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Wellhead Flowlines – Offshore Natural Gas Pipelines
Dexon was tasked by a Southeast Asian company with inspecting offshore wellhead pipelines transporting gas from production wells to a nearby processing platform. The shallow-water lines faced two main threats: geometric deformation from currents and unstable supports and corrosion from exposure to a salty, oxygen-rich environment.
Overview
Key challenge:
Inspect multiple offshore wellhead flowlines for geometry and corrosion threats while managing operational variability and maintaining stable ultrasonic inspection conditions.
Project Details
• Length: 1 km × 8
• Diameter: 6-in., 10-in., & 12-in.
• Type: Raw natural gas offshore wellhead flowlines
• Inspection medium: Water
• Threats Assessed: Geometric deformation & corrosion
• Location: Semi-submerged pipeline
• Continent: Asia
• Tools: UT-MC Falcon for high-resolution metal loss & geometry inspection
Challenges & Solutions
Challenge 1:
• Air ingress into seawater-filled pipelines disrupted ultrasonic signal stability during inspection
Solution:
• Identified irregular ultrasonic readings caused by a partially open skillet allowing air into the line
• Coordinated with site personnel to fully isolate the pipeline prior to inspection
• Restored stable ultrasonic coupling conditions and protected data quality
Challenge 2:
• Site personnel had limited familiarity with ILI procedures due to the infrequent nature of inspections
Solution:
• Conducted operational briefings at each location prior to inspection activities
• Distributed simplified inspection guidelines to supporting personnel
• Maintained close communication with operations teams throughout execution to minimize operational risk and avoid inspection delays
Conclusion
Dexon successfully completed nearly a dozen offshore flowline inspections, with additional runs added following the operator’s confidence in the inspection program.
Through close operational coordination, rapid troubleshooting, and adaptable field execution, Dexon minimized inspection risk while delivering reliable geometry and corrosion data for the operator’s assets.