Today's temporary loss of a line that has been collecting millions of gallons of leaking oil in the Gulf of Mexico hints at the shape of gusher glitches to come.
This time, the line and a containment cap were taken off the wellhead because of a pressure hiccup, reportedly due to an accident involving a remotely operated vehicle. Hours after the cap was detached, the BP oil company put it back over the leak. But BP might well have to repeat the exercise as hurricane season continues.
For more than two weeks, the containment cap has served as the most successful collection point for the oil that has been leaking from BP's broken well since April 20's fatal oil-rig explosion and sinking. The cap system has saved more than 200,000 barrels (8.4 million gallons) of oil so far, at a rate of up to 16,000 barrels (672,000 gallons) a day. Another 10,000 barrels (420,000 gallons) are being captured and burned off every day by a different collection system hooked up to the well's broken blowout preventer.
The source of the problem
So when the cap containment system had to be detached today, that made quite a dent in the oil-sucking operation. Coast Guard Adm. Thad Allen, the point man for the federal oil-spill response, explained during today's news briefing that the cap was removed after workers "noticed there was some kind of a gas rising through the vent that carries the warm water down that prohibits hydrates from forming." Hydrate crystals, which form from water and methane at a certain pressure and temperature, are what foiled the very first efforts to contain the oil flow - so BP wanted to make sure that didn't happen again.
Allen said the glitch was apparently caused by "a remotely operated vehicle that ... bumped into one of those vents that allows the excess oil to come out." When the vent was closed, the pressure built up, causing gas to go the wrong way. As of this afternoon, BP double-checked the system to make sure it was safe to reattach the cap and return to capturing oil.
Was this a remotely operated screw-up? Actually, the way Allen looks at it, this sort of thing is to be expected as the operation proceeds. He pointed out that there's been only one other ROV misstep, made during the early stages of the response to the gulf disaster. "I think the fact that we've had two bumps that have had some kind of a consequence associated with them in the 60-plus days [of the] response is a pretty good record. It's never going to be risk-free out there, and we need to watch it very closely," he told journalists.
The moderators of the Oil Drum discussion forum speculate that an ROV may not have caused the bump at all, but that it was merely a precipitation plug-up that will happen periodically during the oil-capture operation. If that's the case, bringing up the cap and clearing out the lines will have to become part of the maintenance schedule.
More complications ahead
The pace of operations is likely to get even more intense in a couple of weeks, when as many as four oil-capturing operations are to be conducted simultaneously. That will raise the likelihood of ROVs getting in each other's way, and it will take expert choreography to avoid more frequent bumps or plug-ups.
Another complication has to do with hurricane season. So far, the weather has been mostly favorable for the oil-spill response. There's a weather disturbance brewing in the Caribbean, however, and the National Hurricane Center is predicting a 30 percent chance that the disturbance will turn into a tropical cyclone within 48 hours. If a serious storm threatens the oil-spill area, the response team will need about six or seven days to pack up and evacuate.
During the evacuation, every drop of oil - an amount currently estimated at 35,000 to 60,000 barrels (1.5 million to 2.5 million gallons) a day - would be going directly into the Gulf. It would be like today's capless situation, only worse. "The principle is the same. We would detach and move out," BP spokesman Mark Salt acknowledged.
So as things stand now, a serious storm that looks as if it might blow through the Gulf would kill the recovery operation for as much as 10 days at a time. The spill-response team is working on a Plan B, however. Allen mentioned an ambitious scheme that would involve running an underwater pipeline from the broken well to another oil rig or reservoir. "I believe BP is in discussion with other industry producers that have rigs in the area that might be useful for that," he said. "I don't think they have concluded those [talks] yet."
Allen said such an arrangement could keep the oil under control even during a storm. "This would be one way," he told reporters. "If you are actually connected to another drill site, you would not have to rely on service vessels."
It's one more option in a long list of strategies aimed at stopping up the leak. But is this option ready to put into action? Not yet. BP's Salt said he couldn't discuss the pipeline project, other than to note that "we've always said we're assessing multiple options." So what else does the spill-response team have up its sleeve? What other strategies should they be working on? Feel free to pass along your suggestions as comments below.
More links for oil watchers:
- Interactive: All about the physics of oil spills
- Disaster in the Gulf: msnbc.com's special report
- The Oil Drum: Discussions about energy and our future
- Upstream Online: News about the oil and gas industry