A Look at the Aasta Hansteen Norwegian Deepwater Spar FPSO

Abstract

This article, written by JPT Technology Editor Judy Feder, contains highlights of paper OTC 29222, “Aasta Hansteen Spar FPSO—A Pioneer in Norwegian Deepwater,” by Torolf Christensen, Stig Arne Witsøe, and Helge Hagen, Equinor, et al., prepared for the 2019 Offshore Technology Conference, Houston, 6–9 May. The paper has not been peer reviewed. Copyright 2019 Offshore Technology Conference. Reproduced by permission. The complete paper describes the overall project execution of the Aasta Hansteen field development on the Norwegian Continental Shelf (NCS) north of the Arctic Circle. It is the deepest field yet developed on the NCS in 1300 m of water. In a harsh environment, with no other offshore installations in the area, the field is being developed with a spar floating, production, storage, and offloading (FPSO) structure using steel catenary risers and polyester mooring lines. Business Case The field is 300 km off the coast of northern Norway and 140 km from the nearest offshore installation. The field was discovered in 1997, with investment decision taken in December 2012 and production begun in December 2018. Total investment in facilities and infrastructure (including pipeline and modifications at Nyhamna) is approximately $7 billion. Equinor operates the field on behalf of its partners, Wintershall (24%), OMV (15%), and ConocoPhillips (10%). The field’s rich gas is exported through a 482-km-long, 36-in. pipeline to an on-shore processing plant at Nyhamna for further processing to sales gas. From there, the gas is exported to the European market. Stabilized condensate is stored in the spar FPSO and offloaded to shuttle tankers. The development of the field with the platform facilities and the Polarled pipeline was a strategic decision to open a new gas region in the Norwegian Sea and connect it to Europe by the NCS gas infrastructure. The development solution will serve as a gas hub enabling tie-in of future production from discoveries and prospects in the area. The objective of the Aasta Hansteen development is to maximize the recovery of the Aasta Hansteen reserves and to achieve maximum value creation in the value chain. Estimated recoverable reserves are 51 billion scm rich gas and 0.6 million scm condensate. The reserves consist of three separate discoveries—Luva, Haklang, and Snefrid Sør—all in the Nise formation and within the same production license. The development of Aasta Hansteen has been executed as a parallel development of the Polarled pipeline project to establish a new gas transport pipeline from Aasta Hansteen to Nyhamna. The pipeline has several tie-in points from Aasta Hansteen to the Nyhamna gas-processing plant. Snefrid Nord, the first subsea tieback development, is already being developed. The complete paper provides a brief description of the Polarled project.