Calibration of Ultrasonic Meter Against Master Meter

MODEC INTERNATIONAL LLC MODEC Project #:

Document #:

5004 SHELL Project #:

101.18.11

Bijupirá & Salema Field Development

Document Title:

PC-02 – PROCEDURE FOR CALIBRATION OF THE OIL ULTRASONIC METER AGAINST THE ULTRASONIC MASTER METER

A

Issued for Review and Comment

Rev.

Status

20.06.2003 Date

Origin.

Checker

Approved

THIS DOCUMENT INCLUDING, DRAWINGS, PROCEDURES, SPECIFICATIONS, AND ITS CONTENTS IS THE EXCLUSIVE PROPERTY OF MODEC INTERNATIONAL LLC AND IS FURNISHED ON A CONFIDENTIAL BASIS, AND WITH THE EXPRESS AGREEMENT THAT IT WILL NEITHER BE USED, SOLD, TRANSFERRED, COPIED, TRACED, PHOTOGRAPHED, NOR REPRODUCED IN ANY MANNER WHATSOEVER IN WHOLE OR IN PART, NOR ANY ITEM HERIN BE SOLD, MANUFACTURED OR ASSEMBLED WITHOUT THE WRITTEN AGREEMENT OF MODEC INTERNATIONAL LLC THE RECIPIENT OF THIS DOCUMENT AGREES NOT TO DISCLOSE TO ANY OTHER PARTY INFORMATION CONTAINED HEREIN, OR NOT TO USE SUCH INFORMATION, EXCEPT FOR THE SPECIFIC PURPOSE INTENDED AT THE TIME OF RELEASE OF THIS DOCUMENT.

Distribution Status Quantity

Total

Volume X Chapter X Document NoX

AMENDMENT RECORD CHAPTER REVISION INFORMATION Rev.

Date

1

22.06.2003

Comments / Affected Pages

Authorized By:

First issue of the document

Calibration of ultrasonic meter against master meter

Amendment

Volume X Chapter x Document No. x

PC-02 – PROCEDURE FOR CALIBRATION OF THE OIL ULTRASONIC METER AGAINST THE ULTRASONIC MASTER METER TABLE OF CONTENTS Section

Page

1.0 Introduction..........................................................................................................................2 1.1 Purpose ......................................................................................................................2 1.2 Scope..........................................................................................................................2 1.3 References .................................................................................................................2 1.4 Definitions ...................................................................................................................2 1.5 Responsibilities ...........................................................................................................3 2.0 Description of the Facility ....................................................................................................3 2.1 Technical Characteristics of the Ultrasonic Meters .....................................................4 2.2 Secondary Instrumentation .........................................................................................5 2.2.1 Temperature ........................................................................................................5 2.2.2 Pressure............................................................................................................................5 3.0 Calibration Conditions .........................................................................................................6 4.0 Data Collection Time ...........................................................................................................6 5.0 Stabilisation Period for the Calibration.................................................................................7 6.0 Information and Calibration Data .........................................................................................7 7.0 Procedure for Volume Correction ........................................................................................7 7.1 Calculation of MF ........................................................................................................8 Acknowledgement Record........................................................................................................11


Page 1


1.0

Introduction 1.1

Purpose This document outlines the form and content of operating procedures and calculation for the calibration of the oil fiscal meter.

1.2

Scope This procedure describes the principles and methods used in the calibration of the fiscal ultrasonic meter (tag ZAU-1652) that measures the oil flow out of the tanker storage at the FPSO Fluminense. The calibration of this ultrasonic meter is made against an ultrasonic master meter (tag ZAU-1651).

1.3

References 

Petroleum and Natural Gas Measurement Technical Regulation, approved by the joint Directive ANP/INMETRO Nº 01 of 19.June.2000.



ISO 4267-2, Petroleum and Liquid Petroleum Products -- Calculation of Oil Quantities - Part 2: Dynamic Measurement.



