don't forget viscosity
TRANSCRIPT
“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
Agip 1994Mediterranean Basin, Africa, Persian Gulf & North Sea
Almehaideb 1997 United Arab Emirates
Elsharkawy 1999 Middle East
Bergman 2000 North America +
Dindoruk & Christman 2001 Gulf of Mexico
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
Agip 1994Mediterranean Basin, Africa, Persian Gulf & North Sea
Almehaideb 1997 United Arab Emirates
Elsharkawy 1999 Middle East
Dindoruk & Christman 2001 Gulf of Mexico
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
Dead Oil Correlations
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
Dead Oil Correlations
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
-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
Viscosity Comparison 20APILegend Shows Difference from Bergman at 40 and 200 F
after Match at 100F
BP/DFB 15
Dead Oil Correlations
Viscosity Comparison 40APILegend Shows Difference from Bergman at 40 and 200 F
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
-17% 49% Labedi (Lib)
192% -43% Labedi (Nig/Ang)
30% 27% Ng & Egbogah
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)
Labedi (Nigeria/Angola)
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)
Labedi (Nigeria/Angola)
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?
Dead Oil Correlations
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.