BP has asked a New Orleans court to amend a judge's ruling that the company could be liable for as much as $18 billion in damages levied for its role in the 2010 Gulf of Mexico oil spill, or possibly to grant it a new trial.

The British energy conglomerate petitioned a New Orleans court late Thursday, asking that the original ruling by Judge Carl Barbier be amended or even struck down in favour of a new trial.

Earlier this month, Barbier ruled that BP was "grossly negligent" and "reckless" in the aftermath of the 2010 Deepwater Horizon explosion and oil spill, which killed 11 people and damaged thousands of kilometres of coastline.

In his ruling, Barbier said BP was two-thirds responsible for the tragedy (with the rest split between rig operator TransOcean and cement contractor Halliburton), and his use of those two key phrases meant the company can be obliged to pay damages of up to $4,300 for every barrel of oil that spilled — although the law does allow the possibility that the company's financial liability could ultimately be $0.

The underwater well cap spewed oil for 87 days straight, meaning BP could be on the hook for as much as $17.6 billion under rules in America's Clean Water Act.

Essentially, BP's argument for a new trial boils down to the company's view that the evidence presented by one of Halliburton's expert witnesses, Gene Beck of Texas A&M University, should have not been a factor.

BP says it didn't properly counter Beck's testimony at the time because the company believed it had been ruled inadmissible. But the judge nonetheless included his testimony in reaching his decision.

"The court should now ... alter its findings regarding causation, eliminate its finding that BP engaged in gross negligence through a 'series of negligent acts,' and modify the allocation of fault among the defendants​," BP's Geoff Morrell said.

Including the up to $18 billion in civil penalties that BP could be on the hook for, the company says it has set aside $42 billion to cover costs associated with the disaster.

BP has also served notice that it intends to appeal the decision.