Hydraulic Fracturing Operations— Well Construction and Integrity Guidelines

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API GUIDANCE DOCUMENT HF1 FIRST EDITION, OCTOBER 2009

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Copyright © 2009 American Petroleum Institute

Foreword

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Contents

Page

1. Scope 1

2. Normative References 1

3. General Principles 2

   1. Protecting Groundwater and the Environment 2

   2. Well Design and Construction 2

   3. The Drilling and Completion Process 4

4. Casing Guidance 4

5. Cementing the Casing 5

   1. General 5

   2. Cement Selection 7

   3. Zone Isolation 7

   4. Cementing Practices 7

   5. Casing Centralizers 8

6. Well Logging and Other Testing 8

   1. General 8

   2. Open-hole Well Logging 9

   3. Cement Integrity (Cased-hole) Logging 9

   4. Other Testing and Information 10

7. Well Construction Guidelines 10

   1. General 10

   2. Conductor Casing 10

   3. Surface Casing. 11

   4. Intermediate Casing 12

   5. Production Casing 12

   6. Horizontal Wells 13

8. Perforating 14

9. Hydraulic Fracturing 15

   1. General 15

   2. Horizontal Fractures 16

   3. Vertical Fractures. 16

   4. Hydraulic Fracturing Process 16

   5. Hydraulic Fracturing Equipment and Materials 18

10. Data Collection, Analysis, and Monitoring 18

    1. General 18

    2. Baseline Assessment 20

    3. “Mini frac” Treatment and Analysis 20

    4. Monitoring During Hydraulic Fracturing Operations 20

    5. Post-hydraulic Fracturing Monitoring Techniques 21

    6. Post-completion Monitoring 22

Bibliography 23

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Figures

Page

1. Typical Well Schematic 5

2. Cementing the Casing. 6

3. Example of a Horizontal and Vertical Well 13

4. Perforation 14

5. Illustration of a Fractured and a Nonfractured Well 15

6. Least Principal Stress is in the Vertical Direction Resulting in a Horizontal Fracture 17

7. Least Principal Stress in the Horizontal Direction, Vertical Fracture 17

8. Schematic of Typical Fracturing Process 19

Hydraulic Fracturing Operations—Well Construction and Integrity Guidelines

1. Scope

   The purpose of this guidance document is to provide guidance and highlight industry recommended practices for well construction and integrity for wells that will be hydraulically fractured. The guidance provided here will help to ensure that shallow groundwater aquifers and the environment will be protected, while also enabling economically viable development of oil and natural gas resources. This document is intended to apply equally to wells in either vertical, directional, or horizontal configurations.

   
   

   Many aspects of drilling, completing, and operating oil and natural gas wells are not addressed in this document but are the subject of other API documents and industry literature (see Bibliography). Companies should always consider these documents, as applicable, in planning their operations.

   
   

   Maintaining well integrity is a key design principle and design feature of all oil and gas production wells. Maintaining well integrity is essential for the two following reasons.

   
   

   1. To isolate the internal conduit of the well from the surface and subsurface environment. This is critical in protecting the environment, including the groundwater, and in enabling well drilling and production.

      
      

   2. To isolate and contain the well’s produced fluid to a production conduit within the well.

      
      

      Although there is some variability in the details of well construction because of varying geologic, environmental, and operational settings, the basic practices in constructing a reliable well are similar. These practices are the result of operators gaining knowledge based on years of experience and technology development and improvement. These experiences and practices are communicated and shared via academic training, professional and trade associations, extensive literature and documents and, very importantly, industry standards and recommended practices.

      
      

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 Specification 5B, Specification for Threading, Gauging, and Thread Inspection of Casing, Tubing, and Line Pipe Threads

API Specification 5CT/ISO 11960, Specification for Casing and Tubing

API Specification 10A/ISO 10426-1, Specification for Cements and Materials for Well Cementing

API Recommended Practice 10B-2/ISO 10426-2, Recommended Practice for Testing Well Cements

API Recommended Practice 10D-2/ISO 10427-2, Recommended Practice for Centralizer Placement and Stop Collar Testing

API Technical Report 10TR1, Cement Sheath Evaluation

API Technical Report 10TR4, Technical Report on Considerations Regarding Selection of Centralizers for Primary Cementing Operations

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