Geoscience Reference
In-Depth Information
1000.0
Shoreface
trend
Channel
trend
100.0
Heterolithic
cluster
10.0
Channel fill
Gravel lag
Floodplain heterolithic
Middle shoreface sand
Lower shoreface heterolithics
Mudstone
1.0
0.1
0
5
10
15
20
25
30
35
40
Porosity (%)
Fig. 2.13
Six candidate model elements identified from core and log data and clustered into three on a k/phi cross
plot - to lump or to split?
The outcome of this line of argument is that
some reservoirs may not require complex 3D
reservoir models at all (Fig.
2.15
). Gas-charged
reservoirs require high degrees of permeability
heterogeneity in order to justify a complex
modelling exercise - they often deplete as simple
tanks. Fault compartments and active aquifers
may stimulate heterogeneous flow production in
gas fields, but even in this case the model required
to capture key fault blocks can be quite coarse. At
the other end of the scale, heavy oil fields under
water or steam injection are highly susceptible to
minor heterogeneities, and benefit from detailed
modelling. The difficulty here lies in assessing
the scale of these heterogeneities, which can
often be on a very fine, poorly-sampled scale.
