CPGE

Surfactant-Based Enhanced Oil recovery Processes and Foam Mobility Control

Task 4: Simulation of Field-Scale Processes

Center for Petroleum and Geosystems EngineeringThe University of Texas at Austin

Austin, Texas • June 4, 2005

Mojdeh Delshad Gary Pope

Glen Anderson Hourshad Mohammadi

Nariman Fathi

CPGE

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

CPGE

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

CPGE

Permeability Field

Stochastic Permeability Field

Vdp=0.75

x = y = 20 ft

z = 4 ft

CPGE

Relative Permeability Curves

Corey Type Parameters

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Sw

krj

Water

Oil

krwo = 0.4

kroo = 0.6

nw = 2

no = 2

Swr = 0.29

Sor = 0.33

CPGE

Water Injection Rate and Phase Cut during Waterflood

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

1600

0 1 2 3 4 5 6 7

Years Injected

Wat

er In

ject

ion

Rat

e d

uri

ng

W

ater

flo

od

(b

bl/d

ay)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Wat

er P

has

e C

ut

at P

rod

uce

r

RatePhase Cut

CPGE

Design Parameters

Grid 11x11x5 WF Endpoint Mobility Ratio 4.76Dimensions (20 acre well spacing per prod) 660x660x30 Dykstra-Parsons Coefficient 0.75Depth to Pay 4700 ft x- and y-direction Correlation Length 20Water Density 62.43 lb/ft3 z-direction Correlation Length 4

Oil Density 54.33 lb/ft3Water Flood to get to 98% Water Cut 1.8 PV

Water Viscosity 0.7 cp Initial Salinity 1.026 meq/mL

Oil Viscosity 5 cp Surfactant Adsorption 0.3 mg/g

Initial Pressure 1975 psi Polymer Adsorption 10 g/g

Reservoir Temperature 103 oF Surfactant Slug (2 vol %) 0.25 PV

Arithmetic Mean Permeability 80 md Polymer Concentration in Slug 1000 ppm

Geometric Mean Permeability 31.2 md Slug Salinity 0.445 meq/mL

kx/ky 1 Polymer Drive 2 PV

kx/kz 0.1 Polymer Concentration in Drive 1000 ppm

Porosity 0.16 Drive Salinity 0.34 meq/mL

Water/Oil IFT 20 dynes/cmInjection Pressure 2500 psiProducing Pressure 300 psiSkin -3

CPGE

DL-DOE-119: 1.5%N67-7POS,0.5%C2024, 4% SBA, 1% Na2CO3 0.125% Alcomer 60RD w./ MF2 Crude @ 38C

02468

101214161820222426283032

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6

NaCl concentration (wt%)

So

lub

liza

tio

n R

ati

o (

cc

/cc

) . Oil Sol. Ratio after 1 Day

Water Sol. Ratio after 1 Day

UTCHEM Oil

UTCHEM Water

CPGE

Polymer Viscosity vs. Shear Rate

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

0.01 0.1 1 10 100 1000 10000

Shear Rate (1/s)

Po

lym

er V

isco

sity

, cp

!000 ppm polymer

CPGE

Chemical Flood Production Rates (1 PV Polymer Drive)

0

200

400

600

800

1000

1200

1400

0 1 2 3 4 5 6 7 8 9

Time, Years

Wat

er P

rod

uct

ion

rat

e, B

bls

/d

0

20

40

60

80

100

120

140

160

180

Oil

Pro

du

ctio

n R

ate,

Bb

ls/d

ay

CPGE

Chemical Flood Oil Recovery(1 PV Polymer Drive)

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 1 2 3 4 5 6 7 8 9

Time, Years

Incr

emen

tal

Oil

Pro

du

ced

, %

RO

IP

CPGE

Produced Phase Cuts during Chemical Flood(1 PV Polymer Drive)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3

Pore Volumes Injected

Pro

du

ced

Ph

ase

Cu

ts(v

olu

me

frac

tio

n)

WaterOilMicroemulsion

CPGE

Produced Chemical Concentrations(1 PV Polymer Drive)

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0 0.2 0.4 0.6 0.8 1 1.2 1.4

Pore Volumes Injected

Pro

du

ced

Su

rfac

tan

t C

on

cen

trat

ion

(v

olu

me

frac

tio

n)

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1

Pro

du

ced

Po

lym

er C

on

cen

trat

ion

(w

eig

ht

frac

tio

n)

