Digital Reprocessing of Shallow Seismic Data from the Great Barrier Reef

Abstract

The feasibility of transferring conventional reflection processing techniques to analog, shallow-marine seismic surveying has been assessed. The test data are of high-resolution boomer profiles recorded on the Great Barrier Reef. The analog data were digitised using an off-the-shelf, PC-based converter, provided appropriate precautions are observed with respect to timing accuracy, sampling, and dynamic range. The raw digitised data exhibited trace-to-trace timing shifts which could be attributed to changes in the relative vertical positions of boomer and hydrophone streamer. Such static errors were significantly reduced using a conventional pilot-trace residual statics' algorithm. An alternative algorithm which does not use a pilot trace, and whose model is more specifically tailored to the single-fold problem at hand, provided subtle, though significant, enhancement when compared to the pilot-trace technique. Predictive deconvolution was not appropriate owing to failure of required assumptions. On the other hand, deterministic signature deconvolution was successfully applied.Dominant-horizon extractions on the water bottom, and on the prominent Pleistocene reflector, indicate that the intrinsic signature is consistent laterally and temporally. An optimum Wiener spiking filter, designed on the extracted signature, significantly simplified the reflection structure on the test section.