scholarly journals Mechanical Analysis of Flexible Riser with Carbon Fiber Composite Tension Armor

2020 ◽  
Vol 5 (1) ◽  
pp. 3
Author(s):  
Haichen Zhang ◽  
Lili Tong ◽  
Michael Anim Addo
Keyword(s):  
Oil And Gas ◽  
Fiber Composite ◽  
Mechanical Analysis ◽  
Flexible Riser ◽  
Carbon Fiber Composite ◽  
Design Strength ◽  
Oil And Gas Exploration ◽  
Axial Tensile ◽  
Flexible Risers ◽  
Damage Theory

As oil and gas exploration moves to deeper areas of the ocean, the weight of flexible risers becomes an important factor in design. To reduce the weight of flexible risers and ease the load on the offshore platform, this paper present a cylindrical tensile armor layer made of composite materials that can replace the helical tensile armor layer made of carbon steel. The ACP (pre) of the workbench is used to model the composite tension armor. Firstly, the composite lamination of the tensile armor is discussed. Then, considering the progressive damage theory of composite material, the whole flexible riser is analyzed mechanically and compared with the original flexible riser. The weight of the flexible riser decreases by 9.73 kg/m, and the axial tensile stiffness decreases by 17.1%, while the axial tensile strength increases by 130%. At the same time, the flexible riser can meet the design strength requirements of torsion and bending.

Axisymmetric Mechanical Behavior of Flexible Risers

2015 ◽  
Author(s):  
Liu Junpeng ◽  
Murilo A. Vaz ◽  
Menglan Duan ◽  
Xiaotian Li
Keyword(s):  
Correspondence Principle ◽  
Mechanical Analysis ◽  
Axial Stiffness ◽  
Prony Series ◽  
Structural Damping ◽  
Flexible Riser ◽  
Damping Behavior ◽  
Polymer Properties ◽  
Flexible Risers

Polymer properties, i.e. viscoelastic characteristics, may pose a non-negligible impact on the axisymmetric analysis, especially on the axial structural damping behavior. An available mechanical model taking viscoelastic into account is established for capturing such parameters as axial strains and forces on each layer, axial stiffness and so on. In this paper, the flexible riser is divided into helical and cylindrical elements to carry out the mechanical analysis due to the complexity of structure and material property. Prony Series is used to describe the creep and relaxation behavior of material viscoelasticity. A viscoelastic solution is obtained using the correspondence principle. Finally, a case study is performed and some interesting results are presented.

Dynamic Flexible Riser Ancillary Equipment—North Sea Asset Integrity Management Experience and Lessons Learned

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Damir Tadjiev
Keyword(s):  
Case Studies ◽  
North Sea ◽  
Oil And Gas ◽  
Lessons Learned ◽  
Operational Experience ◽  
Flexible Riser ◽  
Remotely Operated Vehicle ◽  
Integrity Management ◽  
Flexible Risers ◽  
Ancillary Equipment

Abstract Dynamic flexible risers are complex engineered systems, which provide a connection between topside (normally floating) facilities and subsea pipeline infrastructure on offshore oilfields. Such systems require the use of ancillary equipment to ensure the riser’s correct configuration is maintained throughout the service life. Industry experience shows that the integrity management of riser ancillary equipment is not always comprehensive, and failure of such equipment is one of the causes of premature removal of flexible risers from service. This article presents some case studies from the operational experience of dynamic flexible risers by an operator in the UK North Sea covering a period of approximately 20 years. The case studies look at the anomalies identified in service by general visual inspection (GVI) using a remotely operated vehicle (ROV) and the lessons learned. Some of the anomalies, had they not been identified and addressed promptly, could have resulted in costly repairs, which demonstrates the importance of inspecting the ancillary equipment of flexible risers as a part of the riser integrity management strategy. The challenges associated with integrity management of ancillary equipment of dynamic flexible risers are also discussed. The case studies presented in this article demonstrate that ROV GVI is an effective method for identifying installation and in-service anomalies related to flexible riser ancillary equipment. The purpose of this article is to share lessons learned with the wider offshore oil and gas community. It is also believed that the information presented in this article may provide useful information to other users of dynamic flexible riser systems when developing and/or implementing their subsea pipelines integrity management programs.

