Drill, baby, drill,,oops!

sad to see what's happening to the wildlife down there and what will be happening in the lives of so many people down the road. i wonder, when it affects you directly, if you have any change of philosophy re fossil fuel society.

 

Everything we are learning about this disaster shows how badly BP, Minerals Management, Transocean, and Haliburton had planned and operated this well. There will be abundant lessons learned and we need a 'safety stand down' to reduce the risk of a second one. But I've been impressed by the 'engineering on demand' and creative responses.

There is a difference between the engineering of a 'tiger team' and ordinary engineering when we can plan and schedule the work. Tiger team engineering requires the best and brightest . . . those who think 'outside the box' and work well with interdisciplinary experts. The ears have to work as well as the brain and communications has to be succinct and to the point.

Although it changes, the measure of success will be a reduction of this overflow:
Live feeds from Skandi ROV2

Bob Wilson

 

like the chaps on apollo 13.

 

The pipe is what, 21 inches diameter? That means the oil is already winning against 360 tons of water pressure.

Then the oil will just push its way through the sediments around the plug and fracture any rock layers in its way, finding yet another path into the ocean.

 

So then use a 400 ton plug.

If oil would find other paths to leak then it would be impossible to cap in any fashion,even using the wellhead structure.

 

I didn't see a clear image of the current cap but the angle iron suggests it isn't clamped on but resting using the weight of the pipe. This limits the stress it can take from the oil flow and the diameter of the pipe limits the flow, Euler's laws.

One option discussed was to stack another blow-out preventer to the existing one. To do this, the original riser pipe would have to be unbolted, leaving the 5" inner pipe. Now that both have been cut-off, this looks to be the best approach.

One news report last week suggested they had stopped the second, relief drilling with a plan to use that one's blow-out protector. This didn't make a lick of sense or worse, suggests there are a limited number of compatible blow-out protectors.

It is my fondest hope that they are building a bolt-on, compatible cap that flares to a larger diameter pipe. Then if they can unbolt the last of the pipe stem remaining, they would have a clean surface to bolt a more secure cap.

To me it looks like:

1. caisson cap - huge structure, it let too much of the 39F water and hydrates choked and started floating the structure. It had too much volume to stay on the floor.
2. 5" siphon - showed a heated pipe could transport oil and gas to surface
3. current cap - uses methanol and does not have the volume so it won't float. There is a significant, upward force and with Euler limits, gravity (unless there is some latching mechanism) is all that keeps it over the pipe stem
4. next cap (?) - needs a clean, flange to bolt on. What isn't clear is if the current cap blocks access to the oil obscured bolts. This would solve the cold water, hydrate problem.

Bob Wilson

 

This is correct, which is why no one is proposing a sealed cap. Any capping system will require a pressure release path until a bypass well is drilled.

Tom

 

I doubt that would hold for even a minute. As soon as the flow slows down, the frictional pressure losses in the pipe flow will be reduced, causing pressure at the wellhead to rise. With no flow, the wellhead pressure will be the similar to that of the underground reservoir supplying the oil, minus the (oil density)*(pipe column height).

Considering that the well is some 35,000 feet deep, the oil's upward force on a plug could potentially be around 5000 tons -- after the 'water hammer' effect of stopping the flow has settled out.

Any wellhead cap depends upon the pipes below being intact, no leakage path on the outside between the pipe and rock, and sufficient grip between the outer pipe and rock to prevent it from being pushed out. Your plan to tear off the wellhead is very likely to ruin its structural integrity.

 

The right wingers and their sycophants in the media (yes, they are there) are already trying to blame the oil spill on Obama. To think these idiots pushed Obama into liberalizing off-shore drilling policies that had been around for few presidents--including Republican ones--when the Republicans were a more responsible political party. Instead of confronting this irrational bunch, Obama tries to appease them. A sign of typical liberal Democrat weakness. I'm not happy about politics in Washington right now--obviously. Where is the old conservatism?

 

Well, so long as we are not letting physics get in the way of ideas, how about this:

Start and maintain a whirlpool say 500 ft above the leak. Perhaps the oil will centrifuge to the perimeter, where it can be collected.

 

There are two technical points that really caught my attention on this disaster.
1) The blowout preventer was incapable of operation anytime a pipe joint was transiting through. Could that be why the whole thing failed?
2) Once the recent shearing of the well head occurred, there were 7 (?) different attachment heads ready to go with each one configured differently based on how the cut turned out. At least someone shot the evil bean counter to come up with a smarter approach to stopping the leak.

 

I'm still trying to find people that are conservative like me, That I can vote for. Not all members of Congress are bad, We have a select bunch that have a "me" mentality.

I do think the drill unit was inside the piping but, The BOP should be able to close if it could have from the surface. Since it was damaged during the rig collapse, They couldn't activiate the system to close the BOP pipe.

 

That may have been true for the initial closure attempts. The later attempts initiated by the remote subs didn't work either. That's the failure I'm referring to.

 

Interesting hypothesis.

