Measurement Data: from Well to Awareness www.SpiritIT.com

CUSTODY TRANSFER DATA MANAGEMENT

Han van Dal

AN INTEGRAL APPROACH TO

STATEMENT

With respect to Custody Transfer Data the current generation of Metering Control Systems is

• dumb

• inaccurate

• time-consuming

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CONTENTS

What is Custody Transfer Data?

What can be improved?

Mismeasurement management

Relation to system uncertainty

Case study

Conclusions

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CUSTODY TRANSFER DATA

API MPMS 21.1 (Gas) & 21.2 (Liquid)

• Quantity Transaction Records

• Configuration Logs

• HW & SW Versions

• Event Logs

• Field Test Reports

• Corrections with their reason

Why?

To verify correctness of data

To allow for correction of failures

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OLD SITUATION Custody Transfer Data = Set of printouts

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CURRENT SITUATION Custody Transfer Data = Set of electronic files

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WHAT CAN BE IMPROVED?

Metering Control Systems are made for:

Daily operation

… and not for:

Technicians

Metering specialists

Auditors

Accounting staff

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PURPOSE #1: CORRECTNESS OF DATA

Are all settings correct?

Any changes in settings, SW or HW?

Calibrations performed in time?

Any maintenance applied?

Have measurement failures occurred?

Have tickets been corrected?

If so, how and why?

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PURPOSE #2: CORRECTION OF FAILURES

How big is the error (financial value)?

Is correction worth the trouble?

What is the best guess for the failed input?

How to accurately recalculate the ticket?

How to convince the Buyer?

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WHAT ELSE CAN BE IMPROVED?

Is the overall system accuracy within spec?

Why wasn’t the frozen value detected earlier?

How is my meter doing?

Is any transmitter drifting?

What’s the density of water in all flowcomps?

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INTEGRAL CT DATA MANAGEMENT

Relational data (meter tickets & audit trail)

IT (data storage, cyber-security, integrity)

Configuration management (FC, EFM)

Mismeasurement management

• Detection

• Overview

• Correction

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MISMEASUREMENT DETECTION Flow computer alarms

But also:

Flow meter diagnostics

Smart transmitter diagnostics

QMI diagnostics

On-line data validation

On-line logical checks

Control Charts

CUSUM Charts

-1.5

-1

-0.5

0

0.5

1

1.5

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MISMEASUREMENT OVERVIEW

CT data trend

Historical Meter Ticket Overview

.. with Financial Correction

Measurement Alarms

Measurement Events

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MISMEASUREMENT CORRECTION

Best guess for failed input?

What was the correct setting?

How to recalculate the ticket?

How to convince the buyer?

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SYSTEM UNCERTAINTY

Metering equipment

Proving

Sampling

Laboratory analysis

Flow computers

Meter ticket recalculation

• API MPMS 12.2

• Proving (Meter factor)

• Sampling (density, BS&W)

Meter ticket correction

• Equipment failures

• Faulty data entries

• Failed field calibrations

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METER TICKET RECALCULATION 1. BATCH NUMBER 050511

2. TYPE OF LIQUID NG

3. METER CLOSING READING (DATE/TIME) 05/06/11 00:00

4. METER OPENING READING (DATE/TIME) 05/05/11 00:00

5. NET DELIVERY TIME 24.001 hours

6. METER CLOSING READING 23208593 bbl

7. METER OPENING READING 23167330 bbl

8. INDICATED VOLUME 41263 bbl

9. AVERAGE FLOW RATE 1705.4 bbl/h

10. GROSS VOLUME 41258.87 bbl

11. AVERAGE METER FACTOR 1.0001

12. OBSERVED RELATIVE DENSITY 0.0000 M

13. OBSERVED TEMPERATURE 0.0 °F M

14. RELATIVE DENSITY AT 60°F 0.6646

15. WEIGHTED AVERAGE TEMPERATURE 94.4 °F

16. TEMPERATURE CORRECTION FACTOR (CTLm) 0.9732

17. WEIGHTED AVERAGE PRESSURE 317.6 psig

18. PRESSURE CORRECTION FACTOR (CPLm) 1.0044

19. COMBINED CORRECTION FACTOR (CCFm) 0.9775

20. NET STD VOL AT 60°F & 14.696 psia (0 psig) 40355.30 bbls

21. NET STD VOL AT 15°C & 101.325 kPa (0 kPa (ga)) 6410.843 m3

22. NET WEIGHT 4185.52 long tons

22. NET WEIGHT 4252.70 metric tons

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METER TICKET RECALCULATION

Up to 0.01% difference at stable conditions

100000 bbl 65 API60

75 ᵒF 195 psi

GSV 99180 bbl

100000 bbl 65 API60

76 ᵒF 205 psi

GSV 99120 bbl

API MPMS 12.2 200000 bbl

65 API60

75.5 ᵒF 200 psi

GSV 198320 bbl

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METER TICKET RECALCULATION

Significant difference at highly

fluctuating conditions

For example

Flow computer

GSV = 37942 bbl

API MPMS 12.2

GSV = 37978 bbl

Up to 0.10%

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METER TICKET RECALCULATION 1. METER CLOSING READING (DATE/TIME) 05/06/11 00:00

2. METER OPENING READING (DATE/TIME) 05/05/11 00:00

3. NET DELIVERY TIME 24.001 hours

6. METER CLOSING READING 23388.593 MMSCF

7. METER OPENING READING 23167.330 MMSCF

8. TOTAL VOLUME 221.263 MMSCF

11. AVERAGE FLOW RATE 221.012 MMSCFD

12. AVERAGE DIFF PRESSURE 23.12 inch WC

13. AVERAGE TEMPERATURE 113.3 °F

17. AVERAGE STATIC PRESSURE 1317.6 psig

18. AVERAGE DENSITY 6.45 lb/SCF

Inaccurate for

Gas

dP flow meters

q ≈ √(dP x P) FWA dP is useless

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METER TICKET CORRECTION

Case : Temperature fails for 35 minutes

What is the additional uncertainty of the different correction methods for liquid and gas ?

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METER TICKET CORRECTION Basic conventional correction method

Optimal conventional correction method

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METER TICKET CORRECTION New API MPMS Ch21 based correction method

* Patent pending *

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METER TICKET CORRECTION

Relative to corrected quantity that would have been calculated at 1 sec resolution

Correction Liquid

Turbine

Steady

Liquid

Turbine

Fluctuating

Gas

Orifice

FWA dP

Gas

Orifice

TWA √dPxP

Basic correction 0.06% 0.83% 3.22% 0.30%

Optimal correction 0.02% 0.14% 3.22% 0.22%

API 21 based cor. 0.00% 0.00% 0.00% 0.00%

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CONCLUSIONS Accurate correction is currently NOT possible for many applications

New API 21 method is accurate for all meter types, liquid and gas

Automation of Mismeasurement Management

• makes systems smart

• saves time and resources

• avoids disputes with buyer

dumb smart

inaccurate accurate

time-consuming time-saving

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Measurement Data: from Well to Awareness www.SpiritIT.com

THANK YOU FOR YOUR ATTENTION Questions?

Smart, accurate and highly automated

Metering Control Systems

to achieve comprehensive and integral

Custody Transfer Data

Management