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Smart and environmentally friendly caisson replacement

A green and cost-effective method of replacing caissons


Client: Wintershall
Industry: E&P
Asset: Brage platform
Location: North Sea
Year: 2019

Challenge

When Wintershall acquired the Brage platform in 2013, one of the oldest producing platforms in Norway, they were approved to extend its lifetime up to 2030 and beyond. Besides optimising its processes, they also needed to repair and replace the damaged structures and components. One example was its aging caissons.  

With over 25 years in service, the caissons have suffered from corrosion and cracking, posing threats to other components of the platform and the subsea architecture. As previously contracted to replace one of the platform’s caissons in 2013, Axess Group was again commissioned to replace seven caissons in 2018 to 2019. 

Solution

An investigation and feasibility study resulted in an innovative and climate-efficient method of replacing the caissons. Instead of using support vessels, Axess’ engineering department performed the lifting operations below the platform deck with the aid of a tailor-made Construction ROV (CROV) that was platform deployed. This prefabricated CROV was designed to carry out various activities with maximum flexibility – cutting, cleaning, torqueing and other clamp capabilities.

The high-risk method involved safety measures for lifting above pressurised equipment according to the strict requirements found in NORSOK R-002 Annex K, including double redundant load paths, and implementing fail-safe systems throughout the design. In addition, a lifting system was also developed to catch potential parts that have fallen off after a breakage in one of the caissons. The lifting clamps were custom-designed to provide a complete material handling solution – a more factory / turnkey way of thinking rather than the conventional offshore project approach.

Results

Due to its compact design and multiple mechanical capabilities, the bespoke platform deployed CROV exceeded the weather-sensitive limitations of large ROV systems on IMR vessels – especially in the splash zones. Not only did the lifting solution provide a huge cost savings on support vessel chartering, it also reduced a significant amount of emissions.  Over 1,700 tons of CO2 were saved by using this method, largely by avoiding the use of support vessels.

Overall, Wintershall was very pleased with the proposed plan and the execution as it was cheaper than the conventional method and with minimal emissions. The work was undertaken in all weather conditions including the challenging winter months in the Norwegian North Sea. 

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Contact Information

Molde
Axess AS
Oscar Hanssens vei 5
6415 MOLDE
+47 982 43 600
Aberdeen
Axess North Sea Ltd.
Units 6 & 19 Robert Leonard Centre
Howe Moss Drive, Kirkhill Industrial Estate, Dyce AB21 0GG, UK
(duty): +44(0) 7912212854
St. John's
Axess Baffin Inc.
702 Water Street, Suite 201
St. John's, Newfoundland
+1 709 758 7937
Bergen
Axess AS
Kokstadflaten 35
5257 Bergen
(duty): +47 982 43 600
Houston
Axess North America Inc
825 Town & Country Lane Suite 1200
Houston Tx. 77024
+1 (281) 994-0367
Ciudad del Carmen
Axess Operations De Mexico S de RL de CV
Calle Bosque de Ciruelos 180 PP 101
Colonia Bosque De Las Lomas CP 11700 Cuidad De Mexico
+52 938-152-7688
Georgetown
Axess Guyana Inc.
2 Avenue of the Republic, Georgetown, Guyana
Stavanger
Axess AS
Travbaneveien 3,
4031 Stavanger, Norway
(duty): +47 982 43 600
Rio de Janeiro
Axess do Brasil Ltda
Rua Dezenove de Fevereiro
171 - Botafogo
CEP 22280-030 Rio de Janeiro
+55 (21) 4108-0532
Trondheim
Axess AS
Nedre Bakklandet 58C
7014 Trondheim
(duty): +47 982 43 600
Orkanger
Axess AS
Grønøraveien 1
Orkanger
7300 Orkanger
(duty): +47 41 78 06 30
Oslo
Axess AS
Fridtjof Nansens plass 4
0160 Oslo, Norway
(duty): +47 982 43 600
Busan
Axess Offshore Korea LLC
22nd Floor KNN Tower, Centum-ro 30
2203-ho, Haeundae-gu
Busan, South Korea
+82 10 2696 2016
Dubai
Axess Middle East DMCC
807 X2 Tower, X Cluster
Jumeriah Lake Towers Dubai, UAE
+971 4565 7913
Mumbai
Axess AIM India Pvt Ltd
B2-306, 3rd Floor
Kanakia Boomerang,
Chandivali Firm Road
Andheri East, Mumbai- 400072, India
Singapore
Axess Offshore Pte Ltd
Nordic European Centre #05-31 South Wing
3 International Business Park
Singapore 609927
+65 6908 4174
Perth
Axess Offshore Australia Pty Ltd
304 Newcastle St
Perth WA 6000
+61 4 3373 0739
Cape Town
Axess Offshore Africa Ltd.
Office 106, 1st Floor, Block 2
Northgate Park, Brooklyn
Cape Town, South Africa
+27 82 202 5266
Luanda
Axess Offshore Africa Ltd.
Edificio Joia Rara, 3º Andar 3.5/3.6,
Av. Revolução de Outubro No 8, Cassenda, Maianga
Luanda, Angola
+27 (0) 87 148 4700
Accra
Axess Petrorig Ghana Limited
3rd floor, The Pelican
8 Blohum Street, Dzorwulu, Accra, Ghana
+233 (0) 30 397 0548
Perth
Axess Offshore Australia Pty Ltd
140 St Georges Terrace L28,
Perth WA 6000
+61 4 3373 0739
Molde Aberdeen St. John's Bergen Houston Ciudad del Carmen Georgetown Stavanger Rio de Janeiro Trondheim Orkanger Oslo Busan Dubai Mumbai Singapore Perth Cape Town Luanda Accra