CPGE Surfactant-Alkali Phase Behavior Adam Jackson Larry Britton Gary Pope David Levitt Varadarajan Dwarakanath Taimur Malik The University of Texas at Austin

CPGE Outline Surfactants Crude Oil Phase Behaviors Conclusions

CPGE Surfactants Studied Manufacturer Trade (Common) Name Abbreviated Chemical Name STEPANNeodol N67 3 POC (PO) 3 SO 4 STEPANNeodol N67 5 POC (PO) 5 SO 4 STEPANNeodol N67 7 POC (PO) 7 SO 4 STEPANC1618C AOS STEPANC2024C AOS SHELLC16 Xylene SulfonateC 16 OXS SHELLIOS 1518C IOS OIL CHEMORS-HF66 CLARIANTHostapur SAS-60

CPGE Crude Oils Studied OperatorField Burlington ResourcesCedar Hills (CH) OccidentalElk Hills (ELK) Occidental Permian Ltd.Midland Farms (MF2) (Batch 2)* Occidental Permian Ltd.Midland Farms (MF3) (Batch 3)* * Two samples from the same field

CPGE Phase Behavior Parameters New Surfactants Electrolyte Concentration Sodium Carbonate Sec-Butyl Alcohol (SBA) Concentration Crude Oil (and associated Temperature) Polymers

CPGE Optimal Salinity for N67-7PO and IOS-1518 with Midland Farms Crude

CPGE Equilibration at Optimal Salinity Time [days] Solubilization Ratio oil water DOE 201: MF3 Na+ = 1.7 wt% Temp. = 38 C 0.75% C (PO) 7 SO 4, 0.25% C SO 3, 2% SBA, 0.02% Na 2 CO 3

CPGE Equilibration Near Optimum Salinity Time [days] Solubilization Ratio oil water DOE 201:MF3 Na+ = 1.6 wt% Temp. = 38 C 0.75% C (PO) 7 SO 4, 0.25% C SO 3, 2% SBA, 0.02% Na 2 CO 3

CPGE Effect of Sodium Carbonate on Equilibration Time 0.75% C (PO) 7 SO 4, 0.25% C SO 3, 2% SBA, 1.02% Na 2 CO 3

CPGE Effect of Varying Sodium Carbonate Concentration on Equilibration Time 0.75% C (PO) 7 SO 4, 0.25% C SO 3, 2% SBA

CPGE d.n.e. Did not equilibrate Effect of Alcohol on Phase Behaviors with N67-7PO, IOS-1518 and MF Crude at 38C

CPGE 2% C AOS, 4% SBA ELK Hills Crude Temp. = 100 C Effect of Sodium Carbonate on Optimal Salinity for Elk Hills Crude with AOS and SBA

CPGE Effect of Sodium Carbonate on Equilibration Time with Elk Hills Crude

CPGE Summary and Conclusions Na 2 CO 3 has little effect on MF solubilization Alcohol reduces equilibration time, viscosity and solubilization –N67-7PO and IOS-1518 can exhibit reasonable equilibration times while maintaining >10 solubilization with SBA Na 2 CO 3 improves Elk Hills solubilization ratio Alcohol shortens phase separation time with Elk Hills crude oil HPAM had little if any effect on the equilibrated phase behavior

CPGE Slug and polymer drive composition for core flood D6 Pore VolumesMixture % N67[7PO], 0.25% IOS C1518, 2% SBA 0.02% Na2CO3, 4.45% NaCl 1500 ppm Flopaam 3330S 0.22% SBA 3.05% NaCl 1500 ppm Flopaam 3330S % NaCl 1200 ppm Flopaam 3330S

CPGE Surfactant selection for MF Core Flood Surfactant formulation was selected for core flooding because it showed –Good solubilization ratio at optimum salinity –Optimum salinity within the desired range of 2% to 6% TDS corresponding to Midland Farms brines –Microemulsion viscosity acceptable –Better dilution behavior than with AOS –Aqueous phase stable and clear at injected salinity –Compatible with HPAM polymer Polymer selected for core flood –Higher viscosity than low molecular weight HPAM used in first core flood and RF expected to be high for good mobility control –Compatible with surfactant at salinity of slug and drive

CPGE 2% C AOS, 4% SBA, 0.02% Na 2 CO 3 with ELK at 100C