On Sunday 20 November it's the 36th anniversary of the 1980 Lake Peigneur drilling disaster. The shallow lake — almost just a puddle at about 3 m deep — disappeared completely when the Texaco wellbore penetrated the Diamond Crystal Salt Company mine at a depth of about 350 m.
Location, location, location
It's thought that the rig, operated by Wilson Brothers Ltd, was in the wrong place. It seems a calculation error or misunderstanding resulted in the incorrect coordinates being used for the well site. (I'd love to know if anyone knows more about this as the Wikipedia page and the video below offer slightly different versions of this story, one suggesting a CRS error, the other a triangulation error.)
The entire lake sits on top of the Jefferson Island salt dome, but the steep sides of the salt dome, and a bit of bad luck, meant that a few metres were enough to spoil everyone's day. If you have 10 minutes, it's worth watching this video...
Apparently the accident happened at about 0430, and the crew abandoned the subsiding rig before breakfast. The lake was gone by dinner time. Here's how John Warren, a geologist and proprietor of Saltworks, describes the emptying in his book Evaporites (Springer 2006, and repeated on his awesome blog, Salty Matters):
The other source that seems reliable is Oil Rig Disasters, a nice little collection of data about various accidents. It ends with this:
If the bit about the location is true, it may be one of the best stories of the perils of data management errors. If anyone (at Chevron?!) can find out more about it, please share!