IMPROVED EMPIRICAL FORMULATION FOR SEABED TRENCH PROFILE AT TOUCHDOWN ZONE AND ITS EFFECTS ON FATIGUE OF STEEL CATENARY RISERS

2021 ◽  
Author(s):  
Suran Zhuang ◽  
Chen Shi ◽  
Min Lou ◽  
Yang Liu ◽  
Xingxian Bao ◽  
...  
Keyword(s):  
Steel Catenary Risers

Dynamic Optimization of Steel Catenary Risers Based on Reliability Using Metamodel

2010 ◽  
Author(s):  
Wenqing Zheng ◽  
Hezhen Yang
Keyword(s):  
Dynamic Optimization ◽  
Computational Cost ◽  
Minimum Cost ◽  
Probabilistic Constraints ◽  
Optimization Approach ◽  
Element Analysis ◽  
Steel Catenary Riser ◽  
Reliability Based Design ◽  
Minimum Cost Design ◽  
Steel Catenary Risers

Reliability based design optimization (RBDO) of a steel catenary riser (SCR) using metamodel is investigated. The purpose of the optimization is to find the minimum-cost design subjecting to probabilistic constraints. To reduce the computational cost of the traditional double-loop RBDO, a single-loop RBDO approach is employed. The performance function is approximated by using metamodel to avoid time consuming finite element analysis during the dynamic optimization. The metamodel is constructed though design of experiments (DOE) sampling. In addition, the reliability assessment is carried out by Monte Carlo simulations. The result shows that the RBDO of SCR is a more rational optimization approach compared with traditional deterministic optimization, and using metamodel technique during the dynamic optimization process can significantly decrease the computational expense without sacrificing accuracy.

Novel installation methods and devices of steel catenary risers (SCR) in the South China Sea

2013 ◽  
Vol 31 (2) ◽  
pp. 93-104 ◽  
Author(s):  
Mao Ye ◽  
Menglan Duan ◽  
Zhigang Li ◽  
Ruiyan Chen ◽  
Yi Wang ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
The South China Sea ◽  
The South ◽  
China Sea ◽  
Steel Catenary Risers

Pragmatic Solutions to Touch-Down Zone Fatigue Challenges in Steel Catenary Risers

2004 ◽  
Author(s):  
Shankar Bhat ◽  
Amit Dutta ◽  
Jack Wu ◽  
Indranil Sarkar
Keyword(s):  
Steel Catenary Risers

Automatic Ultrasonic Inspection of Steel Catenary Risers with a Corrosion-Resistant Alloy Layer

2006 ◽  
Author(s):  
J. van der Ent ◽  
J. van Nisselroij ◽  
F. Kopp ◽  
A. Otter ◽  
N. Weli ◽  
...  
Keyword(s):  
Ultrasonic Inspection ◽  
Alloy Layer ◽  
Corrosion Resistant ◽  
Resistant Alloy ◽  
Steel Catenary Risers ◽  
Corrosion Resistant Alloy

Investigation of Impact of New Design Code on Riser System Design

2009 ◽  
Author(s):  
Alan Yu ◽  
Paul Stanton ◽  
Yongming Cheng
Keyword(s):  
System Design ◽  
Production Systems ◽  
Design Code ◽  
Finite Element Program ◽  
Stress Evaluation ◽  
Element Program ◽  
Steel Catenary Risers ◽  
Ease Of Access ◽  
The Impact ◽  
Gas Lift

Top tensioned risers are fluid conduits from subsea equipment to surface floating production platforms. The advantages of using top tensioned risers are the ability to drill and complete through the production riser, ease of access of the production trees for gas lift operation, and the simplicity of workover and redrill. The integrity of a riser system plays an important role in deepwater developments. Top tensioned risers (TTRs) and steel catenary risers (SCRs) have been widely used with floating production systems such as Spars and TLPs. API RP 2RD [1] has been used to guide riser system design for the last decade. API RP 2RD is being revised as a code (ISO 13628-12) that will also be adopted as a new API code. This paper investigates the impacts of the new design code on the riser system design. This paper first discusses the differences between ISO/WD 13628-12 and the existing API RP 2RD code, particularly the section on design criteria for pipes. The Holstein top tensioned riser system is chosen as an example to evaluate the riser system design impacts. The risers have been installed and successfully producing oil since 2005. The results of the nonlinear finite element program ABAQUS used to analyze the Holstein top tensioned risers were evaluated according to the API RP 2RD. The same analytical results are used for evaluating the impact of the proposed ISO 13628-12 in the area of stress evaluation.

Sensitivity Study of Critical Parameters Influencing the Uncertainty of Fatigue Damage in Steel Catenary Risers

2010 ◽  
Author(s):  
Feng Zi Li ◽  
Ying Min Low
Keyword(s):  
Fatigue Damage ◽  
Cost Effective ◽  
Sensitivity Study ◽  
Structural Safety ◽  
Critical Parameters ◽  
Design Parameters ◽  
Steel Catenary Riser ◽  
Bending Stresses ◽  
Steel Catenary Risers ◽  
Touchdown Point

The most challenging aspect of a deepwater development is the riser system, and a cost-effective choice is the Steel Catenary Riser (SCR). Fatigue is often a governing design consideration, and it is usually most critical at the touchdown point (TDP) where static and dynamic bending stresses are highest. Unfortunately, it is also at this region that uncertainty is the maximum. The increased uncertainty casts doubt on the applicability of generic safety factors recommended by design codes, and the most consistent way of ensuring the structural safety of the SCR is to employ a reliability-based approach, which has so far not received attention in SCR design. As the number of basic random variables affects the complexity of a reliability analysis, these variables should be selected with caution. To this end, the aim of this paper is to draw up a comprehensive list of design parameters that may contribute meaningfully to the uncertainty of the fatigue damage. From this list, several parameters are selected for sensitivity studies using the commercial package Orcaflex. It is found that variations in seabed parameters such as soil stiffness, soil suction and seabed trench can have a pronounced influence on the uncertainty of the fatigue damage at the touchdown point.

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