Page 189 - Fundamentals of Enhanced Oil and Gas Recovery

177
Thermal Recovery Processes

Rate of growth for the heated zone is

dA h _ m s H s
5 G 1 ðt D Þ (5.124)
dt M R T s 2 T R Þh
ð
p
ffiffiffiffiffi
t D
G 1 t D 5 e erfc t D (5.125)
ðÞ
Example 5.3: Radius of steam zone for constant injection rate
The steam with the quality of 80% at pressure of 500 psig is injected to the reservoir
at rate of 500 BWPD CWE. The reservoir has 25% porosity. The initial saturations of
oil and water is S oi 5 0.2 and S wi 5 0.8. The volume occupied by the steam is 40% of
the PV.
2
k h 5 1.5 Btu/h ft F, α 5 0.0482 ft /h, M R 5 32.74 Btu/ft 3 F, M(5k h /α) 5

31.12 Btu/ft 3 F, T R 5 80 F.
Determine the heated area radius while 14 days is passed from injection [36].
At 500 psig, T s 5 470.9 F

H wTR 5 77 Btu/lb m (at 80 F)

H wTs 5 452.9 Btu/lb m (at 470.9 F)

λ s 5 751.4 Btu/lb m
m s 5 (500 bbl/d)(350 lb m /bbl)(24 h/d) 5 7292 lb m /h
_ m s H s M R h
A h 5 Gðt D Þ
4 T s 2 T R ÞαM 2
ð

T s
H s 5 H 2 H T R
w w 1 f s λ s
M 2

αt
t D 5 4
M R h 2
k h
M 5
α
2 !
αt
t D 5 4 M
M R h 2
! 2 !
ð0:0482Þ 14d 3 24 h=d
31:12
5 4
32:74 20 2
5 0:146

G(t D ) 5 0.113
H s 5 (452.9 2 77) 1 0.8 3 (751.4) 5 977 Btu/lb m