COASTAL ENGINEERING FOR THE NORTHSTAR DEVELOPMENT
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