ISO 91-1, Petroleum Measurement Tables – Part 1: Tables Based on Reference Temperatures of 15 °C and 60 °F.



ISO 9770, Petroleum Products – Compressibility factors for Hydrocarbons in the Range 638 kg/m³ to 1074 kg/m³.



API – MPMS, Chapter 11.2.1M - Compressibility Factors for Hydrocarbons: 6381074 Kilograms per Cubic Meter Range.



API – MPMS, Chapter 4.5 - Master-Meter Provers.



Norsok Standard I-105, Fiscal Measurement Systems for Hydrocarbon Liquid.

Other appropriate standards and recommendations may also apply.

1.4

Definitions Base volume - The volume indicated by the master meter under standard conditions. Indicated volume – The meter reading that occurs during a transfer through the meter.


Page 2


K-factor – The number of pulses generated by a meter for a unit of volume delivered.

K  Factor 

pulses generated by meter volume delivered by meter

Meter factor (MF) – The ratio of actual volume of liquid passed through a meter to the volume indicated by the meter. Standard (reference) conditions – For the measurement of petroleum and its products, the reference conditions are 101,325 kPa and 20 °C. Master meter. Meter used as standard in the calibration of other meters. In this case is the ultrasonic master meter tag ZAU-1651. Fiscal meter. Meter that determines the oil volumes offloaded from the ship. In this case the oil fiscal meter is the ultrasonic tag ZAU-1652.

1.5

2.0

Responsibilities The Offshore Installation Manager –(OIM) – is the responsible for the metrological quality assurance/control on board the FPSO, in compliance with the procedures of the Metrological Quality Manual.

Description of the Facility Figure 1 shows a simplified sketch of the facility used in the calibration of the fiscal ultrasonic meter (tag ZAU-1652) against an ultrasonic master meter tag ZAU-1651. The ultrasonic meter tag ZAU-1652 will be called from now on fiscal ultrasonic meter, according to the nomenclature used in the ANP requirements. In this facility, oil from the tanker storage passes through the fiscal meter and, when necessary to perform a calibration, could be diverted to the ultrasonic master meter installed downstream and in series with the fiscal ultrasonic meter, as indicated in the figure. This diversion to the master meter shall be made operating a series of valves and insuring that the correct valves are kept closed.


Page 3

Volume X Chapter x Document No. x PL-V110

Redução 28 x 24” Redução 28 x 24”

PL-V111 PL-F148

PL-F148

Medidor Padrão ZAU-1651 PL-V112 TT-1653

Medidor operacional ZAU-1652

PL-F148

PT-1653

PL-F148 Redução 28 x 24”

TT-1654

PL-V113

PT-1654

PL-V037 PL-F148

PL-V036

Redução 28 x 24”

Figure 1 Calibration facility for the fiscal ultrasonic meter. 2.1

Technical Characteristics of the Ultrasonic Meters

Standardised upstream and downstream pipe lengths are within the specifications of the API MPMS Chapter 3, Section 3. In both case (fiscal and master meter) there are straight pipe lengths of 10D upstream and 5D downstream. Flow conditioners are installed to avoid undesirable influences of the pipework over the meters. 

Ultrasonic master meter (ZAU-1651) Description: 01 Ultrasonic meter Krohne 24” (with flow conditioner) ZAU-1651 Identification and capacity: Model: Altosonic V 125269 1001 Serial number: 7949,4 Max flowrate ( m³/h ): Normal operating conditions: 6662m3/h @ 37,2 °C / 689 kPa g


Page 4




2.2

Fiscal ultrasonic meter (ZAU-1652) Description: 01 Ultrasonic meter Krohne 24” (with flow conditioner) ZAU-1651 Identification and capacity: Model: Altosonic V 125269 1002 Serial number: 7949,4 Max flowrate ( m³/h ): Normal operating conditions: 6662m3/h @ 37,2 °C / 689 kPa g

Secondary Instrumentation

In the calibration of the fiscal meter the following parameters should be measured and recorded: number of pulses, time, oil temperature and pressure in the fiscal meter and in the ultrasonic master meter. The content of water and sediments in the oil shall be measured according to procedure PM-05 –Procedure For Measurement Of BS&W Volume Percentage In Petroleum.

