Qualification of sealing system for flexible pipes using a self-energized gasket

摘要

In order to meet higher technical demands designing flexible pipes at higher pressures and higher temperatures for deeper water depths NOV has introduced and qualified a new sealing system that is self-energized. The sealing material has been qualified and tested in different fluids. The sealing system has shown good functionality at higher pressures as well as at lower pressures. The qualification of the sealing system has been based on multiple full-scale and mid-scale tests according to Recommended Practice API 17B and small-scale tests on the elastomer material including long-term ageing tests and rapid gas decompression tests in high pressure CO_2 up to 900 bar. The recommendations of RP API 17B used in the industry has its limitation with regards to qualification of a new sealing system. This paper gives an overview how to qualify a new sealing system on an existing product range achieving different technology readiness levels according to Recommended Practice API 17N from TRL1 up to TRL5. TRL5 covers system integration testing by full-scale testing of flexible pipes such as burst test, tension-pressure test, tension-tension test and deep immersion performance test. All qualification tests have been witnessed by a third-party Bureau Veritas and the enhanced sealing system has archived a TRL5 statement within its current design envelope.