Abstract
At whatever location we proposed to drill, the shallow site survey invariably predicted the presence of potential shallow gas accumulations. Our credibility with the drillers was very low. We decided to investigate AVO (amplitude versus offset) phenomena in an attempt to discriminate between seismic “bright spots” caused by lithological contrasts and those due to gas-bearing sands. Case histories of three North Sea wells are presented with an analysis of how successful pre-drilling predictions have been. The deliberate search for AVO effects has had a major beneficial impact on our approach to shallow gas hazard detection. Extensive pre-stack analysis has revealed shortcomings in acquisition and processing, and pointed the way forward. We conclude that AVO analysis is potentially an effective tool in the reliable prediction of shallow gas hazards.
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References
Desbrandes, R. (1985). Encyclopedia of Well Logging, Graham and Trotman, London.
Hatton, L., Worthington, M. H. and Makin, J. (1986). Seismic Data Processing: Theory and Practice, Blackwell Scientific Publications, Oxford.
Hilterman, F. J. (1975). Amplitudes of Seismic Waves–A Quick Look, Geophysics 40, 745–762.
Holmes, R. (1977). Quaternary Deposits of the Central North Sea, 5. The Quaternary geology of the UK sector of the North Sea between 56° and 58°N, Rep. Inst. Geol. Sci., 77 /14.
Ostrander, W.J. (1984). Plane-wave reflection coefficients for gas sands at nonnormal angles of incidence, Geophysics, 49, 1637–1648.
Shuey, R. T. (1985). A simplification of the Zoeppritz equations, Geophysics, 50, 609–614.
Taner, M. T. and Koehler, F. (1981). Surface consistent corrections, Geophysics, 46, 17–22.
Widess, M. B. (1973). How thin is a thin bed?, Geophysics, 38, 1176–1180.
Yilmaz, O. (1987). Seismic Data Processing, Society of Exploration Geophysicists, Tulsa, Oklahoma.
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© 1990 Society for Underwater Technology
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Townsend, A.R., Armstrong, T.L. (1990). Shallow Gas Detection Using AVO Processing of High Resolution Seismic Data. In: Ardus, D.A., Green, C.D. (eds) Safety in Offshore Drilling. Advances in Underwater Technology, Ocean Science and Offshore Engineering, vol 25. Springer, Dordrecht. https://doi.org/10.1007/978-94-009-0669-3_7
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DOI: https://doi.org/10.1007/978-94-009-0669-3_7
Publisher Name: Springer, Dordrecht
Print ISBN: 978-94-010-6785-0
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