Don't Forget Viscosity

“Don’t Forget Viscosity”

Dave BergmanBP America

July 28, 2004

Core Laboratories and The Petroleum Technology Transfer Council

2nd Annual Reservoir Engineering Symposium.

“From the Matrix to the Market – What You Don’t Know CAN Hurt You”

BP/DFB 2

Background

Viscosity Important to:• Reservoir Modeling

– Production Rates– Mobility for water Flooding

• Flow Assurance– Rates– Heat Transfer

• Facility– Pump Design– Equipment Sizing– Pipeline Diameters– Heat Transfer Area

• Just about any calculation you make will be dependent on Viscosity.

As Many Correlations as “Fish in the Sea”

Are all equally valid for your data?

Without data, +_50% (1 STD) errors in Prediction

BP/DFB 3

Export Pipeline Example:Pressure Drop by Correlation

76F 60 51 44F 40100F

1

10

100

1000

10000

0 2 4 6 8 10 12 14 16 18 20

Segment(Miles)

Visc

osity

, cp

500

1000

1500

2000

2500

Pres

sure

, psi

a

Thodos cp

Beggs cp

Temperature, F

BP/DFB 4

Review Calculations

Neither Correlation was Correct• BR correlation used LOG(T,F) so

Viscosity= Infinity at T=0F• Wrong temperature Dependency over all

temperatures, but most noticeable below 70F, resulting is too much change with Temperature

• Thodos also had wrong temperature Dependency, under estimating change with Temperature.

• New Correlation Needed for extrapolation Versus temperature, <70F.

BP/DFB 5

What should New Correlation look Like?

• Check viscosity vs temperature for pure compounds.

• Beggs and others had plotted Log Log (Viscosity+1) versus Log(T)

• Started there.• Best Linear fit obtained with

Log Log (Viscosity+1) vs Log(T,F+310)

BP/DFB 6

Pure HC Viscosity vs Temperature

3cp

1cp

.3cp

0.1 cp

100cp

10cp

0F 50F 100F 150F 200F 300F 400F

-2.6

-2.1

-1.6

-1.1

-0.6

-0.1

0.4

0.9

1.4

5.7 5.8 5.9 6 6.1 6.2 6.3 6.4 6.5 6.6

Log (Temperature(F) +310)

Log

Log

(Vis

cosi

ty+1

)

N-Paraffins

Aromatics

CycloHexane's

Napthalene

Olefins

Correlation for Pure Hydrocarbons

BP/DFB 7

Dead Oil Viscosity vs Temperature

50 API

40API

35 API

30 API

25API

20Api

15 API

5cp

100cp

10cp

1000cp

10000cp

200F150F100F50F0F

0.3

0.8

1.3

1.8

2.3

2.8

5.7 5.8 5.9 6 6.1 6.2 6.3

GOM Data

Heavy oils

BP/DFB 8

Correlations available for Calculating Viscosity

• Over 30 in the Literature• Many developed on limited

data set for a given area of the world.

• Inputs Dead Oil: API, Temperature, Watson K, Molecular weight.

