Geology Reference
In-Depth Information
+ noise
& picks
V
sh
V
p
V
s
impedance
BLI
ρ
rock properties pdf's
Bed thickness
distributions
chi
wavelet
shale
1
sand
0
-1
0
12
log bed thickness (m)
Fractal model
Figure 10.21
Generation of pseudo-wells for assessing uncertainty in Connolly's net pay estimation technique (after Connolly,
2010
).
a)
b)
c)
1
1
Pseudo-well model data
mean
0
0
0
0.1
Standard deviation
Apparent thickness (ms)
Average bandlimited
impedance
Figure 10.22
Connolly net pay estimation technique: estimating uncertainty in seismic N:G. (a) An apparent thickness is defined, (b) data
in the thickness class are crossplot with average bandlimited impedance vs seismic N:G - for a given value of Seismic N:G the standard
deviation around the mean is determined (c) the standard deviation is calculated across the range of seismic N:G. The mapped values of
apparent thickness and seismic N:G are then used to derive a seismic N:G standard deviation map.
time-lapse can be significant (e.g. Verbeek et al.,
1999
;
Koster et al.,
2000
) and the industry now perceives the
use of seismic in reservoir monitoring as an integral
part of the field development plan, at least in offshore
production where the costs are high. Justifying the
expenditure is required on an individual project basis,
of course, and each company has their own way of
determining the value of 4D information (e.g. Pinto
238
