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