Page 37 - Introduction to Petroleum Engineering

ACTIVITIES 21
1.6.2 True/False

1.1 A hydrocarbon reservoir must be able to trap and retain fluids.
1.2 API gravity is the weight of a hydrocarbon mixture.
1.3 Separator GOR is the ratio of gas rate to oil rate.
1.4 The first stage in the life of an oil or gas reservoir is exploration.

1.5 Volumetric sweep efficiency is the product of areal sweep efficiency and dis-
placement efficiency.
1.6 Net present value is usually negative at the beginning of a project.

1.7 DCFROI is discounted cash flow return on interest.
1.8 Nitrogen is a greenhouse gas.
1.9 Water flooding is an EOR process.
1.10 Geological sequestration of carbon dioxide in an aquifer is an EOR process.

1.6.3 Exercises
3
3
1.1 Suppose the density of oil is 48 lb/ft and the density of water is 62.4 lb/ft .
Calculate the specific gravity of oil γ and its API gravity.
o
1.2 Estimate recovery efficiency when displacement efficiency is 30%, areal sweep
efficiency is 65%, and vertical sweep efficiency is 70%.
1.3 Calculate volumetric sweep efficiency E and recovery efficiency RE
Vol
from the following data where displacement efficiency can be estimated as
)
S
E D S ( oi S / .
or
oi
Initial oil saturation S oi 0.75
Residual oil saturation S or 0.30
Area swept 480 acres
Total area 640 acres
Thickness swept 80 ft
Total thickness 100 ft

1.4 A. If the initial oil saturation of an oil reservoir is S = 0.70 and the residual
oi
oil saturation from water flooding a core sample in the laboratory is
S = 0.30, calculate the displacement efficiency E assuming displace-
D
or
S
)
ment efficiency can be estimated as E D S ( oi S / .
oi
or
b. In actual floods, the residual oil saturation measured in the laboratory is
seldom achieved. Suppose S = 0.35 in the field, and recalculate displace-
or
ment efficiency. Compare displacement efficiencies.