PROPS Section Schlumberger
114 ECLIPSE Blackoil Reservoir Simulation Training and Exercise Guide Version 2.0
Questions
These questions are for discussion and review.
• What keyword is used to specify the compressibility of the
reservoir rock?
• In a two phase gas / water simulation, what keywords might be
used to enter the saturation functions? What data goes into each
keyword?
• In what cells does the choice of three-phase relative permeability
calculation become significant?
Lesson 5 Saturation Table Scaling
Most reservoirs contain many different types of rock, each of which
exhibit different relative permeability and capillary pressure behavior. It
is important to incorporate this variation in the resulting saturation
functions into a simulation model. In ECLIPSE, there are essentially
two methods to do this.
• Multiple saturation table regions
• Saturation table scaling
The first method, applying multiple saturation table regions, involves
explicitly specifying several different saturation functions and assigning
each to a specific part of the reservoir (e.g., a rock type or perhaps a
fault block, and so forth). This method will be covered in the next
module.
Saturation table scaling, or end-point scaling (EPS), involves
specifying a single set of normalized curves and scaling the end-points
of these on a per grid cell basis. In this manner, a nearly unlimited
number of curves can be used in a simulation, all derived from the
single input function.
In practice, the two methods are complimentary and are often used
together in a single simulation. For example, a separate set of
normalized saturation functions could be entered for each rock type
using multiple saturation table regions.
End-point scaling might be applied to set each grid cell’s connate
water saturation as a function of the cell’s rock quality (i.e.,
permeability or porosity).
In this section, you are introduced to the types of end-point scaling
available in ECLIPSE, and how these may be set up. The SOLUTION
section module discusses some specialized applications of end-point
scaling specific to model initialization.
Horizontal Scaling
Horizontal end-point scaling involves stretching or squeezing the
relative permeability curves along the saturation axis. The water, oil,
and gas relative permeability curves can each be scaled
independently as required. The relative permeability values at the end-
points are retained, with values at intermediate saturations being