Acergy
A formerly international offshore engineering and construction company that specialized in subsea energy infrastructure and merged with Subsea 7 in 2011.
Last updated August 26, 2026
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Overview
Acergy S.A. was an international offshore engineering and construction company serving the oil and gas industry. Its work covered the seabed-to-surface portion of offshore developments, including subsea umbilicals, risers and flowlines, conventional field development, inspection, maintenance and repair, offshore construction, diving, and the installation of subsea facilities. The company operated as a business-to-business engineering contractor and project integrator rather than as a consumer-facing product brand. The business originated in Norway in 1970 as Stolt Nielsen Seaway, a company that supplied divers for North Sea exploration. It expanded geographically and technologically over subsequent decades. Its move into Aberdeen in 1989 strengthened its presence in the United Kingdom's offshore sector, while its 1992 acquisition of French diving specialist Comex Services added subsea expertise. In 1997, the company secured its first ultra-deepwater contract off West Africa. That expansion was followed by acquisitions including Houston-based Ceanic Corporation, Danish flexible-pipeline specialist NKT Flexibles and French contractor ETPM. The company adopted the name Stolt Offshore in 2000. In 2005, the Stolt-Nielsen Group sold its ownership, and the business became publicly listed on the Oslo Stock Exchange and NASDAQ. On 1 March 2006, it changed its name to Acergy. Under the Acergy identity, the company maintained a broad international footprint, with offices or operations in London, Stavanger, Aberdeen, Suresnes, Houston, Rio de Janeiro, Perth, St. John's and Singapore. Its project capabilities were supported by a fleet of specialized construction, diving, installation and heavy-lift vessels, as well as joint ventures such as Seaway Heavy Lifting, SapuraAcergy, NKT Flexibles and Global Oceon Engineers. Acergy announced a combination with Subsea 7 Inc. on 21 June 2010. The transaction was completed on 7 January 2011, creating Subsea 7 S.A. The combined business retained Acergy's Luxembourg domicile and operational headquarters in London but adopted the Subsea 7 name. Kristian Siem became chairman and Jean Cahuzac became chief executive of the combined company. The merger ended Acergy's existence as an independent listed company and discontinued its standalone brand, while its engineering capabilities, personnel, assets and projects were absorbed into the broader Subsea 7 organization.
History
Acergy's origins can be traced to 1970, when the Haugesund-based Stolt Nielsen Seaway began supplying divers for exploration work in the North Sea. The company was associated with the Stolt-Nielsen Group and developed from a diving-services provider into a broader offshore engineering and construction business. Its early activities reflected the growing technical demands of North Sea oil and gas development, where contractors were required to support subsea exploration, installation and maintenance in increasingly challenging marine environments. The company expanded into Aberdeen in 1989, establishing a stronger base in one of the United Kingdom's principal offshore energy centers. In 1992, it acquired the French diving company Comex Services. That transaction broadened its subsea capabilities and helped move the business beyond its original North Sea diving profile. The company later pursued international growth and deeper-water work. In 1997, it won its first ultra-deepwater contract off West Africa, an important step in extending its project portfolio into technically demanding offshore regions. It then acquired Houston-based Ceanic Corporation, Danish flexible-pipeline company NKT Flexibles and French contractor ETPM, adding regional presence, flexible-pipeline expertise and engineering and construction capabilities. In 2000, the company changed its name to Stolt Offshore. The business was separated from the Stolt-Nielsen Group in 2005, when the group sold its ownership. Stolt Offshore was then listed on the Oslo Stock Exchange and NASDAQ. On 1 March 2006, it adopted the Acergy name, signaling a new corporate identity for an international offshore engineering organization. As Acergy, the company organized its operations around several principal areas: Subsea Umbilicals, Risers and Flowlines; inspection, maintenance and repair; and conventional field development. Its work generally extended from engineering and procurement through fabrication, installation, commissioning and operational support. The company served offshore oil and gas operators and participated in complex projects requiring specialized vessels, subsea equipment, diving systems, flexible-pipeline technology and project-management expertise. Acergy's international network included offices in London, Stavanger, Aberdeen, Suresnes, Houston, Rio de Janeiro, Perth, St. John's and Singapore. Its associated ventures included Seaway Heavy Lifting in the Netherlands, NKT Flexibles in Denmark, SapuraAcergy in Malaysia and Global Oceon Engineers in Nigeria. The company also operated or accessed a substantial group of construction, installation, diving and heavy-lift vessels, including vessels carrying the Acergy name and assets held through joint ventures or charter arrangements. On 21 June 2010, Acergy and Cayman Islands-based Subsea 7 Inc. announced their planned combination. Completion took place on 7 January 2011. The resulting company was named Subsea 7 S.A.; it retained Acergy's Luxembourg domicile and London operational headquarters but no longer operated under the Acergy name. Kristian Siem became chairman and Jean Cahuzac became chief executive of the combined group. The transaction therefore marked the end of Acergy as an independent listed company and the absorption of its activities into Subsea 7.
