Energy secretary says ‘top kill’ should have been tried earlier
Engineers working to plug BP’s massive oil gusher in the Gulf of Mexico should have acted sooner to attempt the so-called top kill method to overpower and seal the well to boost its chances for success, Energy Secretary Steven Chu said in a recent interview.
His team of government scientists has struggled since soon after the Deepwater Horizon accident to persuade BP to increase its estimates of how much oil was pouring out of the well — to up to 60,000 barrels a day now, from about 19,000 barrels previously — and to deploy more skimming ships and oil booms accordingly.
Last month, Chu flew to a BP command center in Houston to oversee diagnostics for the top-kill effort, which engineers scuttled after several days of pumping drilling fluid and bits of debris into the blown-out well in hopes of stopping the flow of oil.
He returned this month to help execute a plan to cut off the leaking riser pipe and cover the well with a small dome, which is currently siphoning about 24,000 barrels of oil a day to a holding ship. Chu said his team’s diagnostics convinced BP that cutting the riser would boost the flow of oil by about 5%, instead of 10% to 20%, as the company had feared.
In a wide-ranging interview, Chu, a Nobel-winning physicist, explained why the top kill should have come sooner, why information is so important in the leak response and why deep-water drilling will endure long after this accident.
What has changed about the effort in Houston, and what has improved?
The two most useful things that the science team [has] done is diagnosing the condition of the [blowout preventer on the well] … and also realizing that the initial flows were not what was being estimated.... They had to be higher. And then pushing very aggressively to convince BP that [it shouldn’t] plan for 19,000 barrels a day [leaking]. You’ve got to plan for much, much more....
There’s great resistance … because the more ships you have on the surface, there’s higher risk.... So BP has to be convinced that in order to … risk the lives of additional people, you have to be convinced that [the flow is greater].
Looking back over the last two months, is there any engineering that should have been done better?
That’s hard to say. In hindsight, we’re now actively looking at all the designs whenever they’re asking to be manufactured, whether it’s a new cap or “top hat” [containment system], this or that. This has started in the last couple weeks....
Look, we’re not oil people. We’re mostly physicists, a mechanical engineer or two. But on the other hand, there’s a bunch of smart people here, and what we’ve found is that having a bunch of smart people with a different set of eyes actually see things that other people don’t see and actually help improve things.
What about the top kill?
It was known to be a long shot. It was not known how much flow there was.... The only thing that could have been done differently is, it could have been tried earlier. And the reason it could have been tried earlier — and why you’d want to do it earlier rather than later — is that, as I’ve gotten to understand oil wells, at the very beginning of the leak, the oil and the gas rush out.
You’ve just poked a hole into the reservoir. Think of this as shale and sandy type of stuff. As the oil and gas start to come out and you go up the well … it decreases the viscous flow immediately around the well. So in the first days of the flow, one very typically sees less flow, and it continues to build until you’ve eroded away that and built good-flowing channels — turning the reservoir into a pipe.
Are there other things you’re learning today that should be applied to drilling? Should the practice resume in deep water?
Drilling will resume in deep water. That’s where the oil is … people all around the world are going farther offshore and farther into deeper waters. So we have to develop methods to recover hydrocarbons, and do it in a much safer way.... It kind of creeps up on you, but this tragedy is a wakeup call.