J-Tube Inspections
AISUS was contracted to clean and conduct a thorough internal inspection of eight J-tubes on an offshore platform within the Middle East, to ensure their structural integrity.
Understanding the ovality of the J-tubes is critical, especially for pull-through umbilical lines, helping to identify internal obstructions. Ultrasonic testing provided corrosion data, while laser profiling displayed surface defects within a 3D model.
Project Requirement
The project required a detailed, multi-stage inspection process in a comprehensive report that left no details overlooked. AISUS delivered a streamlined solution which included reinstalling the messenger lines after inspection.
A custom remote crawler equipped with a camera, designed for J-tube inspections, featured bend capabilities, allowing navigation of the tubes’ curves efficiently.
AISUS prepared to safely cut and remove the messenger wire ready, however, due to blockage in the J-Tubes, our crawler with hydraulic shear could not proceed past the objects tied in the wire. Therefore, an ROV cut five of the J-tubes before the AISUS inspection. This stage also included our high-pressure water jet cleaning to remove marine debris and corrosion scale.
The inspection comprised of ultrasonic wall thickness testing to identify corrosion and assess ovality, ensuring structural integrity to prevent messenger line snagging during platform operations. Laser profiling created a 3D model to highlight surface defects and areas of concern.
After inspection, the crawler equipped with gauge plates finalised the evaluation of the J-tubes internal structure, clarifying any misshapen or protruding welds. A final visual inspection verified cleanliness, with before-and-after comparisons provided through our data management platform. The messenger lines were successfully reinstalled in all eight J-tubes, ready for future use.
Challenges
This comprehensive inspection was time-intensive and involved multiple techniques. Each J-tube faced significant blockages and marine debris near the bell mouth, which required extensive high-pressure jetting.
Limited visibility initially made inspections difficult even after flushing, and the crawler had to navigate bends carefully, especially near termination areas.
The AISUS Solution
Remote topside control allowed seamless operation and real-time data analysis. High-pressure jetting removed marine growth and corrosion scale, ensuring a smooth surface for accurate data collection. A camera was remotely deployed to identify obstructions and verify cleaning quality before ultrasonic testing.
Ultrasonic wall thickness testing provided real-time C-scan data, offering a detailed assessment of wall thickness. Laser scans provided an internal profiling, surface defects and weld circumferences. The crawler, equipped with gauge plates, confirmed structural integrity and identified any anomalies post inspection.
Results
AISUS delivered a thorough inspection of the J-tubes, providing the client with a comprehensive assessment and validated structural condition.
Visual inspection confirmed the removal of blockages and cleaning quality.
Circumferential welds were identified, with ultrasonic testing revealing minimal anomalies.
Only a few areas showed external wall loss, as indicated by ultrasonic and laser data.
Overall, the J-tubes were in good condition. All findings, including visual, ultrasonic, and laser data, were securely stored on AISUS’ online data management platform, enabling historical comparisons for future inspections.
Key Benefits:
- Extensive and Accurate Data Collection: Detailed inspection ensured no detail was overlooked, mitigating future risks.
- Real-Time Results: Enabled quick decision-making, minimising downtime within a single streamlined project.
- Increased Safety: Fully remote inspection eliminated the need for a large team.
- Cost-Effective: Reduced personnel requirements and vendor costs.
- Streamlined Reporting: Secure access to comprehensive reports for inspection data.
Reach out to the AISUS team to find out more, Contact AISUS
AISUS Full Inspection on Multiple J Tubes, Middle East Case Study Video.
