Expro ActiveSONAR™  resolves customer metering uncertainty

• An operator of an offshore field with subsea wells tied back to a FPSO was measuring bulk flow rates for a liquid transfer line using daily single point stock tank values
• The customer was experiencing issues reconciling the stock tank to the export line readings
• The customer retrofitted a Vortex meter to the transfer line to provide real-time volumetric measurements to help reconcile the difference between the stock tank and the export readings
• The Vortex meter readings did not match either the stock tank or export line
• Both partner and regulatory reporting requirements meant the customer had to resolve their metering uncertainty
• The customer approached Expro to provide a reliable solution

• Expro proposed using an ActiveSONAR clamp on flow meter to monitor, validate and/or eliminate errors in the existing metering system
• The ActiveSONAR was installed without any modification to the piping
• Initially, the Vortex meter was bypassed and the ActiveSONAR was compared to stock tank readings, which were in agreement
• The Vortex meter was then compared to the ActiveSONAR, which allowed the ActiveSONAR to determine any process issues

• Expro ActiveSONAR™ diagnostic data indicated two different flow characters in the pipe, periods of stable flow and instability
• The Vortex meter showed significant variability in reported flow rates when compared to stable rates reported by ActiveSONAR
• The ActiveSONAR flow rate was within a few percent of stock tank measurements
• Expro was able to highlight the process issues causing the error in the Vortex meter
• The customer resolved the metering issue and was able to report accurate measurements meeting the regulatory requirements

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