How does BP's 'top kill' work? (Updated)

[Ponce]

How does BP's 'top kill' work? (Updated)

44 mins ago
[This post was last updated about 1:30 p.m. ET.]

BP has decided to proceed with what's called a "top kill" to try to stop oil from gushing into the Gulf of Mexico. The procedure will last as long as two days, said BP. The company is providing a live video feed (streamed here courtesy of ABC News). Note to viewers: Traffic spikes may affect the quality of the feed.

A "top kill" consists of pumping huge amounts of mud and cement into the leak in hopes of stopping it. The mud and cement will be pumped at high pressure from barges down 5,000 feet. BP has stockpiled 50,000 barrels of the manufactured mud, AP reported.

The challenge will be to pump the mud at sufficient downward pressure to counteract the upward pressure of the gushing oil. The tactic has been used in above-ground oil leaks, but never underwater.


According to CNN, if the "top kill" doesn't work BP will try a "junk shot": Instead of pumping mud and cement, BP would pump "material like golf balls, pieces of tire and pieces of rope into the blowout preventer."

If neither procedure works, BP will be forced to revert to ideas like a containment dome to try to stop the leak.

http://news.yahoo.com/s/ynews/20100526/sc_ynews/ynews_sc2252

[ximmy]

Oh, that's good.. throw tires and golf balls at it... from underwater

[undgrd]

Any idea how much pressure needs to be overcome?

[gunDriller]

Any idea how much pressure needs to be overcome?


the oil is coming out at 70,000 psi.

http://www.theoildrum.com/

/\ good website for oil industry geology shop talk, and right now they're mostly talking about the BP spill.

[undgrd]

I've seen between 15K and 80K PSI

My question is this. What does the drilling industry have in production today that will push mud/concrete into this hole to overcome 70K PSI?


Also, I've read the slurry like consistency (Oil,Sand, General Grit) of the substance coming out of the hole is wearing away at the pipe. If they fire a mud/concrete mixture into the pipe at greater than 70K PSI, wouldn't that just speed up the damage and give the oil a chance to escape around the pipe?

[Horn]

I've seen between 15K and 80K PSI

My question is this. What does the drilling industry have in production today that will push mud/concrete into this hole to overcome 70K PSI?



70,000 lbs x sq.in of pipe in mud.

[7th trump]

I've seen between 15K and 80K PSI

My question is this. What does the drilling industry have in production today that will push mud/concrete into this hole to overcome 70K PSI?



70,000 lbs x sq.in of pipe in mud.

Easy!
Whats the weight of mud and cement in a good size tube thats 5000 ft tall?
The weight alone when the tube is filled is tremendous. Wouldnt take much of a pump to do the job.
Stack dry cement bags of concrete 5000 ft and see if you can lift it.

[Horn]

I've seen between 15K and 80K PSI

My question is this. What does the drilling industry have in production today that will push mud/concrete into this hole to overcome 70K PSI?



70,000 lbs x sq.in of pipe in mud.

Easy!
Whats the weight of mud and cement in a good size tube thats 5000 ft tall?
The weight alone when the tube is filled is tremendous. Wouldnt take much of a pump to do the job.
Stack dry cement bags of concrete 5000 ft and see if you can lift it.


Plus probably 3/4s the depth of the well hole, they'll let the mud go down there near the bottom then back the pipe out as it fills.

[Horn]

The thing that could make this fail is turbulence. When the mud is released extra turbulent pressure will steadily be exerted on the side walls of the well hole. If it becomes too much it will blow out the side of the tube and create a new path around the mud.

They gotta have "the feel" of whats going on down there as they slowly withdrawl/backoff the mudfeed line.

This is most likely why they give it a 50/50 shot at those depths.

[Saul Mine]

I've seen between 15K and 80K PSI

My question is this. What does the drilling industry have in production today that will push mud/concrete into this hole to overcome 70K PSI?



70,000 lbs x sq.in of pipe in mud.

Easy!
Whats the weight of mud and cement in a good size tube thats 5000 ft tall?
The weight alone when the tube is filled is tremendous. Wouldnt take much of a pump to do the job.
Stack dry cement bags of concrete 5000 ft and see if you can lift it.


I don't know about their mud, but water pressure is 1/2 psi per foot. At 5,000 feet it would be 2,500 psi.

[Glass]

By BEN NUCKOLS and GREG BLUESTEIN

ROBERT, La. (AP) - If oil stops flowing to the surface in the Gulf of Mexico, BP officials will know that their latest effort to plug a blown-out undersea well off the Louisiana coast was successful.



link....... (http://apnews.excite.com/article/20100527/D9FV1OB82.html)

If they can stop the oil from being visible on the surface then they have solved their problem. Wooo ooo good news!

[Defender]

Here's an interesting video on how the top-kill is supposed to work but it doesn't give enough info to make me happy.

He also talks about what comes after top-kill if it doesn't work. If I recall, he doesn't mention the junk-shot. My guess is that the pressure build-up might just pop/rip the BOP off of the well head.

http://bp.concerts.com/gom/kentwells_update24052010.htm

[Spectrism]

There is a difference between weight and pressure. Pressure accounts for the cross sectional area.

If the sea water provides a head (as in overhead) pressure of 2500 psi, figure the weight of the mud with its higher density is 2.5 times that. So the tube of mud without pumps is 6250psi.

My estimation of the well head pressure is 10,000-12,000 psi. So they would need to provide a pump pressure of about 4000-6000 psi.

Since there is mud coming out of the holes, this is a good sign that they have enough pressure to get into the BOP. Otherwise, the oil would be pushing the mud back up the pipe and the color of the leaks would be darker.

It is a start. The question is this- are they actually getting mud down the well pipe? If so, then the pressure at the well head will gradually decrease. If they fill the 18000 foot pipe with mud, and then pump in cement, it is possible that they could achieve a seal deep in the pipe. If the mud is not going down the pipe, they are doomed.

If we see ANY oil coming out of the leaks, they failed.