Specification for Subsea Wellhead and Tree Equipment

API SPECIFICATION 17D

THIRD EDITION, OCTOBER 2021

API MONOGRAM PROGRAM EFFECTIVE DATE: OCTOBER 2022

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Foreword

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Contents

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 10

4. Application, Service Conditions, and Production Specification Levels 12

   1. Application 12

   2. Service Conditions 15

   3. Product Specification Levels 15

5. Common System Requirements 16

   1. Design and Performance Requirements 16

   2. Materials 28

   3. Welding 28

   4. Quality Control 29

   5. Equipment Marking 33

   6. Storing and Shipping 34

6. General Design Requirements for Subsea Tree Systems 35

   1. General 35

   2. Tubing Head and Tree Valving 36

   3. Thermally Induced Pressure Changes 45

   4. Testing of Subsea Tree Assemblies 45

   5. Marking 45

   6. Storing and Shipping 45

7. Specific Requirements—Subsea Tree-related Equipment and Subassemblies 49

   1. Flanged End and Outlet Connections 49

   2. API Clamp Hub-type Connections 70

   3. Threaded Connections 70

   4. Other End Connectors 70

   5. Studs, Nuts, and Bolting 70

   6. Crosses, Tees, and Elbows 71

   7. Completion Guidebase 71

   8. Tree and Tubing Head Connectors 72

   9. Tree Stab/Seal Subs for Vertical Tree 75

   10. Valves, Valve Blocks, and Actuators/Operators 76

   11. Re-entry Interface 89

   12. Subsea Tree Cap 90

   13. Tree Cap Running Tool. 93

   14. Tree and Tubing Head Guide Frames 95

   15. Tree Running Tool 98

   16. Tree, Tubing Head, and Completion Guidebase Piping 101

   17. Flowline Connections 103

   18. Ancillary Equipment Running Tools 106

   19. Tree-mounted Hydraulic/Electric/Optical Control Interfaces 107

   20. Subsea Chokes and Actuators/Operators 111

   21. Miscellaneous Equipment 121

8. Specific Requirements—Subsea Wellhead 122

   1. General 122

   2. Temporary Guidebase 123

   3. Permanent Guidebase 124

   4. Conductor (Low-pressure) Housing 129

   5. Wellhead (High-pressure) Housing 131

   6. Casing Hangers 134

   7. Annulus Seal Assemblies 136

   8. Casing Hanger Lockdown Bushing 137

   9. Bore Protectors and Wear Bushings 139

   10. Corrosion Cap 140

   11. Running, Retrieving, and Testing Tools 140

   12. Overtrawlable Protection Structure 140

   13. Wellhead Inclination and Orientation 140

   14. Submudline Casing Hanger and Submudline Annulus Seal Assemblies 140

9. Specific Requirements—Subsea Tubing Hanger System 141

   1. Design 141

   2. Materials 144

   3. Testing 144

10. Specific Requirements—Mudline Suspension Equipment 145

    1. General 145

    2. Mudline Suspension-landing/Elevation Ring 149

    3. Casing Hangers 149

    4. Casing Hanger Running Tools and Tieback Adapters 150

    5. Abandonment Caps 151

    6. Mudline Conversion Equipment for Subsea Completions 151

    7. Tubing Hanger System—Mudline Conversion Equipment for Subsea Completions 152

11. Specific Requirements—Drill-through Mudline Suspension Equipment 152

    1. General 152

    2. External Drill-through Casing Hangers (Outside of the Drill-through Casing Hanger Housing) 152

    3. Drill-through Casing Hanger Housing 152

    4. Internal Drill-through Mudline Casing Hangers 154

    5. Internal Drill-through Annulus Seal Assemblies 156

    6. Internal Drill-through Bore Protectors and Wear Bushings 156

    7. Tubing Hanger System—Drill-through Mudline Equipment for Subsea Completions 157

Annex A (informative) Subsea Wellhead 158

Annex B (informative) Purchasing Guidelines 160

Annex C (informative) Alternate Requirements for Carbon and Low-alloy Steel Subsea Forgings 177