2.2.1 Temperature Temperature sensors are installed downstream the allocation and master meters, as it is shown in the following table and in figure1. Table 1 Description of temperature sensors Flow meter

Tags of temperature sensors (TT)

Pipe length between temperature tap and ultrasonic meter

ZAU-1651

TT1653

4 500mm

N/A

ZAU-1652

TT1654

6 000mm

N/A

Temperature sensor serial number

2.2.2 Pressure

Pressure transducers are Rousemont model 3051TG 3 A 2B 2 1 B S5 E8 M5, series 3501 smart Gauge Pressure Transmitter. The pressure transducers are assembled upstream of the ultrasonic meters, as indicated in the next table and in figure 1.


Page 5


Table 2 Description of pressure sensors

3.0

Flow meter

TAG of the pressure transducer

Pipe length between pressure tap and ultrasonic meter

Pressure transducer serial number

ZAU-1651

PT1653

4 500mm

1222677

ZAU-1652

PT1652

4 500 mm

1222678

Calibration Conditions Oil volumes passing through the fiscal and master meters are calculated using values given by the flow computers of the ultrasonic flow meters and corrected according to the item 7 of this procedure, that describes the determination and correction of the measured oil volumes. Calibration is finished when the maximum difference among 3 consecutive measurements is smaller than 0,05%. Calibration of the fiscal ultrasonic meter should be made in the normal operating conditions of the facility, observing that the density and viscosity should not deviate more than 2%, temperature should not deviate more than 5°C, and pressure and flow rate should not deviate more than 10%. If there is a deviation of the calibration data in excess of 0,25%, or there is an impossibility to obtain results for new calibration data, there is presumably a fault in the meter and actions should be taken to investigate the causes. During the calibration of the ultrasonic meter, the oil temperatures measured in the fiscal meter and in the master meter should represent an average of at least five readings obtained along the measuring time corresponding to every tested flowrate. During the calibration, the pressure in the fiscal meter and in the master meter should represent an average of at least two readings obtained along the measuring time.

4.0

Data Collection Time The oil volumes in the fiscal and in the master meter should be calculated using the same timing system, in order to avoid measuring errors due to triggering. The data collection time for calibration should be at least 3 minutes long.


Page 6


5.0

Stabilisation Period for the Calibration The system should be kept running at desired flowrate for a period of at least 1 hour before start the calibration.

6.0

Information and Calibration Data All information and data concerning the ultrasonic meter calibration should be written in an appropriate data sheet and according to Appendix A - Meter proving report for master meter method - of this procedure.

7.0

Procedure for Volume Correction The volume flow through ultrasonic flow meters will depend on several factors and should be corrected to standard condition of 20oC and 101,325kPa. These corrections will be carried out according to ISO 4267-2. “Petroleum and liquid petroleum products – Calculation of oil quantities – Part 2 Dynamic measurement”. The ultrasonic flow meters ZAU-1651 and ZAU-1652 have flow computers to which are connected the outputs of the ultrasonic sensors, temperature and pressure measurements. The flow computer corrects the volume to standard conditions (15°C and 101,325 kPa) using the programmed density 15prog at 15°C. In reality, generally oil with slightly different density will be flowing through the meter: the actual density at 15°C is 15 , in which small amounts of water and sediment will be present. The volume value returned by the flow meter should, thus, be corrected to the volume at the standard condition recommended by ANP, accounting for every effect mentioned. The base volume measured will be given by the following expression:

V  MF  C t , ANP  C tlprog  C plprog  C SW  V prog (1) In this equation, 

V- volume at standard conditions.



