January 15, 2011

Oil Exploration: The Trend Toward Ever Deeper Waters

A fascinating piece in the New York Times magazine by Benjamin Wallace-Welles relates the innately hazardous, hugely expensive, and very risky game of oil exploration:
Oil reserves have been declining for a decade, and it is an article of faith among petroleum geologists that the easy oil — easier to find, less complicated to drill — has all been extracted and that the explorers are now into the hard oil. When the Deepwater Horizon rig, drilling an exploratory well deep into rock through a mile of water and three miles into the ocean floor off the Louisiana coast, struck a highly pressurized pocket of oil and gas, causing an explosion, it was in some ways a consequence of this iterative, competitive game, each generation of discoveries pushing further into the unknown.

A few years ago, the industry norm was to drill at depths of 15,000 or 20,000 feet. Now the frontier is 35,000 feet, where engineers find higher temperatures and pressures. “The scarcity of new reserves has been driving companies into plays that have previously been seen as extremely high risk and high cost,” said Brian Maxted, the chief executive officer of Kosmos Energy, a deepwater-exploration company in Dallas. “The trend recently has been in going toward ever-deeper waters and ever-more challenging environments.” . . .
The possibility of a boom commands particular attention now, because the industry’s faith in a limitless future has begun to diminish. The International Energy Agency — which had until recently been optimistic about oil — concluded last fall that the world has very likely already passed its peak oil production.

“The deepwater was one of the last big exploration plays on the planet,” says Gerald Kepes, a partner and head of upstream and gas at PFC Energy, a consulting firm. “We’re now looking at the second half of the global deepwater play. You can see the end of it, maybe 25 years from now.”

This is not the only way of looking at the data; other analysts, recalling the technological advances and the unforeseen finds that have marked exploration’s history, are more positive. But that optimism also depends, in some part, on whether the mass of subsalt off Angola’s coast approaches the size of that off Brazil’s. And the first clues to answer that question will be revealed, in part, by what Cobalt finds at Gold Dust. . . .

Last February, Richard Sears, a geophysicist who was vice president for exploration and deepwater technical evaluation at Shell and is now senior science adviser to the National Oil Spill Commission, appeared at the TED ideas conference in Long Beach, Calif., to give a talk about the future of energy. Sears says that there are between 30 and 50 years left before a broad gap opens between worldwide oil supply and demand. It is hard, he says, to describe a situation that is either a lot more optimistic or pessimistic than that. At TED, Sears held up a pincushion of the globe, with red thumbtacks stuck in. Each thumbtack represented an oil basin. “This is it,” he said. “This is the oil in the world. Geologists have a pretty good idea of where it is.”

These last 650 billion barrels are the hardest. “There are still some areas — Iran or Iraq or Russia — where you can literally fly over in a plane and see big structures lying right out there, and they are undrilled,” Farnsworth told me. But much of that territory has been reserved for national oil companies, and so in the last decade 43 percent of the industry’s new reserves have come from the deep water. “It’s gotten harder all along. And the structures, generally, have gotten smaller.”

But as the map has compressed, and the possibility of finding new basins has dwindled, explorers have returned their attention to the regions where vast deposits of oil have already been found, in the belief that new technologies might allow them to drill deeper. These aspirations drove new finds earlier this decade in offshore Brazil, and the continued work in the Gulf of Mexico. They also compelled the industry toward Angola, where Western oil companies have sustained production onshore and in shallow water for decades, even through a long civil war. . . .

One geologist told me he would show me the tools he used to find oil when all else failed; he then produced a divining rod and a crystal ball. It was a joke, but one made frequently enough that he had a divining rod and a crystal ball lying around. The essential mystery of exploration — that it is impossible to know precisely what exists below until you begin to drill — and the push into more complicated depths and environments mean that an engineer often has only a dim read on what he is drilling into: unexpected pressures, slopes and formations. The enduring oddity of the Deepwater Horizon spill was that it took place in a prospect where major problems seemed unlikely — comparatively shallow, very well mapped, mature.

"It’s frustrating to me,” Farnsworth told me. “It’s never going to change, but the general public always thinks, I should be able to get a gallon of gasoline, and it should be damn cheap, and whether I choose to drive a 10-mile-per-gallon car or a 40-mile-per-gallon car should have no impact on that price. We know how hard it is to explore for oil, and we know how hard it is to get it out of the deep water. And there’s been this incredible disconnect, which might have been lessened by the spill, between what people think it takes to get gasoline in their car and what we do." . . .

Drilling engineers suffer from the tyrannies of darkness and depth, and these conditions limit what they can do when these systems do fail. “The real problem with going so deep is not that the possibility of failure is greater,” Bea said. “But if something does fail, the consequences are so much greater. In shallow water, you can physically contain a spill. But at this kind of depth that becomes dramatically more difficult.”

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