Ballard provided survey, inspection, stabilization, and coating repair services for two four-mile long, twenty-inch diameter crude oil pipelines, crossing at the Straits of Mackinac.
Scope of Work
Prior to Ballard beginning physical stabilization and coating repair operations for the two pipelines, survey and inspection operations were required. An Ultra-Short Baseline (USBL) survey, utilizing a Remote Operated Vehicle (ROV) tied to a Real-Time Kinematic (RTK) surface positioning network, was implemented. This highly accurate video survey was needed to help determine exact span lengths of the pipeline, along the bottom, in addition to 100% visual observation to track coating and/or debris concerns. In addition to the ROV operation, an Autonomous Underwater Vehicle (AUV) was utilized for additional long-range survey work that included both multibeam and side scan sonar. The data was used to accurately measure span lengths, gather data for current pipeline orientation condition, and bathymetry charts.
The stabilization and coating repair services required mobilization of complete gas and saturation diving spreads to the project site. Stabilization repairs included the insertion of hydraulically driven screw anchor pier systems that provided increased vertical and horizontal support. The inspections focused on biological growth on the pipelines, condition of the protective coating, and debris tracking; followed by an overlay of additional coating material in areas deemed suspect by the client. All repairs, inspections, and replacements were completed in water depth that ranged from sixty-five to 270 feet of freshwater.
Operations were conducted off barge and tug platforms or small survey inspection vessels, with multiple platforms performing work at the same time. Ballard managed between thirteen and forty in-house crew members and multiple sub-contractors during the various campaigns, in addition to hosting various client, supplier, and regulatory personnel.
Client: Enbridge Energy
Location: Mackinac, MI
Diver Depth: 65 – 270 ft.