Shell, INEOS Plan More Joint Tiebacks in US Gulf

INEOS Group and Shell PLC signed an agreement Tuesday to jointly invest in more projects that would use their existing Appomattox production hub in the Gulf of America.

"INEOS is acquiring a 21 percent working interest for an undisclosed amount, consistent with its ownership in Appomattox, Rydberg, the recent Nashville discovery and the Mattox pipeline", the chemical company said in an online statement.

As part of initial assets targeted by the agreement, which covers both exploration and development opportunities, the British companies will develop the Fort Sumter discovery, which has yet to reach a final investment decision.

Initial estimated recoverable resources for the deepwater well in Mississippi Canyon Block 566 exceed 125 million barrels of oil equivalent (MMboe), as announced by Shell July 28, 2016.

The tieback collaboration also includes drilling of the Sisco exploration well. Also targeted is another exploration well planned for drilling by 2030.

"The agreement supports INEOS Energy's broader growth strategy, building on established positions in the Gulf of America, Eagle Ford South Texas, offshore Denmark and the UK continental shelf, while further strengthening collaboration with Shell to pursue future growth and expansion opportunities", INEOS said.

INEOS Energy chief executive David Bucknall said, "We are focusing on areas close to existing infrastructure where we can move quickly, control costs and unlock new production. This is disciplined growth targeting exploration, shared risk and returns".

INEOS added, "This agreement builds on a state-of-the-art facility, integrating the early production assets of Appomattox and Rydberg with existing pipeline infrastructure to deliver high-margin barrels".

Rydberg is the first tieback to Appomattox. It went online in the first quarter of 2024. Rydberg has a capacity of 16,000 barrels of oil equivalent a day (boed). Discovered 2014, it has proven and probable (2P) reserves of about 38 MMboe, according to Shell.

Last year Shell put into production the second tieback. Dover, discovered 2018, produces up to 20,000 boed, according to Shell. It estimates 44.5 million boe of 2P reserves in Dover.

The Nashville discovery of 2025, which INEOS said is its "first successful exploration well in the region", is also planned as a tieback to Appomattox.

"The Nashville exploration well was drilled more than five miles beneath the seabed and confirmed high-quality oil in one of the Gulf's most promising deepwater formations", INEOS said in a press release December 22, 2025. "Further technical work is now underway to determine the size of the find".

As of 2025 Shell was operator of 10 production hubs in the Gulf of America, its main production region in the United States, according to the company's annual report. Besides Appomattox, the other hubs are Auger, Enchilada/Salsa, Mars, Olympus, Perdido, Stones, Ursa, Vito and Whale.

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