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Mega gas project off the coast of Africa nears final stages before start-up

Release date:
4 June 2024
It takes extraordinary engineering and technology to keep the world supplied with energy. The latest example – one of bp’s biggest-ever projects – is coming together in the deep waters of the Atlantic Ocean, off the coast of West Africa
🕒 4 min read | 📖 Feature| 💡 Why it matters

Seven years in the making, something remarkable is taking shape in the ocean where Mauritania and Senegal meet. A project, which includes a breakwater, subsea, a floating liquefied natural gas facility (FLNG), and floating production, storage and offloading vessel (FPSO) – each an engineering feat in its own right – is now in place as the finish line approaches for the development of the Greater Tortue Ahmeyim Phase 1 mega-project.


GTA Phase 1, as it’s known for short, is expected to produce up to 2.3 million tonnes of liquefied natural gas (LNG) per year, helping to meet global demand, and boosting the economies of these two developing economies. 


“It’s a massive civil engineering project, two massive shipbuilding projects, and a massive pipelines project all in one – and they all need to be safely and flawlessly integrated,” says Alan Edwards, project general manager for GTA subsea.

Connecting the pieces 

When complete, GTA will be operated by bp on behalf of its partners, including Kosmos Energy, PETROSEN and SMH. Here’s how the parts of this project work together to produce gas and LNG: 


Subsea pipelines and infrastructure – the deepest in Africa – will feed into a floating production, storage and offloading vessel (FPSO) that will process gas delivered from wells 2,800 metres underwater, around three times the height of the world’s biggest skyscraper, the Burj Khalifa.


Constructed in China over the course of six years, the FPSO arrived at its GTA home in May 2024, 40 kilometres offshore. With this final major piece of the puzzle in place, the project can move ahead towards commissioning, start-up and first gas production.


“The scale of the technology and engineering required for this project was in a league of its own. The FPSO alone came with a set of unique challenges – from transporting it to the Atlantic from China, to battling damaging typhoons,” says Anil Senol, project general manager tasked with the transportation and installation of the FPSO.

Connected to the subsea network by flexible pipelines, the FPSO will remove water, other liquids and impurities before the gas is transferred by another pipeline to a floating liquefied natural gas vessel (FLNG), called Gimi, which is owned and operated by Golar LNG. 

The FPSO in numbers

The vessel sits in about 120 metres of water

It will have up to 140 people on board during full operation

It has an area the size of 2 football pitches and is 10 storeys high

It is made up of more than 81,000 tonnes of steel

Located 10 kilometres offshore, Gimi is berthed at a specially-built hub terminal. This includes a 1.25-kilometre-long breakwater made up of 21 giant 16,000-tonne concrete structures, each nearly the size of the Arc de Triomphe. It was constructed to protect both Gimi and visiting LNG carriers from bad weather. 

Once the gas arrives at the FLNG facility, it will be cooled to temperatures below minus 160ᵒC to transform it into liquefied natural gas. In total, Gimi is designed to produce around 2.3 million tonnes of LNG a year. Visiting LNG carriers will then take the LNG to its buyers. 


Integration in gas

bp aims to provide energy to customers in whatever form they need it, and LNG is a key piece of our integrated offer.

With projects like GTA Phase 1 supplying LNG, our trading team, together with our shipping fleet, can move LNG products quickly to where they are needed most. That provides flexible solutions for customers, helping us continue to meet growing demand.


Inside integrated energy at bp

An industry first

Before starting on any construction, bp teams needed to first determine the best way of working in ultra-deep water. 

“Working in these water depths was a first for bp and this project is one of the deepest in the industry. This was without doubt the biggest challenge I’ve faced in my career,” says Tim Farrant, subsea engineering manager. 

The project required the building of hundreds of kilometres of subsea pipelines and control systems to extract and transport the gas safely through the wells and subsea infrastructure on the seabed 120 kilometres off the coast of Mauritania and Senegal. bp’s contractors also installed fibre optic cables and structures on the seabed that then needed to be connected with the utmost precision.

“Working in these water depths was a first for bp and this project is one of the deepest in the industry. This was without doubt the biggest challenge I’ve faced in my career.”

Tim Farrant, discipline lead for subsea engineering


The seafloor in this area of the Atlantic is so deep that robots rather than divers were used to connect the infrastructure. The pipelines also needed to be longer than on most projects, given the locations of the fields, the FPSO and the hub terminal.


“It’s been possible for us to develop this project because of the techniques and expertise we’ve developed working on projects in places like the Gulf of Mexico and the North Sea,” says Edmund Wynne-Williams, project general manager for integration. “GTA phase 1 has taken our capabilities to new limits.”

💡 Why it matters

Demand for LNG around the world is growing. The Greater Tortue Ahmeyim (GTA) project will help to meet that demand, with Phase 1 planned to produce around 2.3 million tonnes of LNG per year for about 20 years. 


GTA Phase 1 is the first step towards creating a potential LNG production hub in Mauritania and Senegal, with expansion options beyond Phase 1 being evaluated.  


To support the GTA Phase 1 operations, bp has hired locally, when possible. Local workforce development is another priority and bp created a national technician training programme with nearly 50 participants taking part.  

“Technicians on our training programme have had the opportunity to work at bp operating assets in Azerbaijan, Oman, Trinidad and Indonesia, so they can gain the operating experience needed to succeed at GTA. The goal is for them to become the core of the team who will operate and maintain the GTA assets for years to come,” says Rebecca King, vice president of production for Mauritania and Senegal. 


bp has also worked closely with communities in Mauritania and Senegal, using local and regional suppliers when possible. Our suppliers must also have local content plans to develop local talent and source goods and services locally, where appropriate.


As part of a social investment strategy, bp has been involved with initiatives related to economic development, health, education and the environment. By 2023, both, Ndiago, Mauritania, and St Louis, Senegal, communities had benefited from social investment implemented projects.

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