A North Sea oil production platform was generating 8,000 m³/day of produced water with oil-in-water concentrations exceeding the OSPAR 30 mg/L discharge limit. Reynolds & Bauhm designed a compact skid-mounted treatment system for platform installation.
The platform was producing oil from a maturing reservoir with increasing water-cut. Produced water volume had grown from 2,000 to 8,000 m³/day over 4 years, exceeding the capacity of existing hydrocyclone separators. Oil-in-water at the overboard discharge point was consistently 45–85 mg/L — above the OSPAR Convention 30 mg/L limit (instantaneous) and 40 mg/L monthly average.
Reynolds & Bauhm designed a compact, ATEX-certified skid combining induced gas flotation and walnut-shell media filtration, meeting the platform weight and footprint constraints:
| Stage | Equipment | Performance |
|---|---|---|
| 1 | Existing hydrocyclone separators (retained) | Oil reduced from 120 to 50–80 mg/L |
| 2 | De-emulsifier dosing (produced gas injection) | Droplet coalescence; d50 >30 µm |
| 3 | Induced gas flotation (3-cell series) | Oil 80 → 15–20 mg/L |
| 4 | Walnut-shell media filter (duty/standby) | Oil 20 → <10 mg/L; iron <2 mg/L |
| 5 | UV fluorescence oil-in-water analyser | Continuous compliance monitoring; OSPAR data logging |
| 6 | Overboard discharge or reinjection | OSPAR compliant at <10 mg/L OIW |
Oil-in-water at discharge consistently <10 mg/L — three times below the 30 mg/L limit. Zero exceedances in first 18 months of operation. Enforcement notice withdrawn.
Total system weight: 38 tonnes ( 45 tonnes). Footprint: 24 m² ( 30 m²). Installed during 14-day scheduled shutdown with no production interruption.
System operates with zero additional operator attendance above existing duties. Automated backwash and dosing control confirmed by 6-month unattended performance review.
SCADA-linked instrumentation transmits performance data to shore-based engineers, enabling predictive maintenance and rapid troubleshooting without offshore visits.
Treatment solutions for produced water from onshore and offshore oil fields.
Produced WaterDissolved and induced gas flotation for oil separation in produced water.
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