Calculating Petroleum

Quantities in the 21st Century

L. Scott Tanner

Flow-Cal, Inc.

Introduction

• History of Electronic Liquid Measurement

(ELM)

• Examine Pre 1980 Computer Hardware

and Software Technology

• It’s Lasting Impact on Our Industry

• Liquid Measurement Data Auditability

• API MPMS Chapter 12.2 Changes

• Conclusions

2

History of Electronic Liquid

Measurement (ELM) • The 1952 Lookup Tables were Replaced

with the 1980 Computer Subroutines

– Known as API Chapter 11.1 (Volume X),

ASTM – D1250, IP 200

• In 1980 Computer Subroutines Separated

the Commodity Groups.

– Letter Designations were Added

• “A” Crude Oils

• “B” Refine Products

• “C” Special Applications

3

Pre 1980 Computer Hardware &

Software Technology Issues • Lack of Computers Standardization

(Mainframe, Mini, and Microcomputers)

• Word Size Representations (4-bit, 8-bit,

16-bit)

• Floating-Point Compatibility Across

Multiple Computing Systems

• Software Rounding Behavior

• General Accuracy of Operations

4

API 11.1 - 1980 Subroutine

Development • Unsuitable Equations Due to Technology

Issues

– Finite Discontinuities

– Derivatives Between Temperature Range

– Complicated Transcendental Functions

– High Order Powers Inside an Exponential

– Limitations Prohibiting Single Precision Non-

Linear Analysis

5

API 11.1 - 1980 Subroutine

Development • Suitable Equation Due to 1980 Hardware

& Software

– An Exponential Equation

• Containing a Second Term

• The Equation Desirable Characteristics

– Simplicity

– Curve Shape

• Integer Arithmetic was Used so “ALL”

Computers Achieved the Same Results

6

Dynamic Measurement Ticket

7

Liquid Data 1980 Method

Flow Computer

2015 Method

Fluid Crude Oil Crude Oil

Observed Weighted Average Density (RHOobs) 834.5 kg/m3 834.4981 kg/m3

Observed Weighted Average Temperature (TWAobs) 42.5 ⁰C 42.47582 ⁰C

Observed Weighted Average Pressure (PWAobs) 2055 kPa 2045.841 kPa

S&W 0.682 % 0.682 %

Meter Data

Closing Meter Reading (MRC) 379,745.351 m3 379,745.351 m3

Opening Meter Reading (MRO) 164,724.273 m3 164,724.273 m3

Weight Average Temperature (TWA) 42.5 ⁰C 42.47582 ⁰C

Weight Average Pressure (PWA) 2055.0 kPa 2045.841 kPa

Weight Average MF 0.9983 0.9983

Temperature Base (Tb) 15.0 ⁰C 15.0 ⁰C

Calculations

Base Density (RHOb) 853.0 kg/m3 852.969 kg/m3

CTL Factor 0.9766 0.976649

Fp Factor 8.45E-07 8.45E-07

CPL Factor 1.0017 1.001738

CCF = (CTL * CPL * MF) 0.9766 0.9766832 Deviation

Indicated Volume: IV = MRC - MRO 215,021.078 m3 215,021.078 m3 0.000 m3

Gross Standard Volume: GSV = IV * CCF 209989.585 m3 210007.475 m3 -17.890 m3

CSW = 1 - (% S&W / 100) 0.99318 0.99318

Net Standard Volume: NSV = GSV * CSW 208557.456 m3 208575.224 m3 -17.768 m3

S&W Volume: = SWV = GSV - NSV 1432.129 m3 1432.251 m3 -0.122 m3

Fluid Physical Properties

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Temp oF 50-160F

Density

g/ml 6C VCF

Table 6C

Predicted

density % delta 6A VCF

Table 6A

Predicted

Density % delta

5th Order

Polynomial

Regression

VCF

5th Order

Polynomial

Predicted

Density

% delta

50 0.827984 1.00485 0.827821 -0.020% 1.00502 0.827961 -0.003% 1.004998 0.827986 0.000%

60 0.823874 1 0.823825 -0.006% 1 0.823825 -0.006% 1 0.823868 -0.001%

70 0.819778 0.99513 0.819813 0.004% 0.99497 0.819682 -0.012% 0.995041 0.819783 0.001%

