03 May 2010

Subsea Oil Recovery System Information

BP is working to deploy a subsea oil recovery system over the largest leak source in the Transocean Deepwater Horizon Rig that it hopes will capture up to 85% of the oil rising from the sea floor following the sinking of Deepwater Horizon on 22 April. This will mark the first time such a system will be used at this water depth (5,000 feet / 1,524 m).

The system is designed to collect hydrocarbons from the well and pump them to a tanker at the surface, where they will be stored and shipped ashore. This effort is one of several BP is attempting to mitigate the leakage or the effects of the leakage at the source (including the application of underwater dispersants) prior to being able to shutting off the flow. _GCC

Efforts to shut off the oil leak in the Gulf of Mexico continue on several fronts: 1. Engineers would still like to engage the malfunctioning in-place blowout preventer (BOP). 2. A subsea recovery system is being constructed and will be lowered over the leak as described below 3. A relief well is being drilled which will allow control access to the original well. The relief well will take between 6 weeks and 3 months to complete. While these efforts are going on, the well is leaking between 5,000 and 25,000 barrels per day of light crude daily. Surface efforts to limit and mitigate the environmental impact of the surface slick are ongoing and intensive.

From the May 3 control center factsheet:
The Subsea Oil Recovery System is a large structure that can be placed over the largest leak source in the Transocean Deepwater Horizon Rig. The system is designed to collect hydrocarbons from the well and pump them to a tanker at the surface, where they will be stored and safely shipped ashore. Weather permitting, deployment of the system is planned within the next six to eight days.

How it works:

The system is made up of a 125-ton, 14’ x 24’ x 40’ structure that will be set on top of the largest leak source. This leak is located at the end of the riser, about 600 feet from the wellhead.

Equipment at the top of the system is connected to a 5,000 foot riser that will convey the hydrocarbons to the surface ship, the Deepwater Enterprise.

Once in place, oil will flow up into the containment system’s dome to the surface ship.

Once on the surface ship, the hydrocarbons will be processed and oil will be separated from water and gas. The oil will then be temporarily stored before being offloaded and shipped to a designated oil terminal onshore.

The Deepwater Enterprise is capable of processing 15,000 barrels of oil per day and storing 139,000 barrels.

A support barge will also be deployed with a capacity to store 137,000 barrels of oil.

This system could collect as much as 85% of oil rising from the seafloor.
How it was developed
This is the first time this system will be used at this water depth.

To develop the system, BP quickly located existing structures that had previously been used as coffer dams in shallow water recovery efforts after Hurricane Katrina.

After Katrina, these structures were lowered over damaged wellheads to allow divers to repair wellheads.

BP engineers have worked closely with the firm Wild Well Controls, Inc. to convert these structures for use in deep waters.

Be sure to check in to the Command Center Website for the latest information.

NOAA Deepwater Horizon Incident Response page updated

Unique insight into oil well drilling procedures involved from a mining instructor and researcher

An interesting historical look at an earlier Gulf oil spill, Ixtoc I

A short analysis of Ixtoc I and a quick summary of events and ongoing mitigation efforts

The Deepwater Horizon explosion, fire, and spill will be studied for many years. Deep water oil drilling is being pushed to the limits of technology, and much can be learned from this tragic incident.

Faux environmentalists within and without the US government, will opportunistically swarm over this tragedy in an attempt to shut down all offshore drilling. That would be a huge mistake, and precisely the wrong response. Instead, we must understand that we are working up the learning curve for safe operations at extreme depths and pressures -- both pressures from the sea mass and pressures involved in deposits of compressed hydrocarbon gases and liquids as they ascend from depth.

More advanced human civilisations need subsea oil, gas, and methane clathrate deposits as they are transitioning to safe nuclear and other viable clean and "renewable" energies. Do not write off undersea oil exploration and production.


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Anonymous Anonymous said...

You've probably seen this, but one of the commenters at the Ace of Spades site posted this link to a Science Daily article stating that lots of oil naturally seeps up from the floor of the Gulf.

Also, another commenter there link to this comic, which is appropriate when we are considering environmentalists.

Monday, 03 May, 2010  
Anonymous Anonymous said...

This operation might contain a bit of risk. It that 125-ton housing crushes the riser as it is positioned, then the rest of the riser is now bearing the full pressure. It would be acting as the shutoff valve, and it might not be designed for that kind of pressure, else why have the subsea BOP?

Ronduck: they had to go 18,000 feet below the ocean floor to reach this resevoir. I'm not sure it seeps too much. You can almost tell that something is different from the satellite photos. That and the fact that BP is pleading for help from anyone who can offer it. Just a couple of reality-based clues.

Monday, 03 May, 2010  
Blogger al fin said...

Apparently they will cut away the riser to provide a better target for the containment operation.

Upstream reports that BP is planning to stack another BOP on the bore.

They started the first relief well, and are moving another rig in for a second relief well.

And they are coming up with other ideas as well.

Monday, 03 May, 2010  
Anonymous Anonymous said...

If they are going to cut the riser then the BOP must be impeding flow, and that's a good thing. They must also be confident that it will remain impeded. I've read that a typical unimpeded flow rate from similar bores at depth are around 30,000 barrels a day, and can range up to 70,000.

The second BOP is a beautiful thing as long as the risk is small of causing unimpeded flow. The aggressive timetables are to be commended, and let's hope all the risks have been assessed.

Monday, 03 May, 2010  
Blogger al fin said...

Let's hope the flow doesn't go up to 70,000 bpd or more.

From the sound of it, the oil is light sweet crude of likely high quality.

At this point everything they do has potential drawbacks, or may simply not work.

I support offshore drilling, but I think taking a pause from new drilling at such depth -- until they get a good understanding of what went wrong and how to avoid it -- is a good idea.

I agree that there are no doubt a number of possible precautions that must seem quite cheap at this point -- not just the acoustic switches.

Monday, 03 May, 2010  
Blogger May said...

I heard something about several tankers sunk in the Straits of Hormuz and a large percentage of oil was recovered. I don't know how long ago that was but I remember it vaguely. I also heard Russia and Dubai offered help to clean the Gulf of Mexico/BP problem up, and Obama refused.

There must be separators existing - perhaps in ships that can mitigate this.

Friday, 04 June, 2010  

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