Chapter from: SG
42: Applications of 3-D Seismic Data to Exploration and Production
Edited by:
Paul Weimer and Thomas L. David Authors:
S. I. Mackie and C. M. Gumley
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 8
Chapter 8: The
Dirkala South Oil Discovery: Focusing on Cost-Efficient 3-D Seismic Reservoir
Delineation, Cooper/Eromanga Basin, Central Australia S. I. Mackie* and C. M. Gumley** |
| Mackie,
S. I. and C. M. Gumley, The Dirkala South Oil Discovery: Focusing on Cost-Efficient
3-D Seismic Reservoir Delineation, Cooper/Eromanga Basin, Central Australia,
in P. Weimer and T. L. Davis, eds., AAPG Studies in Geology 42 and SEG
Geophysical Developments Series No. 5, AAPG/SEG, Tulsa, p. 83-90.
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ABSTRACT
The Dirkala Field is located
in the southern Murta block of Petroleum Exploration Licenses (PELs) 5
and 6 in the southern Cooper and Eromanga Basins of central Australia.
Excellent oil production from a single reservoir sandstone in the Jurassic
Birkhead Formation in Dirkala 1 had indicated a potentially larger resource
than could be mapped volumetrically. The hypothesis that the resource was
stratigraphically trapped led to the need to define the fluvial sand reservoir
seismically and thereby prepare for future development.
A small (16 km2)
3-D seismic survey was acquired over the area in December 1992. The project
was designed not only to evaluate the limits of the Birkhead sand but also
to evaluate the cost efficiency of recording such small 3-D surveys in
the basin.
Interpretation of the dataset
integrated with seismic modeling and seismic attribute analysis delineated
a thin Birkhead fluvial channel sand reservoir. Geological pay mapping
matched volumetric estimates from production performance data. Structural
mapping showed that Dirkala 1 was optimally placed and that no further
development drilling was justifiable.
Seismic characteristics comparable
with those of the Dirkala 1 Birkhead reservoir were noted in another area
of the survey, beyond field limits. This led to the proposal to drill an
exploration well, Dirkala South 1, which discovered a new oil pool in the
Birkhead Formation. A post-well audit of the pre-drill modeling confirmed
that the seismic response could be used to determine the presence of the
Birkhead channel sand reservoir.
The acquisition of the Dirkala
3-D seismic survey demonstrated the feasibility of conducting small 3-D
seismic surveys to identify subtle stratigraphically trapped Eromanga Basin
reservoirs at lower cost and risk than appraisal/development drilling based
on 2-D seismic data. |
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