In March 2003, DEC said, BP and DEC entered into a compliance reporting agreement requiring BP to report the release of low-risk substances including drilling mud to low sensitivity receiving environments, such as gravel pads. DEC said that agreement includes a requirement to report the release of drilling mud in excess of 55 gallons, even when there is no release to the environment. This requirement, DEC said, “is intended to alert both BP and the state so that steps can be taken to prevent future occurrences.”

DEC said its investigation found that no one from BP or their drilling contractor reported drilling mud releases which occurred July 31, 2003, and Dec. 5, 2004, when Nabors Alaska Drilling Rig 9ES experienced an event referred to as wellbore breathing. Approximately 294 gallons of mud were released within the walls of the drill rig.

DEC said the releases did not present an imminent or substantial danger to the environment.

Leslie Pearson, program manager for DEC’s prevention and emergency response program, said: “The state and BP have agreed that certain low-risk spills will be reported based on the quantity released so that problems can be assessed as they occur and corrective actions can be taken to prevent future spills.”

DEC said it “will pursue appropriate corrective actions” to ensure BP reports such releases in the future.

Daren Beaudo, BP Exploration (Alaska) director of public affairs, told Petroleum News in an e-mail that the DEC investigation “concludes, as does BP’s own internal investigation,” that the two releases of drilling mud from a Nabors rig were not a threat to public health or the environment, and occurred within the drill rig, which constitutes secondary containment.

Beaudo said most of the DEC report “is identical to the conclusions reached by BP.” He said BP expects to reach an understanding with DEC regarding the agency’s “expectations of reporting requirements for this and other low-risk substances when they are confined to containment.”