1. Surfactant/Polymer Flood of Midland Farms Dolomite Core D6
Gary Pope
David Levitt
Adam Jackson
Jon Holder
The University of Texas at Austin

2. Outline Objective Phase behavior formulation Core flood design Results
Conclusions

3. Objectives
Achieve initial oil saturation and residual oil saturation to water similar to MF reservoir values and at similar pressure gradients
Recover 90% of waterflood residual oil with surfactant and polymer
Achieve low surfactant retention

4. Phase Behavior and Surfactant Formulation
Criteria:
Low viscosity
Low interfacial tension
High solubilization ratio
Short equilibration time
[Photo]
0.75% N67-7PO, 0.25% IOS C1518, 2% SBA
(WOR 1:1) with MF3 at 38C after 6 days
Scan from 2 - 6%
Equilibration time ~ 12 (days)
Solubilization, s* = 12 (cc/cc)

5. Solubilization and Optimal Salinity
Solubilization (cc/cc)

6. HPAM Polymer Hydrolyzed Polyacrylamide (HPAM)
Flopaam 3330S from SNF Floeger

7. HPAM Polymer

8. HPAM Polymer

9. Midland Farms Dolomite Core Design and Configuration
 = 0.18
kbrine= 166 md
kro = 0.40
krw = 0.03
Swi= 0.26
Sorw= 0.39
Formation Brine:
6.1% TDS
(8:1 NaCl:CaCl2)

10. Injected Fluids Pore Volumes Mixture 0.8
0.75% N67[7PO], 0.25% IOS C1518, 2% SBA
0.02% Na2CO3, 4.45% NaCl
1500 ppm Flopaam 3330S
0.2
2% SBA
3.05% NaCl
1.5
1.93% NaCl
1200 ppm Flopaam 3330S

11. Oil Flood Pressures

12. Water Flood Pressures

13. Sulfate Detected in Produced Formation Brine
Effluent Sample
Sulfate Concentration (ppm) 1
1268 2
1686 3
2094 4
2615
Samples taken from tubes preceding oil breakthrough

14. Oil Recovery Results
Free Oil = 90% Oil from Emulsion = 5%

15. Surfactant Recovery Results
Surfactant Retention: mg/g

16. Surfactant/Polymer Pressure Results

17. Post-flood Polymer Assessment
Polymer Resistance Factor (Rf):
Rf = (DPp/DPw)q, Sw = 23/0.3 = 87
Polymer Permeability Reduction Factor (Rk):
Rk = Rf / (mp/mw) = 87/(5.5/0.911) = 14.5
Previous core flood indicated:
Rk = 2
(Prior HPAM used 2000 ppm Alcomer 60RD)

18. Conclusions Cumulative oil recovery of 95% Sorc = 0.01
High oil recovery in a dolomite without sodium carbonate
50% of the surfactant was recovered
No plugging occurred
Anhydrite is present in core
Sodium carbonate can not be used
Polymer concentration may be reduced