Geoscience Reference
In-Depth Information
Fig. 1.5
Modelling for horizontal well planning based on deterministic data (
a
) vs. a model with significant stochastic
elements (
b
)
include all options including novel well design
solutions, use of time-lapse seismic and second-
ary or tertiary flooding methods (water-based or
gas-based injection strategies), while EOR gen-
erally implies tertiary flooding methods, i.e.
something more advanced than primary deple-
tion or secondary waterflood. CO
2
flooding and
Water Alternating Gas (WAG) injection schemes
are typical EOR methods. We will use IOR to
encompass all the options.
We started by arguing that there is little value
in 'fit-for-all purposes' detailed full-field models.
However, IOR schemes generally require very
detailed models to give very accurate answers,
such as 'exactly how much more oil will I
recover if I start a gas injection scheme?' This
requires detail, but not necessarily at a full-field
scale. Many IOR solutions are best solved using
detailed sector or near-well models, with rela-
tively simple and coarse full-field grids to handle
the reservoir management.
Figure
1.7
shows an example IOR model
(Brandsæter et al.
2001
). Gas injection was
simulated in a high-resolution sector model
with fine-layering (metre-thick cells) and various
fault scenarios for a gas condensate field with
difficult fluid phase behaviour. The insights
from this IOR sector model were then used to
