Manual of Petroleum Measurement Standards Chapter 4.8

Operation of Proving Systems

THIRD EDITION, JULY 2021

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Foreword

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Contents

Page

1. Scope 1

2. Normative References 1

3. Terms and Definitions 1

4. Basic Principles 1

5. The Need to Prove 1

6. Frequency of Meter Proving 2

7. General Considerations for Meters and Provers 2

   1. General 2

   2. Data Recording 2

   3. Temperature and Pressure Measurements 3

   4. Operating Pressure 3

   5. Density 3

   6. Proving Meters with Pulse Output 4

   7. Proving Meters Using Totalizers 4

8. Proving Locations 4

   1. General 4

   2. In Situ Proving 5

   3. Laboratory Proving 5

   4. Ex Situ Proving 5

9. Types of Provers 5

   1. General 5

   2. Displacement Provers 5

   3. Tank Prover 8

   4. Master Meter Prover 8

10. Prover Calibration Frequency 9

    1. Displacement and Tank Provers 9

    2. Master Meter Provers 10

11. Proving Methods 11

    1. Volumetric Proving 11

    2. Direct Mass Proving 11

    3. Inferred Mass Proving 12

12. Assessment of Proving Results 12

    1. The Number of Runs 12

    2. Meter Factor 13

    3. Application of Meter factors 13

13. Proving Concerns 13

    1. Flow Conditioning 13

    2. Temperature and Pressure Variations 14

    3. Viscosity Variation 14

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       Contents

       Page

    4. Valve(s) Leakage 14

    5. Displacer Slippage 15

    6. Meter Wear 15

    7. Effect of Electrical Disturbance 15

    8. Flow Rate Variation 15

    9. Meter Registration (Head) Check 15

    10. Meter and Prover Design 15

    11. Meter and Prover Combinations 16

    12. Air/Vapor in the Proving System 16

    13. Cavitation 16

    14. Debris and Coating 16

    15. Physical Damage 16

    16. Computational Master Meter Provers Zero 16

Annex A (normative) Evaluating Meter Proving Data 18

Annex B (normative) Method for Determining the Frequency of Calibrating Provers 21

Annex C (informative) Meter Prover Operation 24

Annex D (informative) Proving Form Examples 36

Bibliography 39

Figures

B.1 Determining the Frequency of Prover Calibration 23

1. Proving Example—Inferred Mass Proving 36

2. Proving Example—Direct Mass Proving 37

3. Proving Example—Volumetric Proving 38

Tables

1. Repeatability Criteria for 0.027 % Uncertainty (Preferred Uncertainty) for ±0.00027 Random Uncertainty

   in Average Meter Factor 19

2. Repeatability Criteria for 0.073 % Uncertainty (Limited Volume Proving) for ±0.00073 Random Uncertainty in Average Meter Factor 20

1. Prover Calibration Frequency Example 22

2. Example Table—Dynamic or Tank Prover Calibration Frequency for 0.06 % Volume Change Benchmark 23

1. Repeatability Criteria for 0.027 % Uncertainty for ±0.00027 Random Uncertainty in Average Meter Factor 34

2. Repeatability Criteria for 0.027 % Uncertainty for ±0.00027 Random Uncertainty in Average Meter Factor 34

3. Suggested Minimum Prover Volume for ±0.027 % Uncertainty of Meter Factor when Proving Ultrasonic Flow Meters 35

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Operation of Proving Systems

1. Scope

   
   

   This guide provides information for operating meter provers on single-phase liquid hydrocarbons. It is intended for use as a reference manual for operating proving systems.

   
   

   The requirements of this chapter are based on customary practices for single-phase liquids. This standard is primarily written for hydrocarbons, but much of the information in this chapter may be applicable to other liquids. Specific requirements for other liquids should be agreeable to the parties involved.

   
   

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 Chapter 4.2, Displacement Provers

API MPMS Chapter 4.4, Tank Provers

API MPMS Chapter 4.5, Master-Meter Provers

API MPMS Chapter 5.1, General Considerations for Measurement by Meters

API MPMS Chapter 5.6, Measurement of Liquid Hydrocarbons by Coriolis Meters

API MPMS Chapter 12.2, Calculation of Petroleum Quantities Using Dynamic Measurement Methods and Volumetric Correction Factors

3 Terms and Definitions

There are no definitions unique to this document. Terms of more general use may be found in the API MPMS

Chapter 1—Online Terms and Definitions Database.

1. Basic Principles

   
   

   The object of proving meters with a prover is to provide a number with a defined discrimination level, which can be used to convert the meter indication to an accurate quantity of fluid passed through the meter. Refer to API MPMS Ch. 12.2 for volume discrimination levels and calculations or API MPMS Ch. 5.6 for mass discrimination levels and calculations.

   
   

2. The Need to Prove

A meter in service should be periodically proved to confirm its accuracy. The previously determined meter factor may no longer be applicable because of changes in fluid characteristics, operating conditions, and meter wear. Specific reasons for proving meters include the following:

a) minimize financial impact of potential undetected accuracy changes;

b) contractual requirements exist, such as scheduled meter maintenance based on throughput or elapsed time,

or both;

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