By Marco Evers
It all began like a good disaster film. The gas alarm sounded shortly after noon and the emergency evacuation started just moments later on the Elgin drilling platform in the North Sea. Only a small contingent stayed behind, laboring to plug the leak. Having failed to do so after hours of trying, they turned off all the machinery and electricity and fled the platform too.
When the last helicopter lifted off, it left the drilling rig alone on a swelling cloud of highly flammable gas from the deep.
For almost an entire week, though, something else stirred on the eerily deserted platform. Flickering way up at the tip of the 150-meter (490-foot) stack was an open gas flare, which the crew had failed to extinguish last Sunday as it hastily abandoned the platform.
On Saturday, Total, the French energy company that owns the stricken platform, announced to the relief of many that the gas flare had burned itself out. Up to that point, as a company spokesman thankfully noted, the wind had been blowing the gas vapors away from the platform and would hopefully continue to do so.
If it hadn't, and the cloud of gas had come into contact with the flame, there could have been a massive explosion threatening to trigger an environmental catastrophe. In this case, however, no Hollywood-type hero was needed to avert the disaster in the end.
Nevertheless, Total has still lost complete control over the platform. In response, it quickly brought experts from around the world together in Aberdeen, Scotland, which proudly calls itself the "oil capital of Europe." With the aid of special aircraft, diving robots and computer models, they have been trying to figure out exactly what is happening both on and under the platform, which is located 240 kilometers (150 miles) off Scotland's eastern coastline.
Initial findings have provided cause for optimism, at least in the short term. But in the long run, they have sparked worries about how well the many planned North Sea drilling projects that involve deeply buried reservoirs can really be controlled.
The Good News
The good news is that the name Elgin most likely won't become seared into our collective memory in the same way that Deepwater Horizon is. After the BP-owned platform exploded in the Gulf of Mexico in April 2010, killing 11, more crude oil gushed into the sea over the next three months than had ever been released by any man-made disaster. But in the case of Elgin, the mere fact that the volatile natural gas only causes moderate levels of damage in even the worst cases leaves little reason to fear such a devastating "blowout."
Another comforting factor is that the methane surrounding the drilling platform apparently doesn't originate from what is actually the major reservoir 5,300 meters (17,400 feet) below the sea floor but, rather, from what is hopefully a smaller deposit at a depth of roughly 4,000 meters.
Likewise, the gas is not gushing out as freely as the oil did in the Gulf of Mexico disaster. Instead it appears that it is streaming its way to the surface via cavities in the multi-walled annulus, or pipe casing on the well, and that it is first leaking out once it reaches the Elgin platform itself.
That's good news, says Frederic Hauge, president of the Norwegian environmental group Bellona. "If the gas is only coming up through the well, that enables more solutions." That detail, he says, makes him feel "a little more optimistic." Speaking before the flare had extinguished itself, Hauge also stated that, were it not for the danger of explosion, it would also be enough to simply wait for all of the remaining gas to escape.
Total is also hoping that this will be enough. But if the volatile stream of gas surging out of the deep does not abate this week, the company plans to start drilling two relief wells to divert the gas. It estimates that the operation will take six months to complete and cost at least $3 billion (2.2 billion).
The Bad News
Still, for the moment, the open question is how gas even gets into an annulus, or pipe casing, for a well that actually runs much deeper and was already capped roughly a year ago. And that's where the bad news comes in.
The 11-year-old platform is different from most in the North Sea, tapping into what is known as a "high pressure/high temperature" (HP/HT) gas field. Total's drilling operation at Elgin is technically one of the most challenging in the world. The company is pushing the limits in terms of both the materials and expertise available in the early 21st century.
In 2001, when Total launched its operations in the Elgin field, the company became a pioneer. Nobody had ever drilled into such a vast reservoir, pressurized at roughly 1,100 bar, or almost 40 times the pressure in a full tank of propane gas. What's more, the liquid gas shoots out at a temperature of more than 200 degrees Celsius (392 degrees Fahrenheit) and is packed with corrosive hydrogen sulfide. As the company's website boasts, it was an "extreme drilling operation (that) set a record in the North Sea."