Annex D (informative) High-pressure High-temperature 179

Annex E (normative) Mudline Suspension and Conversion Systems 188

Annex F (informative) Assembly Guidelines of API Bolted Flanged Connections 195

Annex G (informative) Design and Testing of Pad Eyes for Lifting 202

Annex H (informative) Design and Testing of Subsea Wellhead Running, Retrieving, and Testing Tools 214

Annex I (informative) Procedure for the Application of a Coating System 216

Annex J (informative) Validation of Valves and Actuators/Operators 219

Annex K (informative) Screening Tests for Material Compatibility 224

Annex L (informative) Subsea Tubing Hanger 229

Annex M (informative) Drill-through Mudline Suspension Systems 233

Annex N (informative) Hyperbaric Testing Guidelines 235

Annex O (informative) Vertical Subsea Trees 237

Annex P (informative) Horizontal Subsea Trees 240

Bibliography 243

Figures

1. Example of a Dual-bore Tree on a Subsea Wellhead 38

2. Example of Vertical Trees on Tubing Heads 39

3. Examples of Horizontal Trees 40

4. Examples of Bore Penetrations 41

5. Examples of Tree Valving for Downhole Chemical Injection and SCSSV 43

6. Type 17SS Integral or Blind Flange 55

7. Alternate Rough and Finish Machining Detail for Corrosion-resistant BX-149 and BX-150 Ring Grooves 59

8. Weld End Preparation for Types 17SS and 17SV Welding Neck Flanges 59

9. Assembled Type 17SV Flange 61

10. Tree Guide Frames 97

11. Choke Common Orifice Configurations 112

12. External Loads on a Subsea Tree and Wellhead 127

13. Permanent Guidebase Loads 127

14. Typical Conductor (Low-pressure) Housing 130

15. Typical Wellhead (High-pressure) Housings. 132

A.1 Subsea Wellhead 159

1. PSL Decision Tree for Subsea Equipment 161

2. Examples of Subsea Tree P&ID 176

1. Mudline Suspension (Wellhead) and Conversion Equipment 189

2. Mudline Conversion Equipment 190

3. Stress Distribution, Axisymmetric Cross Section, Mudline Suspension Components 192

4. Limiting Stress Values, Mudline Suspension Components. 193

1. Flange-to-flange Alignment Tolerances 199

2. Cross-bolt Torque Tightening Sequence for One Tool, Two Tools, and Four Tools 200

1. Shackle and Pad Eye Profiles and Dimensions (Not to Scale) 204

2. Pad Eye Lift Sub Dimensions (Not to Scale) 206

3. Pictorial Representation of Lifting Set Showing the Angle of Sling Leg from Vertical 208

4. Localized Testing of Fabricated Pad Eyes 213

5. NDE Regions on Fabricated Pad Eyes 213

1. Concentric Tubing Hanger 230

2. Tubing Hanger with Multiple Bores 230

3. Tubing Hanger for Horizontal Tree 231

4. Extended Tubing Hanger for Horizontal Tree 232

M.1 Drill-through Mudline Suspension System 234

1. Guideline Style Vertical Tree 238

2. Guidelineless Style Vertical Tree 239

1. Guideline Style Horizontal Tree 241

2. Guidelineless Style Horizontal Tree 242

Tables

1. Material Requirements. 17

2. Equipment Standard Pressure Rating 18

3. Pressure Ratings for Internal Thread End or Outlet Connectors 19

4. Bolting Classifications and Material Requirements 21

5. Minimum Validation Requirements 26

6. Pressure Test Pictorial Representations 46

7. Rated Working Pressures and Size Ranges of API Flanges 49

8. API-type SBX Pressure-energized Ring Gaskets 51

9. Basic Flange and Bolt Dimensions for Type 17SS Flanges for 5000 psi (34.5 MPa) Rated Working Pressure 54

10. Basic Flange and Bolt Dimensions for 3/4 in. (19 mm) and 1 in. (25 mm) Type 17SS Flanges ... 56

11. Hub and Bore Dimensions for Type 17SS Line Pipe Welding Neck Flanges for 5000 psi (34.5 MPa) Rated Working Pressure 57

