Project Profile
Location: Gulf of Mexico, 320 km off Louisiana in Walker Ridge Block 508, USA
Reserves: 250 MMboe
Production: 50,000 boepd (by the end of 2017)
Water Depth: 2,900 metres
Start-up Year: 2016
Shell has decided to move forward with development of its Stones project in the Gulf of Mexico, paving the way for fabrication of the field’s proposed floating production vessel and subsea infrastructure. The ultra-deepwater oil and gas field development would host the deepest production facility in the world, while not disclosing a capital expenditure figure. Shell aims to exploit the field’s estimated 250 million barrels of oil equivalent in recoverable resources using an initial two subsea production wells tied back to a floating production, storage and offloading vessel, with six more wells to be added later.
It will be the first US Gulf field to be developed by the company using an FPSO and only the second such development planned for the region. Petrobras has also utilised such a unit at its Cascade-Chinook project. An FPSO design was selected to develop the find due to the relative lack of infrastructure, seabed complexity and unique reservoir properties. Multiphase seafloor pumping is planned for use in a later phase to pump oil and gas from the seabed to the FPSO, increasing recoverable volumes and production rates. Shell had earlier been working with Dutch contractor SBM Offshore on a front-end engineering and design study based on a dynamically positioned floater.
The floater would have a turret with disconnectable buoy to allow it to weathervane in normal conditions and disconnect from the well systems during the US Gulf hurricane season or in other adverse weather states. It would also have a lazy wave riser configuration with steel centenary risers with buoyancy added with an arch bend to decouple the FPSO’s dynamic motion and so boost riser performance. Shell is targeting peak output of 50,000 barrels of oil equivalent per day under the first phase of development at the field, which holds an estimated 2 billion boe in place and is believed by the company to have significant upside potential. Shell wholly owns and operates the field, discovered in 2005 and located in 2896 metres of water about 320 kilometres off Louisiana in Walker Ridge Block 508. Shell predicts that peak production be achieved during the first phase of development in 2016.
Operators:
Shell: Operator with 100% interest
Contractors:
FMC Technologies: Supply subsea equipment
SBM Offshore: FEED contract based on a dynamically positioned floater and a Floating Production Storage and Offloading (FPSO) vessel for the 10 years
Technip: Contract for the development of subsea infrastructure for the Stones project. Included in the service are two subsea production tie-backs to the Floating Production, Storage and Offloading (FPSO) vessel. The contract covers; the engineering of the required second pipeline end terminations (PLETs), fabrication of the PLETs and piles and installation of the subsea production system, inclusive of associated project management, engineering and stalk fabrication.
Strainstall UK Limited alongside SBM Offshore: Use of an FPSO (Floating Production Storage and Offloading) which has a forward mounted turret with a disconnectable buoy (Buoyant Turret Mooring or BTM) allowing it to weathervane in normal conditions and disconnect from the FPSO upon the approach of a hurricane so that the FPSO can sail to a safer area
Mitsubishi and Nippon Yusen Kabushiki Kaisha Line (NYK Line) Acquired floating production, storage and offloading unit that will service Shell\'s Stones project from SBM Offshore
OneSubsea: Contract to supply subsea processing systems for the Shell Offshore Inc. Stones development in the Gulf of Mexico. This award follows a Technology Qualification Program and will deliver the industry’s first 15,000-psi subsea pump system, to be installed in the Gulf of Mexico at approximately 9500 ft (2900 m). The subsea processing systems scope of supply includes a dual pump station with two 3-megawatt single-phase pumps and two subsea control modules, a topside power and control module, a barrier-fluid hydraulic power unit with associated spares as well as installation and maintenance tools. Manufacturing and testing will take place at OneSubsea’s processing center of excellence facility in Horsoy, Norway.
Sub contractor:
BMT Scientific Marine Services: Provide integrity and structural monitoring systems for SBM Offshore