Deepwater Arctic - Technical Challenges and Solutions

Abstract

Abstract This paper presents the alternatives available and assessment of floating platforms, stationkeeping and riser systems based on studies undertaken for Arctic fields. The industry experience with floating units for both drilling and production operations in the offshore areas subjected to ice features are discussed. The salient aspects of these systems are discussed considering the general characteristics of selected basins. The Arctic fields developed so far are in water depths up to 125 m and have used the Gravity Based Structures and detachable FPSOs, besides other systems such as jacket platforms and islands used in shallower water. There is significant industry interest in the development of Arctic and Sub-Arctic fields in water depths beyond commercial viability of bottom founded designs. The water depths in some North American and offshore Greenland Basins are up to 2,800 m. The development of fields in deeper water would require use and adaptation of floating units and subsea systems, which have been used in many deepwater basins. However, their use in deepwater Arctic would add significant challenges from harsh weather, severe ice features (pack ice, icebergs), lack of infrastructure, remoteness, and reduced accessibility. The floating unit designs, alternatives for sub-systems, and subsea solutions and technologies are enabling development of Arctic fields offshore Norway and Russia, such as Goliat and Shtokman in up to 350 m water depth. Floating units provide flexibility in field development and ability to detach and move the unit from the path of significant ice loading events and icebergs. These features enable improve their technical and commercial feasibility by reducing load effects and risks. Challenges in Arctic The development of hydrocarbon fields offshore Arctic and Sub-Arctic in the North, have gained significant importance due to potential for very large reservoirs increasing their commercial viability. Some of the important leasing areas in the Arctic or Sub-Arctic offshore identified in Fig. 1 are in deepwater and ultra-deepwater: Barent Sea, offshore Norway and Russia; Orphan Basin, offshore Newfoundland; and fields offshore Greenland and Iceland. The water depths vary from 300 m to 3,000 m in these leases and several of these fields are in exploratory drilling or in the development planning stages.