What’s The Problem?

by Bryan

Gulf Gusher flag You fabricate a large funnel and attach it to pipe larger than is used for the well casing. Everything from stainless steel because it’s going into salt water and carrying petroleum. You bolt the thing together so when the emergency is over it can be used for other blow outs. You add flotation collars to reduce the weight, control the descent with support cables, and use flexible joints near the top to prevent it from becoming a large pry bar and snap off the well pipe. At the top you have a ship to keep position, and other ships to store the oil when it comes up the pipe. Oil is lighter than water, so it will come up the pipe without pumps. The pipe is open, so pressure isn’t a problem.

You have an explosives guy construct a shaped-charge collar to cut the well pipe above the well where it is undamaged, and attach cables to the damaged sections to haul them out of the way. This reduces the number of leaks to one, and that one will be shooting the oil up the funnel pipe to be collected.

While the system is being stabilized you have a saddle clamp union constructed by a machine shop that will be used to add an new length of pipe and shut off valve. Tools will need to be modified or built to install the saddle clamp because they will have to tighten bolts under pressures of a ton per square inch, but that is definitely doable. There are all kinds of people in the area who can build this stuff, and the military can supply the cutting collar.

The Remotely Operated Vehicles are already on station, so what’s the delay?

6 comments

1 Jim Bales { 05.02.10 at 9:03 pm }: Bryan,

So I saw this piece on MSNBC

BP, which operates the well, was more optimistic, telling NBC’s “TODAY” show on Sunday that a temporary fix — domes that will be placed over the leaks until they can be cut off — was nearly ready to be deployed. The domes will have piping to send the spewing crude up to tankers for collection.

“We’re forecasting (it) to be complete in eight to ten days,” Doug Suttles, BP’s chief for exploration and production, said of the first dome.

I’m pleased they are going to try this, for (as you note) it is the most promising near-term fix.

However, having spent seven years with a group at MIT building Autonomous Underwater Vehicles (AUVs) for operation down to 6,000-meter depths (~20,000 feet), I will note that doing any work at a significant depth (and 5,000 feet is significant) is intrinsically difficult and time consuming.

I don’t envy anyone trying to plan and execute the process of dropping a “dome” over the point of the leak (even given the fact that they will be working from a vessel with full dynamic positioning capabilities), much less trying to do this with ROVs in the area. (It would be a nightmare to get ROV tethers snarled with the lines for the dome, or the dammaged riser, or any other debris from the platform that may be nearby.)

I wish them all the luck in the world. They need it. And they had better hurry as fast as they can, if this article from the Mobile Press-register site is correct:

BP Plc executive Doug Suttles said Thursday the company was worried about “erosion” of the pipe at the wellhead. A new leak in that piping was discovered Wednesday, suggesting the erosion is worsening.

Sand is an integral part of the formations that hold oil under the Gulf. That sand, carried in the oil as it shoots through the piping, is blamed for the ongoing erosion described by BP.

“The pipe could disintegrate. You’ve got sand getting into the pipe, its eroding the pipe all the time, like a sandblaster,” said Ron Gouget, a former oil spill response coordinator for the National Oceanic and Atmospheric Administration.

Best,
Jim
2 Bryan { 05.02.10 at 9:47 pm }: I know what it’s like down to 30 feet with SCUBA gear, and I had a neighbor who was a diver on oil platforms, who said he spent more time in decompression than working. In just 30 feet with the magical tool that is the human hand, tool use is extremely difficult, and it only gets worse.

With a ton per square inch of pressure at 5000 feet anything with a sealed void in it will probably be crushed, so tools have to be created with that in mind. Fortunately we have NASA down here, and their expertise in devising tools for extreme conditions.

Thinking about it, I would guess that the simple tools are the best, with the inclined plane/screw and lever providing the force multiplier necessary. Finding a convenient way to anchor the ROVs so force can be applied in a fluid environment is an obvious challenge.

The shaped charge doesn’t produce the neatest of results, but it does work well under water, and is used regularly in salvage operations. Obviously they should already be clearing debris.

If it wasn’t for the sand and debris in the oil, you could use plastic, because there is no pressure differential to collapse the pipe. I still don’t understand why there wasn’t and over-sized mechanical gate valve at the well head. That’s how you attach a feed to a water main, by drilling through the valve, then withdrawing the bit and closing the valve until the external plumbing is done.

I wish I could do something beyond laying some barrier at the mouth of bayou, in case it enters the bay at the pass to the gulf. The word is they will put barriers across all of the bridges in an attempt to keep the oil out if the main barrier along the Gulf shore doesn’t work.
3 Jim Bales { 05.02.10 at 10:16 pm }: Bryan,

I believe the blowout preventer was supposed to handle this eventuality, but failed. (If I understand it correctly, a ram-type blowout preventer is essentially the gate valve you describe.) Perhaps this is the valve that they could not close?

Other nations require an automatic shut off valve, but we don’t, so BP didn’t have one. Perhaps it, too, would have failed. Then again, perhaps not.

Best,
Jim
4 Bryan { 05.02.10 at 11:28 pm }: The blowout preventers on the surface can be manually operated if the automatic system fails, but the deep water versions apparently don’t have that option. People are wondering if the gas tanks on the unit were properly pressurized for the depth.

There is a picture of the actual device used and a discussion of what went wrong that includes several oil industry engineers.

One of them guesses that even if the valve worked and sheared the pipe, the valves that actually shut off the flow won’t work because the upper section of pipe is still in the unit, rather than being pulled out. There is apparently a sequence of events that have to occur in order for the valve to actually work as specified.
5 Moi;) { 05.03.10 at 10:21 am }: Brian, don’t ya know, they have to bid out for all of these things? @@ I am sure that is what the holdup is. This is a country full of rocket frigging scientists….

Government makes me crazy. There should be something in place where emergency situations can bypass this, if there isn’t already.

I didn’t realize it was 5000 ft deep there – I was thinking, why don’t they put something FLAT and HEAVY (like granite or something similar) down there on top of the thing. Of course, I am not a rocket frigging scientist. But it doesn’t seem like it should THAT big of a problem to stop. This length of time is just NOT acceptable. I hope it’s not coming your way any time soon.
.-= last blog ..RIP Dr. Greenspan =-.
6 Bryan { 05.03.10 at 2:26 pm }: Moi, it is already South of me and we are just waiting.

The water pressure at that depth is over a ton per square inch, but the oil is pushing out, so it is going to require a massive weight to stop it, which is why I’m focusing on a funnel system to deal with the oil, and then a shut off on the pipe. The walls of the pipe are being sandblasted by the grit in the oil, so the longer this goes on, the greater likelihood of more leaks. The longer it takes, the greater the possibility that the pipe will burst if a valve is installed and closed.