• Compositional Correlations not covered in this presentation

BP/DFB 9

Correlations available for Calculating Dead Oil Viscosity

Dead Oil Viscosity Year Geographic Location Function

Beal 1946 Primarily USA

Beggs & Robinson 1975 North America +

Glaso 1980 North Sea T - temperature, deg F

Labedi 1982 Libya API - oil API gravity

Labedi 1982 Nigeria-AngolaUOPK - characterization factor

Ng & Egbogah 1983 NA Sgg - gas specific gravity

Al-Khafaji, et al 1987 NA

Petrosky 1990 Gulf of Mexico

Kartoatmodjo & Schmidt 1991Indonesia, N. & S. America, Middle East

De Ghetto 1994Mediterranean Basin, Africa, Persian Gulf & North Sea

Agip 1994Mediterranean Basin, Africa, Persian Gulf & North Sea

Fitzgerald 1997 NA

Bennison 1998 North Sea

Elsharkawy 1999 Middle East

Bergman 2000 North America +

Standing 2000 California

Dindoruk & Christman 2001 Gulf of Mexico

Andrade 1930 NA

BP/DFB 10

Correlations available for Calculating Saturated Oil Viscosity

Saturated Oil Viscosity Year Geographic Location Function

Chew & Connally 1959 North & South America

Beggs & Robinson 1975 NA P - pressure, psia

Labedi 1982 Libya T - temperature, deg F

Labedi 1982 Nigeria-Angola API - oil gravity

Khan 1987 Saudi Arabia Sgg - gas specific gravity

Al-Khafaji, et al 1987 NAPb - bubble-point pressure, psia

Petrosky 1990 Gulf of MexicoRs - solution gas-oil ratio, SCF/STB

Kartoatmodjo & Schmidt 1991Indonesia, N. & S. America, Middle East

GOR - total gas-oil ratio, SCF/STB

De Ghetto 1994Mediterranean Basin, Africa, Persian Gulf & North Sea VISD - dead oil viscosity, cp


Almehaideb 1997 United Arab Emirates


Bergman 2000 North America +


BP/DFB 11

Correlations available for Calculating Under Saturated Oil Viscosity

Kouzel 1983 API Data Book

Undersaturated Oil Year Geographic Location Function

Beal 1946 Primarily USA

Vazquez & Beggs 1976 World wide P - pressure, psia

Labedi 1982 Libya API - oil API gravity

Labedi 1982 Nigeria-AngolaPb - bubble-point pressure, psia

Khan 1987 Saudi ArabiaGOR - total gas-oil ratio, SCF/STB

Al-Khafaji, et al 1987 NA VISD - dead oil viscosity, cp

Abdul-Majeed 1990 North America & Middle EastVISOB - bubblepoint oil viscosity, cp

Petrosky 1990 Gulf of Mexico

Kartoatmodjo & Schmidt 1991Indonesia, North America, Middle East & Latin America

De Ghetto 1994Mediterranean Basin, Africa, Persian Gulf & North Sea


Almehaideb 1997 United Arab Emirates



BP/DFB 12

Dead Oil Correlations

Dead OIl Viscosity 20 API

1

10

100

1000

10000

0 50 100 150 200 250 300Temperature, F

Vis

cosi

ty, c

p

Beal

Beggs

Glaso

Labedi (Libya)

Labedi (Nigeria/Angola)

Ng & Egbogah

Al-Khafaji, et al

Petrosky

Kartoatmodjo

De Ghetto

Agip

Fitzgerald(K)

Bennison

Elsharkawy

Bergman

Standing(K)

Dindoruk

Andrade

BP/DFB 13


Viscosity Comparison 20APILegend Shows Difference from Bergman at 40 and 200 F

after Match at 100F

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

2.5 2.55 2.6 2.65 2.7 2.75 2.8 2.85 2.9

Log(TF+310)

Log

Log(

Visc

osity

+1)

40F 200F Diff.fromBergman-39% -6% Beal

13784% -44% Beggs

-1% 29% Glaso

-68% 200% Labedi (Lib)

14% 17% Labedi (Nig/Ang)

24% 75% Ng & Egbogah

-50% -10% Al-Khafaji, et al

-36% 80% Petrosky

6% 24% Kartoatmodjo

-19% 51% De Ghetto

13% 82% Agip

-10% 4% Fitzgerald(K)

-55% 133% Bennison

193% 30% Elsharkawy

-70% 40% Standing(K)

11% 19% Dindoruk

-1% 29% Andrade

BP/DFB 14


1.0

10.0

100.0

1000.0

0 50 100 150 200 250 300Temperature, F

Vis

cosi

ty, c

p

40F 200F Diff.from Bergman

-39% -6% Beal

13784% -44% Beggs

-1% 29% Glaso


14% 17% Labedi (Nig/Ang)


-50% -10% Al-Khafaji, et al

-36% 80% Petrosky

6% 24% Kartoatmodjo

-19% 51% De Ghetto

13% 82% Agip

-10% 4% Fitzgerald(K)

-55% 133% Bennison

193% 30% Elsharkawy

-70% 40% Standing(K)

11% 19% Dindoruk

-1% 29% Andrade


after Match at 100F

BP/DFB 15



after M atch at 100F

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

2.5 2.6 2.7 2.8 2.9

Log(TF+310)

Log

Log(

Visc

osity

+1)

