About This Item
Share This Item
Abstract
Chapter from: SG
42: Applications of 3-D Seismic Data to Exploration and Production
Edited by:
Paul Weimer and Thomas L. David Authors:
Bob A. Hardage, Raymond A. Levey, Virginia Pendleton, James
Simmons, and Rick Edson
Published 1996 as
part of Studies in Geology 42
Copyright © 1996 The American Association of Petroleum
Geologists. All Rights Reserved. |
![](images/indent.JPG) |
---|
*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.
![](images/indent.JPG) |
---|
![](images/indent.JPG) |
CHAPTER 3
Chapter 3: 3-D
Seismic Imaging and Interpretation of Fluvially Deposited Thin-Bed Reservoirs Bob A. Hardage*, Raymond A. Levey*,
Virginia PendletonÝ, James Simmons*, and Rick Edson*
|
|
Hardage,
B. A., R. A. Levey, V. Pendleton, J. Simmons, and R. Edson, 3-D seismic
imaging and interpretation of fluvially deposited thin-bed reservoirs,
in P. Weimer and T. L. Davis, eds., AAPG Studies in Geology No. 42 and
SEG Geophysical Developments Series No. 5, AAPG/SEG, Tulsa, p. 27-34. |
---|
![](images/indent.JPG) |
---|
![](images/indent.JPG) |
---|
![](images/indent.JPG) |
|
|
|
old as 40 years, existed
inside this 3-D grid, and the logs recorded in these wells allowed us to
make a reasonably thorough geologic analysis of the Frio reservoirs. As
shown in Figure 2, we acquired additional data in several wells (the circled
dots) to supplement the historic well log, production, and reservoir pressure
data bases. These supplemental data consisted of modern well logs, cores,
and various pressure tests. Vertical seismic profile (VSP) data were recorded
in the well inside the triangle shown near the center of the 3-D grid.
THIN-BED INTERPRETATION PROCEDURE
The emphasis in this case
study was on demonstrating how geologic and engineering data are essential
in interpreting depositionally generated reservoir compartment boundaries
in 3-D seismic images. The seismic interpretation at Stratton Field was
particularly challenging, because most of the Frio reservoirs were thin
(<15 ft [<5 m]), and they were closely stacked, in some areas separated
by only 10-15 ft (3-5 m) vertically. These conditions required precise
calibration of stratigraphic depth versus seismic traveltime to extract
a depositional stratal surface from the 3-D data volume that would reliably
depict the areal distribution of a particular Frio thin-bed reservoir.
We used VSP data as the primary
measurement to define where a specific thin-bed reservoir was positioned
in the 3-D seismic data volume. The locations of the VSP calibration well
we used is shown in Figure 2. The zero-offset VSP data recorded in this
well were used to establish the precise depth-versus-time control needed
for the thin-bed interpretation . These VSP data are shown in Figure 3,
where the zero-offset image is spliced into a north-south vertical slice
from the 3-D data volume passing through the VSP well. The VSP image has
a wider range of frequency components (10-120 Hz) than does the 3-D seismic
image (10-80 Hz), and we made no attempt to equalize the spectral bandwidths
of these two images when constructing Figure 3. The figure also shows a
graphic representation of the stratigraphic column penetrated by the VSP
well. Only producing or potentially producing Frio reservoirs are shown
in this diagram, and not all of the reservoirs are labeled by name. The
top and base of each reservoir are accurately positioned in terms of two-way
VSP traveltime, and because there is no difference between the VSP time
datum and the 3-D time datum in this instance, the reservoirs are also
correctly positioned vertically inside the 3-D seismic data volume at the
VSP well.
Using these VSP traveltime
control data , we knew exactly where each thin-bed reservoir belonged in
the 3-D seismic reflection waveform at the VSP well. We then extended this
thin-bed calibration away from the VSP well and across the entire 7.6-mi2
(19.7-km2) area imaged by the 3-D data .
We now show the results of
this thin-bed interpretational procedure at Stratton Field and support
the interpretations with geologic and engineering control. |
---|
![](images/indent.JPG) |
ABSTRACT
We investigated the following
problem: "How do fluvial depositional processes create compartmented gas
reservoirs?" Using vertical seismic profile (VSP) data to define where
selected thin-bed gas reservoirs were positioned in a 3-D seismic data
volume, we created horizon slices through this 3-D image that showed the
reflection amplitude behavior across the depositional surfaces where targeted
thin-bed reservoirs were located. We saw intriguing meander features on
these 3-D amplitude displays, which appeared to be realistic depictions
of intermeshed fluvial channels. We then overlaid well-log cross sections
on these 3-D seismic images, which inferred the depositional environments
that were found by wells that penetrated the reservoir system, and these
geologic constraints confirmed that the imaged meander features were indeed
channels.
The most important nonseismic
data that we used to understand how 3-D seismic images can reveal reservoir
compartment boundaries were various forms of reservoir engineering data
that proved which wells shared a common pressure compartment and which
wells did not. Using these engineering constraints, we showed that many
of the seismically imaged channel features created reservoir compartment
boundaries that impeded lateral fluid flow. Equally important, we showed
that some seismically imaged channels had minimal effect on lateral flow
and did not form compartment boundaries. We concluded that in any effort
where 3-D seismic data are used to infer the internal compartmentalized
architecture of a reservoir system, good quality reservoir engineering
control, such as pressure interference tests and pressure decline curves,
must be incorporated into the 3-D interpretation . |
---|
Pay-Per-View Purchase Options
The article is available through a document delivery service. Explain these Purchase Options.
Watermarked PDF Document: $14 |
Watermarked Document A Watermarked Document is branded with the name of the original licensed customer to discourage unauthorized users from sharing the document outside the user's organization. The PDF is no longer restricted to one machine, but can be circulated to others in the same company or department. A Watermarked Document also can be printed for hard copy distribution internally but is not authorized for outside distribution nor posting on the internet. Users will not be able to cut-and-paste text or images from one document to another.
|
Open PDF Document: $24 |
Open Document An Open Document is a fully functional PDF that can be circulated (a digital copy or hard-copy printed documents) outside the purchasing organization. Purchase of an Open Document does NOT constitute license for republication in any form, nor does it allow web posting without prior written permission from AAPG/Datapages ([email protected]).
|
GIS Map Publishing Program