23 May 2010

Decrease in Gusher Velocity Suggests Low Range Flow

[Update 28 May 2010: The live feed above no longer points at the end of the riser, and the riser insertion tube has long since been removed, so the comparison is no longer meaningful. But this live feed is still useful, since it has continued displaying even when other life feeds have gone down. AF]
Compare the above live feed with an earlier video of the gusher taken pre-riser tube:

Note the velocity of hydrocarbon out of the riser pipe originally (bottom video) compared to the velocity out of the pipe after the riser siphon tube was inserted and operational (top live video). What is your best guess of the difference? It is the velocity that is the important parameter.

Equation to solve flow rate "Q": Q=vA where "v" is velocity of fluid and "A" is cross sectional diameter area of the pipe.

Remember that if you can detect a noticeable difference in velocity due to the withdrawal of 5,000 barrels per day through the siphon tube -- with just the naked eye -- the total gush rate prior to the siphon tube was very likely under 20,000 bpd.

Deep Horizon Oil Spill: An Unlikely Series of Unfortunate Events?

A comparison with the larger environmental disaster of Ixtoc 1 in 1979

Top Kill procedure still tentatively scheduled for Tuesday, 25 May 2010.

Update: Something happened to stir things up and create a lot of turbidity around the livefeed camera. One minute everything was clear and you could watch fish and eels swimming by, the next minute there is nothing but gray swirling matter -- with a brief glimpse of an ROV moving through before all goes back to cloudiness.

Remember that this is one mile below the ocean surface, with a lot of things changing almost instantaneously -- including flow rate up the siphon tube. The 5,000 bpd is said to be the average 24 hour rate of extraction out of the riser.

Now you can see one ROV in the distance, while a second ROV seems to be attempting to reposition the livefeed camera......Try not to spend too much time watching this.

Update #2: This AP news report suggests that the siphon tube had retrieved only just over 1,000 barrels over the past 24 hours -- compared to over 2,000 barrels the previous 24 hours. The video below was taken when the retrieval was close to 3,000 barrels per day.
"Spillcam' Streaming Video -- What It Looks Like
If you study the image of the riser siphon tube here, you can locate the drill pipe within the riser, which interferes somewhat with the rubber stoppers on the siphon tube. If the stoppers (or gaskets) were made of a material better able to mould around the drill pipe -- and better seal the outflow -- the siphon tube would likely be more efficient at its task.

Regardless, the high velocity / high pressure injection of highly dense kill mud into the BOP on Tuesday may be the big piece of luck that BP (and everyone else but the ghouls) has been hoping for.


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