40F 200F Diff. from Bergman

20% -32% Beal

1603% -43% Beggs

54% -6% Glaso


192% -43% Labedi (Nig/Ang)


8% -43% Al-Khafaji,

31% 7% Petrosky

103% -24% Kartoatmodjo

46% 21% De Ghetto

24% 30% Agip

4% -1% Fitzgerald

-98% 2353% Bennison

90% 8% Elsharkawy

-40% 8% Standing

39% 2% Dindoruk

54% -6% Andrade

BP/DFB 16

Live Oil Correlations

Saturated Oil Viscosity

0.1

1

10

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Solution Gas-Oil Ratio, SCF/STB

Visc

osity

, cp

Chew & Connally

Beggs & Robinson

Labedi(Nigeria/Angola)

Al-Khafaji, et al

Petrosky

Kartoatmodjo &Schmidt

De Ghetto

Agip

Almehaideb

Elsharkawy

Bergman

Dindoruk &Christman

26 API

BP/DFB 17

Live Oil Correlations

Live Oil Versus Dead Oil Viscosity

0.1

1.0

10.0

100.0

1000.0

1 10 100 1000Dead OIl Viscosity

Live

oil

Visc

Chew & Connally 200scf/stb

Beggs & Robinson

Labedi (Libya)


Khan

Al-Khafaji, et al

Petrosky

Kartoatmodjo & Schmidt

De Ghetto

Agip

Almehaideb

Elsharkawy

Bergman

Dindoruk & Christman

45 Line

22 API

Live Oil Versus Dead Oil Viscosity

0.1

1.0

10.0

100.0

1000.0

1 10 100 1000Dead OIl Viscosity

Live

oil

Visc

Chew & Connally 1200scf/stb

Beggs & Robinson

Labedi (Libya)


Khan

Al-Khafaji, et al

Petrosky

Kartoatmodjo & Schmidt

De Ghetto

Agip

Almehaideb

Elsharkawy

Bergman

Dindoruk & Christman

45 Line

32 API

BP/DFB 18

Under Saturated Oil Correlations

Undersaturated Oil Viscosity

1

1.5

2

2.5

3

3.5

4

4.5

5

5.5

6

0 2000 4000 6000 8000 10000 12000

Pressure, psia

Vis

cosi

ty, c

p

Beal

Vazquez

Labedi (Libya)Labedi (Nig/Ang)

KhanAl-Khafaji,

Abdul-MajeedPetrosky

KartoatmodjoDe GhettoAgip

AlmehaidebElsharkawy

DindorukAPI Kouzel

Experimental

31 api 3.4 cp

Undersaturaturated Oil

0

5

10

15

20

25

30

35

40

45

50

0 2000 4000 6000 8000 10000

Pressure

Vis

cosi

ty

Beal

Vazquez

Labedi (Libya)

Labedi (Nig/Ang)

Khan

Al-Khafaji,

Abdul-Majeed

Petrosky

Kartoatmodjo

De Ghetto

Agip

Almehaideb

Elsharkawy

Dindoruk

API Kouzel

Experimental

19 API

40 cp

BP/DFB 19

How Accurate are They?


Standard Deviation is around +-50% independent of Correlation given a wide data set.

Having 1 data point will significantly reduce your error to about the error in the Data, assuming using reasonable correlation

Live Oil +- 15%

Biggest difference is curvature. Related to Temperature and Gas Gravity

Under Saturated Oil +- 20%

Pressure range very dependent on Correlation

BP/DFB 20

1 Std

1 Std

Expected Errors in Prediction of Dead Oil Viscosity

BP/DFB 21

1 Std

1 Std

Expected Errors in Prediction of Live Oil Viscosity

BP/DFB 22

Comparison of Under Saturated Errors: Live Oils

GOM GOM Africa-West GOM China CanadaAPI 31 19 33.4 27 21 42Psat 1058 1875 4400 7300 343 2132GOR 220 236 980 1168 35 698Viscosity Psat 1.87 11.7 0.48 1 49.5 0.305 Average Maximum

