Page 128 - A Practical Companion to Reservoir Stimulation

DIVERSION AND TREATMENT EVALUATION

EXAMPLE H-7

I k = 10md I Calculation of Bottomhole Injection Pressure
IP = 0.7~~ I from Wellhead Values
h = 75 ft [22.86 m] Calculate the bottomhole injection pressure if the wellhead
In (re/rw) = 8 pressure is 50 psi and the injection rate is 1 BPM. Table H-3
contains all other pertinent variables.
I fg = 0.7
I s = +4 I Solution (Ref. Section 16-2)
IH = 8200ft I The velocity is given by
q
rW = 0.328 ft [0.1 m] u= - = 1 BPM (0.0936ft3/s/BPM) = 2.89 ft /s. (H-27)
A (3.14) ( 0.203)2 /4
Apsafe = 200 psi
D = cm2/s The Reynolds number can be calculated from Eq. 16-4:
IP = 4300psi I N,, = (60 lb/ft3)(2.89 ft /s)(0.203 ft)

I 4 = 0.2 I 1 cp (6.719~ Ib/ft -s)
B = 1 resbbl/STB
= 5.2~ 104 (H-28)
K1 = 6.15 x 10l6 (in Eq. H-14)
Thus, since this is highly turbulent flow, the Fanning
A = 0.7 m2 friction factor can be obtained from Eq. 16-6. This can be done
through trial and error, resulting inf= 0.01.
Table H-2-Carbonate formation variables for Example H-6.
The friction pressure drop is given (in oilfield units) by
Eq. 16-8:

(1.525) (60) ( 12) (0.01) (10,000)
AP/m 11Oll =
( 2.44 1 5

= 106psi. (H-29)
Finally, the bottomhole injection pressure can be calcu-
lated from Eq. 16-1 (with appropriate substitution for the
hydrostatic pressure):

pl,,, = 500 + (60) ( 10,000) - 106 = 4561 psi. (H-30)
144

10,000 ft
dtbg = 2.441 in. [0.203 ft]
I
I H = 10,000ft
I P = 1CP I
Table H-3-Well and treatment variables for Example H-7.

H-7