HOUSTON, Jan 15 (Reuters) - BP Plc will face Clean Water Act fines for its Gulf of Mexico oil spill of up to $13.7 billion, less than a maximum of $17.6 billion it could have been fined, after a judge ruled on Thursday the size of the spill was 3.19 million barrels.
The ruling by U.S. District Court Judge Carl Barbier put the spill's size well below the 4.09 million barrel estimate of the government and the 3.26 million estimated by BP.
All these totals exclude some 810,000 barrels that were collected during clean-up of the worst offshore disaster in U.S. history.
Under a "gross negligence" ruling Barbier issued in September, BP could be fined a statutory limit of up to $4,300 for each barrel spilled, though he has authority to assign lower per barrel penalties. Penalties will be assigned after the third and final phase of the company's trial is held later this month.
U.S.-listed shares of BP rose about 1 percent to $36.20 in after-hours trading. (Reporting By Jonathan Stempel; Writing by Terry Wade)