302
The Stratigraphic Architecture of Fluvial Depositional Systems
�
-
Fig. 9.66. Detection of cross� bedding using the dipmeter and its dependency on
the sensitivity and sample interval of the
tool. (Schlumberger dipmeter manual
1986)
.
.
0
15
30"
Long Interval
(attitude of unit boundaries)
0 ° 15° 30"
Short Interval
(attitude of unit boundaries +
cross�beds)
Deep perennial
braided river
Synthetic Geodip Log
0 10 20304050 70 90
Shallow perennial
Synthetic Geodip Log
braided river
0 10 20304050 70 90
2
1. low angle cross-bedding 2. trough cross-bed edge 3. trough axis 4. planar cross-bedding
5. reactivation surface 6. set bounding surface
Fig. 9.67. Two types of braided river profile (see Chap. 8 for a discussion of these) and the dipmeter patterns that might
be expected from them
of a dipmeter survey run through deltaic distributary channels. The conclusion of both studies is that
actual subsurface dipmeter studies are likely to provide useful paleocurrent data, even when obtained
from single exploration holes.
Dueck and Paauwe (1994) provided an excellent
case study of the gradual development of small-scale
- but nonetheless productive - exploration prospects in channel sandstones based mainly on the
careful use of paleocurrent data obtained from borehole imaging techniques. They were able to plot
cross-bed foreset surfaces as little as 5 em apart
within a borehole succession, allo-wing for the demonstration of variable dip angle from base to top of
individual sets. By carefully considering the «ranl<:"
of the cross-bed sets within the overall hierarchy of
directional indicators (Fig. 2.10), they were able to
make predictions about channel trend from these
readings, predictions that revealed the presence of a
previously unsuspected meander bend. Several new
producing oil wells were drilled using these data.
9.5.9 Surveillance Geology
The term surveillance geology is used to describe the
work done by production geologists to monitor the
pressure and fluid composition of producing wells.
Pressure data can be used to determine the connectedness of specific sandstone bodies, and fluid com-
The Stratigraphic Architecture of Fluvial Depositional Systems
�
-
Fig. 9.66. Detection of cross� bedding using the dipmeter and its dependency on
the sensitivity and sample interval of the
tool. (Schlumberger dipmeter manual
1986)
.
.
0
15
30"
Long Interval
(attitude of unit boundaries)
0 ° 15° 30"
Short Interval
(attitude of unit boundaries +
cross�beds)
Deep perennial
braided river
Synthetic Geodip Log
0 10 20304050 70 90
Shallow perennial
Synthetic Geodip Log
braided river
0 10 20304050 70 90
2
1. low angle cross-bedding 2. trough cross-bed edge 3. trough axis 4. planar cross-bedding
5. reactivation surface 6. set bounding surface
Fig. 9.67. Two types of braided river profile (see Chap. 8 for a discussion of these) and the dipmeter patterns that might
be expected from them
of a dipmeter survey run through deltaic distributary channels. The conclusion of both studies is that
actual subsurface dipmeter studies are likely to provide useful paleocurrent data, even when obtained
from single exploration holes.
Dueck and Paauwe (1994) provided an excellent
case study of the gradual development of small-scale
- but nonetheless productive - exploration prospects in channel sandstones based mainly on the
careful use of paleocurrent data obtained from borehole imaging techniques. They were able to plot
cross-bed foreset surfaces as little as 5 em apart
within a borehole succession, allo-wing for the demonstration of variable dip angle from base to top of
individual sets. By carefully considering the «ranl<:"
of the cross-bed sets within the overall hierarchy of
directional indicators (Fig. 2.10), they were able to
make predictions about channel trend from these
readings, predictions that revealed the presence of a
previously unsuspected meander bend. Several new
producing oil wells were drilled using these data.
9.5.9 Surveillance Geology
The term surveillance geology is used to describe the
work done by production geologists to monitor the
pressure and fluid composition of producing wells.
Pressure data can be used to determine the connectedness of specific sandstone bodies, and fluid com-