Ausgabe 26/2010

Like Being Blind on the Moon The Trouble with Deepwater Oil Exploration

Last week the beleagured oil industry fought back: Despite the flow of crude oil still spoiling the Gulf of Mexico, they successfully protested a US moratorium on deepwater drilling. They're determined to continue exploration on oil's final frontier -- using high-tech methods they have not mastered.


By and

Last Tuesday managers working in the international oil industry gathered for a gala dinner in London. Beforehand, though, they made a serious appeal to the US President. "Obviously we are concerned", says Steven Newman, head of Transocean -- the company whose drilling platform, the Deepwater Horizon, exploded in the Gulf of Mexico on April 20 this year.

Newman was not talking about the approximately nine million liters of crude oil flowing into the sea every day at the site of the accident. The chief executive officer of Transocean meant the moratorium that President Barack Obama had declared, which put a halt to deepwater drilling for six months.

Newman's colleagues agreed that it was a dangerous overreaction by the US administration. "The world does need the oil and the energy that is going to have to come from deepwater production going forward," BP's chief of staff Steve Westwell said. The moratorium will "be a step back for energy security," agreed Jay Pryor, vice president for corporate business development at California-based oil company Chevron.

No Shame, Ten Weeks After 'Deepwater Horizon'

Ten weeks after the drilling platform disaster and oil continues to flow into the Gulf of Mexico. So far, according to some estimates, ten times more oil has leaked into the water than spilled from the Exxon Valdez when it struck an Alaskan reef in 1989. So there is an element of impudence to the oil companies' berating politicians for the deepwater drilling moratorium.

But a fundamental reconsideration of our dependence on oil? Never. Large energy companies rely on humankind's greed for oil. In fact the governor of Mississippi, Hayley Barbour, a Republican, considers the moratorium a far worse thing than the oil leak itself. It is "not only bad for the region, it's bad for America," Barbour said. A New Orleans federal judge then lifted the ban. Better supervision and a few new safety rules, and oil exploration in the deepest waters can carry on -- that is how many Americans see this situation.

Over the past few weeks, others outside the US have shown that they share that view. On Wednesday Norway tendered licenses for oil exploration in 94 sectors of the North Sea. A day before, the shareholders of the Brazilian oil company Petrobras approved a stock offer worth up to €68 billion ($83.2 billion), the largest in history. Petrobras will use this gigantic influx of capital to explore deepwater oil fields off the shore of Rio de Janeiro. And off the coast of the Newfoundland, in Canada, Chevron has started work on a borehole at depths of 2,600 meters below the ocean surface -- over 1,000 meters deeper than the hole that the ill-fated Deepwater Horizon had drilled.

Most New Oil Sources Found in Deeper Water

Deepwater oil exploration will go on, because this is where most of the new sources of oil are being found. "The easy stuff, that you have access to, is already spoken for," explains London-based oil industry analyst Chris Skrebowski. "All that's left is the frontiers, which are necessarily more technically challenging."

Most of those frontiers lie in deep water. Only 3 percent of worldwide oil production originated from the deep sea in 2002; that fraction will rise to 10 percent in two years. The oil industry sees its future in three areas of the Atlantic: The Gulf of Mexico and the Brazilian and West African coasts make up a "golden triangle" of deepwater oil exploration with enormous, if still undeveloped, potential.

"Everyone thought exploring the deep sea would be as exciting as a trip into outer space," says Klaus Wallmann, head of the Marine Geosystems Research Unit at the Leibniz Institute of Marine Sciences, in the German city of Kiel. The reality, though, was different. Compared to conditions in the deep sea, flying to the moon looked easy.

Risk 'Multiplies Exponentially'

A few thousand meters down and the pressure is so great that "it's like parking a small car on a thumb nail," says Peter Linke, also of the Leibnitz Institute, who works on projects as deep as 6000 meters. At those depths, water pressure simply crushes machinery.

With the Deepwater Horizon platform, the hydraulics of the so-called blowout preventer, a giant safety valve on the ocean floor, apparently failed. Linke isn't surprised. Breakdowns with hydraulics are "an everyday occurrence" at those depths, he says. The water is also very cold, around 2 degrees Celsius (35.6 degrees Fahrenheit). At such temperatures the gas that is almost always present in oil fields forms hydrates, as well as ice crystals, and these can block pipes.

"The risk multiplies exponentially in deep water," Linke notes. He's an experienced deep-sea explorer who has salvaged damaged machinery from the ocean floor, where, because of the extreme forces acting on all the materials, "it looks like a giant tied a knot in it."

Drill engineers do not just need to deal with the effects of such depth, they also need to drill through layers of rock. The distance between the drilling platform to the source of the oil is like the distance between a plane in flight to the earth, explains Matthias Reich, a professor of deep sea-drilling technology at the Freiburg Mining Academy in the German state of Saxony. Thick steel pipe can bend like florist's wire.

Drilling Blind

At the contact point between earth and machinery, a drill made out of diamond or tungsten carbide bites into the rock. In the "golden triangle," the oil often lies under layers of salt, kilometers deep. These blanket the oil reserves, and they also muffle the seismic-pulse technology which engineers normally use to find oil. "Below the salt you will be blind," says Inge Manfred Carlsen, petroleum research director at the SINTEF Group, an independent research organization based in Norway.

Drilling blind is dangerous, because the engineers are forced to calculate the pressure in the chambers where the oil will be found. The coveted resource sits in porous rock reservoirs, similar to sponges. The first time the drill hits one of these deposits the pressure of the oil flowing upwards must be equal to the pressure of the oil underneath. It is like walking a tight rope -- to get the desired result specialists inject the holes with drilling mud, made of water, clay, barite and other ingredients. Should the engineers not add enough pressure, the oil can spurt out violently, causing a much-dreaded blow out.

Another potential deepwater drilling catastrophe: The ground underwater is still relatively young, and therefore contains many gas bubbles. Should the drill bit hit one of these bubbles, the whole thing could go up -- this is what is called a "gas kick."


© DER SPIEGEL 26/2010
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