FSO Escravos LPG External Turret
Scope of Work
SOFEC designed and constructed an external turret mooring system for a MODEC purpose-built FSO installed in 42m water depth. The FSO handles the refrigeration and depressurization of LPG for Chevron Nigeria Ltd.
This SOFEC external turret mooring system is ABS classed.
General Description
| Client Name: | Chevron Nigeria, Ltd. |
| Contract Award: | February 1995 |
| Installation Date: | June 1997 |
| Vessel Size: | 37,100 dwt |
| Storage Capacity: | 54,000 m3 |
| Water Depth: | 42.4m (139ft) |
| Fabrication: | Turret - Houston, Texas, USA Vessel - Japan |
Design Environmental Criteria
(100-year storm)
| Significant Wave Height: | 3m (10ft) |
| Wind Velocity: | 30m/s (55.6 knots) |
| Current: | 1.2m/s (2.2 knots) |
Mooring System
Turrets
6-leg Asymmetric catenary:
3-in. ORQ chain
Anchor pile
External Cantilevered Bow
Fluid Swivel Assembly
| LPG: | 2 x 8-in. piggable toroids (690 psi design / 1,035 psi test) |
| Hydraulic Control Swivel: | 8 passes (3,000 psi operating, 4,500 psi test) |
Riser System
2 x 8-in. Flexible riser
Comments
The purpose of this project was the Nigerian goverment’s decree to stop flaring gas from offshore fields. The LPG FSO converts ethane, propane and butane components of the gas stream into liquid products. The liquid products are stored in tanks of the FSO hull prior to being offloaded to LPG tankers that are used to transport the LPG to the market.