Allseas wins pipelay contract for BP's 'biggest project'

Allseas starts subsea pipelay work for BP’s giant LNG project in Africa

Swiss-based construction company Allseas has commenced work on UK energy major BP’s ultra-deepwater Greater Tortue Ahmeyim (GTA) liquified natural gas (LNG) project offshore Mauritania and Senegal, with its vessels executing the subsea pipelay scope.

Courtesy of Allseas

According to Allseas, its construction support vessel (CSV) Oceanic started the offshore campaign by landing the first structure in the target box at 2800 meters of water depth.

Allseas said: “In-house capability is key to our success. The ability of our fabrication team to perform PLET modifications and build the 1000-ton J-mode frame, designed in just two months by our Innovations team. Pipeline Production worked their magic, completing the welding and FJC qualification programs at a super-fast pace. Equipment preparation was a push, but in true Allseas style, everything was delivered on time.”

Construction vessel Pioneering Spirit will complete the pipelay scope, which covers the approximately 75 kilometers outstanding on the two 16-inch export gas lines and four 10-inch CRA infield lines, with multiple structures, Allseas revealed, adding that Oceanic will be on hand to provide first-class support.

To remind, BP awarded Allseas with a contract to perform the subsea pipelay scope for the GTA natural gas project in October 2023.


The GTA project development envisions the production of gas from an ultra-deepwater subsea system and mid-water floating production, storage and offloading (FPSO) vessel, which will process the gas, removing heavier hydrocarbon components. The gas will then be transferred to an FLNG facility. The first phase is expected to produce around 2.3 million tons of LNG per year.

As previously reported, BP sees the GTA gas development as “the biggest project” in its portfolio, which has “enough gas to support production for at least 20 years.”

In November 2023, the company revealed it is two months away from welcoming the floating liquefied natural gas (FLNG) unit Gimi that will be part of the project.

According to Golar LNG, owner and operator of LNG midstream infrastructure, the FLNG Gimi departed Singapore’s Seatrium shipyard on November 19, 2023, and is sailing under its own propulsion, supported by an escort tug, toward the GTA hub.