Page 22 - Pipelines and Risers

Contents XIX

Chapter 20 Design of Deepwater Risers 38 1
20.1 General ................................................................................................................................................. 381
20.2 Descriptions of Riser System ............................................................................................................... 381
20.2.1 General ......................................................................................................................................... 381
20.2.2 System Descriptions ..................................................................................................................... 384
20.2.3 Component Descriptions .............................................................................................................. 384
20.2.4 Catenary and Top Tensioned Risers ............................................................................................. 385
20.3 Metallic Catenary Riser for Deepwater Environments ........................................................................ 386
20.3.1 General ......................................................................................................................................... 386
20.3.2 Design Codes ............................................................................................................................... 387
20.3.3 Analysis Parameters ..................................................................................................................... 387
20.3.4 Installation Studies ...................... ............................................................................................ 388
20.3.5 Soil-Riser Interaction .................. ............................................................................................ 388
20.3.6 TDP Response Prediction ............................................................................................................ 389
20.3.7 Pipe Buckling Collapse under Extreme Conditions ....................................................
20.3.8 Vortex Induced Vibration Analysis .............................................................................
20.4 Stresses and Service Life of Flexible Pipes .........................................................................
20.5 Drilling and Workover Risers .............................................................................................................. 391
20.6 Riser Projects in Norway ..................................................................................................................... 391
20.7 References ............................................................................................................................................ 392

Chapter 21 Design Codes and Criteria for Risers 393
2 1.1 Design Guidelines for Marine Riser Design ............................................................................
21.2 Design Criteria for Deepwater Metallic Risers .................................................................................... 395
21.2.1 Design Philosophy and Considerations ......................................... ................................ 395
21.2.2 Currently Used Design Criteria .................................................................................................... 396
21.2.3 Ultimate Limit State Design Checks .............. ..... ................................ 397
21.3 Limit State Design Criteria .................................................................................................................. 397
21.3.1 General ......................................................................................................................................... 397
21.3.2 Failure Modes and Limit States ................................................................................................... 397
21.3.3 Safety Classes ............................................................................................... 398
21.3.4 Design Procedure ......................................................................................................................... 39Y
2 I . 3.5 Acceptance Criteria ...................................................................................................................... 399
21.3.6 LRFD Design Formats ................................................................................................................. 399
21.3.7 Local Strength Design through Analysis ...................................................................................... 399
2 I . 4 Design Conditions and Loads .............................................................................................................. 399
21.4.1 General ......................................................................................................................................... 399
21.4.2 Design Conditions ........................................................................................................................ 399
21.4.3 Loads and Load Effects ................................................................................................................ 401
21.4.4 Definition of Iaad Cases ............................................................................................................. 402
21.4.5 Load Factors .......................................................................................................................
21.5 lmproving Design Codes and Guidelines ...................................................................................
21.5.1 General ...............................................................................................................................
21.5.2 Flexible Pipes ...................................................................... .................................. 404
21.5.3 Metallic Riser ...................................................................... ................................................. 406
21.6 Comparison of IS0 and API Codes with Hauch and Bai (1999) ......................................................... 406
21.6.1 Riser Capacity under Combined Axial Force, Bending and Pressure .......................................... 406
21.6.2 Design Approaches ...................................................................................................................... 407
21.6.3 Application of codes .................................................................................................... ..... 407
2 1.7 References ............................................................................................................................................ 411

Chapter 22 Fatigue of Risers 413
22.1 General ................................................................................................................................................. 413
22.2 Fatigue Causes ..................................................................................................................................... 413