Surfactant-Based Enhanced Oil recovery Processes and Foam Mobility Control Task 4: Simulation of Field-Scale Processes

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Surfactant-Based Enhanced Oil recovery Processes
and Foam Mobility ControlTask 4 Simulation of
Field-Scale Processes
Mojdeh Delshad
Gary Pope Glen Anderson
Hourshad Mohammadi Nariman
Fathi

• Center for Petroleum and Geosystems Engineering
• The University of Texas at Austin

Austin, Texas June 4, 2005
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Objectives

• Design and optimize a surfactant flood for
  Midland Farm oil reservoir
• Study the effect of wettability on the
  performance of surfactant flood
• Literature survey on effect of wettability on
  petrophysical properties
• Develop and implement a procedure to model
  wettability alteration

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Base Case Midland Farms Simulation

• Matching Water Injection Rate
• Permeability Field
• Relative Permeability Curves
• Waterflood Injection Rate
• Design Parameters
• Base Case Results
• Production Rates
• Cumulative Oil Recovery
• Production History
• Oil Saturation Profiles
• Surfactant Concentration Profiles
• Residual Oil Saturation Profiles
• Sensitivity Analysis

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Permeability Field

• Stochastic Permeability Field
• Vdp0.75
• lx ly 20 ft
• lz 4 ft

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Relative Permeability Curves
Corey Type Parameters
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Water Injection Rate and Phase Cut during
Waterflood
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Design Parameters
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Chemical Flood Production Rates (1 PV Polymer
Drive)
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Chemical Flood Oil Recovery(1 PV Polymer Drive)
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Produced Phase Cuts during Chemical Flood(1 PV
Polymer Drive)
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Produced Chemical Concentrations(1 PV Polymer
Drive)
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Oil Saturation During Chemical Flooding
0.2 PV
0.75 PV
1.25 PV
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Surfactant Concentration
0.2 PV
0.75 PV
1.25 PV
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Reservoir and Fluid Properties
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Effect of Wettability on Sor
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CDC for Berea Sandstone (Amaefule 1982)
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CDC in Berea Sandstone (Mohanty 1983)
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CDC in Carbonates (Kamath 2001)
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Permeability Distribution
md
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Effect of Wettability on Relative Permeability
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Effect of Wettability on Capillary Pressure
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Effect of Wettability on Waterflood Recovery
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Effect of Wettability on Chemical Oil Recovery
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Effect of Wettability on Reservoir Pressure
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Effect of Wettability on Oil Production Rate
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Oil Saturation during Waterflood (Waterwet Case)
0.2 PV
0.9 PV
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Oil Saturation during Waterflood (Mixedwet Case)
1.0 PV
3.5 PV
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Oil Saturation during Waterflood (Oilwet Case)
0.3 PV
1.9 PV
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Oil Saturation during Surfactant Flood
(Waterwet Case)
0.25 PV
2.25 PV
0.75 PV
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Oil Saturation during Surfactant Flood
(Mixedwet Case)
0.25 PV
2.25 PV
0.75 PV
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Oil Saturation during Surfactant Flood (Oilwet
Case)
0.25 PV
2.25 PV
0.75 PV
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Surfactant concentration at 0.75 PV
Waterwet
Mixedwet
Oilwet
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Final Oil Saturation
Mixedwet
Waterwet
Oilwet
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Wettability Alteration

• Wettability Index vs. surfactant properties
• Residual saturation
• Relative Permeability
• Capillary pressure
• Capillary desaturation

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Model 1 Wettability Effect Only

• Read the table of water and relative
  permeabilities vs. water saturation for the
  in-situ wettability i.e mixed-wet
• Read the table of water-oil capillary pressure
  vs. water saturation for the in-situ wettability
• Read another set of tables for the altered
  wettability i.e water-wet
• Check the gridblock value of surfactant
  concentration at each time step
• Switch the tables if the surfactant concentration
  is above an input tolerance

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Model 2 Effect of Wettability and Mobilization

• Relative permeability curves for oil and water at
  two extreme wettability conditions
• Capillary pressure curves for two extreme
  strongly water-wet and strongly oil-wet
• Capillary desaturation curves for each phase at
  the two extreme conditions of wettability

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Model 2 - Linear Interpolation

• Strongly Oil-Wet
• Relative permeability at low IFT
• Capillary desaturation curves
• Relative permeability at high IFT

• Strongly water-Wet
• Relative permeability at low IFT
• Capillary desaturation curves
• Relative permeability at high IFT

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Relative Permeability Curves (Morrow 1973)
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High NC Relative Permeability

• Calculate relative permeability endpoints
• Calculate relative permeability exponent

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Model 2 - Linear Interpolation
F constant
Or
Or Develop new relationship based on lab. data
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Model 3 Under Development!

• Determine the Wettability Index in each gridblock
  and each time step based on surfactant property
• Compute residual saturations as a function of
  Wettability Index

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Sor vs Wettability Correlation
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Sor vs. Wettability Index for Berea Core
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Normalized Residual Oil Saturation vs.
Wettability Index (All Data)
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Wettability and CDC
Indiana Limestone (Abrams)
Capillary Number
Berea Sandstone (Gupta)
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Trapping Number vs Wettability Index Correlation
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Computation Procedure

• Establish relative permeability, capillary
  pressure, and capillary desaturation curves for
  initial and altered wettability conditions
• Determine the change in Wettability Index (IW) in
  the presence of surfactant
• Develop a correlation between residual saturation
  and IW
• Develop a correlation between trapping number
  and IW
• Compute high capillary number relative
  permeability for altered wettability