Manual of Petroleum Measurement Standards Chapter 5.6

Measurement of Liquid Hydrocarbons by Coriolis Meters

SECOND EDITION, DECEMBER 2021

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Foreword

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Contents

Page

1. Scope 1

   1. Field of Application 1

2. Normative References 1

3. Terms, Definitions, And Symbols 1

   1. Terms and Definitions 1

   2. Acronyms and Symbols 4

4. General 8

5. Application 8

   1. Sensor Considerations 8

   2. Transmitter Considerations 10

   3. System Design Considerations 12

6. Installation and Operation 12

   1. Mounting 12

   2. Installation Conditions 12

   3. Meter Commissioning 13

   4. Conditions Affecting Meter Performance 13

   5. Maintenance 16

7. Proving 16

   1. General 16

   2. Proving Considerations 16

8. Auditing, Reporting, and Security Requirements For Coriolis Measurement 19

   1. General 19

   2. Configuration Log 19

   3. Quantity Transaction Record (QTR) 20

   4. Event Log for Coriolis Meters 20

   5. Alarm and Error Log 20

   6. Security and Access 20

Annex A (normative) Observed Zero Verification 21

Annex B (informative) System Design, Diagnostics, and Verification Considerations 27

Annex C (informative) Factory Calibration 31

Annex D (normative) Pressure Effect Compensation for Tube Stiffness 33

Annex E (informative) Volume Ticketing (QTR), Proving Reports, and Records for Coriolis Meters 37

Annex F (normative) Mass Calculations for Coriolis Meters—Mass Ticketing and Mass Proving 39

Annex G (informative) Determination of Net Mass 60

Bibliography 62

Figures

1. Illustrative Impact of Zero Error on Meter Factor 14

2. Illustrative Impact of Zero Stability on Repeatability versus Flow Rate 15

1. Meter Factor Curve “as found” Zero 25

2. Meter Factor Curve “as left” 0.25 lb/min Zero 25

   v

   Contents

   Page

3. Estimated Observed Zero Change, Equation (A.2) 26

C.1 Calibration System Schematic 32

Tables

A.1 Meter Factor Shift with Change in Flow Rate 25

1. Discrimination Levels for Density Values used in Mass Calculations 58

2. Discrimination Levels for Mass Values used in Mass Calculations 59

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Measurement of Liquid Hydrocarbons by Coriolis Meters

1. Scope

   
   

   This standard is intended to be a guide for the specification, installation, verification, and operation of Coriolis meters used to dynamically measure liquid hydrocarbons. API MPMS Ch. 5.6 also includes information that will assist in troubleshooting and improving the performance of the meters.

   
   

   Use of a Coriolis meter as a stand-alone density meter is not addressed by this standard.

   
   

   1. Field of Application

      
      

      This standard describes methods to achieve custody transfer measurement of liquid hydrocarbon quantities (mass or volume) using a Coriolis meter. Coriolis meters can provide outputs for mass flow rate, volumetric flow rate, and density. The choice of the quantity output (mass or volume) depends on commercial, contractual, regulatory, and performance requirements.

      
      

      This document provides guidance for the application, installation, proving, mass calculations, auditing, reporting, and security requirements for Coriolis meters.

      
      

      Some of the guidance provided within also applies to allocation measurement. API MPMS Ch. 20[19] allows for different performance requirements.

      
      

      Guidance for the measurement of density is found in API MPMS Ch. 9[6].

      
      

2. Normative References

   
   

   The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

   
   

   API MPMS Ch. 21 (all sections), Flow Measurement Using Electronic Metering Systems

   
   

   API MPMS Ch. 21.2, Electronic Liquid Volume Measurement Using Positive Displacement and Turbine Meters

   
   

   API MPMS Ch. 21.2-A1, Addendum 1 to Flow Measurement Using Electronic Metering Systems, Inferred Mass

   
   

3. Terms, Definitions, And Symbols

   
   

   1. Terms and Definitions

For the purpose of this document, the following definitions apply. Terms of more general use may be found in the API MPMS Chapter 1, Online Terms and Definitions Database.

3.1.1

calibration (Coriolis)

The process of using a reference standard to determine a coefficient that adjusts the output of the Coriolis transmitter to bring it to a value that is within the specified accuracy tolerance of the meter over a specified flow range. This process is normally conducted by the manufacturer.