SAGD Design Concerns

1
SAGD Design Concerns

• Different Shale types affect steam flow
  differently
• Need to differentiate between Shale Rip-up Clasts
  and laminated shale for optimized SAGD designs

The reservoir was to be produced using SAGD so
some special considerations had to be taken into
account. It is very important to note that
different shale types affect steam and petroleum
flows differently. It was therefore very
important to differentiate between shale rip-up
clasts, which are essentially boulders of shale
surrounded by otherwise normal sand and shale
laminae, which are layered shale bedding that
could extend uninterrupted for the length of the
reservoir.
2
SAGD Design Concerns
Steam flows around rip-up clasts...
Displayed in the diagram, shale rip-ups simply
present an obstacle around which the steam flows
fairly easily.
3
SAGD Design Concerns
But theres no steam flow around laminated shale
bedding
In this diagram however, there is a shale
lamination that prevents the steam from
propagating into the far reaches of the
reservoir. Clearly, if an electrical imaging
tool is to be used in place of cutting core, this
distinction between laminae and rip-ups must be
made correctly for the procedure to be viable.
4
SAGD Design Concerns
Rip-up clasts in core and EMI
That means that the next step was to try to
identify shale rip-up clasts and shale
laminations in the electrical image alone. To do
this, we first found examples of shale rip-ups in
the core and then compared them to the electrical
image over the same interval. Here you can see
another EMI-core composite plot showing both the
normalized and static EMI images. Enlarged, it is
possible to see what is interpreted as a shale
rip-up clast in the static EMI image. They
appear as irregular, dark features that contrast
nicely with the background image of the otherwise
clean sand
5
SAGD Design Concerns
Laminated shale in core and EMI
Contrasted to the appearance of rip-ups,
laminations appear as solid black features in the
static image. The laminations are visible in the
core here as well as in the EMI.
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SAGD Design Concerns
Laminated shale in core and EMI
In the normalized image, there are lamination
boundaries visible. Therefore we need to use the
static electrical image to tell where the shale
laminations are located, then use the one meter
normalized image to verify that the thin shale
feature is actually laminated.