Experimental investigation on vortex-induced force of a Steel Catenary Riser under in-plane vessel motion

2021 ◽  
Vol 78 ◽  
pp. 102882
Author(s):  
Mengmeng Zhang ◽  
Shixiao Fu ◽  
Chang Liu ◽  
Haojie Ren ◽  
Yuwang Xu
Keyword(s):  
Experimental Investigation ◽  
Steel Catenary Riser ◽  
Vessel Motion

ECA Methodology for Fatigue Design of Risers and Flowlines

2007 ◽  
Author(s):  
C. H. Luk ◽  
T. J. Wang
Keyword(s):  
Fracture Mechanics ◽  
Design Method ◽  
Steel Catenary Riser ◽  
Fatigue Design ◽  
Wide Range ◽  
Fatigue And Fracture ◽  
Level 3 ◽  
Fatigue Loads ◽  
Vessel Motion ◽  
Level 2

Engineering Criticality Assessment (ECA) is a procedure based on fracture mechanics that may be used to supplement the traditional S-N approach and determine the flaw acceptance and inspection criteria in fatigue and fracture design of risers and flowlines. A number of design codes provide guidance for this procedure, e.g. BS-7910:2005 [1]. However, more investigations and example studies are still needed to address the design implications for riser and flowline applications. This paper provides a review of the existing ECA methodology, presents a fracture mechanics design method for a wide range of riser and flowline fatigue problems, and shows flaw size results from steel catenary riser (SCR) and flowline (FL) examples. The first example is a deepwater SCR subjected to fatigue loads due to vessel motion and riser VIV. The second example is a subsea flowline subjected to thermal fatigue loads. The effects of crack re-characterization and material plasticity on the Level-2 and Level-3 ECA results of the SCR and flowline examples are illustrated.

Global motion reconstruction of a steel catenary riser under vessel motion

2018 ◽  
Vol 14 (5) ◽  
pp. 442-456 ◽  
Author(s):  
Jungao Wang ◽  
Shixiao Fu ◽  
Rolf Baarholm ◽  
Mengmeng Zhang ◽  
Chang Liu
Keyword(s):  
Global Motion ◽  
Motion Reconstruction ◽  
Steel Catenary Riser ◽  
Vessel Motion

scholarly journals Experimental investigation on the dynamic responses of a free-hanging water intake riser under vessel motion

2016 ◽  
Vol 50 ◽  
pp. 1-19 ◽  
Author(s):  
Jungao Wang ◽  
Sherry Xiang ◽  
Shixiao Fu ◽  
Peimin Cao ◽  
Jianmin Yang ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Water Intake ◽  
Dynamic Responses ◽  
Vessel Motion

Time Domain Computation of Riser VIV From Vessel Motions

2006 ◽  
Author(s):  
Yongming Cheng ◽  
Kostas F. Lambrakos
Keyword(s):  
Velocity Profile ◽  
Fatigue Damage ◽  
Time Domain ◽  
Relative Velocity ◽  
Structural Characteristics ◽  
Time Domain Analysis ◽  
Computer Time ◽  
Steel Catenary Riser ◽  
Vessel Motion ◽  
Time Invariant

Intermittent riser VIV behavior caused by vessel motions can affect both riser strength and fatigue life. There are frequency domain codes available that are used routinely to calculate riser fatigue damage from VIV due to currents. These codes are often adapted to calculations of the vessel motion VIV and fatigue damage. The adaptations reduce the intermittent VIV to steady state VIV by assuming an appropriate time invariant velocity profile over the length of the riser. However, since vessel motions cause a relative velocity profile over the riser that varies with time, and the VIV response is intermittent, a time domain VIV code is best suited for such an analysis. The paper demonstrates the use of Technip’s time domain riser VIV code ABAVIV to calculate steel catenary riser VIV response and fatigue damage due to vessel motions. Since time domain analysis is computer time intensive, the paper also outlines an efficient methodology to perform these calculations. The analysis example in the paper is based on surge, pitch, and heave motions which are the most important vessel motions for the riser fatigue damage near the touch down region. The ABAVIV code accounts for the nonlinear structural characteristics of the SCR, and the unsteadiness of the VIV phenomenon for the present application.

