Seawater package to protect Liza production system from scaling

Oct. 16, 2019
SBM Offshore has contracted VWS Westgarth to supply a seawater treatment package for ExxonMobil’s FPSO Liza Unity offshore Guyana.

Offshore staff

EAST KILBRIDE, UKSBM Offshore has contracted VWS Westgarth to supply a seawater treatment package for ExxonMobil’s FPSO Liza Unity offshore Guyana.

The scope covers design and procurement of equipment with construction technical assistance for a package handling 263,244 b/d of low sulfate water and 31,700 b/d of reverse osmosis process water.

VWS will supply the seawater system as two fully-integrated process modules, incorporating the sulfate reduction (SR) nano-filtration membrane process to selectively remove barium and strontium from the injected seawater, preventing formation of barium or strontium scale in the reservoir or production pipe internals.

The SR process is said to leave other salts, including sodium and chloride, substantially unaffected, maintaining the stability and permeability of the oil reservoir formation clays.

The Liza Unity, the largest capacity FPSO that SBM Offshore has designed, according to VWS, will be spread moored in a water depth of 1,633 m (5,356 ft) and will be able to store around 2 MMbbl of crude oil.

10/16/2019