(Reuters) - BP Plc appeared to gain an edge in the battle over liability for the 2010 Gulf of Mexico spill on Friday, after Halliburton abandoned one of its arguments that tried to paint the British oil company as unconcerned about well safety.
Halliburton, which did the cementing work for BP's well, on Thursday pleaded guilty to destroying evidence of internal tests it conducted showing there was no difference between the effectiveness of putting six or 21 casing centralizers on the well.
Centralizers help stabilize the well bore during cementing and, prior to the settlement with the U.S. Department of Justice, Halliburton had sought in court proceedings to pin blame on BP for the blowout because of its decision to save "time and money" by using only six centralizers.
A payment of just $200,000 to the Department of Justice ends the DOJ's case against Halliburton. At the same time, the plea seems to hurt Halliburton as it seeks to settle its share of private claims over the disaster, currently estimated at $1.3 billion.
John Coffee of Columbia Law School said it would now be less plausible for Halliburton to argue in any litigation between the two companies that it had warned BP about something for which the evidence was destroyed.
"This is a zero sum game between BP and Halliburton, particularly when it undercuts (Halliburton's) argument they had an honest theory of why the cement wouldn't hold," Coffee said. "If it's an honest theory, why would you destroy all the evidence?"
Nonetheless, Halliburton shares rose nearly 4 percent on Friday, since its plea announcement late on Thursday coincided with it unveiling a $3.3 billion share buyback.
Scott Gruber, analyst at Bernstein Research, said the company appeared more confident its oil spill liability was manageable in making a repurchase offer that would represent 8 percent of its outstanding shares at current prices.
James West at Barclays believed Halliburton could even issue new debt to accelerate its buyback program. "Though we think a resolution of the Macondo liability is likely required before (Halliburton) makes any significant changes to its capital structure," he added in a note to investors.
Halliburton, BP and rig owner Transocean Ltd are all defendants in a federal civil trial that began in February to apportion blame and set damages for Macondo. The trial, under Judge Carl Barbier, is scheduled to resume on Sept 30.
According to Margaret Thomas at Louisiana State University's law school, Barbier could admit Halliburton's criminal admission in the case and respond in number of ways, including monetary sanctions. She said he could even go so far as to strike Halliburton's pleadings.
"That's incredibly rare and it's a last resort that happens in very few cases, but he is empowered to do it," she said.
The disaster caused 11 deaths and led to the largest U.S. offshore oil spill. BP and Transocean previously entered guilty pleas and agreed to pay respective criminal fines of $1.26 billion and $400 million. Both declined to comment on the Halliburton plea.
The civil penalties and damages are expected to run into the many billions of dollars, on top of what BP has already spent on clean-up and compensation.
BP is struggling through a separate legal battle over the payment of claims to people and businesses for spill-related losses. A federal appeals court is considering the case, and Halliburton said this process was impeding its push to settle its own liability through talks.
"The pace of those settlement discussions has recently slowed as we understand BP is challenging certain provisions of its settlement," Halliburton said in a quarterly filing with the Securities and Exchange Commission on Friday.
Halliburton also disclosed that its legal fees and other expenses related to Macondo totaled $223 million, of which $190 million is covered by insurance. The company said that last quarter it reached a favorable agreement with some insurers that allows it to continue being reimbursed for covered legal costs.
The prospects of a global settlement of the civil litigation by all parties seems remote, since Barbier has not yet ruled on whether BP or its co-defendants were guilty of gross negligence. Some observers believe he will not issue findings on negligence until the trial's next stage ends, probably in early 2014.
The trial is in re to case: Oil Spill by the Oil Rig "Deepwater Horizon" in the Gulf of Mexico, on April 20, 2010 in the same court, No. 10-md-02179. The evidence case is U.S. v. Halliburton Energy Services Inc, U.S. District Court, Eastern District of Louisiana, No. 13-00165.
Reporting by Braden Reddall in San Francisco, Mica Rosenberg in New York, Kathy Finn in New Orleans and Andrew Callus in London; editing by Andrew Hay and Bob Burgdorfer