  21. #21
    xxl
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    BTW, I sure hope everybody got the memo before they rented their tux:

    http://www.mms.gov/ooc/press/2010/press0428.htm

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    Quote Originally Posted by fabsroman
    Why wouldn't you be able to cut off all the fuel sources? Cut off the diesel fuel and cut off the air intake with an airproof throttle plate. Plus, you can kill the glow plugs. It doesn't seem that hard to me if the motor is air proof other than at the throttle body.
    Diesel engine runaway
    From Wikipedia, the free encyclopedia
    Jump to: navigation, search
    Diesel engine runaway is a common condition affecting diesel engines, where the engine goes out of control, consuming its own lubrication oil and running at higher and higher RPM until it overspeeds to a point where it destroys itself either due to mechanical failure or engine seizure through lack of lubrication. For instance, a 1800 rpm engine can run to 4000 or 5000 rpm or beyond.[1]

    Contents [hide]
    1 Causes
    2 Notes
    3 References
    4 See also

    [edit] Causes
    Unlike a gasoline engine, which has a butterfly valve controlled by the throttle mechanism to control engine speed, a diesel engine's speed is controlled by varying the supply of fuel.

    In many vehicles, a crankcase breather pipe feeds into the air intake to vent the crankcase; on a highly worn engine, gases can blow past the sides of the pistons and into the crankcase, then carry oil mist from the crankcase into the air intake via the breather. A diesel engine will run on this oil mist, since engine oil has the same energy content as diesel fuel, and so the engine revolutions increase as this extra "fuel" is taken in. As a result of increased revolutions, more oil mist is forced out of the crankcase and into the engine, and a vicious cycle is created. The engine reaches a point where it is generating enough oil mist from its own crankcase oil that shutting off the fuel supply will not stop it and it will run faster and faster until it is destroyed

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    Quote Originally Posted by rocco
    Sucks when that happens.

    That was 17 years ago. However, I will agree that the Navy still has flight deck issues. One of my buddy's pilot friends died when he hit the bridge coming in because the LSO gave him the wrong signals and that was less than 10 years ago.
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    Quote Originally Posted by xxl
    Big diesels (bigger than car engines) don't have glow plugs. But they'd quickly aspirate a buttload of methane that was shooting out of the ocean like it was carebureted, to ill effect. I imagine even the friction of the running engine might generate enough static discharge to ignite the gas, but I'm no expert on that.
    Hence, a shut off valve/plate that would cut off the air intake. Honestly, it cannot be that hard on a diesel motor to have a plate somewhere that would drop or close that would cut off the air intake. The only reason a motor doesn't die when you let off of the accelerator is because the throttle plate remains somewhat open to allow air to pass through for idle. If the throttle plate were to have closed all the way, the motor would stall.

    I have no idea about the friction either. I'm guess that methane either needs a spark or a high temp to combust as a gas, but I do not know the particulars of it.
    “Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote.” Modified by unknown from Bovard's original quote<o:p></o:p>

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