Oil Detection Through Bearing Failure: Protecting Critical Equipment with Continuous Oil-in-Water Monitoring
2 September 2026
Rotating equipment is at the heart of many oil & gas operations. Pumps, turbines, compressors and generators all rely on bearings to operate efficiently, with lubricating oil providing the protection needed to minimise wear and maintain reliability. However, when a bearing begins to fail, lubricating oil can escape into surrounding water systems, cooling water circuits or drainage systems, creating both an environmental risk and an early warning sign of mechanical failure.
By continuously monitoring for hydrocarbons in water, operators can identify leaks at an early stage, allowing maintenance teams to intervene before equipment damage becomes severe, production is interrupted or environmental regulations are breached.
Why Bearing Failure Can Lead to Oil Contamination
Bearings are designed to retain lubricating oil within a sealed system. As bearings wear, seals deteriorate or mechanical damage occurs, oil can migrate into cooling water or other process water systems.
Common causes include:
- Bearing wear due to age or inadequate lubrication
- Seal degradation caused by vibration or excessive temperatures
- Mechanical damage from shaft misalignment
- Fatigue resulting from continuous operation
- Unexpected equipment failures during high-load conditions
Even relatively small quantities of oil entering water systems can indicate that a larger mechanical problem is developing. Detecting these leaks early allows maintenance to be planned before catastrophic bearing failure occurs.
The Cost of Undetected Oil Leaks
Waiting until a bearing completely fails can have significant consequences throughout an operation.
These may include:
- Unplanned shutdowns
- Expensive bearing and rotating equipment replacement
- Environmental pollution from oil discharge
- Regulatory non-compliance
- Increased maintenance costs
- Lost production and reduced plant availability
Rather than relying solely on vibration monitoring or routine maintenance inspections, many facilities are now incorporating continuous oil-in-water monitoring as part of their predictive maintenance strategy.
Continuous Oil Detection Provides Early Warning
Oil-in-water analysers continuously sample process or cooling water and measure hydrocarbon concentrations in real time. Instead of waiting for visible oil or laboratory test results, operators receive immediate notification when oil concentrations begin to increase.
This provides valuable time to:
- Investigate equipment condition
- Schedule maintenance during planned shutdowns
- Prevent secondary damage
- Reduce environmental impact
- Protect downstream treatment systems
Continuous monitoring also provides historical trend data, helping engineers understand equipment health over time and identify gradual deterioration before failures occur.
Arjay HydroSense Technology
Arjay Engineering has developed the HydroSense range of Oil-in-Water Analysers specifically for continuous hydrocarbon monitoring in industrial applications.
Using non-contact UV fluorescence technology, the analyser detects petroleum hydrocarbons within a continuous flowing sample. The optical sensor remains above the sample stream, reducing fouling and maintenance requirements while delivering reliable long-term measurement. The technology can be site calibrated to specific oil types, providing accurate indication of hydrocarbon concentrations within the required monitoring range.
Key benefits include:
- Continuous online monitoring
- Early detection of bearing oil leaks
- Non-contact optical sensing
- Low maintenance operation
- Configurable alarms and analogue outputs
- Suitable for hazardous area installations with selected models
- Integration into plant control and SCADA systems
Typical Oil & Gas Applications
Continuous oil monitoring can support numerous applications throughout upstream, midstream and downstream facilities, including:
- Turbine cooling water systems
- Generator bearing lubrication systems
- Compressor lubrication circuits
- Produced water monitoring
- Cooling water discharge monitoring
- Equipment drainage systems
- Environmental discharge compliance
- Separator and processing facilities
For operators running critical rotating assets, these systems provide an additional layer of protection alongside traditional condition monitoring technologies.
Supporting Predictive Maintenance
Modern predictive maintenance programmes increasingly combine multiple monitoring techniques, including:
- Vibration analysis
- Temperature monitoring
- Oil analysis
- Bearing condition monitoring
- Continuous oil-in-water detection
Together, these technologies provide a more complete picture of equipment health, allowing maintenance teams to identify developing faults earlier and reduce the risk of unexpected failures.
Process Instrument Solutions – Your Partner for Arjay Engineering
As an representative for Arjay Engineering, Process Instrument Solutions (PIS) supplies, supports and commissions the complete range of Arjay oil detection and monitoring technologies for industrial applications.
Whether your objective is protecting critical rotating equipment, monitoring produced water, safeguarding environmental discharges or improving predictive maintenance, our engineers can help specify the most appropriate solution for your application.
Our support includes:
- Application advice
- Product specification
- System integration
- Commissioning
- Technical support
- Ongoing service and maintenance
With extensive experience supplying instrumentation to the oil & gas industry, Process Instrument Solutions works closely with customers to deliver reliable monitoring solutions that improve equipment reliability, reduce environmental risk and minimise costly downtime.
Speak to the Experts
If you’re looking to improve early detection of bearing failures, enhance environmental compliance or strengthen your predictive maintenance strategy, contact Process Instrument Solutions to discuss the Arjay HydroSense range of Oil-in-Water Analysers and discover how continuous hydrocarbon monitoring can help protect your critical assets.