British energy company BP plans to begin the operation intended to permanently seal its damaged oil well in the Gulf of Mexico within a few hours. Crews will move forward cautiously, however, checking pressures and watching for leaks as they pump mud into the well bore.
Speaking to reporters here in Houston, retired U.S. Coast Guard Admiral Thad Allen, head of the U.S. government's effort to deal with the Gulf oil spill, said a minor hydraulic leak that was detected Monday had now been fixed.
He said the first step in the operation to permanently kill the well is an "injectivity test" in which mud is pumped down pipes from ships on the surface into the cap over the wellhead. Eventually, the mud will force oil back into the reservoir thousands of meters below the seabed. Then BP engineers will pump in cement to permanently seal the pipes from above.
The danger in carrying out this so-called "static kill" is that pressure inside the well could become too great and cause more leaks. The operation is being watched with cameras attached to underwater robots called ROVs. Allen says engineers will closely monitor the well as each barrel of mud goes down the pipe.
"The most important thing in this test and in the static kill itself will be measuring the volume that is going in and the pressure that it produces," said Allen. "We have three different sites where we are going to be taking pressure readings and those readings will be transferred every 12 to 15 seconds by wireless modem to the ROVs that are down there, and they will be transmitted up to the control room here in Houston and they will be monitored continuously."
If all goes well, the damaged well could be sealed by Wednesday or Thursday. At that point, U.S. government representatives and BP engineers will concentrate on the plan to kill the well from the bottom, through a relief well that has been drilled within a few meters of the sub-seabed well bore. That operation could take a few weeks to complete.
The government's latest estimate of oil released into the Gulf of Mexico by the Macondo site leak is close to five million barrels. Of that, containment systems captured only about 800,000 barrels. The estimate makes this disaster the worst spill of oil in history, much bigger than Mexico's Ixtoc blow out in 1979 in the Bay of Campeche that lasted nine months and poured about three million barrels of crude into Gulf waters.
The Macondo site spill began after an explosion and fire on the BP-leased Deepwater Horizon drilling rig on April 20 that killed 11 workers. Oil from the leak has spread to marshes and beaches in Louisiana, Mississippi, Alabama and Florida. BP has agreed to set aside $20 billion in a fund to help coastal areas affected by the spill and could face fines from the U.S. government ranging from $4.5 billion to as much as $14 billion.