Technip - Ensuring the integrity of deep-sea pipelines

BUSINESS CHALLENGE

In May 2003, Technip was awarded a major contract by Total E&P to construct a pipeline for the deepwater Dalia oil field, discovered in 1997, 135 km off the Angolan coast. The project entailed the use of a 16-inch diameter pipe-in-pipe (PiP) flowline. This would be constructed onshore, spooled onto a ship-mounted reel in batches of 5-6km, then unwound onto the seabed at the Dalia site. To ensure the integrity required of such deep-sea pipelines, Technip sought a third-party monitor who would oversee quality inspections during the welding and coating processes, and provide quality control for both documentation and materials.

SOLUTION

Adherence to strict industry norms during the construction of the Dalia pipeline was crucial, especially as it is expected to remain functional for 20 to 30 years at depths of 1,400 to 2,000 meters below sea level. Consisting of a standard production pipe insulated within a larger-diameter ‘carrier’ pipe, the PiP system both protects the inner pipe from external pressure and maintains the temperature required for a continual flow of extracted crude oil. Technip assembled the reeled PiP flowline for Dalia at its spool base in Dande, about 80km north of the Angolan capital of Luanda; Bureau Veritas provided eight experts to oversee quality control. Three welding inspectors monitored the results of NDT (non-destructive testing) procedures – radiography and ultrasound – used to verify each weld as the 12-meter-long steel PiP sections were assembled into one continuous length. Next, two more Bureau Veritas experts oversaw inspections during the corrosion-preventing coating process. While rigid pipe is usually coated at the mill where it is produced, ends are left untreated so as not to inhibit the welding process. These bare zones require on-site coating after welds have passed inspection; high precision is essential, to ensure the protective layer’s continuity and uniformity. Away from the manufacturing chain, Bureau Veritas provided experts to monitor both documentation (work permits, non-conformity reports, corrective claims, etc.) and traceability of materials from receipt of goods to manufacturing.

BENEFITS

With a firm presence already established in Angola, and years of experience conducting inspections in the petrochemical industry, Bureau Veritas immediately integrated itself at Technip’s spool base as a key partner. First, oversight of documentation and materials guaranteed transparency and traceability on the administrative side of the project. Furthermore, trust in Bureau Veritas’ inspections expertise allowed Technip to focus entirely on the construction process, promoting efficiency in the manufacturing chain. Finally, by trusting a third-party monitor to oversee quality control, Technip could thus ensure the long-term integrity of the pipeline to its employer, Total, with a potential long-term benefit of lower maintenance costs.