Qualification and Field Trial of a Metal Expandable Well Annular Barrier

Abstract

The ability of cement to achieve a pressure seal across the reservoir section for the life of a well becomes ever more difficult to achieve because of increasing depths and more complexity in well design and operations. Mature fields with depleted zones combined with the desire and ability for extended reach wells exacerbates the challenge of delivering a cement-only, fit-for-purpose liner. To address this challenge, an operator and service company have joined forces to design, develop, and qualify a hydraulically expandable metal well annular barrier (WAB) assembled on the outside diameter (OD) of a liner while maintaining full-bore inner diameter (ID). Intended initially for use in Norway's Valemon field, the operator is also exploring options for other applications in the Snorre and Brage fields, also offshore Norway. This paper discusses the design, development, and qualification of the metal WAB, including: review of the design, material selection to achieve the required expansion, the unique outer seal design to deliver the pressure differential requirements, and intended applications to date. The final qualification process exceeds the industry-established guidelines in ISO standard 14310 (which defines requirements for packers and bridge plugs for the oil and gas industry).