Page 319 - Principles of Applied Reservoir Simulation 2E

Chapter 29

Initialization

It is important when making cross-section or 3D runs that the pressures
in the model are correctly initialized. If not, phase potential differences due to
gravity terms could cause fluid migration even though no wells are active.
Consequently, a simple pressure initialization algorithm is used in WINB4D.
It is reviewed below along with an option to correct pressures to a user-specified
datum and an option to initialize saturations using gravity segregation.

29.1 Pressure Initialization

Consider a gridblock that may have a gas-oil contact and a water-oil
contact as in Figure 29-1.

Datum
> „
X EL(+) w
y
\r fjL.\
GOC, ^ '
) t
\r * \ f
I woe

Figure 29-1. Depths for pressure initialization algorithm.

We assume the pressure in the gridblock at model location (/, j, k) is
dominated by the density of the phase at the block midpoint and that there are

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