Abstract

ColdShield is an innovative solution for making structural repairs and reinforcements in marine environments, specifically intended for the on-site maintenance of FPSO hulls. The purpose of this original process is to strengthen - in a safe and controlled manner - weakened offshore steel structures, without resorting to hot work such as welding or grinding, which involve naked flames. This paper presents the results of various laboratory tests, together with computer models for bringing this new technology up to qualification standard. The R&D campaign was conducted as a partnership between Total, the French Petroleum Institute (IFP - Energies Nouvelles) and COLD PAD, and involved four different private and public French laboratories.

ColdPad's original generic innovation has a potentially broad range of offshore applications such as bonded connections or structural repairs effected in situ. Its main advantage is that it allows safe repair with no down time. This permanent solution is designed to be installed under any environmental conditions, and even underwater. The prime specifically industrial application of ColdShield is in the maintenance and repair of FPSO hulls, mainly those damaged by severe corrosion. The renovation is intended to permanently restore the initial structural capacity and durably protect the damaged area against further corrosion.

This new technology is based on the proven techniques of bonded composite reinforcement already used in other industries such as aerospace, military and civil engineering. The current R&D program seeks to demonstrate through a qualification process that the ColdShield solution offers a reliable and lasting means of repairing FPSO hulls. This was achieved by demonstrating the full preservation of the bonded repair under severe offshore conditions.

Qualification of this bonded composite reinforcement involved many different steps. This paper focuses on one of them, showing how the material for the seal, the most critical component, was selected and tested through various research and development stages.

Although bonded composite reinforcements provide a real alternative to conventional " hot" structural repairs, they remain vulnerable to the humidity inherent to the offshore environment. ColdShield is designed to remain impervious to marine conditions, especially during the two critical phases of installation and servicing, suggesting high-potential future applications. In addition, the prequalified installation procedure has been turned into an industrial process intended to be faithfully reproduced on site for reliable, repeatable performances.

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