This paper summarizes the shore crossing options and considerations associated with Arctic subsea pipelines. A summary of what has been installed as well as other options not yet installed are covered. Some options have been ruled out for some projects, and while at the same time, they are either actively being pursued or may be in the process of consideration for other projects.
Offshore project development in the Arctic may utilize pipeline tiebacks to shore. These tie-backs will require a shore crossing transition. There are design aspects for Arctic shore crossings that are similar to non-Arctic conditions. However, in many locations in the Arctic, there are unique Arctic- specific conditions that will influence the shore crossing design details. These Arctic design influences may be of a technical or non-technical nature. Both types of influences may require consideration of technologies and techniques that might not otherwise be considered for non-Arctic locations. These influencing factors will affect almost every aspect of the work as follows:
pre-planning work, which includes geophysical and geotechnical site investigations
the design details for the shore crossing, which is the ultimate goal of the work
construction techniques, which are required to bring the design to fruition
operating requirements and monitoring for the life of the development
One of the main conclusions is that the project and site specific conditions will influence the available shore crossing design options for a project, the option that is ultimately selected for a particular Arctic pipeline project, and the design details required for that project. The site conditions at one project location may be different than the site conditions at another project location, regardless of distance between the two projects. While two different projects at two different locations may utilize the same shore crossing method, the relative costs between the two project's shore crossings may be different due to more conducive site-specific conditions at one location versus less conducive site- specific conditions at the other.
There are several Arctic subsea pipeline projects with shore crossings that have been successfully designed, constructed, and have been operating without incident for more than 15 years. Each illustrates that, despite the increased costs and effort compared to non-Arctic shore crossings, the industry has "been there and done that" safely.