Why Capping Blown Oil Wells Is So Difficult

Last year's Deepwater Horizon oil spill dumped an estimated 9.8 million litres of oil A DAY into the Gulf of Mexico - you'd think someone would have gotten on that faster. Oh, they did? Fire on the Horizon explains what took so damn long.

Nature provides no shortage of elaborate, even bizarre mating rituals. The fierce head-butting of elk bulls in rut, the four hundred distinct mating chirps of the grasshopper, even the female praying mantis's habit of decapitating the male during copulation and ingesting his head - all are astonishing in their own right, but they pale in comparison to what happened above the Macondo well on February 9, 2010.

After the Marianas was towed away for repair on Thanksgiving Day, it took some tinkering and horse trading and a few more lost months before Transocean's drilling schedule could be rearranged and another company asset could be redirected to Block 252 in the Mississippi Canyon. That turned out to be Deepwater Horizon, which was the first available of the 22 Transocean ships or rigs capable of drilling in ultra-deep water. The dynamic positioning operator on the Horizon's bridge input the GPS coordinates of the Macondo wellhead, and the computer pointed the rig in the right direction and fired the thrusters. That part was simple. But after the Horizon reached its destination, things got considerably more complicated.

The Marianas had left Macondo a 1189m deep, steel-lined hole to nowhere. The well was less than a third completed and topped by a metal funnel that stuck up just above the ocean floor. The assemblage resembled a supersize version of one of those funnel and tube combinations used to pour gas from a 19-litre jug into the empty tank of a stranded car. In this case, the purpose of the funnel, otherwise known as the wellhead, was to receive the protruding 27-inch diameter male end of the 325-ton blowout preventer dangling from the end of a 1524m steel string attached to a vessel bobbing in the waves high above.

To conceive how difficult it is to drop the BOP stack's connector pipe into the well's hole, first imagine standing on the observation deck of the Empire State Building and attempting to lower a soda bottle at the end of a 366m long string into a garbage can on the footpath. It's extremely windy, and you're wearing roller skates. Now consider that, with the building encased in clouds, it's impossible to see the footpath, much less the garbage can.

Imagine an observer with a cell phone at the bottom giving directions as the bottle descended. Every motion made by the person on the observation deck would take time to translate down the long string, and the effect on the bottle of his movements interacting with the swirling winds would be virtually unpredictable.

But all of that would be easy compared with what the crew of the Horizon was attempting to accomplish. Instead of hundreds of metres of insubstantial air to contend with, they were dealing with 1524m of water exerting 1000kg of pressure on every square centimetre of surface area. An assistant with a mobile phone wearing even the most advanced scuba gear would be dead before he got a fifth of the way to the bottom. Even a nuclear submarine would be crushed like a grape about halfway down. And instead of simply unspooling a string, the Horizon's drilling crew would have to assemble, piece by piece, 23m segments of 50cm-diameter steel pipe weighing more than 14,000kg each, and feed them slowly through the centre of a moving rig.

Before any of that happened, they had to locate the wellhead. This wasn't as easy as motoring to the coordinates locked into their GPS system. The GPS coordinates referred to a point on the surface of the ocean and were all but useless in locating a precise point 1524m down. For any practical purpose, there was no "straight down" in the Gulf of Mexico. "Straight" was a theoretical concept rendered all but meaningless by the constantly swirling currents and the prodigious distance, just as there was no dropping a bottle on a string "straight down" from the Empire State Building.

But the Horizon could do a lot better than an assistant with a mobile phone.

From the book FIRE ON THE HORIZON by John Konrad and Tom Shroder. Copyright © 2011 by John Konrad and Tom Shroder. Reprinted courtesy of HarperCollins Publishers.

John Konrad is a veteran oil rig captain; a former employee of the Deepwater Horizon's owner, Transocean; and the founder of the world's leading maritime blog, gCaptain.com. A graduate of SUNY Maritime College, he lives in Morro Bay, California.

Tom Shroder was an editor and writer at The Washington Post from 1999 to 2009. Under his stewardship, The Washington Post Magazine won the Pulitzer Prize for feature writing in both 2008 and 2010. He is the author of the nonfiction bestseller Old Souls. He lives in Vienna, Virginia.

Fire on the Horizon is available from Amazon.com