Geoscience Reference
In-Depth Information
Upscaled dataset for
fullfield reservoir model
Near
wellbore
Model
Core
Data
Wireline
logs
Model-based flow functions
2598
10000
V
shale
k
logh
Kx
Kz
1000
100
10
1
0,1
0,01
2599
0,001
0
0,2
0,4
0,6
0,8
1
Mud fraction, Vm
2600
Fig. 6.18
Workflow for upscaling heterolithic tidal deltaic reservoir systems
the reservoir scale directly, or as part of further
upscaling steps at the geological architecture scale.
The extra effort involved in multi-scale
modelling of tidal deltaic systems clearly pays
off in terms of the value gained by achieving
realistic oil recovery factors from these relatively
low quality reservoirs (Elfenbein et al.
2005
).
Good modelling can lead to significant commer-
cial benefit.
the majority of onshore US oilfields. They might
well be regarded as an 'easy kind' of reservoir
in terms of oilfield development and are indeed
one of the few reservoir types to occasionally
behave like 'tanks of sand' - the reservoir
engineer's dream. However, shallow marine
(paralic) reservoir systems are in fact very varied
and can contain important heterogeneities at the
sub-log scale.
Under the shallow marine group we include
fluvial- and wave-dominated deltaic systems
which characteristically build out into true shal-
low marine shoreface and offshore transition
zones. The
6.4
Shallow Marine Sandstone
Reservoirs
principal
depositional
settings
involved are:
delta plain and delta front,
upper shoreface (usually storm and wave
dominated),
middle and lower shoreface (mainly below
the fair-weather storm wave base),
offshore and offshore transition zone (mud-
dominated or heterolithic).
6.4.1 Tanks of Sand?
Shallow marine sandstones are among the most
prolific class of reservoirs in terms of volumes of
oil produced and are characterised by especially
good recovery factors - up to 70 % or even 80 %
(Tyler and Finlay
1991
). They account for a large
portion of the Jurassic North Sea reservoirs and
