November 1, 2016

Uncharted Alaskan Waters: Subsea Pipeline Installation

First-of-its-kind is kind of our thing.

When it comes to solving complex problems, the MORRISON team has it covered – even in uncharted waters. We’re known for our work throughout the Gulf of Mexico and beyond, but one recent project took us somewhere we’d never been before: the icy waters off the coast of Alaska.

For this particular job – a subsea natural gas pipeline installation – we found ourselves doing familiar work under unfamiliar circumstances. Though we’ve operated in a wide range of environments before, the Kitchen Lights gas field in Cook Inlet presented some unique challenges. Currents up to 6 knots and extreme tidal ranges up to 35 feet every six hours required additional resources, planning and engineering to manage. That turbulence – along with glacial silt loads – made water visibility essentially zero. And with cold temperatures and wind gusts up to 30 mph it was far from an ideal working environment.

Despite this challenge, our crew was tasked with installing 83,000 feet of 10 inch-diameter pipeline with 3 inches of concrete in 130 feet of water depth, connecting the offshore production platform to the onshore production facility. In order to accomplish this, we outfitted our pipe laying equipment on a 260-foot by 72-foot deck barge called the Nilnilchik. We also prefabricated key components for the pile template, including legs and braces. The Nilnilchik was further set up with on-board stations to facilitate the assembly of the nearly 16 miles of concrete-coated pipe. On the stern, a 160-foot steel stinger structure was installed to guide the readied lengths of pipe gently to the sea floor.

The MORRISON team of more than 40 workers formed a key part of the full project team which included multiple companies working together to achieve a common goal. Nearly 24 hours of continuous daylight enabled round-the-clock shifts, making the coordination of various teams particularly important. With the pressure of the approaching end of summer, when ice in surrounding waters could complicate their exit, everyone on the project understood the importance of staying on schedule.

“The extreme currents caused this to be the most challenging pipelay operation I’ve seen in my 25 years in the oilfield. Planning played a major role in our ability to successfully complete this project on schedule, and according to the customer’s requests.”

Just like with the Aerial Pipeline Dismantlement, this project benefited tremendously from our early involvement during the planning phases. Our team was able to identify the best approach and provide the necessary resources because of that early partnership and sufficient planning lead time. This job was a great example of our team’s ability to tackle even the most complex and challenging of projects, bringing our unique expertise with pipeline services in marine environments to an entirely new arena.