This paper describes the underwater noise characteristics of an underwater diamond wire cutting operation during the severance of a 0.76 m diameter conductor at an oil and gas platform in the North Sea. The conductor was cut approximately 10 m above the seabed using a “36-inch” (0.91 m) diamond wire cutting machine, in a water depth of approximately 80 m. The analysis revealed that the sound radiated from the diamond wire cutting of the conductor was not easily discernible above the background noise, which was present during the cutting operation (it should be noted that the cutting process involved the presence of several operational vessels). Increases of between around 4 dB and up to 15 dB were detectable for one-third octave band spectral levels at some frequencies, during the period which broadly corresponded to the cutting operation, with the higher frequencies showing greater increases. There was generally an observable increase in the spectral level for the one-third octave bands at frequencies above 5 kHz. No tonal components in the data could be directly attributed to the diamond wire cutting. These data are the first description of the radiated noise from a diamond wire cutting operation available in the public domain.

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