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Typical Application of Vibration Survey Data

Added Compressor:
A compressor was installed on an existing platform (photo right) to enhance production. A vibration survey was done prior to adding the compressor and again after. The resonant frequencies were used by engineers to verify the structural analysis prediction of platform stiffness.

Foundation Integrity:
The platform shown below ( photo left) suffered a shallow gas release during drilling, which formed a crater around the well bay. The platform had been surveyed as part of an earlier resonant frequency database expansion. A subsequent survey was carried out to obtain the resonant frequencies. Comparison of the before and after frequencies showed that the foundation capacity had degraded only slightly. Engineers deemed the platform fit-for-purpose.

Vibration survey during repair:
(1) An offshore platform suffered a parted jacket leg during a severe hurricane. The photo (photo left) shows the parted jacket leg with the pile (ungrouted) exposed. The apparent rings plates on the jacket leg are actually leg material that was flattened into the rings by the motion of the jacket leg during the storm. Vibration data was not available from before the storm, but data was obtained prior to the leg repair and again after. The data showed a significant increase in frequency following the repair (jacket stiffened) and the platform was returned to service.

Vibration survey during repair:
(2) The platform shown at the (photo left) was damaged during Hurricane Ivan (2004). A primary diagonal member parted and other joints were damaged. No prior vibration data was available, but surveys were done before, during and after the repair. These showed considerable stiffening of the jacket; the platform was deemed fit-for-purpose. The following year Hurricane Katrina passed nearby. A subsequent survey indicated no loss of stiffness.


Tripod - Added Compressor
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