The FPSO Turritella, which is named after a small sea snail, is part of the company's multibillion-dollar 100%-owned high pressure/high temperature Stones development.
Stones is located some 320km southwest of New Orleans, Louisiana, and is expected to start production in the new year.
Shell approved the Stones development in 2013, almost eight years after the discovery well.
Shell announced the development at a time when much of the deepwater Gulf of Mexico industry was paralysed by BP's blunder at Macondo, a field that is nowhere near as deep as Stones.
SBM Offshore converted and will operate the Turritella, a converted Suezmax vessel.
There has been a move away from platforms in the Gulf, especially in remote deepwater areas, in order to make new field developments economically viable, and with swivel turrets FPSOs may be better placed to ride out hurricanes.
The facility is expected to hit a peak production of 50,000 barrels per day from two subsea wells of early production, with plans to add six more wells as the field matures.
Stones is a Lower Tertiary field in the Walker Ridge area of the gulf, estimated to hold more than two billion barrels of oil equivalent in place, with a recoverable 250MMboe.
The Lower Tertiary is potentially the GoM's most lucrative play with an estimated 15Bbl play, which has only been produced since 2010's start up with the Perdido platform.
The reservoir depth is around 8077m below sea level and 5181m below the mud line, and
Shell is pushing the limits of technology given the pressures and temperatures involved, and the uneven porosity and permeability that offer geological risks.
Further, the low gas-to-oil ratio means the reservoirs have relatively low energy.
Turritella is the company's first FPSO in the Gulf of Mexico although it operates similar vessels at other locations worldwide, including the Parque das Conchas development offshore Brazil, and is planning one of the world's first floating LNG facilities in Australia at Prelude.
Elsewhere in the Gulf, Shell has awarded a contract to Oceaneering International for the supply of 60km of electro-hydraulic steel tube control umbilicals for the deepwater Appomattox development located in the Mississippi Canyon area.
This contract is another award by Shell to Oceaneering for a state-of-the-art umbilical under an enterprise frame agreement executed in November 2012.
The Appomattox development will initially produce from the Appomattox and Vicksburg fields, with average peak production estimated to reach 175,000 boepd.
Appomattox sits in 2200m of water about 130km from the Louisiana coast.
It will be Shell's eighth and largest floating platform in the Gulf.
Onshore, Shell has cancelled its Westward Ho pipeline in Texas.
The Louisiana-to-Texas has been shelved after years of delays and reductions in scope, which saw the development of other pipelines.
Proposed in 2011 at a top capacity of 900,000 bopd, Shell said Westward Ho would move Gulf of Mexico and imported crudes from the St James oil hub to Houston.
The line was intended to accommodate growth in medium sour and other crudes.
It also would restore a flow from Louisiana to Texas after Shell reversed its Houma-to-Houston pipeline - now called Zydeco - to move Texas crudes to Louisiana.
In mid-2012 the company scaled back the capacity to 300,000bopd, but said it would be possible to increase capacity to 900,000bopd, however there was a lack of interest in the project, and it was soon outpaced by other pipelines.
