Design, Selection, Operation,

and Maintenance of Marine Drilling Riser Systems

API RECOMMENDED PRACTICE 16Q SECOND EDITION, APRIL 2017

Special Notes

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Copyright © 2017 American Petroleum Institute

Foreword

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1. Scope 1

2. Normative References 1

3. Terms, Definitions, and Abbreviations 2

   1. Terms and Definitions 2

   2. Acronyms and Abbreviations 11

4. Component Function and Selection 12

   1. Introduction 12

   2. Component Selection Criteria 13

   3. Marine Drilling Riser System 13

   4. Tensioner System 13

   5. Diverter System (Surface) 16

   6. Telescopic Joint (Slip Joint) and Riser Tension Ring 16

   7. Riser Joints 17

   8. Lower Marine Riser Package 19

   9. Flex and Ball Joints 20

   10. Flexible C/K and Auxiliary Lines 21

   11. Riser Running Equipment 22

   12. Riser-mounted C/K and Auxiliary Lines 23

   13. Buoyancy Equipment 25

   14. Speciality Equipment 26

5. Riser Response Analysis 27

   1. General Considerations 27

   2. Riser Analysis Considerations 28

   3. Design and Operating Limits 29

   4. General Riser Modelling and Analysis Approach 36

   5. Drive-off/Drift-off Analysis 43

   6. Weak Point Analysis of Riser/Well System 44

   7. Recoil Analysis 44

   8. High-current Environment 45

   9. Disconnected Riser Analysis Methodology 47

6. Riser Operations 49

   1. Introduction 49

   2. Riser Operations Documentation 49

   3. Riser Operations Information Systems 50

   4. Preparing to Run Riser 50

   5. Riser Running and Retrieval 53

   6. Installed Riser Operations 54

   7. Drive-off/Drift-off 57

7. Riser Integrity 58

   1. Basis of Inspection Requirements 58

   2. Inspection Objectives and Acceptance Criteria 59

   3. Operational Records for Riser Components 62

   4. Guidance for Inspection of Riser Components 64

   5. In-service Inspection and Maintenance 65

   6. Scheduled Inspection and Maintenance 67

   7. Running, Transportation, and Storage of Joints 67

      v

      
      

8. Special Situations 68

   1. Deepwater Drilling 68

   2. Cold Weather Considerations 69

   3. Riser Collapse Considerations 70

   4. H2S Considerations 71

   5. Well Testing Operations 71

   6. Managed Pressure Drilling 72

   7. Load and Resistance Factor Design 72

Annex A (informative) Riser Management System (QA/QC) 73

Annex B (informative) Typical Riser Analysis Datasheet 76

Annex C (informative) Fatigue 80

Annex D (informative) Load and Resistance Factor Design 82

Bibliography 83

Figures

1. Marine Riser System and Associated Equipment 14

2. Allowable Stress and Significant Dynamic Stress Range 32

3. Determination of Marine Riser Length 52

4. Schematic Illustration of Riser System 61

Tables

1. Marine Drilling Risers-Maximum Design and Operating Guidelines 31

2. Commonly Used Values of Cd and Cm 40

3. Drilling Riser Inspection Requirements 58

4. Data Required for Rationalizing Inspection 63

Design, Selection, Operation, and Maintenance of Marine Drilling Riser Systems

1. Scope

   
   

   API 16Q provides requirements for the design, selection, operation, and maintenance of typical marine riser systems for floating drilling operations from a mobile offshore drilling unit (MODU) with a subsea blowout preventer (BOP) stack. Its purpose is to serve as a reference for designers, for those who select system components, and for those who use and maintain this equipment. It relies on basic engineering principles and the accumulated experience of offshore operators, contractors, consultants, and manufacturers.

   
   

   Since technology is continuously advancing in this field, methods and equipment are improving and evolving. Each owner and operator is encouraged to observe the recommendations outlined herein and to supplement them with other proven technology that can result in a more cost-effective, safer, and/or more reliable performance.

   
   

   The marine drilling riser is best viewed as a system. It is necessary that designers, contractors, and operators realize that the individual components are recommended and selected in a manner suited to the overall performance of that system. For the purposes of this document, a marine drilling riser system includes the tensioner system and all equipment between the top connection of the upper flex/ball joint to the lower flex joint. However, it specifically excludes the diverter. Also, the applicability of this document is limited to operations with a subsea BOP stack.

   
   

   Sections 1 through 7 are applicable to most floating drilling operations. In addition, special situations and topics are addressed in Section 8 dealing with deepwater drilling, cold weather environments, riser collapse, hydrogen sulfide (H2S), well testing, and managed pressure drilling (MPD). It is important that all riser primary load-path components addressed in this document be consistent with the load classifications specified in API 16R and API 16F.

   
   

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 16C, Choke and Kill Equipment

API Specification 16F, Specification for Marine Drilling Riser Equipment

API Specification16R, Specification for Marine Drilling Riser Couplings

API Specification 17D, Design and Operation of Subsea Production Systems—Subsea Wellhead and Tree Equipment

API Standard 53, Blowout Prevention Equipment Systems for Drilling Wells

API Recommended Practice 64, Recommended Practice for Diverter Systems Equipment and Operations

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