Geoscience Reference
In-Depth Information
Fig. 5.6
Alternative
approaches to uncertainty
handling
Best Guess
Anchored on a preferred 'base case'
BG
MS
MD
Multiple Stochastic
Models selected by building
'equiprobable' realisations from a base
case model
Multiple Deterministic
Models designed manually based on
discrete alternative concepts
a
b
BG
BG
MS
MD
MS
MD
Concept
Concept
% - Base case outcome + %
% - Base case outcome + %
low case
base case
high case
Fig. 5.7
Base case-dominated, rationalist approaches (Redrawn from Bentley and Smith 2008, The Geological
Society, London, Special Publications 309
#
Geological Society of London [2008])
to that guess. This may be either a percentage
factor in terms of the model output (e.g.
choice of the boundary conditions for the
simulations, such as assumed correlation
lengths. Yarus and Chambers (
1994
) give sev-
eral examples of this approach, and the
options and choices are reviewed by Caers
(
2011
).
Multiple deterministic approaches, which avoid
making a single best-guess or choosing a
preferred base-case model (Fig.
5.9
). In this
approach a
20 % of the base case volumes in-place) or
separate low and high cases flanking the base
case. This approach can be viewed as 'tradi-
tional' determinism.
Multiple stochastic approaches, in which a large
number of models are probabilistically
generated by geostatistical simulation
(Fig.
5.8
). The deterministic input lies in the
smaller number of models
