Client: Member of the Petroleum Industry

In 1995, Coastal Frontiers was selected to serve as a member of the Northstar Development Alliance. The group designed and constructed the first free-standing Arctic offshore production facility requiring a subsea pipeline. Located to the northwest of Prudhoe Bay, the Northstar Development includes an armored production island in a water depth of 38 ft and a buried pipeline that extends six miles from the island to a shore crossing on the mainland coast. Coastal Frontiers personnel provided engineering support for the design and construction of the project facilities, and continue to provide post-construction monitoring and maintenance advisory services. Representative tasks are described below.

Coastal Engineering Support

  • Wide-ranging bathymetric surveys to evaluate prospective locations for the production island and routes for the subsea pipeline to shore

  • Annual pre-construction bathymetric surveys in the planned pipeline corridor to quantify ice gouge and strudel scour characteristics

  • Selection of an optimum location for the pipeline shore crossing based on an evaluation of coastal erosion

  • Design of an articulated concrete mat slope protection system for the island, including 2- and 3-dimensional hydraulic model testing

  • Support for permit acquisition and regulatory compliance, including presentations to North Slope Native villagers and regulatory agencies

  • On-site advisory during armor installation

  • Survey support for subsea pipeline installation

  • As-built surveys of the island, pipeline, and shore crossing, along with an underwater inspection of the island slope protection system

  • Annual monitoring of the island and shore crossing in concert with bathymetric surveys of the subsea pipeline right-of-way