The use of subsea corrosion-resistant-alloy (CRA) -clad pipelines is increasing, and plans exist to expand their use in developing large reservoirs and transporting high-pressure, high-temperature, highly corrosive fluids. The complete paper compares traditional welding techniques, such as above-water repair methods and underwater hyperbaric welding, with novel options offered by subsea connectors purposely developed for CRA-clad pipelines. These connector solutions ensure continuity of containment of corrosive fluid by means of engineered nonelastomeric metallic seals.
Grip and Metal Seal Connector (GMSC)
System Description. The presented novel repair connector is a mechanical connection system to be fitted onto the pipeline cut end, which is to be prepared in advance. Key features include the following:
- Permanent repair by means of a metallic sealing technology
- Allowance of full piggability of the pipeline after the intervention by not restricting the pipeline inner diameter (ID)
- Restoration of original operational functionality of the pipeline
- Allowance of diverless permanent repair intervention
- Confirmation of correct installation by backseal testing
- Design life of 30 years
- Maximum design pressure of pipeline of 360 barg (extendable)
- Maximum water depth of pipeline of 2000 m (extendable)
The GMSC is composed of a body with grip and seal elements and a flange or hub welded to the main body.