Every drill head, casing and piece of metal used in this kind of extreme drilling operation must be able to withstand forces that are hardly controllable. "There remains a general concern that not all HP/HT hazards have been identified yet," cautioned a report by the British health and safety regulator in 2005.
Seven years later, this appraisal still holds true. The BP oil field in the Gulf of Mexico was also one of the HP/HT variety, a factor that significantly contributed to the catastrophe's severity. Indeed, as the senior Total engineer Jean-Louis Bergerot wrote in the Journal of Petroleum Technology last October, drilling HP/HT exploration wells "remains a challenge, despite years of experience."
These advanced drilling projects get increasingly dangerous as time goes on, Bergerot writes, specifically addressing the Elgin field. The more the deposit is depleted and the gas pressure decreases, the greater the chances that the whole geological substratum will become brittle. Small but regular earthquakes deep down wreak havoc on the drilling equipment. As a result, Bergerot writes, the entire steel casing of the drill pipe can be deformed "by compaction or by tectonic movements along faults or other bedding planes," which might also ultimately result in its being "sheared off completely."
This is what has most likely happened with the Elgin platform: After the steel protective casing broke down deep beneath the surface, the compressed gas surged into the punctured pipe and began shooting upward. However, this accident was not without warning. Weeks earlier, engineers working on the Elgin had noted troubling pressure fluctuations in the capped line. They tried to stop it with so-called drilling mud -- but the gas was quicker.
Despite the massive expenses and technical challenges involved in HP/HT drilling projects, multinationals like Total are currently investing several billion euros in them. The reason for this is simple. As Hauge, the Norwegian environmental activist, puts it: "The easily recoverable reservoirs in the North Sea will soon be empty."
Indeed, there are not many deposits left that can be exploited using conventional means. The combined output of all British drilling platforms now lies at only half of what it was in 1999. In the meantime, the fleet of several hundred British platforms is becoming superannuated, with accidents as well as minor oil and gas spills more common.
Forty-four of these monsters even date back to the 1970s, and workers on them are forced to labor just as hard against rust as they do for oil. Jake Molloy, an organizer for the union representing oil workers, has said "ageing infrastructure, a lack of maintenance and installation integrity" are among the union's primary concerns and noted that oil-rig crews often work under life-threatening conditions.
The major oil companies are increasingly handing over their ancient equipment to smaller firms, which then go after every last drop of oil and liquid gas they can. Hauge, the Norwegian environmentalist, finds this worrisome. "Small companies have less capacity to manage big accidents, both financially and technologically," he says.
Bigger Rewards, Bigger Risks
Nevertheless, the big oil companies -- such as BP, Chevron, Total and Shell -- are in no way pulling completely out of the North Sea, as some had feared they would as recently as a few years ago. Instead, they are venturing into ever deeper waters and rock formations, into colder regions and increasingly precarious extraction areas. Doing so has meant a steep rise in both costs and technical complexity. But given today's oil prices, it's now worth it for companies to go after deposits that would have once been considered uneconomical.
Though it has only just recovered from the "Deepwater Horizon" shock, BP recently obtained permission from Britain's Department of Energy and Climate Change to drill for oil in waters more than 1,200 meters deep northwest of the Shetland Islands, off Scotland's northeastern coast. Despite obvious dangers, the region's rich deposits make it appealing.
BP has acknowledged that, in the worst-case scenario, a blowout here could threaten the far northern regions with an oil spill that would far exceed even the 2010 Gulf of Mexico disaster in size. It calculates that twice as much oil would gush up and cause several times as much environmental damage. But the company also adds that this is, of course, "extremely unlikely."
That is also precisely what engineers thought when they were drilling for oil over 21 years ago off the Scottish coast under contract from the energy giant Mobil, which would later become today's ExxonMobil. Their huge drill was penetrating at a depth of some 500 meters when it inadvertently punctured a methane bubble under high pressure.
In an instant, the sea surrounding the drilling platform was transformed into something resembling a whirlpool. As has happened with the Elgin, the entire crew made it safely off the platform. But methane, which as a greenhouse gas is extremely harmful to the climate, continues to bubble up out of the sea floor even today. And nobody can stop it.
Translated from the German by Josh Ward
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