Maintaining asset integrity on offshore structures is a priority, which is why owners invest in developing regular maintenance programs to identify irregularities as soon as possible. During a scheduled inspection on an offshore production unit working offshore Africa, workers discovered corrosion on a 26-in. (660-mm) topside production piping system. The pipe needed immediate attention, but the owners did not want to shut in production while the repair was being made. They contracted CSNRI to provide an engineered composite repair solution to be carried out with the critical production line in service.
The complete pipework had suffered severe external corrosion that affected straight pipe lengths, girth welds, pipe support, T’s, tight radius bends and offtakes. CSNRI engineers determined the extent of the corrosion and performed a complete in-house engineering analysis to develop a bespoke repair solution that was manufactured in the company’s design facility in Houston.
Because of the range of areas affected, the solution included Clock Spring fully cured laminate as well as CSNRI Contour wet layup repair, which would be used for the complex geometry configurations. CSNRI engineers presented the client with a detailed design report outlining the complete repair in accordance with both ASME PCC-2 and ISO TS24817 guidelines.
A team of CSNRI trained and certified technicians installed standard Clock Spring 8-layer pre-cured coil sleeves to the straight piping sections, pipe supports, girth welds and 12-inch (305-mm) offtake systems. Because of the extent of the corrosion, installers applied high-compressive-strength filler by hand, molding it in place before installing the Clock Spring coils. The limited clearance between the pipework and deck grating required installers to use a spool feeder to place the repair sleeves.
With repairs made to the straight pipe runs, the team turned its attention to the complex geometry sections that interfaced with the reinforced sections. CSNRI engineers designed the Contour system specifically for this repair, supplying materials to the work site in component form and mixing them by hand to form the composite repair around the structure on site.
With the repair complete, the topsides was restored to a safe condition for extended service. The CSNRI design team not only provided safe, quickly executed and effective specialized repairs, but offered complete engineering support following installation.
- 26-inch (660-mm) topside production piping system; and
- Severe external corrosion .
- Clock Spring and Contour repairs were carried out to restore extensively corroded 26-inch (660-mm) topside production piping system on an offshore asset;
- The complete pipework was subject to severe external corrosion that affected straight pipe lengths, girth welds, pipe support, T’s, tight radius bends and offtakes;
- CSNRI engineers designed a specialized composite repair solution that addressed straight pipe as well as complex pipe geometries; and
- Production continued while repairs were carried out.
CSNRI training prepares installers to execute repairs using supplied field kits that contain all the materials necessary to perform cost-effective, long-lasting repairs.