The static pressure from the reservoir might exceed the structural limits of the blowout preventer. Only the flow friction being enough to keep the pressures below the mechanical limits of the existing well-head. Yet they tried to pump mud down the pipe last week.

Pumping mud would have had to slow and stop the oil column and move the mud down the drill hole. Those would have been some impressive pressures.

I would still like to see an attempt to bolt on a new head to the top of the blow-out preventer . . . assuming the current cap is just a gravity coupling.

Bob Wilson

ps. Trying to lay blame while the well is still spewing reminds me of a story the late Jerry Clower told about a boy who the game warden suspected was illegally fishing.

So the warden pulled an under cover operation and went fishing with the boy and sure enough, they got out on the water and the boy pulled out a stick of dynamite. The warden yelled, "Ah Ha! I got you now for illegal fishing!"

Lighting the fuse, the boy handed it to the warden and said, "Do you want to talk or fish?"

Arguing about who did what now is sort of like running away from a burning house to hunt the arsonist.

 

[This isn't my field, I hope no one mistakes me as an expert.]

The upper bore section is at least two concentric pipes, and I thought they often had openings somewhere as part of the mud fluid path between them. This would also be part of the process for inserting the concrete for sealing the well, such as was happening when this disaster was triggered. If these openings still exist, then the pressure to pump mud down one path, while oil continues up through the other, is far less than the pressure needed to stop the whole oil column.

Very well put.

Some of the reports and calls out there make me believe that numerous folks are placing a higher priority on taking down a mega oil company than on controlling and recovering from this environmental disaster. Death threats, calls to seize all BP assets right now, and prominent criminal investigations right now, can only hinder efforts to stop the spill.

While some are likening this to an American Chernobyl, the Administration is certainly not treating it as such. If it were, we wouldn't have stories such as CNN's Would federal intervention in oil disaster make U.S. liable?:

President George H.W. Bush, during the Exxon Valdez tanker spill off the coast of Alaska in 1989, turned down a request by Alaska's governor to declare the incident a major disaster. That declaration, under the Stafford Disaster Relief and Emergency Assistance Act, would commit federal resources and control over the cleanup efforts.

According to the nonpartisan Congressional Research Service, the rationale for the turndowns was that a declaration by Bush "would hinder the government's litigation against Exxon that promised substantial compensation for the incident."

The CRS report, which is prepared for members of Congress, said that such a declaration carries expectations that are difficult to manage, which "may be a consideration for the oil spill in the Gulf Coast."

When defining liability and compensation are higher priorities than stopping and containing the oil, then we are not treating this as a catastrophe.

 

You can get up to 45 MPa but that is risky and usually the pumping system is incapable of maintaining that sort of pressure for long

That would be the logical step

Smart boy

The casing and string are sized such that mud can readily flow down the length to the bit, flush away the cuttings, and then readily flow back up to the bell nipple

The bell nipple is used to separate out the mud return. The "mud" is usually a bentonite mix, it acts as a drill bit lubricant and to carry away the cuttings.

There are many possible configurations for allowing the fluid to flow: annular openings, slotted openings, etc

The "cementing in" refers to sealing the gap between the casing and the surrounding earth that was used to transport up the working fluid. This is a tricky part of finishing the well

Not quite, it can actually be quite a bit more. Considering that the pressure at 5,000 ft of water is about 15 MPa, and the oil is coming out at a good rate, the reservoir may be >30-45 MPa already. You need to overcome those intense pressures

I agree, it's turning into theatrics. The most important step right now is to have BP "s*** or get off the pot," fix this problem. Afterwards the blame game can begin, along with criminal investigations

All a criminal investigation accomplishes right now is to ensure extra income for the lawyers. It doesn't fix the problem at all

 

They have three ROV cameras running: Shandi ROV1, ROV2, and Enterprise ROV2. If we knew the dimensions of that hydraulic actuator, we could estimate the volume of the 'oil plume'. Then using successive frames from the video, figure the upward velocity. Together, we could come up with as good of an estimate as anyone else.

What I notice today are the angular points of the alignment fins are frequently being obscured compared to a day or so ago. This could simply be they've closed vents that were further up the cap.

I keep seeing pale, whispy stuff, biologicals?, being sucked in the oil plume, especially where it is back lit. I'm also seeing what I suspect are hydrate globs ejected . . . I think.

I've not heard anything about sulfides. I well remember sour wells in Oklahoma that would sometime require highways to be closed.

Bob Wilson

 

I agree that simple comparison of the video will provide estimates of the volume ejected

The whispy stuff and white globs are hydrates. At those depths and temps, you can expect the formation of hydrates

Gulf oil isn't as "sour" as the wells you are referring to in OK. However, most Gulf oil has very high napthalene content

Napthalenes have a high molecular weight. One thing that occurs is that this oil will tend to emulsify FAR more than regular crude. What that means is that this crude will tend to "mix" with the seawater, hence forming those underwater plumes.

Most crude would tend to rise to the top and readily undergo biological decomposition and evaporation. This stuff tends to emulsify and stick around

 

At least we won't have to worry about a moth problem in the Gulf.

Tom