Multi-Objective Collaborative Flexibility Optimization Design of the Strengthening Layer of a Flexible Riser

2021 ◽  
pp. 1-32
Author(s):  
Zhixun Yang ◽  
Lifu Wang ◽  
Jun Yan ◽  
Dong Yan Shi ◽  
Zhirui Fan ◽  
...  
Keyword(s):  
Cylindrical Shell ◽  
Optimization Design ◽  
Oil And Gas ◽  
Bending Stiffness ◽  
Flexible Riser ◽  
Cross Sectional ◽  
Multi Objective ◽  
Flexible Risers ◽  
Ocean Environment ◽  
Torsion Stiffness

Abstract Marine flexible risers are widely used in ocean oil and gas extraction, and need to withstand environment loads (wave and current) and the large offset of the floater. Therefore, the flexible riser is subjected to tension, bending and torsion loads, which are mainly resisted by the key strengthening layer. Small bending stiffness of a cross section of the strengthening layer with larger tension and torsion stiffness are required to be compliant with the ocean environment. The traditional design of the key strengthening layer is partially rigid with larger cross-sectional stiffnesses. Therefore, the innovative configurations of the strengthening layer are imperative to make sure that the flexible riser is reliable and safe during the installation and operation. The strengthening layer of the flexible riser is treated as the cylindrical shell composed of periodic unit-cell beam structures, which is a hypothetical model. The optimization design is conducted through the novel implementation of the asymptotic homogenization (NIAH) method. The multi-objective collaborative flexibility optimization formulation of cylindrical shell structure is proposed, considering the ratio of cross-sectional tensile torsion stiffness to bending stiffness of the strengthening layer as the objectives. The optimal configuration results, the helically wound structures, are obtained, which are the alternative strengthening components of flexible risers. Finally, the optimal structures are compared with the commonly used marine flexible riser, which gives a great verification of the methodology feasibility, and explains why the strengthening layer is designed as the type of helically wound structure.

The Installation of Flexible Risers and Flowlines Systems With PLET on the Subsea End

2017 ◽  
Author(s):  
Kee Chien Ting ◽  
Kishor Chavan ◽  
Samuel Balmford ◽  
Daniel Sullivan
Keyword(s):  
Gulf Of Mexico ◽  
Deep Water ◽  
Oil And Gas ◽  
Intermediate Structure ◽  
Flexible Riser ◽  
Flexible Risers ◽  
Offshore Oil And Gas ◽  
Offshore Oil ◽  
Flexible Products

Flexible riser and flowline systems used in offshore oil and gas developments in shallow and deep water are typically terminated with vertical connectors with goosenecks or with horizontal connectors. An alternative arrangement is to terminate with PLET although it is not as commonly adopted. PLETs usually have a sizeable dimension and weight compared to the vertical and horizontal connectors hence present handling and deployment issues. A number of flexible risers and flowlines terminated with PLETs recently installed in a deepwater development in Gulf of Mexico showed that with careful engineering such deployment is viable and can be performed safely by a typical flexlay vessel. The installation engineering, installation aid requirements, the deployment methodology are presented and discussed. The observations from ensuing offshore operation showed that the flexible torsion and twist during deployment need to be carefully monitored and managed offshore. Flexibles terminated with PLETs could be potentially suitable where life of field gooseneck load may be excessive or for bigger and stiffer flexible products where making the 2nd end connections might be a challenging undertaking offshore. A PLET could also be used where an intermediate structure is required along a MEG line for example where In-Line Terminations (ILTs) are needed for flying leads plug-in. This would save on requirement for an intermediate structure and connectors.

Study on Damping Properties of Fiber Reinforced Compositefor Stayed Cable

2010 ◽  
Vol 163-167 ◽  
pp. 288-292
Author(s):  
Yan Liang Du ◽  
Jian Zhi Li ◽  
Bao Chen Sun
Keyword(s):  
Loss Factor ◽  
Vinyl Ester ◽  
Fiber Composite ◽  
Mechanical Analysis ◽  
Reinforced Composites ◽  
Damping Properties ◽  
Fiber Reinforced ◽  
Carbon Fiber Composite ◽  
Temperature Spectrum ◽  
Different Temperatures

Fiber reinforced vinyl ester composites and fiber reinforced epoxy composites were prepared by the pultrusion method. Due to the extensive application of fiber reinforced composites, the temperature spectrum and frequency spectrum of loss factor for the composite were tested using dynamic mechanical analysis (DMA) equipment. The damping properties and damping mechanism of the composite were investigated and discussed at different temperatures and frequencies. The result indicates that the loss factor of the composites is increasing with the increase of the frequency from 0.1Hz to 2 Hz and decreasing with the decrease of the temperature from -20°C to 60°C. The loss factor of the carbon fiber composite is higher than that of the glass fiber for the same matrix. The loss factor of the vinyl ester composite is higher than that of the epoxy composite for the same fiber.