12. Rough Machining Detail for Corrosion-resistant API Ring Groove 58

13. Hub Dimensions for Type 17SV Flanges—USC Units 62

14. Ring Dimensions for Type 17SV Flanges—USC Units 64

15. Hub Dimensions for Type 17SV Flanges—SI Units 66

16. Ring Dimensions for Type 17SV Flanges—SI Units 68

17. Wellhead Systems—Standard Sizes and Types 72

18. Operating Parameters of Valves and Actuators/Operators 78

19. Center Distances of Conduit Bores for Dual Parallel Bore Valve Blocks 79

20a Example of PSL 2 Valve Factory Acceptance Test Documentation 84

20b Example of PSL 3 Valve Factory Acceptance Test Documentation 84

20c Example of PSL 3G Valve Factory Acceptance Test Documentation 85

1. Example Documentation of the Factory Acceptance Testing for a Hydraulic Actuator 85

2. Marking for Subsea Valve Actuator/Operator 87

3. Marking for Subsea Valve and Actuator/Operator Assembly 87

4. Example Documentation of the Factory Acceptance Testing for a Subsea Choke with Actuator/Operator—Mechanical Override Operational Test 115

5. Example Data Sheet for the Factory Acceptance Testing of a Hydraulic Actuator 117

6. Example Documentation of the Factory Acceptance Testing for the Operational Test of a Subsea Choke with Actuator/Operator 118

7. Example Data Sheet for the Factory Acceptance Testing of a Manual Operated Subsea Choke 118

8. Marking for Subsea Chokes 120

9. Marking for Subsea Choke Manual Operators 120

10. Marking for Subsea Choke Actuator/Operator 120

11. Marking for Subsea Choke and Actuator/Operator Assembly 120

12. Test Pressure 133

13. Recommended Minimum Vertical Bore Sizes for Casing Hangers, Bore Protectors, and

    Wear Bushings 135

14. Maximum Allowable Stress Due to Pressure (for Mudline Equipment Only) 146

15. Drill-through Casing Hanger Housing—Pressure Rating and Test Pressure 154

C.1 SFC 2 Subsea Components 178

1. HPHT Equipment Standard Pressure Rating 180

2. Minimum CVN Absorbed Energy in Longitudinal and Transverse Direction 186

1. Example Flange Bolt Torques (0.07 Friction Factor) for 67 % Yield Strength Tension 197

2. Flange Connection Make-up Record 201

G.1 Enhancement Factors for Pad Eyes on Subsea Equipment 202

J.1 Valve Cycle Position 219

N.1 Hyperbaric Testing Guidelines 236

Specification for Subsea Wellhead and Tree Equipment

1. Scope

   
   

   This document provides specifications for subsea wellheads, mudline wellheads, drill-through mudline wellheads, and both vertical and horizontal subsea trees. It specifies the associated tooling necessary to handle, test, and install the equipment. It also specifies the areas of design, material, welding, quality control [including factory acceptance testing (FAT)], marking, storing, and shipping for individual equipment, subassemblies, and subsea tree assemblies.

   
   

   The user/purchaser is responsible for ensuring that subsea equipment meets any additional requirements of governmental regulations for the country in which it is installed. This is outside the scope of this specification.

   
   

   This specification is not applicable to the rework and repair of used equipment. In situ testing is beyond the scope of this specification.

   System integration test (SIT) is beyond the scope of this specification.

   
   

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, except that new editions may be used on issue and shall become mandatory upon the effective date specified by the publisher or 6 months from the date of the revision (where no effective date is specified).

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

API Specification 5CT, Casing and Tubing

API Specification 5DP, Drill Pipe

API Specification 6A, Specification for Wellhead and Tree Equipment, 21st Edition API Standard 6AV1, Validation of Safety and Shutdown Valves for Sandy Service API Specification 16A, Specification for Drill-through Equipment

API Recommended Practice 17A, Design and Operation of Subsea Production Systems—General Requirements and Recommendations

API Standard 17F, Standard for Subsea Production Control Systems

API Standard 17G, Design and Manufacture of Subsea Well Intervention Equipment

API Recommended Practice 17H, Remotely Operated Tools and Interfaces on Subsea Production Systems

API Recommended Practice 17P, Recommended Practice for Subsea Structures and Manifolds API Recommended Practice 17R, Recommended Practice for Flowline Connectors and Jumpers API Technical Report 17TR7, Verification and Validation of Subsea Connectors

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