Page 68 - Primer on Enhanced Oil Recovery

Oil recovery stages and methods 59

Figure 7.6 Oil recovery stages and applied extraction technologies.

Figure 7.7 Enhanced oil recovery processes.

other advanced oil production technology that is implemented during any ongoing
oil recovery process. Examples of IOR are any technology method leading to
increase in oil production that is used during the primary, secondary or tertiary
recovery of hydrocarbons. Other examples of IOR applications are: hydraulic frac-
turing, sedimentation prevention, acidizing, drilling additional wells to densify pro-
duction well grid (infill drilling), and using horizontal wells (see Fig. 7.7).
Fig. 7.8 demonstrates current methods of enhanced oil recovery. Table 7.1 shows
the underlying mechanisms (basic macroscopic processes) of enhanced oil recovery
for the most used methods of enhanced oil recovery.
Chemical methods of enhanced oil recovery are characterized by the addition of
chemical compounds to the injected water in order to modify the physicochemical
properties of the fluid or interfacial tension. The later is more favorable for oil dis-
placement. In polymer flooding, polyacrylamides or polysaccharides are used - this
is a conceptually simple and inexpensive solution, and despite the fact that the tech-
nological efficiency of the method is not so high, it is used for commercial