An Analytical Approach for Predicting the Collapse Pressure of the Flexible Risers With Initial Ovalization and Gap

2019 ◽  
Author(s):  
Xiao Li ◽  
Xiaoli Jiang ◽  
Hans Hopman
Keyword(s):  
Analytical Approach ◽  
Oil And Gas ◽  
Gas Production ◽  
Analytical Models ◽  
Flexible Riser ◽  
Flexible Pipe ◽  
Collapse Pressure ◽  
Initial Imperfections ◽  
Collapse Strength ◽  
Flexible Risers

Abstract A flexible riser is a flexible pipe that transports materials between seafloor and topside structures. As oil and gas production heads to water depths greater than 3000 meters, huge hydrostatic pressure may cause the collapse failure of flexible risers. Generally, the collapse strength of a flexible riser is designed by considering the effects of initial imperfections, e.g., ovality of the carcass, and radial gap between the carcass/liner and pressure armor. These two imperfections may cause a significant reduction in the collapse strength of flexible risers under the flooded annulus condition. However, there are few analytical models available in the public literature that could take those factors into account. In this paper, an analytical approach is presented to predict the critical collapse pressure of the flexible risers with initial imperfections. The analytical results were compared with the numerical simulation, which showed reasonably good agreement.

Composite Repair and Reinforcement Technology for Oil and Gas Pipeline and its Development Trend

2012 ◽  
Vol 562-564 ◽  
pp. 397-400
Author(s):  
Jin You Wang ◽  
Xiu Yun Wang ◽  
Min Xu Lu
Keyword(s):  
Carbon Fiber ◽  
Oil And Gas ◽  
Fiber Composite ◽  
Basalt Fiber ◽  
Development Trend ◽  
Composite Fiber ◽  
Carbon Fiber Composite ◽  
Composite Repair ◽  
Fast Development ◽  
Transmission Pipeline

Pipeline repair and reinforcement technology can generally be categorized into three main types: Welding, Clamp, Fiber Composite. Fiber Composite Repair recently undergoes fast development because it does not require heat or welding and can be directly applied to high pressure transmission pipeline. This article summarizes Fiber Composite Repair technology and its mechanism, also compares the application characteristics of Glass Fiber, Carbon Fiber and Basalt Fiber composites and finally concludes broad application prospects of Carbon Fiber Composite in pipeline repair and reinforcement.

scholarly journals Numerical simulation of creep behaviour of flexible riser inner liner

2020 ◽  
Vol 37 (3) ◽  
pp. 79-86
Author(s):  
Jiayu Zhang ◽  
Junpeng Liu ◽  
Kexuan Duan ◽  
Wenbo Li ◽  
Menglan Duan
Keyword(s):  
Structural Integrity ◽  
Creep Behaviour ◽  
Tensile Force ◽  
Complex Structure ◽  
Mechanical Analysis ◽  
External Pressure ◽  
The Finite Element Method ◽  
Axial Tensile ◽  
External Pressures ◽  
Flexible Risers

The creep behaviour of an inner liner, one of the reasons for carcass tearing, may affect the structural integrity of flexible risers. This has been previously discussed without conclusive results owing to complex structure and time-dependent material properties. The present paper proposes a numerical model for predicting creep responses by means of the finite element method. In this model, series coefficient is used to characterise the viscoelastic properties of material. Consequently, the influence of geometric parameters such as span of the carcass layer and thickness of the inner layer on the deformation is observed. Moreover, a threedimensional model assembling the carcass and inner liner was established for mechanical analysis, during which the viscoelasticity of inner liner and the internal friction of the carcass are considered, after which the stress and strain distribution on each layer under the combined external pressure and axial tensile force generated by the inner liner are obtained. Additionally, the effect of external pressures on the stress distribution of the carcass cross-section was found through sensitivity analysis.

Analysis of Micro Structure and Elastic Property on 3-D Tubular Woven Carbon Fiber Composite

2014 ◽  
Vol 887-888 ◽  
pp. 11-16
Author(s):  
Zhi Hong Sun ◽  
Yang Chen ◽  
Shen Hua Zhou
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Carbon Fiber ◽  
Elastic Constants ◽  
Fiber Composite ◽  
Tensile Load ◽  
Micro Structure ◽  
Carbon Fiber Composite ◽  
Axial Tensile ◽  
Element Method

For the further research of 3D tubular woven carbon fiber composite, a unit cell division method and a mechanical model were put forward to predict the engineering elastic constants. The model adopted raceway shape as the yarns cross-section, and prediction methods of volume fractions and elastic modulus were established based on the micro structure and geometric parameters of the yarn. Then the finite element method was used to analysis the mechanical behavior under the circumstances of axial-tensile load, and the stress state was revealed. The results shows that the predicted values using finite element method agree well with the theoretical calculation values, thus the model and analysis method of elastic constants is verified.

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