Page 71 - Principles of Applied Reservoir Simulation 2E
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Chapter 7
Pattern Floods
The effectiveness of a displacement process depends on many factors.
These factors include reservoir and fluid characteristics that are beyond our
control, such as depth, structure, and fluid type. Other factors that influence
displacement efficiency can be controlled, however. They include the number
and type of wells, well rates, and well locations. The distribution of wells is
known as the well pattern. The impact of well pattern on displacement effective-
ness is discussed after definitions of recovery efficiency are presented.
7.1 Recovery Efficiency
Recovery efficiency is quantified by comparing initial and final volumes
of fluid in place. It takes into account volumetric and displacement efficiencies.
The different aspects of recovery efficiency are defined and then combined to
form overall recovery efficiency.
Displacement efficiency accounts for the efficiency of recovering mobile
hydrocarbon. To be specific, we define displacement efficiency for oil as the
ratio of mobile oil to original oil in place at reservoir conditions:
V S - V S S - S (7
° ^ ^r -°
F - P oi P or - oi or /"? i \
where
initial pore volume
V p
initial oil saturation
S oi
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