By Joel Achenbach
Washington Post Staff Writer
Tuesday, August 3, 2010; 3:44 PM
BP began pumping fluids into the blown-out Macondo well Tuesday afternoon in advance of a heavy dose of mud that could choke the well once and for all.
After a roughly 24-hour delay to deal with last-minute leaks in equipment both at the surface of the Gulf of Mexico and at the sea floor, BP engineers initiated a diagnostic procedure called an injectivity test to see if they could push oil in the well back into its source rock.
"Based on the results of the injectivity test, pumping of drilling mud for the static kill could commence later today," the company said in a statement.
Engineers had labored overnight to stop a leak in a valve on the new capping stack of BP's Macondo well to prevent oil from flowing once again into the gulf.
"We could have had hydrocarbons [flowing] into the environment had we not located it," said retired Coast Guard Adm. Thad Allen, the national incident commander for the gulf oil spill.
If all goes perfectly with the effort to choke the well with mud, the procedure could culminate in a dose of cement that would end any chance that Macondo could pollute the gulf further.
But there are no guarantees: On the 106th day of the crisis that began with an explosion on the Deepwater Horizon drilling rig, engineers and scientists still don't know the condition of the well below the gulf floor, or where, precisely, the hydrocarbons are flowing.
The oil and gas could be surging up the drill pipe. Or they could be coming up through the casing, a larger steel pipe that surrounds the drill pipe in much of the well. Or they could be rising through the annulus, the area between the casing and the rock wall of the well. The annulus was cemented before the blowout, but there have been questions about whether the cement job failed in some way and allowed the hydrocarbons to exploit that path into the gulf.
"There's enormous anticipation," Deputy Secretary of the Interior David J. Hayes said as he waited in a control room in Houston for the static kill procedure to begin. "Obviously we've been waiting here; there have been some small issues that have delayed the start of it."
In the control room, Hayes sat with Allen, Energy Secretary Steven Chu and top BP officials as data streamed in. There was tension in the air, contributing to a sense that Tuesday could be a big day in the 15-week battle against the nation's worst oil spill.
The first maneuver in the static kill, the injectivity test, gradually injects "base oil" and then drilling mud into the well via the choke line on the blowout preventer. Initially, the engineers will send in only about one barrel of mud per minute. Later, they will ramp that up to two barrels and then three, while carefully watching the pressure in the well.
If the pressure, currently close to 7,000 pounds per square inch, rises beyond 8,000 psi, the test will be terminated, said Allen, who is observing the static kill from the operations room at BP's headquarters in suburban Houston.
It's impossible to peer into the well to see where the mud flows. But engineers and scientists have placed charts on the wall that model the expected changes in pressure in the well, and the amount of mud necessary to cause those pressure changes, depending on where the hydrocarbons are flowing and where the mud is moving. So as the static kill progresses, officials will get a good idea of what they're dealing with in the depths of the well.
"We should have an indication within the first two or three hundred barrels injected what's going on," Allen said.
The ultimate goal is to cram so much mud into the well that the pressure begins to drop, eventually reaching zero. At that point, officials would have to decide whether to follow the mud with a plug of cement.
Allen continued to emphasize that a relief well, which is angling in on Macondo at its base, will be completed and is the ultimate answer for plugging the blown-out well. Even if cement is shot into the well from the top, the relief well will intercept Macondo and ensure that nothing is flowing upward from the reservoir, he said.
Staff writer Juliet Eilperin contributed to this report.