Recent sightings of oil sheens in the Grand Banks area where the offshore rig Glomar Grand Banks is working have created some public concern over the use of offshore drilling fluids and their potential impact on the marine environment.

Sightings reported on Tuesday, January 11, and Wednesday, January 19 are both under investigation by the Canada-Newfoundland Offshore Petroleum Board. It is estimated that the first sheen involved some 15 litres of synthetic based fluids (SBF) used as drilling lubricants, and reports of the second sighting indicate that the volume of fluids in that sheen was considerably less The findings of the C-NOPB investigation will be reported when the process has been completed.

Synthetic based drilling fluids are approved for use as lubricants in offshore drilling activity. They are non-toxic to marine life, and disperse quickly in the ocean. While potentially they can be harmful to any sea-birds which may come into contact with a sheen, no such incidents have been reported to date.

The fluids enter the ocean environment because of their presence on the rock cuttings created by the drilling process. These cuttings are processed on the drilling rigs before being discharged underwater and deposited on the ocean floor. Current technology is able to remove about 85% of the fluids from the cuttings, and this level of performance was deemed acceptable in the Offshore Waste Treatment Guidelines established by the National Energy Board, the Canada-Nova Scotia Offshore Petroleum Board, and the Canada-Newfoundland Offshore Petroleum Board. These guidelines are currently under review to determine if new technology will allow the SBF residue level to be reduced in the waste discharge, or whether further restrictions will be necessary.

Meanwhile, some jurisdictions are moving toward a 1% level of SBF content in drilling discharges. This can only be accomplished by either re-injection of the cuttings into a well, or by capturing all the waste cuttings on board a rig, packaging them, and shipping them back to shore for treatment and disposal in the land environment. This latter option relocates the disposal problem, and in some cases may be less acceptable than the current practice. The United States Environmental Protection Agency, after a detailed analysis of treatment and disposal options for SBF, recently determined that treatment and offshore discharge was superior, on a full “life-cycle” basis, to onshore disposal.

In the Newfoundland and Labrador jurisdiction, Hibernia is already preparing to re-inject its SBF cuttings, and should be ready to begin this process before the end of this year. Re-injection is more challenging for floating drilling systems than for fixed platforms such as Hibernia and Sable, therefore a final determination has not yet been made on whether or not the Terra Nova operation will be able to avail of the re-injection option. While this evaluation is being made, Terra Nova has been granted temporary permission to discharge treated cuttings for the first six of its 24 wells or until first oil is produced, whichever comes earlier.

As the regulatory body responsible for the offshore oil and gas industrial activity in the Newfoundland and Labrador area, the C-NOPB continually monitors the offshore discharges in all drilling operations. In the case of SBF, both the concentration of fluid on cuttings and the overall mass of cuttings discharged are reported.

Production operators must also develop and submit for C-NOPB approval environmental effects monitoring programs for their projects. Both Hibernia and Terra Nova programs were designed in consideration of international experience and site-specific discharge modelling. Hibernia’s program includes seabed sampling at 44 points around the platform as well as a scientific fishery in the vicinity of the facility. Sediments have been found to be generally non-toxic, and elevated chemical concentrations were limited to 500 metres or less from the platform. No elevated contaminants have been detected in fish, nor were fish samples tainted.

The Board also monitors and investigates incidents of spills of other fluids from offshore operations to determine the causes of such incidents and their potential effect on the environment. Since the start of Grand Banks oil production in 1997, a total of 92 incidents have been reported and investigated, and most of these have involved very small quantities of fluid (less than 10 litres). While some incidents are still under active investigation, none of the completed investigations indicated any evidence of operator neglect or disregard for safety and environmental regulations.

All information gathered by the C-NOPB is available to federal and provincial governments, and the Board works closely with all relevant government departments and agencies, and with industry, to ensure that safety of workers and the protection of the environment are paramount principles in the development of offshore oil and gas resources.

REFERENCE:
David Burley
Manager, Environmental Affairs
(709) 778-1403