Page 339 - Fundamentals of Reservoir Engineering

REAL GAS FLOW: GAS WELL TESTING 274

m(p ) m(p wf n ) FQ 2 n
−
−
i
Q Q
j log(t − t ) n
j 1
n
Q t Q n − p wf m(p wf)
2
Mscf/d hrs psia psia /cp F = 0 .04 .05 .06
10×10 3 1 0 4160 1023.35×10 6 4494 4094 3994 3894
20× " 2 .1505 3997 967.00 " 5065 4265 4065 3865
30× " 3 .2594 3802 899.59 " 5623 4423 4123 3823

40× " 4 .3450 3577 821.81 " 6162 4562 4162 3762

TABLE 8.6

−
∆ m(p) FQ 2 n F = 0.0
Q n
2
6000 (psia / cp / Mscf / d)

5500

5000

F = 0.04
4500

F = 0.05
4000

F = 0.06
∆ Q j
log (t − t j − 1 )
n
Q n
3500
0 0.1 0.2 0.3 0.4
Fig. 8.12 Essis-Thomas analysis of a multi-rate gas well test under assumed transient
flow conditions. Data; table 8.6

Initially, the plot is made ignoring the effects of non-Darcy flow (F = 0) and this exhibits
a marked upward curvature for large values of the abscissa, corresponding to the fact