MF - meter factor.



C t , ANP - corrects the volume to 20o in accordance to ANP compliance requirements.



Ctlprog - corrects the volume due to operating temperature effects, using 15prog .



C plprog - corrects the volume due to operating pressure effects, using 15prog .


Page 7




C SW - Sediment and water factor.



Vprog – Volume output by the flow computer of the ultrasonic flow meter, using 15prog .

The coefficients given above are calculated according to the methodology outlined in procedure PM-01 – “Procedure for calculation of oil volume using ultrasonic flowmeter”. During calibration, the same oil flows in both meters (the master meter and meter under test) and therefore, C SW will be the same in both. The correction to ANP’s standard will also be the same.

7.1

Calculation of MF The meter factor is the ratio of actual volume passed through the ultrasonic to the volume indicated by the meter. MFt 

prog prog MFm  Ctlprog ,m  C pl ,m  C SW  C t , ANP  Vm prog prog Ctlprog ,t  C pl ,t  C SW  C t , ANP  Vt

or, prog prog Ctlprog ,m  C pl ,m Vm MFt  MFm  prog prog  prog (1) Ctl ,t  C pl ,t Vt

In this equation,  MF –meter factor. 

Ctlprog - corrects the volume measured to 15 oC.



C plprog - corrects the volume for different operating pressures to zero gauge

pressure.  P - number of pulses output by the turbine.  K - K-factor given in number of pulses per cubic meter delivered by the turbine meter. subscripts: m – master meter ; t – meter under calibration. The oil density programmed in the flow computer 15prog is close to the actual density of the oil flowing in the ultrasonic flow meters 15 . Since the temperature and pressure in both ultrasonic flow meters (master meter and meter under test) are very close, the correction coefficients for temperature and pressure are very close in both meters. Therefore the ratio of these coefficients is very close to one. Adopting this approximation, the meter factor of the meter under test will be given by:

Vmprog MFt  MFm  prog Vt


...(2)

Page 8


The meter factor may be calculated from the base volumes given by the output of the flow computer.

8.0

Conclusion Equation (2) is used to determine the meter factor of the ultrasonic flow meter under test. The density programmed in the ultrasonic flow meter flow computer should be as close as possible to the density of the oil actually flowing in the flow meters. The temperature and pressure of both flow meters should be very close.


Page 9


APPENDIX A - Meter proving report for master meter method Proving report Nº : Flow rate : m³/h Time: Operator’s name (signature):

Batch: Meter N°: Date:

Density: Liquid: Station:

kg/m³ at 15°C

DATA FROM MASTER METER Run 1

Run 2

Run 3

Run 1

Run 2

Run 3

1. Meter pressure, kPa gauge pressure 2. Meter temperature, °C 3. Closing meter reading, m³ 4. Opening meter reading, m³ 5. Indicated metered volume, m ³ (3 – 4) 6. Meter factor 7. Cplm 8. Ctlm 9. CCF (6 x 7 x 8) 10. Corrected master meter volume, m³ (5 x 9) DATA FROM LINE METER

11. Meter pressure, kPa gauge pressure 12. Meter temperature, °C 13. Closing meter reading, m³ 14. Opening meter reading, m³ 15. Indicated metered volume, m ³ (3 – 4) 16. Cplm 17. Ctlm 18. CCF (16 x 17) 19. Corrected line meter volume, m³ (5 x 8) METER FACTOR CALCULATION 20. Run meter (10 x 19) 21. Average meter factor

Local: ________________________________

Inspected by: ______________ Calibration of ultrasonic meter against master meter

Date: ____/____/_______

Approved by: _________________ Page 10


Acknowledgement Record With my signature, I do hereby acknowledge that I have read and understood the preceding document and all appendices, if applicable. Signature


Date

Signature

Date

Page 11

Calibration of Ultrasonic Meter Against Master Meter

Recommend Documents