Dynamic Risers for Floating Production Systems

API STANDARD 2RD

SECOND EDITION, SEPTEMBER 2013

REAFFIRMED, SEPTEMBER 2020

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Contents

Page

1. Scope 1

2. Normative References 1

3. Terms, Definitions, Symbols and Abbreviated Terms 2

   1. Terms and Definitions 2

   2. Symbols 13

   3. Abbreviated Terms 15

4. Design Loads and Conditions 16

   1. General 16

   2. Loads 17

   3. Design Load Cases 17

5. Design Criteria for Rigid Pipe 19

   1. Objective 19

   2. Design Format 19

   3. Capacities of Pipe 19

   4. Design Criteria 22

6. Components 28

   1. General 28

   2. Fatigue 28

   3. Pressure-containing Components 28

7. Materials 29

   1. Scope 29

   2. General Requirements 29

   3. Steel 32

   4. Other Materials. 33

   5. Requirements for Elevated Temperature 33

   6. Requirements for Sour Service 33

   7. Requirements for Strain-based Design 33

   8. Prevention of Brittle Fracture 34

   9. Corrosion Protection 35

   10. Products 37

   11. Manufacture, Welding and Fabrication 40

   12. Examination and Non-destructive Testing (NDT) 44

8. Fabrication and Installation 45

   1. General 45

   2. Fabrication 46

   3. Transportation, Shipping and Marine Operations 47

9. Riser Integrity Management 53

   1. Introduction 53

   2. Riser Integrity Management Plan 53

Annex A (informative) Example TTR Design 55

Annex B (informative) Example SCR Design 69

Annex C (informative) Supplemental Design Information 74

Bibliography 75

Figures

Page

1. Hardness Locations in Seamless and Seam Welded Pipe 36

2. Hardness Locations for Clad Materials. 37

A.1 Production Riser Stack-up 58

Tables

1. Representative Intact Strength Load Cases 18

2. Representative Damaged Strength Load Cases 18

3. Representative Fatigue Load Cases 18

4. Applicable Material Specifications 30

5. Test Temperature for Charpy Impact Testing of Steel and Steel Welds 34

6. Carbon and Low-alloy Steel Bolts and Nuts for Pressure-bearing or Main Structural Applications 38

1. Production Riser Load Case Matrix 55

2. Riser Pipe Sizes and Materials 59

3. Internal Overpressure Limits for Outer Riser 60

4. Internal Overpressure Limits for Inner Riser 60

5. External Overpressure Limits for Outer Riser 62

6. External Overpressure Limits for Inner Riser 63

7. Riser Keel and Stress Joints 63

8. Capacities of the Outer Riser 64

9. Riser Loads at Bottom of Keel Joint 65

1. A Typical Load Case Matrix for SCR Design 69

2. Load Case Matrix for SCR Performance Assessment 70

3. 100-Year Hurricane Environmental Data 70

4. Pipe Properties 70

5. Capacity Utilization for ALS and ULS Load Cases 71

6. Summary of Pipe Capacity 72

7. Riser loads at TDZ for ULS 72

Introduction

Since the first edition of API RP 2RD, Recommended Practice for Design of Risers for Floating Production Systems (FPSs) and Tensioned-Leg Platforms (TLPs), was issued in June 1998, hydrocarbon exploration and production in deep water environments have increased significantly. As a consequence, the need was identified to update that code of practice to address the issues and lessons learned from that experience. The title of the document has been changed to eliminate reference to any one type of floating hull. A broad scope of marine dynamic risers is covered, including various steel catenary risers and top tensioned risers.

Dynamic Risers for Floating Production Systems

1. Scope

   
   

   This standard addresses riser systems that are part of a floating production system (FPS). Guidelines for design, construction, installation, operation and maintenance of floating production systems (FPSs) are in API 2FPS. A riser is a subsystem in a floating production system.

   
   

   The provisions of this standard do not apply to the riser systems of mobile offshore drilling units (MODUs).

   
   

   There is significant interaction among the subsystems in a floating production system. Hull motions affect risers and mooring, and conversely, risers and mooring affect hull motions. Global behavior of the system provides input to assessment of subsystems. Assessment of a subsystem provides feedback (loads) for assessment of the hull and other subsystems.

   
   

   Determination of the boundaries of a riser system and management of the interactions with other subsystems is the responsibility of the operator.

   
   

   A riser system is an assembly of components, including pipe and connectors. A riser system can include a riser tensioning system, buoyancy modules, etc. Pipe components can be steel, titanium, or unbonded flexible pipe. Design considerations for unbonded flexible pipe are included primarily by reference to API 17B and API 17J. Design considerations for titanium alloy pipe are included primarily by reference to DNV-RP-F201. Steel and titanium pipe are referred to as rigid pipe and unbonded flexible pipe is referred to as flexible pipe.

   
   

   All or part of several existing codes, standards, specifications, and recommended practices are included by reference.

   
   

   Design loads and conditions are described in Section 4. Structural design criteria for rigid pipe are in Section 5. Structural capacity formulae for steel pipe are also in Section 5. Additional requirements for components, including pipe, are in Section 6. Material requirements are in Section 7. Fabrication and installation requirements are in Section 8. Integrity Management is addressed in Section 9.

   
   

2. Normative References

The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

API Spec 5CT, Specification for Casing and Tubing

API RP 5C5, Recommended Practice on Procedures for Testing Casing and Tubing Connections

API Spec 5L, Specification for Line Pipe

API RP 5L1, Recommended Practice for Railroad Transportation of Line Pipe

API RP 5LW, Recommended Practice for Transportation of Line Pipe on Barges and Marine Vessels

API RP 17B, Recommended Practice for Flexible Pipe API Spec 17J, Specification for Unbonded Flexible Pipe API Spec 17K, Specification for Bonded Flexible Pipe