Culzean: A Large Gas Project in the North Sea

Location: United Kingdom
Partners: TotalEnergies (49.99%), BP (32%), JX Nippon (18.01%)
Main activity: Gas condensate production
Commissioning: 2019

of the United Kingdom’s gas demand to be met by Culzean
United Kingdom map
The Culzean project in the British North Sea

Culzean is a gas condensate field located in the North Sea, 230 kilometers off the coast of Aberdeen. It was discovered in 2008 in an area that had been left unexplored for a long time. The field is made up of two deep reservoirs, with reserves estimated at between 250 million and 300 million barrels of oil equivalent, making it the largest gas project developed in the United Kingdom in the last 25 years.  

The largest North Sea gas project in a quarter of a century

Culzean is a high-pressure, high-temperature (HPHT) gas condensate field located in Block 22/25a in the East Central Graben area of the central North Sea. It is made up of two deep reservoirs 4,300 meters below sea level, with reserves estimated at between 250 million and 300 million barrels of oil equivalent. Production started in June 2019 and should meet 5% of the United Kingdom’s gas demand, bringing to 18% the proportion of the country’s gas demand supplied by TotalEnergies.

The depth and size of the reservoirs require a unique approach to production. For this reason, the Culzean project will have three platforms, linked together with bridges. The first platform will be used for drilling and hydrocarbon production, the second for processing and export of produced gas and condensate, and the last for the crew’s living quarters. The project will also include a floating storage and offloading (FSO) vessel measuring 52 meters at its highest point and 243 meters in length – the equivalent of three Airbus A380s, the biggest airplane in the world. Called the Ailsa, the FSO can store up to 430,000 barrels of oil equivalent of condensate.

Since taking operatorship of the Culzean project following the acquisition of Maersk Oil in 2018, we have worked alongside our partners to perfect our technologies and operating methods at each stage of development. For example, we have implemented more efficient drilling techniques, allowing us to reach depths of up to 5,000 meters. We have also optimized the supply chain. These efforts helped reduce costs by $500 million, or about 10% of the initial estimated budget.


million barrels of reserves
of the United Kingdom’s gas demand met by Culzean
depth* of the reservoirs
* in meters

A project using cutting-edge technology

Culzean is TotalEnergies' most advanced digital offshore facility. Right from the earliest stages of the project, new technologies were used to ensure safety and performance and to facilitate communication and collaboration within the operations teams.

During the design phase, a virtual-reality model of Culzean was created – complete with walk-in software and avatars – to assess risks and identify solutions. This also enabled engineers to optimize the infrastructure by improving space efficiency and making access to equipment easier for the operators.

Digital technologies also ease day-to-day operations by bringing onshore and offshore staff closer together. For example, Culzean includes a SMART (Support and Monitoring of Assets in Real Time) room where data is collected to help manage production and maintenance work. More than just a physical space, the SMART room is an operating philosophy underpinned by a range of digital tools, designed to ensure seamless, effective communication among onshore support crews, SMART room staff and offshore operators. As part of this, offshore technicians are provided with hand-held devices so they can receive real-time information from the onshore support sites, enabling them to react rapidly if needed and increasing efficiency. Thanks to all the technologies deployed, Culzean is a truly forward-looking project.