SurfactantPolymer

CPGE

Oil Saturation During Chemical Flooding 0.2 PV 0.75 PV

1.25 PV

CPGE

Surfactant Concentration

0.2 PV 0.75 PV

1.25 PV

CPGE

Reservoir and Fluid Properties

LxWxH 660x660x30 ft

Grid Blocks 11x11x5

Depth to Pay 4700 ft

Initial Pressure 1975 psi

Reservoir Temperature 103 oF

Average Permeability 80 md

Porosity 0.16

Water Compressibility 3x10-6 psi-1

Oil Compressibility 1x10-5 psi-1

Water Density 62.43 lb/ft3

Oil Density 54.33 lb/ft3

Water Viscosity 0.7 cp

Oil Viscosity 5 cp

Water/Oil IFT 20 dynes/cm

Constant Injection Rate 250 bbl/day

Constant Production Pressure 300 psi

CPGE

Effect of Wettability on Sor

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

-1 -0.75 -0.5 -0.25 0 0.25 0.5 0.75 1Iw

So

r

Jadhunandan and Morrow, 1991Owolabi and Watson, 1993

Chen et al, 2004

CPGE

CDC for Berea Sandstone (Amaefule 1982)

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

1.0E-07 1.0E-06 1.0E-05 1.0E-04 1.0E-03 1.0E-02 1.0E-01 1.0E+00

Capillary Number

Res

idu

al P

has

e S

atu

rati

on

(F

rac.

of

PV

)

OilWater

Oil Ncc

Water Ncc

CPGE

CDC in Berea Sandstone (Mohanty 1983)

0.00

0.10

0.20

0.30

0.40

0.50

0.60

1.0E-07 1.0E-06 1.0E-05 1.0E-04 1.0E-03 1.0E-02 1.0E-01 1.0E+00

Capillary Number

Res

idu

al O

il S

atu

rati

on

(F

rac.

of

PV

)

Oil WetWater WetMixed Wet

CPGE

CDC in Carbonates (Kamath 2001)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.00E-09 1.00E-08 1.00E-07 1.00E-06 1.00E-05 1.00E-04 1.00E-03 1.00E-02

Capillary Number

Res

idu

al O

il S

atu

rati

on

(F

rac.

of

PV

) Iw = -0.25Iw = -0.19Iw = -0.04

CPGE

Permeability Distribution

md

CPGE

Effect of Wettability on Relative Permeability

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Water Saturation (Frac. of PV)

Re

lati

ve

Perm

ea

bil

ity

(Fra

c. o

f A

bs

. P

erm

.)

Case #1Case #4

Case #2 and #3

CPGE

Effect of Wettability on Capillary Pressure

-15.000

-10.000

-5.000

0.000

5.000

10.000

15.000

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Water Saturation (Frac. of PV)

Cap

illar

y P

ress

ure

(p

si)

Case #1

Case #4

Case #2 and #3

CPGE

Effect of Wettability on Waterflood Recovery

0

10

20

30

40

50

60

70

0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 2.25 2.5 2.75 3 3.25 3.5

Pore Volumes of Waterflood

Cu

mu

lati

ve

Oil

Re

co

ve

ry (

%O

OIP

)

Case #1

Case #2

Case #3

Case #4

CPGE

Effect of Wettability on Chemical Oil Recovery

0%

10%

20%

30%

40%

50%

60%

70%

0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 2.25

Pore Volumes of Chemical Injection

Inc

rem

en

tal O

il R

ec

ov

ery

(%

RO

IP)

Case #1

Case #2

Case #3

Case #4

CPGE

Effect of Wettability on Reservoir Pressure

0

1000

2000

3000

4000

5000

6000

7000

0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 2.25

Pore Volumes of Chemical Injection

Av

era

ge

Re

se

rvo

ir P

res

su

re (

ps

i)

Case #1

Case #2

Case #3

Case #4

CPGE

Effect of Wettability on Oil Production Rate

0

50

100

150

200

250

300

350

0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 2.25

Pore Volumes of Chemical Injection

Oil P

rod

uc

tio

n R

ate

(S

TB

/D) Case #1

Case #2

Case #3

Case #4

CPGE

Oil Saturation during Waterflood (Waterwet Case)

0.2 PV

0.9 PV

CPGE

Oil Saturation during Waterflood (Mixedwet Case)

1.0 PV

3.5 PV

CPGE

Oil Saturation during Waterflood (Oilwet Case)

