Why not collect all the oil at the bottom?

[docellen]

There was an interview this morning by John Roberts on CNN, talking to Owen Kratz, the CEO of Helix Energy Solutions, the company which has just provided a ship capable of processing 60,000 barrels per day. There are some problems with having the right hardware to make the connection, and that will limit the additional capacity to 25,000 bpd, but the total capacity of the two ships will then be 50,000 bpd, and that should allow them to finally stop the flow at the bottom. According to Mr. Kratz, BP is also planning on adding additional capacity in case the flow is more than 50,000 bpd.

What I take from this is that the problem is *not* with the cap or the riser, but the capacity to process the oil at the surface. That would explain all the bogus information we have been hearing about the problems with shutting off the vents, making a better seal, etc.

My question now is - Why not get all the oil to the surface, even if they can't process it? Surely burning it will be better than letting it discharge at such great depths.

 

[shawnpeter]

double e's...

 

[docellen]

I guess I should clarify my question, which depends on earlier discussion.

The reasons given so far for allowing the leak to continue are:
1) Can't shut off the vents on the cap, because that will allow hydrates to form and plug the riser.
2) Can't shut off the vents on the cap, because it will raise the pressure in the well too much, risking a possible blowout of the well casings.

These reasons don't make sense because:
1) The water is kept out of the cap by a small positive pressure inside the cap. Closing the vents will raise that pressure, and make it even more difficult for water to get in.
2) The pressure just below the well head is 4400 psia. That drops to 2500 psia at the cap. Adding a few tens of psi at the cap will have no significant effect on the pressure below the wellhead.

There must be a reason. I just have no clue as to what it might be.

 

[DrillerNic]

docellen- I don't think this is much of a secret..... BP stated that as the Discover Enterpise is a drill ship rather than a production vessel, it's processing capacity is limited, it's storage space is limited (and it has no offtake facility) and so the amount collected by the current cap has been limited by the capacity of the flare on the Discoverer Enterprise.

I remeber posting something along these lines on one of these boards a few days ago.

Now that a proper FPSO and subsea manifold has been mobilised and installed, hopefully, all of the fluid flowing from the well can be captured.

 

[docellen]

I'm still mystified as to what special hardware is required to connect as many flares as are needed. Even if there is not a connector in stock somewhere, they could make one in a lot less time than the weeks we have been watching the oil gushing out.

It may not be secret what is going on, but it is certainly being kept quiet. Reporters don't know what questions to ask, and BP seems happy to let the misinformation go uncorrected.

 

[docellen]

OK, forget about the special hardware, just let it burn coming out of the top of the riser. That can't be any worse than if the rig didn't sink, and was still burning.

 

[DrillerNic]

The problem might not be so much the flare capacity as the radiant heat coming off the flare... even with a water curtain, I know that 3000bopd going down a 50ft flare boom is pretty hot on the deck next to the flare (and makes a hell of a noise), so I dread to think what 20,000bopd + would be like....

 

[docellen]

Yes, it would be an impressive display.

OK, here is my theory. There is no technical problem with closing the vents and stopping the leak at the bottom. There is some legal or political factor at work. Someone has made a calculation that the additional few weeks of oil dumped into the Gulf will cost them less than the alternative we are discussing.

If this is true, then the Coast Guard should intervene, and tell BP to do what is right for the environment. Maybe the Coast Guard is not the right agency. They don't seem to have an engineer who can recognize BS, like what we have seen so far.

 

[shawnpeter]

The problem with closing the "vents" is that it is a mile under the ocean, and that is quite a challenge. Throw a ten speed in the bottom of your pool, let it sit for a year, and finally go down there and try to ride it around on the bottom of the pool, shift gears, break, etc.

Sounds hard? Times that by 1,000,000 and go swim down to the bottom of the gulf and shut off a bop. You have to kill the well first. It's not like your kitchen sink where we just need to get someone down there to turn a valve off.

 

[docellen]

Shawn, we are talking about the vents on the top of the LMRP cap, not the BOP valves. See Lower Marine Riser Package (LMRP) Top Hat Design at

http://energy.gov/open/oilspilldata.htm.

