BP PLC and Anadarko Petroleum Corp. announced today that they have settled claims against each other over last year's Deepwater Horizon oil spill in the Gulf of Mexico.

Anadarko, which had a 25 percent interest in the doomed Macondo well, has agreed to pay BP $4 billion and give up its stake in the well.

Both companies have agreed to drop allegations against each other over their conduct in relation to the April 20, 2010, explosion and resulting spill of an estimated 4.9 million barrels of oil.

Under other terms of the complicated agreement, BP will indemnify Anadarko against various claims, including those brought under the Oil Pollution Act while Anadarko retains the possibility of recovering 12.5 percent of anything BP wins in damages against other companies involved in the incident.

The $4 billion will go toward BP's $20 billion compensation fund set up in the aftermath of the spill.

The deal does not cover civil or criminal fines and penalties or punitive damages. Civil penalties under the Clean Water Act alone could be as high as $21 billion if the spill is found to have been caused by negligence.

Today's agreement is the third BP has reached with its Macondo partners. In May, it reached a similar arrangement with Mitsui & Co. Ltd., which had a 10 percent stake in the well (Greenwire, May 20).

And in June, BP reached a deal with Weatherford International Ltd., which provided drilling equipment (Greenwire, June 21).

The oil giant has yet to resolve similar claims against other Macondo partners and contractors, including Transocean Ltd., which owned the rig, and Halliburton Co., the cement contractor on the well.

It is an issue BP pointedly noted in its press release today.

"There is clear progress, with parties stepping forward to meet their obligations and help fund the economic and environmental restoration of the Gulf," BP CEO Bob Dudley said in the statement. "It's time for the contractors, including Transocean and Halliburton to do the same."

Anadarko CEO Jim Hackett said in a statement that the agreement was "the right action for our stakeholders, as it removes considerable uncertainty regarding future liabilities and associated risks."

The company noted in its statement that BP had initially wanted $6.1 billion.

The various settlements BP has reached should help simplify somewhat the complex liability questions that are before a federal judge in the Eastern District of Louisiana. A trial is scheduled for February.