Page 302 - Principles of Applied Reservoir Simulation 2E

Part V: Technical Supplements 287

where K is a permeability tensor that is usually assumed to be diagonalized along
its principal axes, k riis relative permeability and |l, is viscosity of phase i. The
phase potentials ^ t are given as functions of depth z by

o z o z o z
A =p _.L£__ $ = P -P --L2L. d> =p +p _£*_ (2781
0 w cow cgo l j
° 144' ° 144' * ° 144
Phase densities are calculated from input PVT data as

=
+
+
P 0 = -^-[P 0,c ^ 0PgJ' P w "-[P 0,c ^wP gJ' P^-f^ (27.9)
5 5 5
o w g
Expressions for rock and phase compressibilities are
1 84) 1 dB g
^ 4> p * Bd P
£. — ~ f\ = 2.
5
_L^- B 8R (27.10)
* >»
C*. ~ ~
" dP B dp

These equations are discretized and solved numerically in WINB4D. The
procedure for solving these equations is outlined in Chapter 32.

27.2 Coordinate Orientation

The WINB4D reservoir model assumes a block-centered grid with the
axes aligned iising the right-handed coordinate system illustrated iri Figure 27-1.

I

K *
y \ 1
z

Figure 27-1. Coordinate system.