Apparently... Some Of Us Never Learn... The Lake Peigneur Disaster (Louisiana 1980)

[WillyT]

So I'm watching Hardball and Chris has a guy from Shell (former Employee, CEO, or something), and the Shell guy says one of the reasons you would want to be careful using explosives (especially nukes) to try and seal the BP well, was because they drilled through a salt dome under the seafloor, and you wouldn't want to destablize it. Not knowing what a salt dome is, I go to Google... found this...



Lake Peigneur

Rig: Rig not known, owned by Wilson Brothers Corporation

Date: 20 November 1980

Location: Lake Peigneur, Louisiana

Operator: Texaco

<snip>

Summary

On the morning of Thursday, 20th November 1980, a Wilson Brothers Corp. rig was drilling for Texaco in Lake Peigneur, Louisiana, which had an average water depth of 6 feet. Around 0430 hours Thursday morning, the drilling assembly became stuck around 1228 ft and could not be freed by jarring or working the pipe. By 0630, the drilling rig began to tilt so the crew abandoned the rig and headed for the shore due to fears that the rig was on unstable ground. Over the following hours, the crew and nearby residents watched in shock as the drilling rig collapsed and disappeared into the shallow lake.

The rig crew had been drilling a test well into deposits alongside a salt dome under Lake Peigneur. By some miscalculation, the assembly drilled into the third level of the nearby Diamond Crystal Salt Mine. The initial consequence was the stuck pipe, but fresh water from the lake soon began trickling into the salt mine. Over the course of the morning, the fresh lake water began dissolving the salt and enlarging the hole until water was literally flooding into the mine.

The mine itself consisted of a number of levels up to 1500 feet below the surface, with each tunnel around 100 feet wide and 80 feet high. Pillars of salt, which were left in place to support the ceiling of each level, were dissolved away by the fresh lake water causing the collapse of the salt above the mine. As the bottom of the lake fell away creating a vast sinkhole, a witness stated, "there was a huge noise like compressed air coming out of the mine. It was because the water was going into the mine faster than the air could get out. It created a geyser that went up 400 feet - spraying water and debris into the air." Fortunately, the men working in the mine managed to evacuate early with no loss of life, thanks in part to the early warnings of some of the mine employees.

The sinkhole grew so rapidly that a 50 foot waterfall formed where the Delcambre Canal reversed direction and flowed back into the newly formed crater. A large whirlpool formed in the lake, sucking down a second drilling rig, 11 barges and a tugboat. The tugboat at full throttle was unable to overcome the strong flow dragging it backwards down the canal into the sinkhole. After two days and an estimated 3.5 billion gallons of water draining in from the Gulf of Mexico, the lake refilled and stabilised. The lake that was once around 6 feet deep was now around 1300 feet deep, with the ecosystem radically altered by increased salt content.

Federal experts from the Mine Safety and Health Administration were not able to apportion blame due to confusion over whether Texaco was drilling in the wrong place or that the mine's maps were inaccurate. Of course, all evidence was lost.

<snip>

Link (w/Pix and Video): http://home.versatel.nl/the_sims/rig/lakepeigneur.htm

Apparently... salt domes aren't particularly stable when liquid is introduced.

:shrug:

[Angry Dragon]

1. If I understand this correctly

The oil, gas, and possibly sea water could be dissolving the sea floor.
If that is the case then we could end up with one big hole.

[WillyT]

2. That's What It's Starting To Sound Like...

Especially with the BOP starting to lean more than the Tower of Piza.

:shrug:

[MadMaddie]

3. geeze....

[localroger]

4. There's a lot more to it

I'm not sure whether Live Oak Gardens, the historic Joe Jefferson estate, is still open; it was closed at one point and I heard it had reopened. In the Jefferson mansion they had a model which was created for the trial when Texaco faced the class action. It had, we were told wryly, been carefully designed to obscure the fact that they had penetrated the mine. Look at that mode, which was like a three-dimensional pie cutout of the mine, salt dome, and lake area on the surface, and you could see the drill hole didn't get anywhere the mine. Or at least the people who spent tens of thousands of dollars to have that model built wanted you to think that.

Lyle Bayless, who owned the gardens at the time of the Great Peigneur Whirlpool, watched helplessly as his new home on the lakefront was sucked into the lake and smashed; when we visited only the chimney remained, about fifty feet offshore from the new beach. The Joseph Jefferson mansion's foundation cracked into four pieces and had to be laboriously reassembled, all of which was done on a "cost is no object" basis as part of the settlement. As a result the Jefferson mansion was one of the best restored mansions of its age in all of Louisiana.

Bayless was an avid breeder of camellias. He had just completed a $2 million greenhouse which, like his new home, was smashed to bits as the land gave way beneath it. Naturally they had the film of news footage from the disaster, and standing in that then restored place watching what the chaos had done to it gave one a rather horrible feeling for the instability of the ground beneath one's feet.

[Mimosa]

5. Lake Peigneur Whirlpool

Being from Louisianam you probably know that all of South Louisiana was built on silt deposited by the Mississippi river. And that since the river has been 'harnessed' no silt is being deposited, so that's why the ground has been sinking for a century. :(