0.3 PV

1.9 PV

CPGE

Oil Saturation during Surfactant Flood (Waterwet Case)

0.25 PV

0.75 PV

2.25 PV

CPGE

Oil Saturation during Surfactant Flood (Mixedwet Case)

0.25 PV

0.75 PV

2.25 PV

CPGE

Oil Saturation during Surfactant Flood (Oilwet Case)

0.25 PV

0.75 PV

2.25 PV

CPGE

Surfactant concentration at 0.75 PV

Waterwet Mixedwet

Oilwet

CPGE

Final Oil Saturation

Waterwet Mixedwet

Oilwet

CPGE

Wettability Alteration

Wettability Index vs. surfactant properties

Residual saturation

Relative Permeability

Capillary pressure

Capillary desaturation

CPGE

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

CPGE

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

CPGE

Model 2 - Linear Interpolation

Strongly water-Wet

Relative permeability at low

IFT

Capillary desaturation curves

Relative permeability at high

IFT

Strongly Oil-Wet

Relative permeability at low

IFT

Capillary desaturation curves

Relative permeability at high

IFT

wwrjk

owrjk

CPGE

Relative Permeability Curves (Morrow 1973)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Water Saturation (Frac. of PV)

Re

lati

ve

Pe

rme

ab

ility

(F

rac

. of

Ab

s. P

erm

.) Water Wet

Mixed Wet

Oil Wet

Sw r Sor krwo kro

o nw no

Water Wet 0.12 0.25 0.26 1 3 1.3Neutral Wet 0.12 0.2 0.38 0.94 1.8 1.7

Oil Wet 0.12 0.28 0.56 0.8 1.4 3.3

CPGE

High NC Relative Permeability

Calculate relative permeability endpoints

Calculate relative permeability exponent

lowhighlow orj

orjhigh

r'jlow

r'j

r'jlow

r'jorj

orj kk*

SS

SSkk

lowj

highjhigh

r'jlow

r'j

r'jlow

r'jlowjj nn*

SS

SSnn

CPGE

Model 2 - Linear Interpolation

wwrkF1ow

rkFmwrk

F = constant

surfC

adssurfC

F Or

Or Develop new relationship based on lab. data

CPGE

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 Amott-Harvey Wettability Index versus Residual Fluid

Saturation

0

0.2

0.4

0.6

0.8

1

-1 -0.75 -0.5 -0.25 0 0.25 0.5 0.75 1

Ammot-Harvey Wettability Index

No

rmalized

Resid

ual

Flu

id S

atu

rati

on

CPGE

Sor vs Wettability Correlation

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

-1 -0.5 0 0.5 1Iw

So

r

Berea - Jadhunandan and Morrow, 1991

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

-1 -0.5 0 0.5 1Iw

So

r

Berea - Chen et al. 2004

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2Iw

So

r

Portland Chalk - Graue

CPGE

Sor vs. Wettability Index for Berea Core

0

0.1

0.2

0.3

0.4

0.5

-1 -0.5 0 0.5 1Iw

So

r

Jadhunandan and Morrow, 1991Owolabi and Watson, 1993Chen et al, 2004

CPGE

Normalized Residual Oil Saturation vs.

Wettability Index (All Data)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

-1 -0.5 0 0.5 1Iw

No

rma

lize

d S

or

CPGE

Wettability and CDC

0

0.1

0.2

0.3

0.4

1.E-07 1.E-05 1.E-03 1.E-01

Capillary Number

So

r

Lab

Model

Indiana Limestone (Abrams)

0

0.1

0.2

0.3

0.4

0.5

1.E-07 1.E-06 1.E-05 1.E-04 1.E-03 1.E-02 1.E-01 1.E+00

Capillary Number

Res

idu

al S

atu

rati

on

Data - Oil

Model -Oil

Data- Water

Model -Water

Berea Sandstone (Gupta)

L

PwkcN

cj

jrcjrwjrcjr NT1

SSSS

Capillary Number

CPGE

Trapping Number vs Wettability Index Correlation

y = 451492e-6.8363x

R2 = 0.9078

y = 3E+06e-7.0002x

R2 = 0.9048

100

1000

10000

100000

1000000

10000000

-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1

Amott-Harvey Wettability Index, Iw

Tra

pp

ing

Pa

ram

ete

r

Wetting Phase

Non-Wetting Phase

CPGE

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