Foam for mobility control in alkaline surfactant EOR process

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Foam for mobility control in alkaline surfactant
EOR process

• Wei Yan
• George J. Hirasaki
• Clarence A. Miller

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Outline

• Bulk foam apparent viscosity in fractures
• Foam stability with the presence of residual oil
• Salinity and Calcium tolerance of NI blend
• Alkaline-surfactant-polymer-foam flooding in
  vertical silicone sand pack

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Bulk foam at medium to low gas fractional flow
Water
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Model for bulk foam apparent viscosity
Crowding factor
Viscosity of continuous phase
Internal circulation factor
Viscosity of dispersed phase
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Pals Model matches the experimental results for
bulk foam apparent viscosity
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Short pack device for foam stability
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Foam stability test results
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NI Surfactant Blends Improve Salt Tolerance
Cloudy after 9 months.
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NI Surfactant Blends Improve Calcium Tolerance
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Experimerntal conditions for ASPF in sandpack
Flow direction Vertical
Surfactant concentration 0.2
Surfactant composition N67-7POIOS (41)
Polymer concentration 0.35
Viscosity of polymer 47 cp
Salinity 2 NaCl, 1 Na2CO3
Temperature 24 C
Oil viscosity 19 cp
Residual oil saturation 25
Superficial velocity (ft/day) 5
Recovery efficiency 98
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Experimental procedure for ASPF flooding

• Fill the sand pack with crude oil
• Brine flood until no oil comes out
• Na2CO3/NI-blend/Polymer flood for 0.5PV
• IOS/Polymer flood for 0.2PV
• Foam (fg 0.67) flood as drive

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ASP Experiment in 40 darcy vertical silica
sandpack
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Effluents for different pore volume for ASPF
experiment
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Conclusions

• Bulk foam apparent viscosity at medium to low gas
  fractional flow can be described by
  semi-empirical model.
• IOS is a good foamer with the presence of
  residual crude oil
• NI blend can improve the surfactants tolerance
  to calcium and salinity
• Foam drive can be used to replace polymer drive
  in alkaline-surfactant-polymer process