COMPACT SLEEVE-GUN SOURCE ARRAYS

Data derived from far-field signature measurements have inspired several guidelines for using clustered sleeve guns effectively in tuned marine seismic source arrays. Primarily, these data show that for a given volume the signature produced by a cluster of sleeve guns has a comparable bubble period, increased primary amplitude, and reduced bubble-pulse amplitude compared to the signature of a single gun. These results agree with those reported for clusters of conventional air guns. However, when the data are analyzed in terms of acoustic and operational efficiency, we find that for array elements with volumes greater than 150 in3 two-gun clusters are more desirable than equivalent volume clusters of several small volume guns. For array elements with volumes up to 150 in3, the data show no significant advantages for using clusters instead of single guns. These guidelines have led to the design of sleeve-gun arrays that produce signatures with temporal and spectral characteristics equal to or exceeding those produced by conventional air-gun arrays incorporating almost twice the total gun volume. Moreover, these new arrays operate with a total number of individual guns comparable to conventional arrays, thus improving the performance of source arrays on small survey vessels without having to increase air compressor capacity or ancillary source equipment.