Beaufort Sea Exploration: Past and Future

Abstract

1. INTRODUCTION The Arctic Ocean and the Beaufort Sea present a significant challenge to those wishing to explore for or produce oil and gas. Twenty years ago, the North Sea environment represented a quantum leap for operators familiar with such areas as the Gulf of Mexico. The extreme wave cl imate., cold temperatures and deep water necessitated the development of new offshore technologies. Companies and countries who mastered its environment and met its demands have become world leaders offshore. Similarly, the Arctic Ocean has challenged industry and government since the late 19601s, the heavy ice cover envi ronment making demands on techno1 ogy beyond those of the North Sea. 140 wells have been drilled successfully in perhaps the most hostile environment in the world. Technology, ingenuity and good management have enabled operators to meet the challenge of an environment where, only a few years ago, no one but a few explorers had been. The success of this intensive effort bodes well for future endeavours. The purpose of this paper is to review and document past Beaufort Sea activities in both Alaska and Canada, describe existing drill ing systems and relevant environmental parameters, and so assist with planning of future activities. Possible future directions in Arctic offshore exploration are out1 ined. The structures themselves are considered in four categories; existing bottom founded structures, floaters, gravel or sand islands and spray ice islands. While details of the structures are readily available, there is less clarity on their operational constraints and limits and an attempt is made to sumnarize this information. Lists are provided of all wells drilled so far in the Beaufort Sea indicating the structure type, water depth and the total time taken for each well, along with other pertinent information. This information is provided together with environmental mapping and curves of thickness for multi-year ice floes and ridges, all of which provide an overview of the history of offshore drilling in the entire Beaufort Sea and valuable information for future platform selection in this challenging area. 2. ARCTIC ICE ENVIRONMENT Ice loads govern the design of structures in the Beaufort Sea, being the largest loads the structure will be subjected to by a substantial margin. Encroaching ice menaces drill ships and causes interruptions or abandonment of drilling operations during the short open water period of summer. Thus the ice environment dictates many of the decisions made regarding operations and cost feasibility. The search for oil and gas ' has resulted in the accumulation of a large base of data which describes the ice cover by type and season and which contains information on ice strength, pressures and measured forces [1]. Sumnary ice cover information for the Beaufort Sea has been prepared in the form of maps presented in Figures 1, 2 and 3. Sources of the ice information are given in the reference Section [2], [3], [4]. A thorough review of available information was conducted and relevant excerpts have been plotted. Variables covered include:Water depth contoursSumner ice concentrationSumner ice zonesSeasonal 1a ndfast ice Winter landfast ice development by yearMaximum and minimum winter landfast ice.