Thad Allen, the retired U.S. Coast Guard admiral leading the federal response to the BP oil spill in the Gulf of Mexico, announced the Macondo well was intercepted during an effort to drill a relief well.
Allen said in a late Thursday statement that sensors at the bottom of the ocean verified that "BP engineers and the federal science team have concluded that the Development Driller III relief well has intersected the Macondo well."
BP scientists can now go ahead with an operation known as "bottom kill," in which mud and cement will be pumped into the well through the relief well to permanently seal it off.
The Macondo well failed in April, causing gas to erupt, ignite and sink the Deepwater Horizon oil platform off the coast of Louisiana. A process used to cement the well was blamed in part for the series of malfunctions that led to the explosion.
BP was able to place a containment system over the leaking well in July while engineers worked on relief well operations.
The gas explosion that killed 11 workers resulted in the worst accidental oil spill in the history of the industry.
Outgoing BP Chief Executive Officer Tony Hayward expressed his "deep regret" to British lawmakers during testimony before a climate-change panel Wednesday.