Integrity issue

The upper section of a 36 inch produced water caisson was suffering from external corrosion. It was proposed to use a Futurewrap composite repair to reinstate the strength and therefore integrity of the caisson as the remaining wall thickness was down to 2 mm in some locations.

Design 

The design of the Futurewrap repair was according to ISO 24817.  The design approach was to strengthen and locally leak seal. The design parameters were; internal pressure 1.5 bar, axial load 194 kN, bending moment 176.8 kNm, temperature 600C, design lifetime 20 years. The repair design resulted in a thickness of 6.2 mm (4 layers) of Futurewrap Carbon/Aquasplash composite repair with an axial length of 2300 mm.

Installation

The installation steps are shown in the photographs. The caisson was depressurised. The surface preparation was to ST3 in 1 meter bands. Full QA/QC measurements were made to demonstrate that the Futurewrap repair was applied in accordance with ISO 24817. The repair was applied off ropes

Summary

A 36 inch section of produced water caisson was repaired using Futurewrap Carbon/Aquasplash composite repair. The repair was completed within 14 days allowing the pipework to be re-pressurised and  returning it to its original integrity.