- 2011
Acergy becomes part of Subsea 7
[1]The combination was completed on 7 January 2011, creating Subsea 7 S.A. and ending Acergy's standalone existence.
- 2010
Combination with Subsea 7 announced
[1]Acergy and Subsea 7 announced their plan to combine their offshore engineering businesses.
- 2006
Adoption of the Acergy name
[1]Stolt Offshore changed its name to Acergy on 1 March 2006.
- 2005
Separation from Stolt-Nielsen and public listings
[1]Stolt-Nielsen sold its ownership, after which the company was listed on the Oslo Stock Exchange and NASDAQ.
- 2000
Renamed Stolt Offshore
[1]The company adopted the Stolt Offshore name as it developed into a broader offshore engineering and construction contractor.
- 1997
First ultra-deepwater contract
[1]The company won its first ultra-deepwater contract off West Africa and subsequently expanded through several acquisitions.
- 1992
Acquisition of Comex Services
[1]The French diving company Comex Services was acquired, expanding the group's subsea diving capabilities.
- 1989
Expansion into Aberdeen
[1]The company opened an Aberdeen presence, strengthening its position in the United Kingdom offshore market.
- 1970
Business established as Stolt Nielsen Seaway
[1]The Haugesund-based company began by providing divers for North Sea exploration.
Products and positioning
A global, technically specialized contractor for offshore oil and gas infrastructure, positioned around integrated subsea engineering, construction, installation and lifecycle-support capabilities.
Offshore oil and gas engineering
Subsea Umbilicals, Risers and Flowlines
Acergy's SURF activities addressed the engineering, fabrication, installation and project execution of subsea umbilicals, risers and flowlines. These systems connect seabed production equipment with floating or fixed offshore facilities and require specialized design, installation vessels and subsea construction expertise.
Subsea lifecycle services
Inspection, Maintenance and Repair
The inspection, maintenance and repair business supported the continued operation of offshore and subsea infrastructure. Services could involve subsea inspection, intervention, repair planning and execution, often using diving systems, remotely operated equipment and specialized vessels.
Offshore field-development services
Conventional Field Development
Acergy provided engineering and construction support for conventional offshore field developments. The work covered project integration and the installation of pipelines, risers, seabed facilities and related infrastructure required to connect offshore production assets.
Subsea engineering services · 1970
Diving and subsea intervention
Diving was part of the company's historical foundation and remained relevant to subsea construction, inspection and maintenance work. The capability developed from North Sea exploration support into a wider set of offshore intervention and construction services.
Brand decisions
2011
Completion of the Subsea 7 mergerM&ABackground
The planned combination required the integration of Acergy's business, people, assets and corporate structure with Subsea 7.
Action taken
The combination was completed on 7 January 2011, creating Subsea 7 S.A.
Aftermath
Acergy ceased to operate as an independent company and its standalone brand was retired.
2010
Agreement to combine with Subsea 7M&ABackground
Both companies operated in offshore subsea engineering and construction, creating a rationale for combining complementary capabilities and assets.
Action taken
Acergy and Subsea 7 announced a combination on 21 June 2010.
Aftermath
The transaction was completed in January 2011, and the combined company adopted the Subsea 7 name.
2006
Adoption of the Acergy identityStrategyBackground
Following the 2005 separation from Stolt-Nielsen and the company's public-market development, management adopted a new standalone identity.
Action taken
Stolt Offshore changed its name to Acergy on 1 March 2006.
Aftermath
Acergy operated as an independent international subsea contractor until its combination with Subsea 7.
2000
Rebranding as Stolt OffshoreStrategyBackground
The business had expanded beyond its original diving roots into international offshore engineering and construction.
Action taken
The company changed its corporate name from Stolt Comex Seaway to Stolt Offshore.
Aftermath
The Stolt Offshore identity remained in use until the company adopted the Acergy name in 2006.
Sources1 sources
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