Oil Spill Insights from a Retired Manager

[lanichol]

Oil Spill Insights from a Retired Manager of an Offshore Underwater Service Company

Interesting article with details not mentioned in any published articles to date.

Talking to field people here are a few other details.
1. The BOP is fail closed. If something happens or lines come loose from the BOP, the BOP closes shearing the casing and the drill pipe.

2. A fishing boat watched the well flowed for nearly 30 minutes before catching fire. Plenty of time to activate the BOP.

3. The last casing cemented has a bottom cement shoe that has a floating ball. After pumping cement is finished, the ball floats up into a seat, preventing the cement from entering the casing (or O&G). Normally they run a latch down plug on the end of the drill pipe in addition to the cement shoe.

4. At 8,000 ft they were in the process of setting a wet plug which is running cement through open ended drill pipe and dump into the casing. Later this cement would be drilled out. The rig starting flushing the 14 lb mud with sea water. The hydrostatic difference between 14 lbs mud and sea water at 8,000 ft is about 2,000 psi.

[All_In]

Very revealing, thanks Larry for the rest of the real story...

[j bird]

Larry, so who's going to be the ultimate scapegoat, or maybe I should ask, perpetrator?
I sure hope for the environments sake, and the cost to the people who make a living from the gulf, this disastrous leak is capped fairly soon.

[lanichol]

Look at some of the references to the Senate hearings yesterday and post by Rockman. If you read through you find the initial leak was around 1,000 bbls day. My concern the first day was sand from the formation was cutting away at the cement and the BOP.

BP has some of the best people in the world working on this problem. We will know more details when they can get control and back in the borehole. It may not be until the other rigs drills into the bottom of the problem well.

Honey combing the cement from natural gas, or having a microannulus does happen. The regs do require 3 boundaries of protection when cementing to prevent such an incident. I have a gut feeling the plug gave, casing collapsed or spit at the bottom of the hole due to pressure differential when they displaced the mud for the final cement plug. Methane hydrate is the new variable that keeps creating problems.

Jay,

This type work is like dealing with volcanoes, tsunamis, tornadoes, earth quakes. The earth throw curves that nobody has seen before. I have heard pressures of 30,000 psi which sounds impossible to me. Engineers spend alot of time calculating, but they are plugging industry standard numbers into the equations. It is a cascade of failures. The big failure is when all engines on the rig were lost and it began to drift, then they were in trouble. Read Rockman's link above if you are technically interested.

[All_In]

Methane hydrate that could explain how it started the fire?

[lanichol]

No doubt methane hydrate is part of the culprit, and maybe in combination with the warm cement as it cured.

I don't understand why they were not injecting methanol in the first coffer dam. I see they got permission to use methanol in the 2nd.

Very good post.

[Arnie Madsen]

I only have an opinion from a long distance and a few weeks ago I was very happy to hear that off shore exploratory (American) drilling was going to be allowed again.

To now have this well blow is just plain unfortunate timing .

For the sake of the industry I hope they can get it capped and still retain good public opinion. We need the oil but not the accidents.

[Resasi]

Larry thank you. This has been the first time I have been able to see something that contained cold clear information and not frantic hand-wringing.

The public/Government want the convenience of oil and all too often simply blind to the difficulties, complexities and dangers of it's extraction.

Every effort is made by the big oil companies to prevent this sort of thing for many reasons, but life has shown us that events do not always go as planned.

'Forest Gump' summed it up.

[lanichol]

Thanks guys. This should give an idea of the integration of data and communication on such a rig.

Last two hours

The link above is the data presentation people associated with operations see at their PCs on the rig, the war room, engineers and geologist in the main office and contractors like Halliburton. Each person can set alarms for the various curves. A geologist may want to know if the rig is suddenly drilling fast or gas increases which is an indication of a pay zone. The Toolpushers watches everything. There is a PC next to his bed with a custom presentation and alarms he has set. Depending on the job, a person can add comments. There is a chat session for nearly everyone including onshore.

The data resides on a server which is owned by the company that provides the service. Example of services. Login Example Everything is documented on the Tower Sheets; safety meetings, crew hours, stop & start times of events, mud conditions, cost.

The crews are very structured. You either follow orders and chain of command or find another job. The Toolpushers and Drilling Superintendent are usually crusty old guys with years of experience, that when they give orders people move. In my opinion the crew thought they could handle the problem, assumed the equipment would performed (BOP), and 11 died.

[lanichol]

Top Kill.

The posts give a good perspective.

Regardless of new regs as a result of the blowout. BOPs will be redesigned and rigs modified for this situation. Deep water drilling from a floating platform is fairly new.


http://www.theoildrum.com/node/6513 [Best description of Process]
http://www.theoildrum.com/node/6515
http://www.theoildrum.com/node/6511


A few good comments.
***
I won't try to guess what the videos are indicating. No idea if their pressure sensors can tell much about the kill process. But I would think there will be an obvious answer when they stop pumping mud: if the've put enough head on the bottom hole to stop the flow then we should little or no return coming out of the leaks. Since they aren't circulating through mud tanks as in a normal kill op then there's no info there. The big question remains for me (and probably BP also): the mud is pumping in but where exactly is it going? Down the drill pipe, the producing csg, the prod csg annullus, out another failed cement shoe? Or any combination there of.
***
Thanks, but I am trying to work out why they still have some pressure in the well - it may be that the blockages down the well are slowing the mud drive down to TD (the bottom of the well). The partial blockage would have to be significantly above TD if they are unable to get it to balance out yet. Though maybe it is just a case of holding the pressure until the mud works past the block and all the way down to the bottom. Of course it is also assuming that the problem is located down at the bottom, and not in a higher layer than we are assuming.
***
Good job everybody who has been sweating in the 'war room'. Either Forbes or WSJ reported that there are almost 500 people working 12 hr. shifts...70ish companies. All the major deepwater operators included - and we already know that the service co's are all represented.

It's too bad that that kind of stuff doesn't get more widely publicized....might give everybody out there an idea of how tough a nut this really is, and how much is actually being done on it.

[GrantR]

Looks like they finally plugged it http://www.latimes.com/news/nationwo...,5782115.story

[Trez]

Originally Posted by grantr

looks like they finally plugged it http://www.latimes.com/news/nationwo...,5782115.story

Trust, but verify.............

[All_In]

Originally Posted by cracker

Trust, but verify.............

Yaw Mon!!!

[lanichol]

BP Feed

They are still pumping mud against pressure. Gas can still be in the mud or until the mud overbalances the gas it can break loose again. It is a engineers balancing test. Once the mud is holding down the gas, they will start pumping materials (rubber ect) to plug the leak in the BOP.

The leak in the BOP is actually very small. They evidently have pressure feed back. If they can block the leak in the BOP, the pressure will rise and they will be pumping against the hole. Then they can pump cement which will go down hole into the down hole leak. If they pump too hard, the heavy cement could break down the formation. The goal is to fill the hole from top to bottom with cement.

[lanichol]

BP halted pumping operations this afternoon. Can't get ahead to bring the well static

Interesting link on what is happening.