Onshore Pipeline Design and Installation Considerations for Northwestern Alaska

Abstract

Ever since oil potential was first discovered on the North Slope of Alaska, oil companies have been drawn to this cold region. Following the 1967 Prudhoe Bay discovery, an increased number of production pads and wells were developed and drilled. The Dalton Highway was built, paving the way for the construction of the Trans-Alaskan Pipeline System (TAPS). More wells were drilled, and large fields were developed. To date, however, development of discoveries on Alaska's North Slope have been limited to a relatively small area comprising Prudhoe Bay, the Kuparuk Area, small outliers of Badami and Point Thomson to the east, and the expanding Alpine field / Colville River area to the west. Development is just starting to extend further west into the National Petroleum Reserve Area (NPRA). The overall developed area encompasses an approximate 133 mile tract of land running east-west along the North Slope's coastal plain, of which, approximately 70 miles extend west of the TAPS pipeline. In comparison, there are approximately 260 to 300 miles between the Chukchi Sea coast and the TAPS pipeline. The majority of Alaska's North Slope area is undeveloped with almost no infrastructure. Although there are a few gravel airstrips, including the village of Atqasuk, there are no roads in between that might provide efficient access to oil prospects in Northwestern Alaska from the closest major road artery, which is the Dalton Highway. There are offshore U.S. lease blocks in the Chukchi Sea. There are also prospects at Smith Bay. One of the challenges with development of these Northwestern Alaska prospects is bringing their potential resources to market. Options include installing an onshore pipeline from the prospects to the TAPS pipeline. This paper addresses the technical aspects associated with the planning of a major pipeline across Northwestern Alaska (West of TAPS). While non-technical considerations are equally important in the planning of such a pipeline, the topical focus of this paper is to highlight the technical aspects. The ultimate goal of such a project will be to install a pipeline system. However, the project costs and routing decisions may be driven more by logistics, the environment, and the associated Right-of-Way access, as opposed to the pipeline construction itself. Furthermore, the shortest straight line route, with the least expected straight line pipe quantities, may not necessarily equate to the least costly route, design, and construction option. This will become more evident once the design aspects for such a pipeline in this area are realized and the impacts from site specific geological, geotechnical, and meteorological conditions are incorporated into the design and installation planning. Having this understanding will help better prepare an organization for permitting approvals and for adjustments once the non-technical risks and external input are considered.