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Barbara J. Radovich1,
David L. Connolly2,
David M. Angstadt2
(1) Texaco, Bellaire, TX
(2) Texaco, Bellaire
Abstract: Deep water sequence architecture in Central Offshore Nigeria and Gulf of Mexico and characterization of fans from seismic data and attribute displays
Deep water wells that are likely to exceed economic thresholds must penetrate fans with the greatest thickness and lateral continuity. Seismic sequence architecture analysis of the deep water central Offshore Nigeria and Gulf of Mexico shows a vertical series of sequences dominated by a predictable succession of lowstand fan types and depositional processes. Using simplified criteria, fan plays can readily be interpreted on the seismic data and compared to key wells. The seismic section is divided into four seismic facies zones, each with a dominant fan type. The two most important zones for deep water exploration are; basin floor fans that have the greatest reservoir continuity but also show the fewest fan features on the seismic data, and the distal slope fans, terminal lobes at the end of channelized delivery systems with low mounded fan forms on seismic data. Combining instantaneous attribute analysis with an understanding of sequence stratigraphic architectures from passive margin settings can improve predrill predictions and post-drill assessment of these factors. The application of combined response amplitude and frequency displays, within this sequence stratigraphic framework can give insight into several fan interpretation problems. The ‘Discontinuity’ attribute has received attention primarily for fault identification but can lend quantitative support to interpreted sequence boundaries and facies. These displays modernize seismic sequence interpretation of fan types, aid in discerning seismic amplitudes of sand-prone fans from those of condensed sections, and can help find subtle sequence boundaries.
AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana