Steel lazy-wave riser(SLWR)is one of the key technical components of offshore oil-gas production systems and is widely utilized in deepwater areas.On the basis of the vector form intrinsic finite element(VFIFE)method,...Steel lazy-wave riser(SLWR)is one of the key technical components of offshore oil-gas production systems and is widely utilized in deepwater areas.On the basis of the vector form intrinsic finite element(VFIFE)method,this study develops a reasonable numerical model for the SLWR to investigate the effects of the buoyancy section on its mechanical characteristics.In the SLWR model,the buoyancy section is simulated using an equivalent riser segment with the same outer diameter and unit weight.The riser is considered to be composed of a series of space vector particles connected by elements,and virtual reverse motions are applied to establish the fundamental equations of forces and displacements.The explicit central difference technique is used to solve the governing equations for particle motion within the riser through programming implementation.To provide a detailed explanation of the process by which the SLWR achieves a stable lazy-wave configuration,a numerical model of a 2800-m-long riser is established at a water depth of 1600 m,and the feasibility of this model for riser behavior analysis is validated.The remarkable influences of the position,length,number and spacing of the buoyancy section on the mechanical behavior of the SLWR are observed,which provides a theoretical foundation for the optimal design of the SLWR in deepwaters.展开更多
Evaluation of abandonment and recovery operation of steel lazy-wave riser in deepwater is presented in this paper.The calculation procedure includes two single continuous SLWR and cable segments, which are coupled tog...Evaluation of abandonment and recovery operation of steel lazy-wave riser in deepwater is presented in this paper.The calculation procedure includes two single continuous SLWR and cable segments, which are coupled together to form the overall mathematical model. Then the equilibrium equations of SLWR and cable are established based on minimum total potential energy principle. The coupled equations are discretized by the finite difference method and solved by Newton-Raphson technique in an iterative manner. The present method is validated by well-established commercial code OrcaFlex. Recovery methods by considering different ratios of vessel’s moving velocity to cable’s recovery velocity are evaluated to optimize the abandonment and recovery operation. In order to keep the tension more stable during the recovery process, the rate ratio before leaving the seabed is increased, and the rate ratio after leaving the seabed is reduced.展开更多
为了对海上粘接式输油软管设计进行适用性研究,从而掌握悬链锚腿式系泊(Catenary Anchor Leg Mooring,CALM)单点Lazy-wave(懒波型)和Steep-wave(陡波型)构型的水下软管系统适用的水深和环境条件,在海洋工程水池中分别对2种构型的软管进...为了对海上粘接式输油软管设计进行适用性研究,从而掌握悬链锚腿式系泊(Catenary Anchor Leg Mooring,CALM)单点Lazy-wave(懒波型)和Steep-wave(陡波型)构型的水下软管系统适用的水深和环境条件,在海洋工程水池中分别对2种构型的软管进行运动响应试验。模拟静水与规则波环境条件,并对软管顶端进行强迫振荡,观察Lazy-wave和Steep-wave两种构型的水下软管系统的运动响应。试验结果表明:对于静水海况和规则波海况,2种构型的软管在顶端运动为周期运动时,各方向上的动态应变呈周期性变化且皆有高频成分;在规则波海况下二阶模态的振动幅值与静水相比均有所增加;Steep-wave构型比Lazy-wave构型更容易激发高阶模态。展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.52471275,U23A20663,51809048,51909236)the Natural Science Foundation of Fujian Province(Grant No.2022J01092)+1 种基金the Natural Science Foundation of Zhejiang Province(Grant No.LY23E090004)the Ningbo Natural Science Foundation(Grant No.2021J039).
文摘Steel lazy-wave riser(SLWR)is one of the key technical components of offshore oil-gas production systems and is widely utilized in deepwater areas.On the basis of the vector form intrinsic finite element(VFIFE)method,this study develops a reasonable numerical model for the SLWR to investigate the effects of the buoyancy section on its mechanical characteristics.In the SLWR model,the buoyancy section is simulated using an equivalent riser segment with the same outer diameter and unit weight.The riser is considered to be composed of a series of space vector particles connected by elements,and virtual reverse motions are applied to establish the fundamental equations of forces and displacements.The explicit central difference technique is used to solve the governing equations for particle motion within the riser through programming implementation.To provide a detailed explanation of the process by which the SLWR achieves a stable lazy-wave configuration,a numerical model of a 2800-m-long riser is established at a water depth of 1600 m,and the feasibility of this model for riser behavior analysis is validated.The remarkable influences of the position,length,number and spacing of the buoyancy section on the mechanical behavior of the SLWR are observed,which provides a theoretical foundation for the optimal design of the SLWR in deepwaters.
基金financially supported by the National Natural Science Foundation of China (Grant No.52271299)the Science Foundation of China University of Petroleum,Beijing (Grant No.2462020YXZZ046)。
文摘Evaluation of abandonment and recovery operation of steel lazy-wave riser in deepwater is presented in this paper.The calculation procedure includes two single continuous SLWR and cable segments, which are coupled together to form the overall mathematical model. Then the equilibrium equations of SLWR and cable are established based on minimum total potential energy principle. The coupled equations are discretized by the finite difference method and solved by Newton-Raphson technique in an iterative manner. The present method is validated by well-established commercial code OrcaFlex. Recovery methods by considering different ratios of vessel’s moving velocity to cable’s recovery velocity are evaluated to optimize the abandonment and recovery operation. In order to keep the tension more stable during the recovery process, the rate ratio before leaving the seabed is increased, and the rate ratio after leaving the seabed is reduced.
文摘为了对海上粘接式输油软管设计进行适用性研究,从而掌握悬链锚腿式系泊(Catenary Anchor Leg Mooring,CALM)单点Lazy-wave(懒波型)和Steep-wave(陡波型)构型的水下软管系统适用的水深和环境条件,在海洋工程水池中分别对2种构型的软管进行运动响应试验。模拟静水与规则波环境条件,并对软管顶端进行强迫振荡,观察Lazy-wave和Steep-wave两种构型的水下软管系统的运动响应。试验结果表明:对于静水海况和规则波海况,2种构型的软管在顶端运动为周期运动时,各方向上的动态应变呈周期性变化且皆有高频成分;在规则波海况下二阶模态的振动幅值与静水相比均有所增加;Steep-wave构型比Lazy-wave构型更容易激发高阶模态。
