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.

Multidisciplinary Optimization Design for Section Layout of Complex Umbilical Cables Based on Intelligent Algorithm

2015 ◽  
Author(s):  
Zhixun Yang ◽  
Jun Yan ◽  
Guojun Ma ◽  
Qingzhen Lu ◽  
Minggang Tang ◽  
...  
Keyword(s):  
Optimization Design ◽  
Oil And Gas ◽  
Power Transmission ◽  
Optimal Solution ◽  
Point Of View ◽  
Multidisciplinary Optimization ◽  
Intelligent Algorithm ◽  
Control Functions ◽  
Offshore Oil And Gas ◽  
Ocean Environment

Umbilical which links the top floater and the subsea devices provides control functions through electrical cables and hydraulic remote transmission. They are treated as the “lifeline” of the subsea production system for offshore oil and gas exploitation. During operation, umbilical needs to undertake self-weight and periodical load due to the ocean environment. Meanwhile, the heat during power transmission in electric cable is released to the umbilical body, which influences the mechanical properties and optical transmission in the cable. However, there are a number of components and many kinds of sectional arrangement for the umbilical. So the sectional design with multiple components needs to be solved as a multidisciplinary optimization problem. From the mechanical point of view, the umbilical structure should be designed with more compacted and symmetric layout to obtain even probability of resistance to loads and reduce structural stress to improve its fatigue performance. Concerning thermal effect, these units should be arranged to dissipate the heat easily to avoid the influence on the functional and structural components. In this paper, compactedness, symmetry and temperature distribution are quantified through introducing corresponding indices. Then multidisciplinary optimization framework is established. Particle Swarm Optimization (PSO) intelligent algorithm is adopted to carry out the optimization to obtain the optimal solution, which is far superior to the initial design. The optimization design strategy is proved to be effective and efficient by some numerical examples, which provides reference for design of umbilical cables.

scholarly journals Construction design based on particle group optimization algorithm

2021 ◽  
Vol 30 (1) ◽  
pp. 1040-1053
Author(s):  
Ying Xia ◽  
Mohammad Asif Ikbal ◽  
Mohd Asif Shah
Keyword(s):  
Intelligent Agents ◽  
Optimization Design ◽  
Design Method ◽  
Target Function ◽  
Pso Algorithm ◽  
Design Parameters ◽  
Program Optimization ◽  
Cross Sectional ◽  
Multi Objective ◽  
Run Time

Abstract The machines exhibit an intelligence which is artificial intelligence (AI), and it is the design of intelligent agents. A system is represented by an intelligent agent who perceives its environment and the success rate is maximized by taking the action. The AI research is highly specialized and there are two subfields and each communication fails often. The popular AI approaches include the traditional symbolic AI and computational intelligence. In order to optimize the seismic design of the reinforced concrete pier structure, the particle swarm optimization (PSO) algorithm and the reaction spectrum analysis method are combined; they establish a regular bridge of the design variable with cross-sectional characteristics and reinforcement ratios, with the target function. The seismic optimization design framework of the pier is transformed into a multi-objective optimization problem. Calculations show that the method can quickly obtain the optimal design parameters that meet multi-objective requirements. The improved PSO main program and the calling push-over program run time are 4.32 and 1347.56 s, respectively; the push-over program running time is 99.68% of the run time of the total program. Optimization of the seismic performance of the rear bridge pier is significantly improved and is more in line with the design method; the design method proposed in this article is more practical.

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.

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.

Multi-Objective Design Optimization of Drilling Riser Operability Envelope for Ultra-Deep Water

2018 ◽  
Author(s):  
Hezhen Yang ◽  
Chan Ghee Koh ◽  
Ying Min Low ◽  
Peter Francis Bernad Adaikalaraj
Keyword(s):  
Design Optimization ◽  
Deep Water ◽  
Optimization Design ◽  
Oil And Gas ◽  
Minimum Weight ◽  
Optimization Strategy ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Deep Waters ◽  
Riser Design

