Page 374 - Standard Handbook Petroleum Natural Gas Engineering VOLUME2

340 Reservoir Engineering

DEPTH, feet
5 Q) ai P fu
b b b b b
0 0 0 8 0
0 0 0 0 0

-
f
DEEP ENOUGH FOR REQUIRED PRESSURE u,
-I
c
v)
c
LIMITED BY TEMPERATURE ;[I
n
B
4
LIMITED BY TEMPERATURE 3
m
n
D
5
NOT CRITICAL D
E
m

I
’0
G,
D
v)
Figure 5-177. Depth requirements for EOR processes [386].

The range of values are indicated on the graphs by the open areas, and by cross-
hatching along with general words such as “more difficult,” “not feasible,” etc.
The “good” or “fair” ranges are those usually encompassed by the screening
parameters in the table. However, the notation of “good” or “very good” does
not mean that the indicated process is sure to work; it means simply that it is
in the preferred range for that oil or reservoir characteristic.
The inf hence of viscosity on the technical feasibility of different enhanced
recovery methods is illustrated in Figure 5-176. Note the steady progression, with
increasing viscosity, from those processes that work well with very light oils
(hydrocarbon miscible or nitrogen) to oils that are so viscous that no recovery
is possible unless mining and extraction are employed.