CASE STUDY

China National Offshore Oil Company (CNOOC) – FPSO 116 at Wenchang oil field


Background

CNOOC was seeking a new technology to replace the water treatment technology at the FPSO.The FPSO is receiving and treating feed from threedifferent platforms, each with verydifferent produced water characteristics.  The water treatment technology should handle 350 m3/hr (52,500 BPWD) and ensure that the water has less than 30 PPM  oil in water for discharge to sea.


Performance

CNOOC was seeking a new technology to replace the water treatment technology at the FPSO.The FPSO is receiving and treating feed from threedifferent platforms, each with verydifferent produced water characteristics.  The water treatment technology should handle 350 m3/hr (52,500 BPWD) and ensure that the water has less than 30 PPM  oil in water for discharge to sea.

Stauper field test:

Stauper brought its test unit to the FPSO in February 2017. Tied in at the separator,and acting as the only water treatment unit, the inlet oil in waterinto the Stauper CFU varied from 92 to 142 PPM.  During the test, the Stauper CFU cleaned the water down to 10 PPM OIW (with target of 30 PPM). The conclusion was that the Stauper CFU is suitable and robust enough to replace the current water treatment system on the FPSO.

Stauper full scale unit

In 2018, a 350 m3/hr CFU was installed at the FPSO. Operating as the only water treatment technology on the FPSO and without any use of flocculant the full scale unit is treating the water down 10 ppm oil in water and with an average oil in water of 17 PPM, well below the requirement of 30 PPM. No flocculants are used in the process. The CFU installation was delivered in partnership with Stauper´s partner, BOMESC Offshore Engineering Company Limited.


Conclusion

The CFUs are installed as the only water treatment technology at the FPSO and the full-scale units are performing at par with the pilot. The water fed into the CFU is a complex composition with small oil droplets from several separators. The CFU is proving to be efficient and stable and as a result CNOOC has approved the delivery.


Key stat

Oil in Water Out: 10 PPM

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