Once constricted by the crumpled riser pipe, the full flow of the runaway Macondo wellhead in the BP oil spill burst forth last week when BP sawed through the pipe left over from when the Deepwater Horizon rig exploded and eventually sank on April 20.
BP placed a "top cap" device with a rubberized seal on top of the pipe to siphon away the oil, a move that some marked as a long-awaited breakthrough in the six-week battle against geologic forces, tapped by man, that now threaten the ecology and livelihood of the US Gulf of Mexico.
But judging from recent images from the BP live feed "spill cam," the gusher is still gushing – and hard. And even if BP is capturing 14,800 barrels a day, as Coast Guard Adm. Thad Allen said it did yesterday, the increased flow at the wellhead itself could, some scientists say, mean the operation is a wash, or may even have worsened the ultimate flow as a result.
“That is the big unknown that we’re trying to hone in and get the exact numbers on,” Mr. Allen, President Obama's point man on the spill, told reporters Monday. “And we’ll make those numbers known as we get them. We’re not trying to low-ball it or high-ball it. It is what it is.”
The question of how much oil is leaking has been crucial from Day 1 of the crisis. Since BP is liable for every barrel spilled, its estimates have been viewed with skepticism and even ridicule. A NOAA flow-rate group eventually raised the original BP estimate of 5,000 barrels per day, placing it between 12,000 and 19,000 barrels a day. Others have said it's really more, perhaps as much as 30,000 barrels per day.
Considering the questions about earlier estimates and the increased flow from the cut riser pipe, at least one expert – Ira Leifer, a member of the government's Flow Rate Technical Group (FRTG) – believes the current flow could be greater than before. The group had estimated a 20 percent increase in the flow after the cut of the riser pipe.
“The well pipe clearly is fluxing way more than it did before,” Dr. Leifer, a researcher at the University of California, Santa Barbara, tells The New York Times. “By way more, I don’t mean 20 percent, I mean multiple factors.”
The flow rate is difficult to measure, but the new top cap device should make it easier, since the oil flowing onto surface tankers can be measured to the pint. But those tapping into the BP live feed can witness the massive geyser rising from around the top of the lower marine riser package to which BP attached the top-cap device.
Even at the current capture rate of 14,800 barrels, or 621,000 gallons, a day, the containment cap would represent BP’s greatest success so far.
At the higher end of government estimates, nearly 40 million gallons of oil have escaped, four times that of the Exxon Valdez. BP could incur fines of up to $4,800 per barrel of oil that's escaped. BP says it simply does not know the true extent of the leaking oil. "How much that is, we'd all love to know," Kent Wells, a BP executive, told reporters Monday. "It's really difficult to tell."
The company has an obligation to come up with a firm flow-rate number, says Rep. Edward Markey (D) of Massachusetts, a sharp critic of BP throughout the spill. "At this time, BP appears to know how much oil is being captured, which is encouraging," he wrote in a letter to BP Tuesday. "Yet BP still does not appear to know precisely how much oil is actually escaping, which is discouraging."
Estimating the size of the spill at the source instead of as it approaches the shore, Representative Markey says, "is critical, not only in terms of the efficacy of the temporary cap solution, but also in terms of the size and extent of the needed spill response and the ultimate effects on the environment."
BP has learned lessons from earlier attempts to capture the oil, and moved cautiously over the weekend in shutting several valves and manifolds to reduce the escaping oil, calibrating so as not to build up pressure that could blow the device off or allow water to enter the siphoned oil, which could lead to the kind of build up of methane crystals that thwarted an earlier attempt to put a larger cofferdam over the wellhead. There are also questions about the availability of enough processing capacity at the surface to hold the siphoned crude.
Concerns about the real effect of the top-cap procedure put into sharp relief the difficult work being done by the FRTG, which was convened to study the extent of the plume.
If some 14,000 barrels per day is being siphoned off the current geyser, it could throw that group's preliminary estimates of up to 19,000 barrels a day into question, as well. The committee expects to issue a new estimate later this week, but it wasn't clear Tuesday whether that estimate would include the post-top-cap situation.
The backdrop is that a subgroup of the FRTG has not been able to determine an upper range for the flow estimate.
The analysis done has used satellite maps and high-definition images of the spurting oil itself to estimate the rate of flow. Leifer, the flow-rate group member, says BP has been stonewalling attempts to get more accurate images of the plume to analyze. Allen said last week that all his requests to BP chief Tony Hayward have been honored quickly.
The lack of a "downhole" sensing device to accurately measure the flow has unduly complicated spill mathematics, says Elgie Holstein, a former Department of Energy chief of staff and currently an oil-spill expert at the Environmental Defense Fund in Washington.
"This is a bit like watching some sort of grainy crime video from a 7-Eleven robbery," he says. "People have been treating this as though it's some exotic science, but the problem is we have to engage in all these mathematical gymnastics when the basic monitoring devices aren't available to us."