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View Diary: BP LiveBlog - Diary 11 (303 comments)

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  •  cutting off the mud flow temporarily (1+ / 0-)
    Recommended by:
    johnsonwax

    Is fine as long as you aren't too slow about it.   Suppose you pump mud for four hours.  If 10% of that goes down the hole, it will take around 22 minutes for it to come back out.   Switch over in 2 minutes and you wasted 22 minutes worth of pumping plus the 2 minutes you were idle, take 22 minutes to switch and you lost all 4 hours of pumping.

    •  Exactly, however I think (1+ / 0-)
      Recommended by:
      Jaygar

      it takes a fair bit of time to switch over because I think they're unhooking from one ship and hooking to another. Remember, they never have to do it this way - this is all learning on the fly.

      Leave it to Republicans to set the house on fire and then rant that the fire department is socialist.

      by johnsonwax on Fri May 28, 2010 at 03:05:48 PM PDT

      [ Parent ]

      •  I heard they had the ability to run (1+ / 0-)
        Recommended by:
        johnsonwax

        lines through a full reservoir  bypassing it and switching over quicker.

        •  Yeah, that would make sense. (2+ / 0-)
          Recommended by:
          lightfoot, Jaygar

          They do this in firefighting. They stage two tankers and one delivers water while a 2nd is filling the first as fast as it empties. When the 2nd is empty (and the first is still full) a 3rd arrives, hooks up and catches up to filling the first.

          The kill rig has its own reservoir, but I don't know how big it is. But even if they can do it as you describe, then they should be able to pull this off given enough mud parked out there in the gulf. 50K bbl is a pretty good cushion, I'd think.

          Leave it to Republicans to set the house on fire and then rant that the fire department is socialist.

          by johnsonwax on Fri May 28, 2010 at 03:21:21 PM PDT

          [ Parent ]

          •  My concerns are possible (0+ / 0-)

            fractures or obstructions deep below the surface. That there isn't a heavy enough mud or enough distance to build the needed pressure to overcome the natural pressure of the formation.

      •  switchover (2+ / 0-)
        Recommended by:
        johnsonwax, lightfoot

        Yeah, you would think they would have a Y-valve but that valve would take quite a beating so they may be doing the low tech approach.   Another alternative would be to pump mud from tanker 2 into the hold of tanker 1 and not stop pumping at all.

        Now, suppose they have to stop for 1 minute every hour to meassure the pressure so they know how much mud they have down the hole.   That would lose about 1/6 of the mud.   But they probably don't have to stop entirely; if they lower the mud pressure below the well head pressure, that is good enough.    As they get closer to the correct amount of mud in the bore, they would have to stop and measure more frequently.   Fortunately, the more mud you have down in the hole the slower you lose your in bore mud.   If it takes 16 hours to fill the bore and you stop temporarily after 4 hours, then the mud loss rate would be 3/4 of what it would have been at the beginning.   After 8 hours, 1/2.   After 12 hours, 1/4.

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