Key facts

Location: Gulf of Mexico, USA; 320 kilometres (200 miles) south-west of New Orleans, Louisiana

Water depth: 2,900 metres (9,500 feet)

Interests: Shell 100% owner and operator

Field: Stones field, discovered in 2005

Production: An estimated 50,000 barrels of oil equivalent (boe) per day at peak production.

Project overview

Shell announced the final investment decision to develop the Stones field in May 2013. Work then began to construct and fabricate the floating production, storage and offloading (FPSO) vessel and subsea infrastructure. The FPSO, called Turritella, set sail from the shipyard in Singapore in October 2015 and arrived in the Gulf of Mexico in January 2016.

Development of the Stones field began with two subsea production wells tied back to Turritella. Six further production wells will be added later, as well as a multi-phase system to pump oil and gas from the seabed to the FPSO, increasing recoverable volumes and production rates. All eight wells will be connected to Turritella. The reservoir depth is around 8,077 metres (26,500 feet) below sea level, and 5,181 metres (17,000 feet) below the mud line.


An FPSO design was chosen to produce oil and gas safely and efficiently from the Stones ultra deep-water field. Tankers transport oil from Turitella to US refineries, while a pipeline transports gas.

Stones uses a special type of flexible pipe, known as a steel lazy wave riser, to carry oil and gas to Turritella for processing. Shell pioneered steel lazy wave risers, which have additional buoyancy creating an arched bend in the pipes between the seafloor and the surface. This bend helps to absorb the motion of the FPSO and boosts production performance at extreme depths.

The FPSO features a turret, into which fits a disconnectable buoy carrying mooring lines and risers from the well system. The turret and buoy design allows the vessel to turn with the wind during normal weather conditions. If a heavy storm or hurricane approaches, the vessel is able to disconnect from the buoy and sail to safer waters.The Stones project represents the first use of a disconnectable buoy configured with steel lazy wave risers to unlock resources of oil in ultra-deep waters.

Shell has more than a dozen deep-water FPSOs around the world. Turritella is the first FPSO we are using in the Gulf of Mexico.

Environment and society

Shell prioritises social and environmental responsibility. Our Gulf of Mexico operations are closely tied to Louisiana and the city of New Orleans. Following Hurricane Katrina we contributed to several recovery programmes. Shell is also involved in projects to protect the Louisiana coast and restore wetlands.

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View of the floating production, storage and offloading vessel (FPSO) at sea.

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