FPSO BOHAI SHI JI Tower Yoke
Scope of Work
SOFEC designed and provided project management for a tower yoke mooring system for a new 172,000 dwt purpose-built double-hull vessel. CNOOC’s nominated fabrication and installation contractor was China Offshore Oil Engineering Corporation (COOEC).
General Description
| Client Name: | China National Offshore Oil Corporation (CNOOC) |
| Contract Award: | December 1999 |
| Installation Date: | August 2001 |
| First Oil: | October 2001 |
| Vessel Size: | 172,000 dwt |
| Storage Capacity: | 1,000,000 bbls |
| Water Depth: | 20m (66ft) |
| Fabrication: | Tower Jacket - China Topsides - China Mooring Yoke and Vessel Support Structure - China Vessel - China Vessel Topsides - China |
Design Environmental Criteria
(100-year storm)
| Significant Wave Height: | 5.1m (16.7ft.) |
| Wind Velocity: | 26m/s (50.6 knots) |
| Current: | 2.1m/s (4 knots) |
| Earthquake | |
| Ice |
Fluid Swivel Assembly
| Production: | 2 x 18-in. toroid (740 psi design) |
| Production / Water Injection: | 1 x 18-in. toroid (740 psi design) |
| Water Injection: | 1 x 18-in. toroid (740 psi design) |
| Medium Voltage: | 3 x 3 phase 10.5 kV @ 510 amps |
| Utility / Control: | 80 Electrical paths (power and signal) |
Riser System
(6) Jacket mounted J-Tubes for subsea pipelines
(3) Jacket mounted J-Tubes for submarine cables
Comments
The SOFEC tower yoke mooring system is located in the QHD32-6 field development in Bohai Bay China, in a water depth of 20m. The FPSO generates and provides medium voltage electrical power to six fixed unmanned satellite platforms. The medium voltage power transmission to the platforms is achieved through a medium voltage slipring assembly mounted on the rotating tower topsides module. The medium voltage power is used to drive 128 submersible pumps installed in the QHD32-6 reservoir. The FPSO is designed to produce a total of 270,000 BPD of combined fluids including 80,000 BPD of crude oil. Processed crude is exported through a tandem offloading arrangement.
The SOFEC tower yoke mooring system is DnV classed.