Recovery Efficiency of an EOR method 
CHAPTER 2
RECOVERY EFFICIENCY OF AN EOR METHOD
2.1 SWEEP EFFICIENCY
The overall recovery factor (efficiency) RF of any secondary or tertiary oil recovery method is the product of a combination of three individual efficiency factors as given by the following generalized expression:
Fluid properties influence all three components of recovery efficiency.
1. Viscosities are found in the definition of mobility ratio, which affects areal and vertical sweep efficiency, including viscous fingering.
2. Phase densities define the degree of gravity segregation, which in turn affects vertical sweep efficiency by gravity bypassing (tonguing) in gravity-dominated processes.
3. Interfacial tensions, viscosities, inter-phase mass transfer (i.e. vaporization and condensation), and miscibility affect the residual oil saturation (ROS) de fining microscopic displacement efficiency.
Aerial sweep efficiency EA is the fraction of the pattern area from which reservoir fluid is displaced by the injected phase at the time of breakthrough.
Factors affecting Aerial Sweep Efficiency are:
Formation dip angle
Mobility ratio
Injection pattern and directional permeability
Vertical sweep effiency EV is the ratio of the cumulative height of the vertical sections of the pay zone that are contacted by injection fluid to the total vertical pay zone height.
The factors affecting vertical sweep efficiency are:
Total volume of fluid injected
Mobility ratio
The displacement efficiency ED is the fraction of movable oil that has been displaced from the swept zone at any given time or pore volume injected. Because an immiscible gas injection will always leave behind some residual oil, ED will always be less than 1.0.
2.2 AERIAL SWEEP EFFICIENCY
The areal sweep efficiency E A is defined as the fraction of the total flood pattern that is contacted by the displacing fluid. It increases steadily with injection from zero at the start of the flood until breakthrough occurs, after which E A
RECOVERY EFFICIENCY OF AN EOR METHOD
2.1 SWEEP EFFICIENCY
The overall recovery factor (efficiency) RF of any secondary or tertiary oil recovery method is the product of a combination of three individual efficiency factors as given by the following generalized expression:
Fluid properties influence all three components of recovery efficiency.
1. Viscosities are found in the definition of mobility ratio, which affects areal and vertical sweep efficiency, including viscous fingering.
2. Phase densities define the degree of gravity segregation, which in turn affects vertical sweep efficiency by gravity bypassing (tonguing) in gravity-dominated processes.
3. Interfacial tensions, viscosities, inter-phase mass transfer (i.e. vaporization and condensation), and miscibility affect the residual oil saturation (ROS) de fining microscopic displacement efficiency.
Aerial sweep efficiency EA is the fraction of the pattern area from which reservoir fluid is displaced by the injected phase at the time of breakthrough.
Factors affecting Aerial Sweep Efficiency are:
Formation dip angle
Mobility ratio
Injection pattern and directional permeability
Vertical sweep effiency EV is the ratio of the cumulative height of the vertical sections of the pay zone that are contacted by injection fluid to the total vertical pay zone height.
The factors affecting vertical sweep efficiency are:
Total volume of fluid injected
Mobility ratio
The displacement efficiency ED is the fraction of movable oil that has been displaced from the swept zone at any given time or pore volume injected. Because an immiscible gas injection will always leave behind some residual oil, ED will always be less than 1.0.
2.2 AERIAL SWEEP EFFICIENCY
The areal sweep efficiency E A is defined as the fraction of the total flood pattern that is contacted by the displacing fluid. It increases steadily with injection from zero at the start of the flood until breakthrough occurs, after which E A