With the sail away of the Cygnus Alpha Compression Module yesterday evening (July 20, 2015), the last of four main structures left Heerema Hartlepool, part of Heerema Fabrication Group (HFG), after two and a half years of construction.

According to Heerema, the Cygnus Bravo Wellhead Platform (BWHP) and the Cygnus Alpha Process & Utilities (APU) topside left earlier to the final offshore destination in the Southern North Sea. The key infrastructure, being the Cygnus Alpha Wellhead Platform (AWHP), sailed already in May 2014.

The Cygnus field consists of two drilling centres, the Alpha and Bravo. Heerema Hartlepool received the frame agreement from operator GDF SUEZ E&P UK Ltd (part of ENGIE Group) in August 2012 for the construction of three topsides, a compression module, with two bridges to connect the three Alpha platforms and a flare tower for the Cygnus field.

Koos-Jan van Brouwershaven, Chief Executive Officer of the Heerema Fabrication Group (HFG), said: “Within a period of two and a half years we have successfully delivered three topsides and a module from our Hartlepool yard. Alpha Wellhead was built first and the other structures were built simultaneously. The successful completion of such a large-scale project is due to committed teamwork with our client GDF SUEZ E&P UK Ltd. During the fabrication of the topsides we implement the design changes.

“This shows the strength and flexibility of our organisation when it comes to building complex structures. During the peak period of this project over 2000 people worked on our Hartlepool yards, where we successfully finished the project safely without major incidents.”

The APU platform is the largest one in the Cygnus field. It is 65x35x25 metres in size and weighs about 4,600 tonnes. The APU platform receives the gas from the Alpha and Bravo Wellhead platform and optimizes the gas to prepare for transportation through a pipeline to the Bacton gas terminal onshore. Once the APU is installed the ACM module, with the 25 metres tall flare boom, will be incorporated on top of the APU topside.

The BWHP, an unmanned Satellite platform, is 42x25x13 metres in size and weighs approximately 3,200 tonnes and is situated circa 7 km from the main hub. The BWHP will be operated remotely from the APU platform. Maintenance and other personnel can reach the platform by helicopter.

The Cygnus field is located in the Southern North Sea, 150 kilometres off the coast of Lincolnshire. It has gross 2P reserves of approximately 18 billion cubic metres. The gas production equals approximately 5 % of UK gas production. The Cygnus partnership is led by operator GDF SUEZ E&P UK Ltd (38.75%) with partners Centrica Energy (48.75%) and Bayerngas (12.5%).

The detailed development concept for the field consists of two drilling centres; the Cygnus Alpha and Cygnus Bravo and in total four platforms. The planned export route is through the ETS pipeline system to the Bacton gas terminal in North Norfolk.

Source: www.offshoreenergytoday.com

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