The Canada-Nova Scotia Offshore Petroleum Board’s (CNSOPB) ongoing investigation into the unauthorized discharge of drilling mud that was reported on June 22, 2018 has determined the cause to be a loose connection in the mud booster line. The purpose of the mud booster line is to pump drilling mud into the riser to lift drill cuttings from the well to the drilling unit for processing.
BP Canada Energy Group ULC (BP Canada) has identified and implemented a number of responsive actions to prevent a reoccurrence of this type of failure. These include:
- Replaced the section of the mud booster line where the leak occurred and pressure tested the assembled components.
- Conducted inspections of all similar connections in the mud booster line, along with those in other auxiliary piping systems that are affixed to the riser.
- Implemented a pressure system alarm of the mud booster line that will be monitored at all times on board the West Aquarius drilling unit as well as at the BP Global Well Monitoring Centre in Houston.
- Routine inspections and pressure tests of the mud booster line at regular intervals to ensure its integrity for the remainder of the project.
“We have verified that all the responsive steps have been implemented,” said CNSOPB CEO, Stuart Pinks. “We are satisfied that the responsive actions taken, including the additional monitoring and testing that will be done for the remainder of the project, allows for drilling operations to resume safely.”
As a result, approval to recommence drilling operations was granted to BP Canada during the evening of Sunday, July 22, 2018.
As part of our continuing compliance monitoring activities, the CNSOPB will ensure that the ongoing responsive measures that BP Canada has put in place to prevent reoccurrence are being carried out as committed.
Identifying the cause and responsive actions needed to put equipment back into service is only one part of the investigation that is ongoing. As the investigation continues, the CNSOPB will be evaluating the extent of any potential regulatory non-compliances that may be identified in relation to this incident and determining enforcement actions, if any, that may be taken by the CNSOPB.
The ongoing investigation also includes an assessment of the environmental effects of the batch discharge of drilling mud. Preliminary findings indicate that the environmental effects are likely to be minimal. This is based on:
- The drilling mud and its constituents were selected in accordance with the Offshore Chemical Selection Guidelines that are jointly published by the CNSOPB, the Canada-Newfoundland & Labrador Offshore Petroleum Board and the National Energy Board. These guidelines promote the use of low toxicity mud components to minimize potential environmental impact.
- The drilling mud is specifically designed for use in the marine environment. Some drilling mud is retained on drill cuttings that are routinely discharged to the seabed during drilling operations. Additionally, drilling mud can end up in the marine environment in the case of an emergency disconnect from a well, or as the result of an accidental discharge.
- The pre-drilling video survey of the seabed showed no aggregations of habitat-forming corals or sponges, or any other environmentally sensitive features, on the seafloor in the vicinity of the well site location prior to the commencement of drilling operations. The typical benthic habitat observed at the well site location is relatively bare and generally devoid of epifauna (benthic marine life), with sparse solitary macrofauna (e.g. brittle stars) scattered in the surveyed area, when present.
- Results of previous post-drilling Environmental Effects Monitoring Programs conducted in the Atlantic Canada offshore areas indicate no significant effects on benthic marine life from the discharge of drilling muds adhered to drill cuttings.
The ongoing investigation will continue to assess potential environmental effects. This includes:
- The collection and review of video footage of the seabed area around the well location after the batch discharge.
- The collection and analysis of samples of suspected deposits of drilling mud on the seafloor.
Video footage and details of the analysis will be made available once the investigation concludes.
The CNSOPB will refrain from commenting further on the investigation at this time. An investigation report will be made public once the investigation has concluded.
- Pre-drilling video survey of the seabed
- Third-party marine scientist review of Pre-drilling video survey of the seabed
- Drilling mud questions and answers
- Drilling mud composition for BP’s Exploration well