Manual of Petroleum Measurement Standards Chapter 20.5

Recommended Practice for Application of Production Well Testing in Measurement and Allocation

FIRST EDITION, DECEMBER 2017

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Foreword

This edition of API Manual of Petroleum Measurement Standards (MPMS) Chapter 20.5 supersedes the below listed sections of API MPMS Chapter 20.1, Allocation Measurement, First Edition, 1993:

• 1.7.2.2.2 Test Separator;

  
  

• 1.11.1 Well Tests;

  
  

• 1.16.3.2 Field Test Separators;

  
  

• 1.16.3.3 Portable Test Separators;

  
  

• 1.16.5.1 Full-Scale Separator Test Report;

  
  

• Appendix J.

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Contents

Page

1. Scope 1

2. Normative References 1

3. Terms, Definitions, Acronyms, Abbreviations, and Symbols 2

   1. Terms and Definitions 2

   2. Acronyms, Abbreviations, and Symbols 5

4. Production Well Testing in Upstream Measurement and Allocation 6

   1. Introduction 6

   2. Reasons for Production Well Testing 6

   3. Production Well Testing and Additional Methods for Determining Well Rates 7

5. Conducting a Production Well Test 9

   1. Preparation 9

   2. Initiation and Measurement 11

   3. Validation 23

   4. Special Case: Continuous Measurement 25

   5. Special Case: Production Well Test By-difference 26

6. Calculating Production Well Test Volumes and Rates 27

   1. General 27

   2. Phase Behavior (Production Well Testing PVT Application) 28

   3. Separator Measurement Systems 32

   4. Multiphase Measurement Systems 40

   5. Tank Measurement Systems 45

7. Applying Production Well Test Data for Use in Allocation 54

   1. General 54

   2. Production Well Test Rate Assumed Constant 54

   3. Production Well Test Rate with Applied Downtime 55

   4. Production Well Test Rate Validation and Updating of Well Flow Models and Virtual Flow Meters 56

   5. Production Well Test Volume Adjustment of Gas Well Continuous Measurement

      with Single-phase Meters 60

   6. Special Case: Continuous Measurement 63

Annex A (informative) Types of Oil and Gas Well Tests 64

Annex B (informative) Description of the Production Well Test System 67

Annex C (informative) Example Analysis for Establishing Production Well Test Duration During

Nonstable Flow Conditions 85

Annex D (informative) Example Production Well Test Report 89

Annex E (informative) Field Determination of Oil Volume Correction Factor 91

Annex F (informative) Calculation of Water Volume Correction Factor 92

Annex G (informative) Example Calculations of Production Well Test Rates 93

Annex H (informative) Example Calculations of Production Well Test Use in Allocation 109

Bibliography 114

Contents

Figures

Page

1. Well Rate Determination Tree 8

2. Production Well Test Initiation and Measurement Workflow 12

3. Summary of Production Well Test Elements and Workflow 22

4. Two-phase and Three-phase Separator Measurement System Process Flow Diagram 33

5. Multiphase Measurement System Process Flow Diagram 41

6. Tank Measurement System Process Flow Diagram 46

7. Gas Wells Continuously Measured with Single-phase Meters with the Ability to Align

with a Production Well Test System 60

1. The Complete Production Well Test System 67

2. Reservoir Fluid Types 68

3. Example Hydrocarbon Phase Envelope 71

4. Solution-gas Drive 73

5. Gas-cap Drive 73

6. Water Drive 74

7. Gravity Drainage 75

8. Example Phase Envelope for Separator Operations 82

C.1 Production Well Test Data Showing Flow Variability at the Measurement Points 86

Tables

1. Summary of Suggested Fluid Verification Activities 14

2. Summary of Suggested Production Verification Activities 16

3. Summary of Suggested Equipment Verification Activities 17

1. Uncertainty Result for 2-hour Production Well Test 87

2. Combined Uncertainty Results for 2-, 4-, 6-, and 8-hour Production Well Tests 88

Introduction

This document establishes a framework to conduct and apply production well testing for well rate determination in measurement and allocation. Production well testing addressed in this document refers to measurement of gas, oil, and water quantities from a single well during a specified length of time under controlled operational conditions. The intent of this document is to provide operators with a consistent and transparent approach for conducting, applying, and managing production well testing within an upstream measurement and allocation system. It is not intended to prescribe a particular production well test method, or particular application of production well test data use in allocation. Allocation methodologies are addressed in API MPMS Ch. 20.1.

Recommended Practice for Application of Production Well Testing in Measurement and Allocation

1. Scope

   
   

   This document provides recommendations and guidelines for the application of production well testing in production measurement and allocation. The recommendations and guidelines apply to conducting a production well test, calculating production well test volumes and rates, and the application of production well test data for use in measurement and allocation. This includes production well testing preparation, initiation, measurement, validation, and volume and rate calculations for separator, multiphase flow meter, and tank production well test systems. Additionally, this document addresses the proration of production well test results for use in allocation, the application of production well tests for validation and update of well flow models and virtual flow metering, and the adjustment of gas well continuous measurement results with production well test data.

   
   

   This document also provides recommendations and guidelines for the application of well flow modeling and virtual flow metering in production measurement and allocation.

   
   

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 Draft Standard Application of Hydrocarbon Phase Behavior Modeling in Upstream Measurement and Allocation Systems

API Manual of Petroleum Measurement Standards (MPMS), Chapter 3.1A, Standard Practice for the Manual Gauging of Petroleum and Petroleum Products

API MPMS Chapter 3.1B, Standard Practice for Level Measurement of Liquid Hydrocarbons in Stationary Tanks by Automatic Tank Gauging

API MPMS Chapter 3.3, Standard Practice for Level Measurement of Liquid Hydrocarbons in Stationary Pressurized Storage Tanks by Automatic Tank Gauging

API MPMS Chapter 3.6, Measurement of Liquid Hydrocarbons by Hybrid Tank Measurement Systems

API MPMS Chapter 8.1, Standard Practice for Manual Sampling of Petroleum and Petroleum Products

API MPMS Chapter 8.2, Standard Practice for Automatic Sampling of Liquid Petroleum and Petroleum Products

API MPMS Chapter 11.1, Temperature and Pressure Volume Correction Factors for Generalized Crude Oils, Refined Products, and Lubricating Oils

API MPMS Chapter 14.1, Collecting and Handling of Natural Gas Samples for Custody Transfer

API MPMS Chapter 18.1, Measurement Procedures for Crude Oil Gathered from Small Tanks by Truck

API MPMS Chapter 20.1, Production Measurement and Allocation Systems

API MPMS Chapter 20.2, Production Allocation Measurement Using Single-phase Devices

API MPMS Chapter 20.3, Measurement of Multiphase Flow

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