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
www.SpiritIT.com
2
CONTENTS
What is Custody Transfer Data?
What can be improved?
Mismeasurement management
Relation to system uncertainty
Case study
Conclusions
www.SpiritIT.com
3
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
www.SpiritIT.com
4
OLD SITUATION Custody Transfer Data = Set of printouts
www.SpiritIT.com
5
CURRENT SITUATION Custody Transfer Data = Set of electronic files
www.SpiritIT.com
6
WHAT CAN BE IMPROVED?
Metering Control Systems are made for:
Daily operation
and not for:
Technicians
Metering specialists
Auditors
Accounting staff
www.SpiritIT.com
7
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?
www.SpiritIT.com
8
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?
www.SpiritIT.com
9
WHAT ELSE CAN BE IMPROVED?
Is the overall system accuracy within spec?
Why wasnt the frozen value detected earlier?
How is my meter doing?
Is any transmitter drifting?
Whats the density of water in all flowcomps?
www.SpiritIT.com
10
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
www.SpiritIT.com
11
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
www.SpiritIT.com
12
MISMEASUREMENT OVERVIEW
CT data trend
Historical Meter Ticket Overview
.. with Financial Correction
Measurement Alarms
Measurement Events
www.SpiritIT.com
13
MISMEASUREMENT CORRECTION
Best guess for failed input?
What was the correct setting?
How to recalculate the ticket?
How to convince the buyer?
www.SpiritIT.com
14
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
www.SpiritIT.com
15
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 60F 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 60F & 14.696 psia (0 psig) 40355.30 bbls
21. NET STD VOL AT 15C & 101.325 kPa (0 kPa (ga)) 6410.843 m3
22. NET WEIGHT 4185.52 long tons
22. NET WEIGHT 4252.70 metric tons
www.SpiritIT.com
16
METER TICKET RECALCULATION
Up to 0.01% difference at stable conditions
100000 bbl 65 API60
75 F 195 psi
GSV 99180 bbl
100000 bbl 65 API60
76 F 205 psi
GSV 99120 bbl
API MPMS 12.2 200000 bbl
65 API60 75.5 F 200 psi
GSV 198320 bbl
www.SpiritIT.com
17
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%
www.SpiritIT.com
18
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
www.SpiritIT.com
19
METER TICKET CORRECTION
Case : Temperature fails for 35 minutes
What is the additional uncertainty of the different correction methods for liquid and gas ?
www.SpiritIT.com
20
METER TICKET CORRECTION Basic conventional correction method
Optimal conventional correction method
www.SpiritIT.com
21
METER TICKET CORRECTION New API MPMS Ch21 based correction method
* Patent pending *
www.SpiritIT.com
22
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%
www.SpiritIT.com
23
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
www.SpiritIT.com
24
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
