Science of oil rigs: surviving Gulf storms
As more drilling moves into the path of hurricanes, giant rigs get stronger moorings and GPS devices.
Just a day before hurricane Emily pounded into the Mexican coastline, BP's recovery team finished righting Thunder Horse, the world's newest and biggest oil and gas platform, located 150 miles southeast of New Orleans in the Gulf of Mexico.
It had partially collapsed during hurricane Dennis - just four months after US Interior Secretary Gale Norton declared in a dedication ceremony that it was an "anchor of energy stability," designed to "withstand the worst that winds and waves will throw against it."
The tipping of Thunder Horse, weighing more than 50,000 tons and capable of drilling in waters up to 6,000 feet deep, points up just how vulnerable the industry is to powerful storms - even with the most advanced technology.
But so far this season, offshore oil production has continued relatively unaffected.
That's in part because the storms have not been as damaging as in past years. But it also has much to do with lessons learned from last year's hurricane Ivan, which tore through the Gulf damaging more than 30 drilling platforms and shutting down 83 percent of oil production at its peak.
That storm is unlikely to be repeated, experts say, but it usefully revealed the strengths and weaknesses of the growing US offshore industry, currently accounting for a quarter of US energy production.
And since that September storm, perhaps the biggest to wreak havoc on infrastructure in the Gulf, oil companies have been working overtime to make sure their structures can survive even the most severe storm.
It's an especially important issue since the Gulf is in a cycle of higher storm activity that began a decade ago and could continue for years, according to the National Oceanic and Atmospheric Administration.
The most recent hurricane to threaten the Gulf oil industry was Emily. Before landfall, more than 15,000 offshore workers on 112 US oil rigs and platforms were evacuated.