Update on Surfactant EOR in Fractured, Oil-Wet Carbonates

1
Update on Surfactant EOR in Fractured, Oil-Wet
Carbonates

• D. Leslie Zhang
• 06/04/05
• UT, Austin

2
Outline

• Problems with the old blend TDA-4PO S CS-330
  11
• Introduction of the new blend N67-7PO S
  IOS1518 41

• Phase Behavior
• IFT
• Adsorption
• Oil recovery by centrifuge imbibition

3
Soap/Synthetic Surfactant Mole Ratio Correlation
Acid number of crude oil0.2 KOH mg/g oil
14
TC Blend TDA-4PO S/CS-33011
12
10
8
Optimal NaCl Conc.,
6
4
2
Formation brine salinity
0
1E-02
1E-01
1E00
1E01
Soap/Synthetic Surfactant Mole Ratio
4
0.05 TC Blend / 1Na2CO3 / NaCl _at_
WOR101 (27 weeks after settling at
30 C in the environmental room) 2 4 6
6.2 6.4 6.6 6.8 7 7.2 7.4 7.6 7.8 8
9
5
3 TC Blend/1Na2CO3/NaCl (7 weeks after settling
at 30 C in the environmental room) 0 2 5
7 9 10 11 12 13 14 15 16
Gel/viscous emulsion
6
(2.4)N67-7PO S (0.6)IOS-15/18
7
(0.04)N67-7PO S (0.01)IOS-15/18 In 1 Na2CO3
/ xNaCl, WOR31, Room Temperature
X 0 0.2 0.4 0.6 0.8
1.0 1.2 1.4 1.6 1.8 2.0
3.0
Settling time 7 days
Settling time 1 month
8
Soap/Synthetic Surfactant Mole Ratio Correlation
Acid number of crude oil0.2 KOH mg/g oil
14
12
TDA-4PO S CS-33011
10
8
Optimal NaCl Conc.,
6
N67-7PO S IOS-151841
4
2
Formation brine salinity
0
1E-02
1E-01
1E00
1E01
Soap/Synthetic Surfactant Mole Ratio
9
Surfactant Solution Should Be Single Phase At
Injected Composition
10
IFT of (0.04)N67-7PO S (0.01)IOS-15/18 In 1
Na2CO3 / xNaCl, WOR31, Room Temperature
1E01
1E00
IFT, dyne/cm
1E-01
1E-02
1E-03
0
1
2
NaCl,
11
Adsorption of (N67-7PO S IOS-15/18 41) on
Calcite
2.5
2
1.5
Adsorption, mg/m2
1
BET surface area of the calcite 17.851 m2/g
0.5
0
0.00
0.50
1.00
1.50
2.00
Residual Surf Conc, mmol/l
0.1 new blend/1 Na2CO3
12
Schematic Setup for Imbibition in Centrifuge
x x x x x x x x x x x x x
Brine or Surf. Sol.
Stainless Screen
rotor
13
Oil Recovery by Imbibition in Centrifuge Aged at
80C for 48 hours
RPM6000, centrifuge time4days
NaCl, core k, md Porosity, PV, ml OOIP, ml So OR, ml Sor Recovery, OOIP
Water Flood 1 10 4.933 21.2 2.661 2.11 0.79 1.45 0.25 69
Water Flood 1 23 6.821 22.4 2.897 2.36 0.81 1.53 0.28 65
0.05 new blend /1 Na2CO3 1 65 6.592 22.8 2.865 2.45 0.79 1.58 0.24 70
0.05 new blend /1 Na2CO3 2 38 7.776 24.0 3.02 2.50 0.79 1.75 0.21 74
0.05 new blend /1 Na2CO3 3 11 4.915 21.2 2.651 2.06 0.78 1.5 0.21 73
0.05 new blend /1 Na2CO3 4 17 4.615 21.2 2.798 2.14 0.77 1.33 0.29 62
0.05 new blend /1 Na2CO3 5 28 4.480 20.7 2.588 1.99 0.77 1.53 0.18 77
14
Oil Recovery by Centrifuge Imbibition
0.05 New Blend/1 Na2CO3/xNaCl
80
75
Oil Recovery
70
65
60
1
2
3
4
5
NaCl,
15
Why and When Surfactant Improves Oil Recovery
At 6000 RPM
IFT, mN/m NB
30 1.610-6
1 4.710-5
0.1 4.710-4
0.01 4.710-3
0.001 4.710-2
Ref Lake, 1989 (Camilleri, 1983)