80 0.815718 0.99025 0.815793 0.009% 0.98992 0.815521 -0.024% 0.99011 0.81572 0.000%

90 0.811672 0.98535 0.811756 0.010% 0.98485 0.811344 -0.040% 0.985196 0.811672 0.000%

100 0.807636 0.98045 0.80772 0.010% 0.97978 0.807168 -0.058% 0.980291 0.807631 -0.001%

110 0.803589 0.97553 0.803666 0.010% 0.97469 0.802974 -0.076% 0.975387 0.803591 0.000%

120 0.799542 0.97059 0.799597 0.007% 0.96958 0.798765 -0.097% 0.970479 0.799547 0.001%

130 0.795497 0.96565 0.795527 0.004% 0.96447 0.794555 -0.118% 0.965561 0.795495 0.000%

140 0.791435 0.96069 0.791441 0.001% 0.95934 0.790329 -0.140% 0.960632 0.791434 0.000%

150 0.787362 0.95573 0.787355 -0.001% 0.9542 0.786094 -0.161% 0.95569 0.787363 0.000%

160 0.78328 0.95075 0.783252 -0.004% 0.94905 0.781852 -0.182% 0.950735 0.783281 0.000%

Calculated

60oF kg/m3 823.825

Calculated

alpha 0.0004864

Calculated

60oF kg/m3 823.868

Fluid Physical Properties

9

Fluid Physical Properties

10

Oxygenate Gasoline Oxygenate

Gasoline Gasoline Oxygenate Oxygenate Total Weight Weight Volume

Sample Gasoline Additive Volume Weight Volume Weight Weight Percent Percent Percent

21 RF-Q ETBE 720 531.864 180 134.118 665.982 20.14 79.86 20%

22 RF-F DIPE 765 552.636 135 98.361 650.997 15.11 84.89 15%

23 RF-F MTBE 720 520.128 180 134.316 654.444 20.52 79.48 20%

24 RF-K Methanol 135 103.397 765 608.940 712.337 85.48 14.52 85%

25 RF-F ETBE 720 520.128 180 134.118 654.246 20.50 79.50 20%

26 RF-Q TAME 810 598.347 90 69.795 668.142 10.45 89.55 10%

27 RF-K Ethanol 810 620.379 90 71.451 691.830 10.33 89.67 10%

28 RF-Q ETBE 810 598.347 90 67.059 665.406 10.08 89.92 10%

29 RF-P MTBE 720 520.344 180 134.316 654.660 20.52 79.48 20%

30 RF-K MTBE 765 585.914 135 100.737 686.651 14.67 85.33 15%

31 RF-Q DIPE 720 531.864 180 131.148 663.012 19.78 80.22 20%

32 RF-Q TAME 765 565.106 135 104.693 669.798 15.63 84.37 15%

33 RF-P DIPE 810 585.387 90 65.574 650.961 10.07 89.93 10%

34 RF-P ETBE 765 552.866 135 100.589 653.454 15.39 84.61 15%

35 RF-P TAME 720 520.344 180 139.590 659.934 21.15 78.85 20%

36 RF-Q Ethanol 810 598.347 90 71.451 669.798 10.67 89.33 10%

37 RF-P DIPE 720 520.344 180 131.148 651.492 20.13 79.87 20%

38 RF-K MTBE 720 551.448 180 134.316 685.764 19.59 80.41 20%

39 RF-P MTBE 765 552.866 135 100.737 653.603 15.41 84.59 15%

40 RF-P TAME 765 552.866 135 104.693 657.558 15.92 84.08 15%

Fluid Physical Properties

11

Fluid Physical Properties

12

Fluid Physical Properties

13

Conclusion

• Measurement Forefathers Created ELM

Standards Based on 1970 Technology

• Todays Smart Phones have More

Horsepower than the Apollo Missions

Computers

• There are Better Curve Fit Equations

• Measurement Biases SHOULD NOT be

Created By Calculations

• Hydrocarbon Fluids of Today have Changed

• Industry Needs to Move Into the 21st Century 14

Thank You

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