Case study - 4 inch seawater injection flowline suffering internal corrosion
Integrity issue
A 4 inch seawater flowline was suffering from internal corrosion. The measured wall thickness of 12.8 mm was below the CONC value. It was proposed to use a FutureWrap composite repair to reinstate the integrity of the pipework.
Design
The design of the FutureWrap repair was according to ISO 24817. The design approach was for pipework strengthening only with allowance for the remaining wall thickness of the pipework. The design parameters were; internal pressure 355 bar, temperature 400C, design lifetime 2 years, remaining wall thickness of steel 12 mm. The repair design resulted in a thickness of 11.35 mm (15 layers) of FutureWrap Glass/LT with an axial length of repair of 440 mm.
Installation
The installation steps are shown in the photographs. The pipework was depressurised. The surface preparation was to ST3. Full QA/QC measurements were made to demonstrate that the FutureWrap repair was applied in accordance with ISO 24817.
Summary
A 4 inch seawater flowline suffering internal corrosion was repaired using a FutureWrap Glass/LT composite repair. The repair was completed within 3 days allowing the pipework to be re-pressurised with the pipework returned to its original integrity.
