DeepWater Horizon-- Digging for Facts

Various --- Oil Drum initially ^ | June 21, 2010 | Ernest at the Beach

[Ernest_at_the_Beach]

An attempt to look thru various sources and answer some basic questions .

1. Can we get a handle on a basic Fact ...What was the pressure at the bottom of the drilled hole in the formation ?

From the Oil Drum:

BP's Deepwater Oil Spill - Matt Simmons on Dylan Ratigan Today, Closing the Relief Ports, and Open Thread 2
Comment by avonaltendorf on June 8, 2010 - 12:06am

Thread Posted by Prof. Goose on June 7, 2010 - 9:00am

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Comment by avonaltendorf on June 8, 2010 - 12:06am

I received a personal note, which I acknowledge gratefully.

Down to business. I agree with Matt Simmons and posted as much evidence as I could garner from publically available ROV feeds. We aren't being shown the IR or sonar images. Low res video is crap compared to what the ROV pilots and BP folks are looking at. Obviously USCG is in the dark or has been ordered to follow the White House playbook until they get a handle on how big a problem they have. In my view, it is a medium-sized problem, not quite as gigantic as Simmons suggested to Ratigan.

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Let's roll the movie back to the events of April 20. Simmons thinks that the reservoir pressure is 30,000 psi judging by the force of the blowout. This is clearly impossible. If true, it would have blown out immediately on penetration April 17. The scout ticket tells us that the pressure at the top of the reservoir was no greater than ~13,000 psi based on mud weight to control lost circulation:

LWD (RLL, BATSON, PWD) @17173, M 14.1, NO SWC, 9 7/8 LNR @14759-17168, LOT 15.9, LWD (RLL, BATSON, GEOTAP, PWD) @18260, LOST CIRC W/14.4 MUD, C&C SPTTD LCM

LWD=Logging While Drilling
RLL=Recorded Lithology Log with gamma ray and resistivity
NO SWC=No Side Wall Cores

PWD=Pressure While Drilling
LOT=Leak Off Test to measure strength of wellbore wall

At 18260 ft, Lost Circulation with 14.4 lb/gal mud, then Circulated and Conditioned the mud and Spotted a Lost Circulation Material pill to cure the losses. They had drilled into the top of the reservoir (gas cap) and mud started leaking away into the reservoir, because 14.4 mud weight was greater than the reservoir pressure. Assuming a vertical well, reservoir pressure was less than 14.4 x .052 x 18260 = 13768 psi, or mud would not have been lost.

It was a slow process of gas reaching bubble point plus a nonsense negative test ordered by Kaluza that sandbagged the drillers into displacing to seawater without watching mud returns or understanding what was happening. When a gas bubble formed it expanded rapidly as it travelled up the riser unopposed, blowing out the seawater and mud. It was followed by very light liquid and more gas. The BOP did not fire on EDS from the bridge because hydraulics were gone or malfunctioned, but there was mux control to one or both of the pods. Only when the rig sank and riser collapsed did the BOP see a "deadman" condition and attempt to shear the drill pipe -- except by then it was clogged with debris and couldn't shear or close fully.

Thus we have gas and light oil at low pressure spewing from the riser swivel. Below the BOP should be ~8,000 psi, which is sufficient to find paths of opportunity to nearby vents. However we have to keep in mind that collapsed casing and broken cement gives the reservoir a path to salt welds (thin mostly vertical remnants of salt withdrawl) and fractured slump faults. It is therefore possible that light oil at 13,000 psi could migrate updip miles away.

I posted such evidence as I found. It is not enough to prove anything, but convinced me that Simmons knows the deepwater GoM geology.

[Cold Heat]

I once lived in North Dakota for several years when I was in my teens, and I pretty much grew up with sharptails, and quail, pheasants, and doves.

My legs sorta gave up a couple decades ago and I have not been since, but it was the best hunting I ever experianced.

[CharlesWayneCT]

I thought the Q4000 had the best video, but I don’t know what the real capabilities are. I do like how the Q4000s have a text description of their mission, and generally a better readout of depth.

[Cold Heat]

I plan to do some watching today. Should be interesting.

[mad_as_he$$]

We go Chukar hunting..not much killing. I won't try the steep basalt hills anymore. Fell off of one 18 months ago and still have issues.

[Marine_Uncle]

Went similar route with the rifles. Got married and wife wondered why I wanted to kill Bambi. Sold all my firearms many years back.

[Marine_Uncle]

I believe your analysis of why they did not try current method from the start is probably pretty accurate. They did seem to think the big box would work. And the Robot collosion did put them back a bit.

[Cold Heat]

The government is having a fit now, because they plan to remove the cap and remove the cutoff top section. This will take a week or two at least, and they will have to leave it open for that time.

I just listened to the Well's audio briefing for the 28th of last month where he described what the plans were. All of what they are planning to do will coincide with the relief well which will probably come in within a couple weeks of the new topper.

We used to call this a christmas tree. It is flange mounted and bolted to the flange that is currently under the cutoff pipe on top. From that, once installed and they get a chance to play with it for a while as to pressures and such, they can actually cut this well off 100%.

That would be best case scenario, but it fits the relief well kill plan like a glove because if the need to throttle the flow back, they can and the kill is much easier and faster. Normally a kill takes weeks, and they could do it in days with the christmas tree and worst case they could use the shutoff valve to kill it from the top and bottom at the same time. Add to that the pumping capacity they will soon have and.....

Talk about redundancy!

Anyway, this well will be killed within 6 weeks (weather permitting)and that I think you can take to the bank.