Wellbore Plugging and Abandonment

API RECOMMENDED PRACTICE 65-3 FIRST EDITION, JUNE 2021

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Copyright © 2021 American Petroleum Institute

Foreword

This document was prepared with input from oil and gas operators, drilling contractors, service companies, and consultants. Guidance is provided to accomplish the following:

• permanently abandon wells;

  
  

• place wells on inactive status (temporary abandonment).

Permanent abandonment is performed when there is no further utility for a wellbore by sealing the wellbore against fluid migration.

A well is placed on inactive status when there are plans for future utility of the wellbore. Temporary abandonment is performed by sealing the wellbore for the anticipated time of inactivity.

The purpose of this document is to address wellbore plugging and abandonment practices. The primary goals are protection of useable water sources, isolation of hydrocarbon bearing or water injection intervals, prevent any leakage to the surface, and prevention of unintended cross flow. Topics discussed include cementing practices and the placement of well barriers. This document does not address regulatory requirements nor surface reclamation.

The content of this document is not all inclusive and not intended to alleviate the need for detailed information found in textbooks, manuals, technical papers, or other documents. The formulation, adoption, and publication of API standards are not intended to inhibit anyone from using any other practices. Research into the installation and evaluation of permanent abandonment well barriers are ongoing. As new materials, isolation methods, placement techniques, and evaluation methods emerge these should be effectively reviewed by the user prior to use.

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iii

Contents

Page

1. Scope 1

   1. General Considerations 1

   2. Well Construction and Abandonment Practices 1

2. Normative References 3

   1. Use of SI and U.S. Customary Units 3

3. Terms and Definitions, Symbols, and Abbreviations 3

   1. Terms and Definitions 3

   2. Symbols and Abbreviations 4

4. Applications and Operating Environment 5

   1. Formation Types 5

   2. Positions 5

5. Material Consideration for Barriers 12

   1. General 12

   2. Environment 13

   3. Pumpable Sealants 13

   4. Natural 14

   5. Mechanical 14

6. Installation 15

   1. Placement Methodology 15

   2. Balanced Plug Best Practices 21

7. Evaluation and Verification Criteria 26

   1. General 26

   2. Annulus 26

   3. Inside Pipe (In-Pipe) 26

Annex A (informative) Balanced Plug Calculations 28

Bibliography 44

Figures

1. Example Schematic of a Permanent Well Abandonment 2

2. Illustration of a Continuous Barrier across the Wellbore at the Natural Seal Location 6

3. Two Continuous Barriers Adjacent to Natural Seals where Formation Integrity exceeds Pressure from Potential Flow Zone 7

4. Open Hole Abandonment by Balanced Plugs 8

5. Open Hole Abandonment with a Cement Retainer Set at Casing Shoe 8

6. Cased Hole Abandonment with a Perforation Squeeze and a Balanced Plug 9

7. Cased Hole Abandonment with a Cement Retainer 9

8. Casing Shoe Balanced Cement Plug 10

9. Casing Shoe Squeeze Cement Plug with Cement Retainer 10

10. Casing Stub Abandonment 11

11. Liner Top Abandonment 11

12. Balanced Cement Plug inside Casing across a Usable Water Source 12

13. Example of a Barrier with a Mechanical Base 15

14. Example of a Pump and Pull Procedure 17

15. Example of the IBOP Method to Set a Cement Plug 18

16. Example of the Modified IBOP Method to Set a Cement Plug 19

    v

    Contents

    Page

17. Through-tubing Method Isolating a Potential Flow Zone 20

1. Example Wellbore with a) Workstring Out and b) Workstring In 30

2. Calculation Volumes for the Total Cement Volume 31

3. Calculation Volumes for Top of Cement with Workstring In 32

4. Calculation Volumes for Spacer Behind with Workstring In 37

5. Calculation Volumes for Spacer Behind with Workstring Out 40

6. Calculation Volumes for Displacement 42

Tables

1 Reduced Diameter Stinger Selection 25

A.1 Wellbore Capacities for Calculations: Example 30

vi

Wellbore Plugging and Abandonment

1. Scope

   
   

   1. General Considerations

      
      

      This document provides guidance for the design, placement, and verification of cement plugs in wells to be temporarily or permanently abandoned, as well as remediation and verification of annular barriers. Wells temporarily abandoned (suspended) are intended to be re-entered in the future. The placement of barriers may depend on whether the well is to be temporarily or permanently abandoned.

      
      

      The information in this document is general in nature. Wellbore plugging and abandonment practices will vary with regulatory requirements, well type, and purpose. Sound engineering and operational practices should be applied to each wellbore plugging operation. Cement plug lengths are not considered in this document.

      
      

   2. Well Construction and Abandonment Practices

This document assumes that generally accepted well construction practices were followed during the installation of the cemented casings.

As specified in API 65-2, properly designed casing strings cemented in place provide multiple barriers during well operations.

Abandonment barriers may include those placed:

• across any exposed casing/liner shoe;

  
  

• in open hole;

  
  

• above perforated intervals in cased hole;

  
  

• at points where casing has been removed;

  
  

• across liner tops;

  
  

• above and below usable water sources;

  
  

• above or below hydrocarbon bearing zones or other potential flow zones;

  
  

• at the surface or mudline.

See Figure 1 for an example of a permanent well abandonment.