Page 25 - Fundamentals of Reservoir Engineering

CONTENTS XXV

Fig. 10.23 Referring oil and water phase pressures at the interface to the centre line in the
reservoir. (Unstable segregated displacement in a horizontal, homogeneous
reservoir) 372

Fig. 10.24 Comparison of the oil recoveries obtained in exercises 10.2 and 10.3 for
assumed diffuse and segregated flow, respectively 376

Fig. 10.25 The stable, segregated displacement of oil by water at 90% of the critical rate
(exercise 10.3) 378

Fig. 10.26 Segregated downdip displacement of oil by gas at constant pressure; (a)
unstable, (b) stable 380

Fig. 10.27 (a) Imbibition capillary pressure curve, and (b) laboratory measured relative
permeabilities (rock curves,- table 10.1) 382

Fig. 10.28 (a) Water saturation, and (b) relative permeability distributions, with respect to
thickness when the saturation at the base of the reservoir is S w = 1 − S or (P c =0)383

Fig. 10.29 Water saturation and relative permeability distributions, as functions of thickness,
as the maximum saturation, S w = 1 − S or, is allowed to rise in 10 foot increments
in the reservoir 385

Fig. 10.30 Averaged relative permeability curves for a homogeneous reservoir, for diffuse
and segregated flow; together with the intermediate case when the capillary
transition zone is comparable to the reservoir thickness 387

Fig. 10.31 Capillary and pseudo capillary pressure curves. 387

Fig. 10.32 Comparison of oil recoveries for different assumed water saturation distributions
during displacement. 387

Fig. 10.33 Variation in the pseudo capillary pressure between +2 and -2 psi as the
maximum water saturation S w = 1−S or rises from the base to the top of the
reservoir 388
Fig. 10.34 Example of a stratified, linear reservoir for which pressure communication
between the layers is assumed 390

Fig. 10.35 (a)-(c) Rock relative permeabilities, and (d) laboratory measured capillary
pressures for the three layered reservoir shown in fig. 10.34 391

Fig. 10.36 (a) Water saturation, and (b) relative permeability distributions, with respect to
thickness, when the saturation at the base of the layered reservoir (fig. 10.34) is
S w = 1−S or (P c° = 2 psi) 392

Fig. 10.37 (a)-(h) Water saturation and relative permeability distributions,as functions of
°
thickness,for various selected values of P (three layered reservoir, fig 10.34) 394
c
Fig. 10.38 Averaged relative permeability functions for the three layered reservoir,
fig. 10.34: (a) high permeability layer at top, (b) at base of the reservoir 396