With pressure inside the Macondo well continuing a slow climb Tuesday, the federal government authorized another 24-hour monitoring period of the capped well to search for signs of well damage beneath the sea floor.
Meanwhile, BP and government officials are weighing whether to try to stop the flow of oil inside the Gulf of Mexico well by pumping it with mud before the relief well is complete next month. The company could seek approval for its “static kill” this week, BP Vice President Kent Wells said.
Pressure inside the well had climbed to 6,834 pounds per square inch, or psi, Tuesday afternoon, Wells said. Pressure was rising one to two psi per hour. The blown-out well has been undergoing an integrity test since it was capped Thursday to determine whether it is intact or whether there are ruptures somewhere beneath the sea floor through which oil can escape.
“Minor leaks” have been discovered both on the capping stack and blowout preventer used to shut in the well, as well as almost two miles away at another production site, Allen said.
“We don’t consider them consequential,” Allen said.
The government last week asked for increased surveillance at the spill site to detect any signs of oil escaping. Allen said he is satisfied with BP’s response so far and comfortable with extending the well integrity test.
“We continue to be pleased with the progress of response to anomalies,” Allen said.
Scientists studying the well’s pressure are still trying to determine whether the lower-than-anticipated pressure readings are the result of leaks somewhere in the wellbore or a depletion of the well.
“At this point we do not have anomalies that say we don’t have integrity,” Wells said. “As each day goes along it gives us confidence.”
At the same time, however, pressure has not risen enough to suggest with absolute certainty that the well is completely intact, or that it does have integrity.
“We have not reached a consensus on how we would determine our total assurance that there was integrity in the well,” Allen said. “That revolves around the competing theories for depletion and leakage.”
In the meantime, BP is researching a method of stopping oil flow by pumping mud into the top of the well. Unlike in the failed “top kill” attempt mud would be pumped a low pressure and rates of speed. Higher levels would be unnecessary because the well is now capped, meaning the mud would likely stay inside the well. Just like in top kill, the idea would be for the heavy mud to slowly overcome the oil flow.
“No decisions have been made yet on proceeding forward with that,” Wells said. “But we are continuing with preparation and planning.”
The procedure would need Allen’s approval.
It could be 24 to 48 hours before a decision is made on whether to attempt the static kill, Wells said.
The procedure would not be started until well casing had been installed inside the relief well. BP crews are putting the casing in place today and Thursday, Wells said. The company wants the casing in place to minimize the risk of damage to the relief well when mud begins flowing.
Also before the static kill could begin, the Q4000 platform, which had been used to pump mud during the failed “top kill” and was retrofitted to suck oil, would have to be changed back into a mud pumper, Wells said.
Even if the static kill is conducted, the relief well would still be used to plug the blown-out well with mud and cement. A relief well is considered the ultimate solution for stopping the oil flow.
BP plans to intercept the Macondo well with a relief well at the end of this month. Wells said Tuesday that the relief well is “exactly where we want it.”
Plugging the well mud and cement could take a number of days or a few weeks, depending on where oil is flowing inside the well.
The static kill could speed up that process by stanching the flow before the relief well is completed, Wells said.
“Working in tandem, these can have an ability to have the well completely killed in less time and it could also reduce the execution risk of it,” Wells said. “It’s clearly worth the analysis of it.”