This document discusses primary recovery processes for petroleum extraction. It describes the natural reservoir drive mechanisms that provide energy for initial hydrocarbon production, including solution-gas drive, gas-cap drive, water drive, and combination drives. The document estimates typical oil recovery factors during primary recovery range from 5-30% for solution-gas drives to 30-60% for water drives. Primary recovery relies solely on the natural energy present in the reservoir to produce oil and gas.

1. Petroleum Recovery
Processes
2

2. Petroleum Recovery
Processes
Primary Recovery
Introduction
Natural Flow Secondary
Recovery
Waterflood
Thermal Gas
Miscible/Immiscible
Chemical Other
Pressure Maintenance
Water Dry Hydrocarbon
Gas Injection
Pump Gas Lift Other
Artificial Lift
Tertiary Recovery
In-situ Combustion
Cyclic Steam
Steam Drive/Flood
Hot Water Drive
Hydrocarbon
CO2
Nitrogen
Flue Gas
Alkaline
Polymer
Micellar/Polymer
Foam
Microbial
Conventional
Oil
Recovery
Enhanced
Oil
Recovery
3

3. Primary Recovery
Hydrocarbon production is resulting
from natural reservoir energy
Petroleum Recovery
Processes
4

4. Primary Recovery
Reservoir Energy Sources
Liberation, expansion of solution gas
Influx of water from aquifer
Expansion of reservoir rock into pore space
Expansion of original reservoir fluids
- Free gas
- Interstitial water
- Oil, if present
Gravitational forces
Petroleum Recovery
Processes
5

5. Primary Recovery
Oil Reservoir Drive
Mechanisms
Solution-gas drive
Gas-cap drive
Water drive
Combination drive
Gravity-drainage drive
Gas Reservoir Drive
Mechanisms
Volumetric reservoir
(gas expansion drive)
Water drive
Petroleum Recovery
Processes
6

6. Primary Recovery
Oil
A. Original Conditions
B. 50% Depleted
Oil-producing wells
Oil-producing wells
Petroleum Recovery
Processes
Solution-Gas Drive In Oil Reservoir
7

7. Primary Recovery
Wellbore
Secondary
gas cap
Petroleum Recovery
Processes
Solution-Gas Drive In Oil Reservoir
8

8. Primary Recovery
Rapid and continuous
pressure drop, rate of
decline falls at bubble
point pressure.
Rs (solution gas oil ratio)
low until p=pb, then
increases to maximum and
declines.
Absent or minimal water
influx (water cut).
Well production declines
rapidly, early pumping
required. Time
Pressure
GOR (R)
Rsi Water Cut
Petroleum Recovery
Processes
Solution-Gas Drive In Oil Reservoir
9

9. Primary Recovery
Estimating Oil Recovery Factors
Solution-gas drive - API study
( )
( )
m
-
f
=
1741
.
0
a
b
3722
.
0
wi
0979
.
0
ob
1611
.
0
ob
wi
R
p
p
S
k
B
S
1
8
.
41
E
Petroleum Recovery
Processes
10

10. Primary Recovery
Gas Cap Drive in Oil Reservoirs
Cross Section
Oil-producing well
Oil
zone
Oil
zone
Gas cap
Petroleum Recovery
Processes
11

11. Primary Recovery
Pressure drops continuously,
but slowly.
Rs (solution gas oil ratio)
increases continuously.
Water influx (water cut)
absent or minimal
Wells have long flowing
life (depending on the size
of the gas cap).
Pressure
GOR (R)
Rsi
Water Cut
Time
Petroleum Recovery
Processes
Gas Cap Drive In Oil Reservoir
12

12. Primary Recovery
Water Drive in Oil Reservoirs
Edgewater Drive
Oil-producing well
Water Water
Cross Section
Oil Zone
Petroleum Recovery
Processes
13

13. Primary Recovery
Water Drive in Oil Reservoirs
Bottomwater Drive
Oil-producing well
Cross Section
Oil Zone
Water
Petroleum Recovery
Processes
14

14. Primary Recovery
Pressure remains high,
small drop.
Rs (solution gas oil ratio)
remains low.
Water influx starts early
and increases to
appreciable levels.
Residual oil may be
trapped behind the
advancing water.
Wells flow freely until
water production (water
cut) becomes excessive
Pressure
GOR (R)
Rsi
Water Cut
Time
Petroleum Recovery
Processes
Water Drive In Oil Reservoir
15

15. Primary Recovery
Water Drive in Oil Reservoirs
Effect of Production Rate on Pressure
Time, years
2000
1900
1800 2
1
0 60
40
20
0
1700
20
15
10
5
0
Pressure,
psia
Oil
production,
Water
Cut,
%
Gas/oil
ratio,
MSCF/STB
MSTB/D
Reservoir pressure
Water
Gas/oil ratio
Oil
Production data - lower oil production rate
Petroleum Recovery
Processes
16

16. Primary Recovery
Estimating Oil Recovery Factors
Water drive - API study
( )
( )
m
m
-
f
=
-
2159
.
0
a
i
1903
.
0
wi
0770
.
0
oi
w
0422
.
0
oi
wi
R
p
p
S
k
B
S
1
9
.
54
E
-
Petroleum Recovery
Processes
17

17. Primary Recovery
Combination Drive in Oil Reservoirs
Water
Cross Section
Oil zone
Gas cap
Petroleum Recovery
Processes
18

18. Primary Recovery
PRESSURE TRENDS
0 20 40 60 80 100
100
80
60
40
20
0
Gas-cap
drive
Water drive
Solution-gas drive
Reservoir
pressure,
Percent
of
original
Reservoir
pressure
trends
Cumulative oil produced, percent of original oil in place
Petroleum Recovery
Processes
19

19. Primary Recovery
Oil Reservoir Drive Mechanisms
Summary of Source(s) of Reservoir Energy
Solution-gas drive
Gas-cap drive
Water drive
Combination drive
Gravity-drainage drive
Petroleum Recovery
Processes
24

20. Primary Recovery
Average Recovery Factors
Oil Reservoirs
Average Oil Recovery
Factors,
% of OOIP
Drive Mechanism
Range Average
Solution-gas drive 5 - 30 15
Gas-cap drive 15 - 50 30
Water drive 30 - 60 40
Gravity-drainage
drive
16 - 85 50
Petroleum Recovery
Processes
26