Skip to main content

View Diary: Daily Kos Oilpocolypse ROV #25: Cutting the Riser (299 comments)

Comment Preferences

  •  force lowering riser (0+ / 0-)

    Is like trying to attach a firehose onto a fire hydrant with the hydrant on.   If we imagined trying to slide a section of 21"OD 0.812" wall thickness pipe across the stream into the flow, it would take about 6tons of force (at 400PSI+20%) just on the edge of the pipe:
    ((21inches/2)^2*pi-((21inches-0.812inches*2)/2)^2*pi)/2*400psi*1.2/1gravity = 6.1798857 tons
    But this is going to have much more cross section, plus there is the flow resistance in the pipe to add to the force.  Think of that as a lower bound.

    An upper bound is pressing a plate over the leak (but ignoring the pressure rise to around 9000PSI which would occur if you really patched it up).   The hose will obviously resist less than that:
    ((21inches/2)^2*pi)*400psi*1.2/1gravity = 83.126542 tons

    The new riser assembly itself is so heavy, though, that it will lower under its own weight.

Subscribe or Donate to support Daily Kos.

Click here for the mobile view of the site