Vortex-Induced Vibration of Steel Catenary Riser Under Vessel Motion

2014 ◽  
Author(s):  
Jungao Wang ◽  
Shixiao Fu ◽  
Rolf Baarholm
Keyword(s):  
Wave Speed ◽  
Ocean Basin ◽  
Mean Square ◽  
Wall Effects ◽  
Vortex Induced Vibration ◽  
Steel Catenary Riser ◽  
Out Of Plane ◽  
Push Down ◽  
Vessel Motion ◽  
Scr Model

A truncated steel catenary riser (SCR) model was experimentally tested in the ocean basin by oscillating the top end of the model to simulate the heave and surge vessel motion in order to investigate the vortex-induced vibration (VIV) features. Out-of-plane VIV responses were generally analyzed revealing that although the root mean square (RMS) strain distributed rather broadband, the displacement was quite consistent within a narrowband from 0.2D to 0.3D, and the touch-down point (TDP) area was found not to be the place suffering the maximum out-of-plane VIV response due to near wall effects. What’s more, strong wave propagations were firstly reported and summarized as a distinguished feature for VIV of a SCR under vessel motions, and further results reveal that wave propagation during the ‘lift up’ phase was quite different from that during ‘push down’ in terms of both wave speed and ‘power-in’ region location which is assumed to be caused by the tension variation along the model.

scholarly journals Feasibility Study of Selected Riser Concepts in Deep Water and Harsh Environment

2017 ◽  
Author(s):  
Gilang Muhammad Gemilang ◽  
Daniel Karunakaran
Keyword(s):  
Deep Water ◽  
Time History ◽  
Bending Moment ◽  
Harsh Environment ◽  
Steel Catenary Riser ◽  
Main Challenge ◽  
Large Motion ◽  
Touchdown Point ◽  
Heave Motion ◽  
Vessel Motion

One of the well-known riser systems, the Steel Catenary Riser (SCR), has been an attractive choice for the riser system in deep water. However, the main challenge of the SCR is large motions from the host platforms due to the harsh environment. The large motion of host platforms may induce excessive buckling and fatigue at the touchdown point. By screening the downward velocities at the hang-off point in the time history graph, the time at which the critical responses (i.e. buckling utilization, bending moment and compression) peak is identified. This study investigates the feasibility of the SCR configuration in terms of the capability to cope with the vessel motion. Several types of the SCR configurations are proposed in this study. The selected configurations of SCR in this study are conventional SCR, Weight Distributed SCR (WDSCR), and Steel Lazy Wave Riser (SLWR). The feasibility of the three riser configurations was analyzed in terms of strength and fatigue performance to understand the limitation of one over the other. The “lazy wave” configuration efficiently absorbs the vessel heave motions. Thereby the SLWR configuration is proven to be the most robust configuration to cope with large motion of the host platform. This study proves that although the SCR feasibility is limited due to vessel heave motion, innovative solutions can be established to extend its feasibility in order to cope with the vessel heave motion in harsh environment.

Multi-Pronged Approach for the Design of HP/HT Deepwater Steel Catenary Risers

2019 ◽  
Author(s):  
Gurudutt Bangalore ◽  
Yongming Cheng ◽  
Surya Banumurthy
Keyword(s):  
Problem Solving ◽  
Wall Thickness ◽  
Pipe Wall ◽  
Steel Catenary Riser ◽  
Riser Pipe ◽  
Successful Design ◽  
Steel Catenary Risers ◽  
Grade Material ◽  
Motion Characteristics ◽  
Vessel Motion

