Publication Name: The North West Shelf Australia
Authors: T.J. Allen, D. Brown and J. Wardell
Date Published: July 1988
Number of Pages: 21
Reference Type: Book Section
Abstract:
The North West Shelf includes large areas with water depths less than 20 m, and which require specialisedshallow water seismic surveying procedures. A shallowwater crew operating in the area during late 1987-early
1988 collected approximately 4000 km of seismic data. The equipment and operating procedures were designed
to collect high quality data over as much of the shallow water areas as possible, while still using fairly conventional equipment for economy's sake. The vessel was a drop-front landing barge, towing a conventional
analogue streamer, and using a single string 1000 cubic inch airgun array. The streamer was kept as deep as
possible, to a maximum of about 10 m, using remote control depth controllers. A second vessel, with a full
set of radio navigation equipment, was used to scout lines in advance of shooting to determine water depths
and check for reefs. Some unique shallow-water data processing problems were encountered. In many areas,
a very low velocity, low frequency, ground roll type of noise is generated; elsewhere, in areas of hard sea
bottom, very strong reverberations are present on the short offset traces. These noise problems were solved
by the appropriate processing methods and the final product was a set of high quality seismic sections.