Fig. 1.8 Models for CO 2 storage: Faulted top structure map with seismic-based porosity model and positions of
models based on thoughtful model design, tai-
lored to answer specific questions at hand. Such
models have a short shelf life and are built with
specific ends in mind, i.e. there is a clear model
purpose. The design of these models is informed
by that purpose, as the contrast between the
models illustrated in this chapter has shown.
With the fit-for-purpose mind set, the long-
term handover items between geoscientists are
not a set of 3D property models, but the underly-
ing building blocks from which those models
were created, notably the reservoir database
(which should remain updated and 'clean') and
the reservoir concept, which should be clear and
explicit, to the point that it can be sketched.
It is also often practical to hand-over some
aspects of the model build, such as a fault
model, if the software in use allows this to be
updated easily, or workflows and macros (if these
can be understood and edited readily). The pre-
existing model outputs (property models, rock
models, volume summaries, etc.) are best archived.
The rest of this topic develops this theme in
more detail - how to achieve a design which
addresses the model purpose whilst representing
the essential features of the geological architec-
ture (Fig. 1.9 ).
When setting about a reservoir modelling
project, an overall workflow is required and this
should be decided up-front before significant
modelling effort is expended. There is no 'cor-
rect' workflow, because the actual steps to be
taken are an output of the fit-for-purpose design.
However, it may be useful to refer to a general
workflow (Fig. 1.10 ) which represents the main
steps outlined in this topic.