What a "top kill" is.

[yella_dawg]

There seems to be a lot of confusion about the process involved in this "top kill" process.


The blowout preventer has various lines attached to allow the well to be worked in the event that the blowout preventer activates and seals the wellhead. In a blowout, the BOP squeezes down on the drill pipe (extremely heavy-wall tubing tipped by the drill bit). Should this fail, the BOP has a ram capable of cutting through the steel alloy drill pipe, sealing the well like a monstrous hardware store gate valve. There is no conclusive evidence as to why this final failsafe failed, but some believe that the cutoff ram closed on a joint (drill pipe commonly runs 31 feet long, with massive threaded ends), which is significantly stronger and effectively impossible to cut. Whatever the case, best estimate is that there are approximately 90 joints of drill pipe still in the well (~2800 feet). The drill pipe runs through drill casing, which in this case is approximately one half inch larger in inside diameter than the large joints in the drill pipe in outside diameter. This "annulus" means a 1/4 inch gap around the drill pipe joint.

The top kill requires that the operators pump high viscosity drilling mud (primarily cat litter mixed with water to the viscosity, in this case, of peanut butter) through the service lines into the casing. The flow rate must overcome the outflow of oil through the disable BOB sufficiently to begin flowing down into the drill casing. Then, while gushing out through through the BOP, the flow must also overcome the downhole pressure so that mud can be forced through 90 narrow cracks between the drill pipe joints and the drill casing. Sufficient mud has to fill the casing such that the weight of the mud column overcomes the formation pressure which may exceed 100,000 psi. It was hoped that by tossing trash into the mud (junk shot), the leaky blowout preventer could be plugged sufficiently to allow mud to be forced down hole. In short, the kill requires pumping mud into the BOP faster than it could squirt out of the top to such an extreme that mud flows not only out the top, but out the bottom, into the well, against extreme pressure. Through a couple of three inch lines. Then through narrow gaps between drill pipe and drill casing. Ninety of them.

The problem is that if you just add more pumps and more power, eventually, you will explode the BOP or pump it off the surface pipe, which at the moment is the only thing holding the oil back.


I've seen something like this done with gangs of turbine-powered monster pumps on dry land. That was indescribable. The heat and sound was overwhelming. The ground quivered with the forces involved. In that case, the BOP held. This kill is an order of magnitude more difficult.

BP's claim of a 60-70% probability of success was propaganda or opium dreams.

[TransitJohn]

1. Thanks, +1

Trying to explain anything about drilling operations here on DU has gotten me vilified for weeks, good luck. :hi:

[yella_dawg]

2. Oh well...

You pays your money, you takes your chances. I just got tired of all the misleading metaphors and confusion. It's too hot and muggy to play in the garden today. :-)

[Richardo]

3. I love it when the experts weigh in.

thanks and rec. :patriot:

[bobmorr1]

4. cat litter

Going to start sending my used cat litter to BP to use in this top kill procedure. The post states that the mud is primarily cat litter. The used cat litter will just add bulk. I think we should all send our used litter to BP!

[obxhead]

6. I second the idea!!! Needs to go viral.

:applause: :rofl: :rofl: :rofl:

[obxhead]

5. so more smoke and mirrors.

I have a feeling that in the end it is going to take months and months and more than the 2 relief wells currently being drilled to drop the pressure enough to stop this gigantic spill that was caused by shortcuts.

BP - Beyond Prevention.

[yella_dawg]

7. At the moment it's only one relief well.

The second has been cannibalized so they can use parts on the failed BOP.

Junkyard tech. I'm impressed.

[obxhead]

8. Damn.

Thanks for the update. :cry:

[slackmaster]

14. Wouldn't one relief well lower the pressure in the runaway well only by about 50%?

I mean, without intensive pumping operations to actively suck out oil and gas, if such a thing is even possible.

[Statistical]

16. Purpose of relief well ins't to relieve pressure.

Relief well will intersect with primary well and then inject drilling mud directly into bottom of primary well. Once that stops the flow, cement will be forced in and then more drilling mud to hold it in place. This "bottom kill" will effectively kill both the main well and relief well as they share the same "bottom".

Interesting thing about pressure is that a second well doesn't reduce pressure. Pressure exists everywhere in the system. The only thing that lowers pressure is removing sufficient amount of oil and that will take years.

[slackmaster]

17. Ah, I see what you mean

Interesting thing about pressure is that a second well doesn't reduce pressure. Pressure exists everywhere in the system. The only thing that lowers pressure is removing sufficient amount of oil and that will take years.

That makes sense. A productive oil reserve is vastly larger than any hole we can punch into it, therefore it behaves somewhat like a limitless reservoir.

Thanks.

[NNN0LHI]

9. Is the BOP gone? And is the hole where it once was getting much deeper?

http://www.bp.com/liveassets/bp_internet/globalbp/globalbp_uk_english/homepage/STAGING/local_assets/bp_homepage/html/rov_stream.html

You sound like you know what you are talking about so I thought I would ask.

Thanks in advance if you can tell.

Don

[yella_dawg]

10. Nah, they've moved the camera back to the riser pipe.

They're getting ready to cut the riser so they can super glue another BOP in place.

[Swamp Rat]

11. like a band aid over a 'caldera' of oil

[Cerridwen]

12. I have two questions I hope you can answer.

What would happen if lightning hits any of the surface oil?

What happens to the "cavern" from which the oil is gushing? Um, let me try to explain that. I'm from the Las Vegas valley in NV. We have underground aquifers. As the decades have gone by and we've drained the water from those aquifers, the valley is "sinking." The pressures and depths of the gusher are far different but I'm wondering what happens to the "space" left "empty" (does it stay empty?) as the oil gushes out.

I imagine I can google this some where but I'll be damned if I'd know a knowledgeable answer from a sci-fi manuscript. As you can tell, I don't even know the nomenclature for this.

If you can send me in the right direction I'd greatly appreciate it.

Thank you.

:hi:

[TransitJohn]

13. Water and petroleum don't exist in caverns.

Aquifers or petroleum reservoirs aren't caverns. The fluids exist in the pore spaces of rock. And yes, because of Newton's Second Law, the fluids are exerting outward pressure on the rock which is exerting an inward pressure on the fluid. When the fluid is tapped and withdrawn, subsidence occurs.

[Cerridwen]

15. Thank you.

My geology classes were few and are now lost in the mists of time; or the mists of my mind, as the case may be. :)