Page 156 - Principles of Applied Reservoir Simulation 2E

Part II: Reservoir Simulation 141

symmetric pattern. The symmetry can be lost if there is some heterogeneity in
the system.
Fingering can be a reservoir heterogeneity problem or a fluid displacement
problem. Most reservoir simulators do not accurately model lingering effects.
It is possible to improve model accuracy by using a very fine grid to cover the
area of interest, but the benefits associated with such a fine grid are seldom
sufficient to justify the additional cost.

Exercises

Exercise 14.1 Data set EXAM3.DAT is a model of a Buckley-Leverett water-
flood. (A) Multiply horizontal permeability by 0.5 and run the model. Plot oil
rate as a function of time and WOR as a function of time. (B) Repeat A by
multiplying horizontal permeability in the original data set by 10. (C) Explain
the difference between parts A and B. Consider breakthrough times (time when
water production begins), water-oil ratio, and cumulative oil produced at the end
of the run. See Chapters 24.3.1 and 24.3.2 for a description of permeability input
data. Cumulative production can be found in WTEMP.PLT.

Exercise 14.2 Repeat Exercise 14.1, but modify horizontal transmissibility
instead of horizontal permeability. See Chapter 24.3.3. for details.

Exercise 14.3 Double water relative permeability in EXAM3.DAT and
determine the effect on water-oil ratio and breakthrough times.