Abstract As the industry plans to move forward with the development of high pressure and high temperature (HP/HT) fields, challenges exist for the design of complaint risers in deepwater applications. The conventional wet tree application risers such as Steel Catenary Risers (SCRs) have proven to be mature technologies in the deepwater applications around the world. HP/HT application leads to many challenges in deepwater risers. This paper investigates ways to overcome the design challenges of deepwater SCRs using a multi-pronged approach. The paper first addresses the challenge in riser pipe wall thickness. The HP/HT applications require higher pipe wall thicknesses mainly governed by the burst pressure design requirements. The pipe wall thicknesses required for the HP/HT applications will result in very high installation loads, reeling issues with low D/t, fabrication (welding) challenges, high payloads to the host vessel, etc. Any optimization to the wall thickness design in terms of using higher grade material, advancements in welding technology and advantages to be gained in the use of design codes can potentially help in overcoming of these challenges. The pipe sizes used in the HP/HT applications can pose significant challenges to the touchdown zone (TDZ) of standard steel catenary riser configurations, in terms of experiencing large TDZ compressions and having fatigue life concerns. Use of different SCR problem-solving approaches — TDZ clump weights, Lazy Wave Steel Riser (SLWR) and weight optimized risers will be reviewed in this paper. Vessel motion characteristics can significantly affect the riser performance. Vessels with improved motions, particularly from the riser response viewpoint, can play a significant role in the selection of optimum riser configurations. This has to be achieved in the early stages of the project. Some of the work done recently in development of the optimized vessel performance particularly in the case of semi-submersibles and their implications on the riser design are studied in this paper. Design of the risers in HP/HT fields in deepwater applications presents significant challenges and requires a multi-dimensional problem solving approach. An example is provided in this paper for the investigation. A multi-pronged approach has to be adopted for the successful design of riser system for HP/HT deepwater applications.

scholarly journals Dominant parameters for vortex-induced vibration of a steel catenary riser under vessel motion

2017 ◽  
Vol 136 ◽  
pp. 260-271 ◽  
Author(s):  
Jungao Wang ◽  
Shixiao Fu ◽  
Carl Martin Larsen ◽  
Rolf Baarholm ◽  
Jie Wu ◽  
...  
Keyword(s):  
Vortex Induced Vibration ◽  
Steel Catenary Riser ◽  
Vessel Motion

New Frontiers in the Design of Steel Catenary Risers for Floating Production Systems

2001 ◽  
Vol 123 (4) ◽  
pp. 153-158 ◽  
Author(s):  
Basim B. Mekha
Keyword(s):  
New Technologies ◽  
Production Systems ◽  
Random Wave ◽  
Environmental Loads ◽  
Steel Catenary Riser ◽  
Field Development ◽  
Steel Catenary Risers ◽  
Motion Characteristics ◽  
Vessel Motion ◽  
Water Depths

The steel catenary riser (SCR) concept has recently been used in almost every new deepwater field development around the world. Shell pioneered the implementation of the SCR concept in 1994 on its Auger tension leg platform (TLP) in 872 m (2860 ft) water depth. Since then, SCRs have been vital to deepwater field developments. Their use has given a new dimension to oil exploration and transportation in water depths where other riser concepts could not tolerate the environmental loads or would have become very costly. SCR designs are very sensitive to floating support platform or vessel motion characteristics to which they are typically attached. In addition to pipe stresses, the main design issue for the SCR concept is fatigue related. There are two main sources for fatigue: random wave fatigue and vortex-induced vibration (VIV) fatigue. The former is due to wave action and the associated platform motion characteristics. The VIV fatigue is mainly due to current conditions. Fracture mechanics assessment is also an essential issue that must be addressed in the design of SCRs. This paper presents a brief history in the use and development of SCRs since the first project implementation on Auger TLP in 1994. The paper also summarizes major steps that must be considered in the design of SCRs and how to explain their behavior in different water depths and environmental conditions. Existing design boundaries for SCRs are discussed with emphasis on the capabilities of new technologies that enable engineers to go beyond these boundaries. Projects with unique SCR features and their implementation are compiled and presented.

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