Page 192 - A Practical Companion to Reservoir Stimulation

PRACTICAL CONSIDERATIONS FOR FRACTURE TREATMENT DESIGN

is shown in Fig. P-40. These tests confirm the earlier claims r Coy$;;ity 1
r;ed Permeability
that guar is more damaging than HPG. However, the overall Type of Fluid
level of damage is significantly greater as polymer concen-
trations increase. I 30-lb Guar + Borate 1 I I
With a better understanding of fracturing fluid damage, it 100 2200
has become increasingly evident that higher breaker concen- I 40-lb Guar + Borate I 89 1 1950 I
trations are necessary to overcome polymer damage. In the 30-lb HPG + Borate 95 2100
past, breaker concentrations have been determined based on
the base polymer loading of the fracturing fluid. Since the 40-lb HPG + Borate 89 1950
base polymer loading is concentrated severalfold, conventional
breaker concentrations are generally ineffective in minimiz- Table P-74mpact of base fluid on proppant-pack
permeabiiity, 1 lb/ft2 (from Wine, J.D. et al., SPE paper
ing polymer damage (Fig. P-41). 18969; 1989).

100 [

90

80

70
h
8
v
x
-
c 60
E
m
a
50
a

0 100 200 300 400 500
Polymer Concentration (Ib/lOOO gal)

Figure P-40-Effect of polymer load on retained permeability of 20/40 northern white sand, 2 lb/ft2, 160°F (from Brannon,
H.D. and Pulsinelli, R.J., SPE paper 20135, 1990).

P-33