In gas applications with high-pressure drops and/or high-velocity
gas flow, acoustic-induced vibration (AIV) occurs when very high
sound levels are propagated in piping. If the sound levels are high
enough, they will excite the circumferential vibration modes of the
pipe. This allows the pipe to vibrate in and out as the sound wave
moves through the piping. Most often this occurs downstream of
pressure-reducing valves or safety-relief valves, but AIV can occur
at any location where the pressure drop or mass flow rate is sufficiently
large. The level of pipe wall vibration is so high that it can
induce fatigue cracking of the pipe and can potentially cause catastrophic
pipe failure. The West Delta Deep Marine (WDDM) concession
onshore of the slug catcher M9001 had a recent failure in the
flare header as result of accumulating AIV effect. As a consequence
of this failure Enppi/Burullus and Foster Wheeler have undertaken
an engineering assessment study to investigate the risk of AIV for
the plant and determine the corrective and engineering solutions to
protect the plant from any failure that may occur as a result of AIV.
This paper will present a case study as reference for gas-production
facilities to consider the AIV application in regard to the design
phase, and what might have prevented fatigue of pipes during the
operation phase.