Chapter from: SG
42: Applications of 3-D Seismic Data to Exploration and Production
Edited by:
Paul Weimer and Thomas L. David Authors:
Goeffrey A. Dorn, Kenneth M. Tubman, Dennis Cooke, and Rob
O'Connor
Published 1996 as
part of Studies in Geology 42
Copyright © 1996 The American Association of Petroleum
Geologists. All Rights Reserved. |
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*Editorial Note: Page numbers in this digital version
(HTML and PDF) do not correspond to those of the hardcopy.
Otherwise, the two are the same.
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CHAPTER 11
Chapter 11: Geophysical
Reservoir Characterization of Pickerill Field, North Sea, Using 3-D Seismic
and Well Data Geoffrey A. Dorn*,
Kenneth M. Tubman*, Dennis CookeÝ,
and Rob O'Connor§
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| Dorn,
G., K. Tubman, D. Cooke, and R. O'Connor, Geophysical Reservoir Characterization
of Pickerill Field, North Sea, Using 3-D Seismic and Well Data, in
P. Weimer and T. L. Davis, eds., AAPG Studies in Geology No. 42
and SEG Geophysical Development Series No. 5 AAPG/SEG, Tulsa, p.
107-122. |
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ABSTRACT
Pickerill Field is a relatively
thin, highly faulted gas reservoir in the southern gas basin of the North
Sea. The 100- to 250-ft (30-to 76-m) thick, Permian Rotliegend reservoir
consists primarily of thin dune and interdune deposits overlying generally
poorer-quality fluvial sands. There is a rapid lateral variation in reservoir
quality due to facies changes and compartmentalization due to diagenesis
associated with faults.
A combination of petrophysics
and geophysics was used to develop seismic criteria that could be used
to optimize the location of development wells. An analysis of horizon attributes
from the 3-D seismic survey produced a detailed reservoir fault map. Analysis
of log data, seismic modeling, and horizon attributes produced an estimated
reservoir porosity map. These have been used to help optimize the position
of development wells in the field.
A detailed interpretation
was made of several horizons in the 3-D seismic survey, including the Top
Rotliegend (top reservoir) reflection. A set of seismic horizon attributes,
based on horizon structure and reflection amplitude, were generated at
the Top Rotliegend. Reservoir faults with throws as small as 15 ft (5 m)
were interpreted and mapped. Since many faults were sealed by diagenesis
subsequent to faulting, these results have helped identify potential compartmentalization
and have allowed development wells to be positioned away from these potential
barriers to flow.
Synthetic seismic modeling
using log data from exploration wells indicated a linear relationship between
reservoir reflection amplitude and average reservoir porosity. Log-based
wavelet extraction was used to correct phase errors in the seismic data.
Phase-corrected reflection amplitude from the Top Rotliegend reflection
was correlated with porosity at exploration wells. The resulting empirical
amplitude-porosity relationship has been used to successfully predict gross
reservoir porosity in several wells drilled since the work was concluded. |
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