The Largest LNG Supplier in the Middle East
The client operates a liquid butane custody transfer skid equipped with a Coriolis flow meter, pressure, and temperature transmitters. To ensure compliance with stringent custody transfer regulations, the client sought verification that their system could achieve the required ≤±0.25% total uncertainty at 95% confidence level. While confident that pressure and temperature compensation was sufficient, the client required independent validation to confirm system accuracy.
Key notes
- Industry: Oil & Gas (Custody Transfer – LNG / NGLs)
- Fluid: Liquid Butane
- System: Coriolis flow meter with temperature & pressure compensation
- Impact: Identified hidden uncertainty source (standard density); enabled pathway to achieve ≤±0.25% compliance
- Quantified actual skid uncertainty and proved it exceeded the custody transfer threshold.
- Pinpointed standard density as the dominant uncertainty driver.
- Corrected the misconception that P&T compensation alone was sufficient.
- Provided clear recommendations to reduce uncertainty and achieve compliance.
Engineerim was engaged to conduct a detailed measurement uncertainty analysis of the butane skid. Our team:
- Evaluated the complete skid configuration, including Coriolis flow meter, temperature, and pressure elements.
- Applied ISO GUM methodology to calculate overall uncertainty at 95% confidence.
- Identified the contribution of each measurement component and assessed compliance against regulatory custody transfer limits.
The analysis revealed that the skid’s overall uncertainty was higher than the ±0.25% regulatory limit. The single largest contributor was the standard density assumption, driven by the absence of live density measurement. This finding was a significant revelation for the client, who had previously relied on pressure and temperature compensation alone to meet requirements. Engineerim’s proprietary calculation approach highlighted the precise source of error and provided actionable guidance on how to reduce uncertainty to within acceptable levels.
By leveraging Engineerim’s independent analysis, the LNG supplier gained unprecedented clarity into the true drivers of their metering skid’s performance. The findings enabled the client to take corrective steps toward compliance with custody transfer regulations and safeguarded the integrity of their commercial transactions.
Engineerim’s independent uncertainty analysis exposes hidden error contributors, ensuring custody transfer systems meet regulatory standards and giving operators defensible assurance of accuracy.