% %Beal 4 15 15 2 4 4 7 15

Vazquez & Beggs 34 6 6 1 15 2 11 34Labedi (Libya) 1 4 4 26 17 0 9 26Labedi (Nigeria/Angola) 5 31 30 8 26 2 17 31Khan 9 15 15 8 18 1 11 18Al-Khafaji, et al 12 33 32 4 35 5 20 35Abdul-Majeed 31 30 29 7 4 1 17 31Petrosky 14 36 36 12 36 2 23 36Kartoatmodjo 8 13 13 7 4 10 9 13De Ghetto 3 10 9 33 8 1 11 33Agip 2 12 12 17 20 0 11 20Almehaideb 4 26 25 6 15 1 13 26Elsharkawy 5 27 26 3 28 4 15 28Dindoruk & Christman 10 3 2 5 90 1 18 90API Kouzel 10 6 5 7 1 3 5 10

BP/DFB 23

Comparison of Under Saturated Errors: Dead Oils

GOM STO Ecoflow PetroFreeAPI 28 47 48Psat 15 15 15GOR 5 5 5Viscosity Psat 4.3 1.26 0.74 Average Maximum

% %Beal 10 16 10 12 16Vazquez & Beggs 171 242 300 238 300Labedi (Libya) 21 6 2 10 21Labedi (Nigeria/Angola) 288 352 561 400 561Khan 4 4 3 3 4Al-Khafaji, et al 22 26 21 23 26Abdul-Majeed 4810 722 1075 2202 4810Petrosky 12 0 2 5 12Kartoatmodjo 10 20 18 16 20De Ghetto 1 10 7 6 10Agip 50 7 22 27 50Almehaideb 71 50 74 65 74Elsharkawy 83 101 161 115 161Dindoruk 23 21 28 24 28API Kouzel 2 4 2 3 4

BP/DFB 24

Export Pipeline Example:Pressure Drop with Improved Correlation

Pipeline Pressure Drop and Viscosity

40F44F51F60F76F100F

1

10

100

1000

10000

0 5 10 15 20Segment(Miles)

Visc

osity

, cp

500

1000

1500

2000

2500

Pre

ssur

e, p

sia

Thodos cpBeggs cpBergviscTemperature,F

BP/DFB 25

Well Flow rate vs Viscosity Correlation

Field Well Oil Viscosity Correlation

Calculated Oil Rate (STB/D)

% Deviation in Oil Rate from Beggs Tr (F)

Calculated Twh (F)

Gas Condensate Case 1 Beggs 652.3 0.00% 229 137.0

12565 GOR Beal 649.1 -0.49% 229 136.7

Petrosky 650.5 -0.28% 229 136.9

High Shrinkage Oil Case 2 Beggs 152.9 0.00% 177 101.15

2717 GOR Beal 165.2 8.04% 177 101.92

Petrosky 180.5 18.05% 177 102.84

All cases Used Glasco for Pbp, Bo, and Rs

BP/DFB 26

Case 1: Condensate Viscosity Plot (T=137 & 229 F)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

0 200 400 600 800 1000 1200 1400WH Pressure (psig)

Visc

osity

(cp)

Petrofsky UoBeggs UoBeal Uo

Case 2: Oil Viscosity (T=102 & 177 F)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 100 200 300 400 500 600 700

WH Pressure (psig)

Visc

osity

(cp)

Petrofsky UoBeggs UoBeal Uo

Viscosity by Correlation

BP/DFB 27

Flow Rate vs Viscosity

Effect of Viscosity on Horizontal Pipeline

7000.00

7500.00

8000.00

8500.00

9000.00

9500.00

10000.00

10500.00

11000.00

0 5 10 15 20 25 30 35 40 45

Oil Viscosity, cp

Rat

e, B

bl/D

ay

-25%

-20%

-15%

-10%

-5%

0%

5%

10%

15%

Perc

ent C

hang

e

Single Phase10 miles,0.75 Density Oil1137 DP4 inch Diameter0.0018 Roughness

BP/DFB 28

Conclusions

• No correlation will always be the best, and none will ever be perfect.

• Experimental data near temperature of interest very important to minimizing errors.

• Dead Oil correlation determines the accuracy of your results.

• Using a better correlation may not give significant improvement

• Using a bad correlation can be disastrous• Correlations are very dependent on

range of data used in Development.• Compositional Correlations are less

predictive than Field Parameter ones.

Documents

Don't Forget Viscosity