Arctic Offshore Islands - Lessons Learned

Abstract

Abstract Five general categories of offshore structures incorporating granular material (‘islands’) have been utilized in the Beaufort Sea, primarily in the 1970's and 1980's. Although each concept has generally served its purpose, there have been many issues both during construction and during operations. This paper reviews the major issues by referring to three specific case histories. Introduction Five general categories of offshore structures incorporating granular material (‘islands’) have been utilized in the Beaufort Sea. Such ‘islands’ include sandbag retained islands, sacrificial beach islands, gravel islands (mainly in the U.S. Beaufort Sea), caisson retained islands and a water ballasted caisson on a berm. The majority of these structures, which total close to seventy, were constructed in the 1970's and 1980's. Apart from a few more recent production islands, these structures were primarily constructed to support exploratory drilling operations. Although the majority of these islands were in water depths less than 10 metres (approx. 30 feet) some hybrid islands have been successfully constructed in depths up to 31 metres (approx. 100 feet).