These valves are designed to be operated by an ROV, and they have been doing that every day to adjust the flow up the riser.

To re-phrase the question that is the subject of this thread: Why don't they turn those vent valves all the way OFF and push *all* the oil up the riser?

 

[shawnpeter]

land based oilfield only... sorry. never been interested in offshore since i can't swim well

 

[docellen]

No problem. I know even less about oil drilling than you. What's interesting about this situation is that it doesn't take any more than general engineering knowledge to understand the basics and draw some simple conclusions. There is always the possibility that we non-experts might be missing something, so that is why I ask questions in these forums.

 

[docellen]

I just heard an explanation that I find hard to believe. According to Congressman Ed Markey, and oil-industry expert Bob Cavnar, speaking on the MSNBC Keith Olbermann show, BP is trying to avoid fines based on the amount of oil released, and bringing it all up would allow a precise measurement of the flow rate.

This just doesn't make sense to me - tens of billions in extra damages that are real, and that BP will pay for, just to generate some uncertainty in the amount of a possible fine, an uncertainty that could go either way?

I guess the response to BS from BP is BS from the anti-BP crowd.

 

[waross]

In the first days after the blowout all the oil was coming up the riser and burning. It created so much heat that the platform sank. They are collecting and/or burning all the oil that can be safely collected and/or burned. You want to bring up all the oil, and possibly sink another vessel. Don't forget the gas component and the possibility of large volumes of gas being released. As i see the issue, bp believed their own BS as to the flow rate and didn't mobilize enough surface capacity to handle the total flow. I expect that when they get more surface capacity on site we will see a change. Possibly all or almost all of the oil collected being collected or some other story.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[docellen]

They are collecting supposedly 40% of the flow now, and the gas is going to one large flare. Surely, they could have three flares if that were necessary. Even if they had to just dump it on an old barge, and let the barge burn, surely that would be less costly than all the cleanup on the coast.

 

[JRMacGregor]

Oil/gas processing at the surface is limited by the technology on the vessels.

To separate oil, gas and water at the surfacs is what PRODUCTION RIGS do. They process large quantities of hydrocarbon every day and have the safety systems to permit this. A DRILLING rig like Deepwater Horizon is not designed to do that. They are designed to allow small quantities of hydrocarbon onboard occasionally.

The production plant capacity is designated in barrels of oil per day, total liquids per day and total gas per day. The hardware to handle this varies from 1500 tonnes for small simple production to 30,000 tonnes for big, gassy production.

Since the US has only recently accepted FPSOs as a proper way of oil and gas production, there is limited capacity of mobile floating production available to help here.

That includes;
1) DISCOVERER ENTERPRISE - a drillship, with a tiny 18,000 bopd well test spread and limited probably more by gas than oil
2) tiny well test vessel TOISA PISCES
3) small capacity on Helix Q4000
4) reasonable capacity on the Helix producing vessel (60,000 bopd) but she has no storage, so needs permanent connected tanker

Personally, I think big risks are being taken with handling this oil flow at Macondo with inadequate vessels and inadequate protection against it. These would not normally be accepted.

There has alreqdy been a fire on DISCOVERER ENTERPRISE when lighning ignited a gas vent.

Lets hope there are no major accidents in all this. So many vessels close together.

 

[docellen]

JR, I understand there are limits to how much can be properly processed. What I don't understand is why they can't just burn whatever cannot be processed. Surely that is better than releasing it at 5000 feet depth.

 

[docellen]

I think I have an explanation. I just saw the latest news. BP has removed the old cap, and is about to install LMRP #10, a marvelous feat of engineering, with new and thoroughly-tested rams. This will be bolted to the old BOP, so it should take the full pressure. They are not saying it will shut the well down, but I'll bet that is what they are going to do.

This will be a huge PR triumph, maybe enough to offset the bad PR they have been getting. Had they just installed LMRP #4, with only a rubber seal around the old flange, it would collect all the oil, but not shut off the flow up the riser. The PR would have been - Why didn't you do this weeks ago? Now, they can say - it really took all this time to design and build LMRP #10.

It all comes down to a calculation of PR impact vs cost of the additional pollution.