This paper presents an efficient methodology for multi-objective design optimization of drilling riser in ultra-deep water considering maximum operability window and minimum weight of drilling riser system. As exploration activity moves to ultra-deep waters, the associated drilling cost increases, putting pressure on the operators to expand the drilling operability and reduce costs. Drilling systems are an integral part of oil and gas exploration particularly in deep waters. The drilling riser design requires a time-consuming design loops and scenarios analyzed with different FEM models, such as connected mode, drift-off, hang-off, recoil analysis, emergency disconnection, etc. The main purposes of this work is to improve the safety and cost-effective for drilling riser design by employing multi-objective optimization based on metamodel. The Radial Basis Function (RBF) metamodel is constructed by the design of experiment sampling and is utilized to solve the problem of time-consuming analyses. In the optimization module, multi-objective optimization by a non-dominated sorting genetic algorithm II is performed. Thereby, RBF optimum solutions forming a Pareto set are obtained and compared with accuracy analysis to determine their validity. The optimization results indicate that the proposed optimization strategy is valid and provide an efficient optimization design method for drilling riser in ultra-deep water.

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.

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.

On the Effects of Bending Stiffness for Flexible Riser Model Tests

2014 ◽  
Author(s):  
Alex Ruskin ◽  
Zak Tahana ◽  
Shuhong Chai ◽  
Cheslav Balash ◽  
Henri Morand ◽  
...  
Keyword(s):  
Model Test ◽  
Oil And Gas ◽  
Production Systems ◽  
Water Channel ◽  
Gas Production ◽  
Bending Stiffness ◽  
Model Tests ◽  
Scale Model ◽  
Flexible Riser ◽  
Current Loading

Oil and gas production systems are continually moving into more challenging environments. Therefore having a precise understanding of the flexible pipeline behaviour for various configurations is becoming even more important. This paper presents a medium scale test of a flexible riser in a wave configuration aiming at representing the bending stiffness characteristic of a flexible riser. Results are then compared tothose of a dynamic analysis software to validate the experimental modeling. This paper addresses the problem of scaling a flexible steep wave riser for model tests, where the global bending response is considered under quasi-static current loading. A methodology for cost-effective and robust model construction is presented, including an effective method of determining the bending stiffness of the model. A 1/15 scale model of a 8″ flexible riser was constructed from silicon hose and foam for testing within the Australian Maritime College’s Circulating Water Channel (CWC). Variances in the model’s buoyant section length, system offset and bending stiffness were tested at different flow velocities to observe the changes in curvature experienced by the riser. The model test regime was formulated specifically to compare the results of CWC testing with numerical modelling results. Comparison between model test and numerical results demonstrate good agreement.

scholarly journals Research on Blank Optimization Design Based on Low-Carbon and Low-Cost Blank Process Route Optimization Model

2021 ◽  
Vol 13 (4) ◽  
pp. 1929
Author(s):  
Yongmao Xiao ◽  
Wei Yan ◽  
Ruping Wang ◽  
Zhigang Jiang ◽  
Ying Liu
Keyword(s):  
Optimization Model ◽  
Optimization Design ◽  
Design Method ◽  
Low Cost ◽  
Route Optimization ◽  
Low Carbon ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Blank Design ◽  
Process Route

The optimization of blank design is the key to the implementation of a green innovation strategy. The process of blank design determines more than 80% of resource consumption and environmental emissions during the blank processing. Unfortunately, the traditional blank design method based on function and quality is not suitable for today’s sustainable development concept. In order to solve this problem, a research method of blank design optimization based on a low-carbon and low-cost process route optimization is proposed. Aiming at the processing characteristics of complex box type blank parts, the concept of the workstep element is proposed to represent the characteristics of machining parts, a low-carbon and low-cost multi-objective optimization model is established, and relevant constraints are set up. In addition, an intelligent generation algorithm of a working step chain is proposed, and combined with a particle swarm optimization algorithm to solve the optimization model. Finally, the feasibility and practicability of the method are verified by taking the processing of the blank of an emulsion box as an example. The data comparison shows that the comprehensive performance of the low-carbon and low-cost multi-objective optimization is the best, which meets the requirements of low-carbon processing, low-cost, and sustainable production.

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