The influence of sea state on dynamic behaviour of offshore pipelines for deepwater S-lay

Gong, Sha; Xu, Peng

doi:10.1016/j.oceaneng.2015.11.013

Cited by 40 publications

(9 citation statements)

References 30 publications

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“…A full finite element model for deepwater S-lay systems has been developed by Gong et al (2014), and Gong and Xu (2016) using the software OrcaFlex to simulate the three-dimensional dynamic responses of offshore pipeline from the pipelay vessel via the stinger to the seabed in time domain. On the basis of this work, the purpose of this study is to thoroughly explore the influences of pipe-soil interaction on the dynamic behaviour of offshore pipelines in the TDZ during deepwater installation by S-lay method using a time domain analysis.…”

Section: Introductionmentioning

confidence: 99%

Influences of pipe–soil interaction on dynamic behaviour of deepwater S-lay pipeline under random sea states

Gong

2016

Ships and Offshore Structures

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The pipe-soil interactions have an important influence on the dynamic behaviour of offshore pipelines in the touchdown zone (TDZ) during deepwater S-lay. This paper mainly aims to reveal the dynamic behaviour of the pipeline in the TDZ, and its actual dynamic lay effects. A full finite element model for deepwater S-lay systems is primarily developed to simulate the dynamic responses of offshore pipeline from the pipelay vessel via the stinger to the seabed, in which pipelay vessel motions, pipeline hydrodynamics, clashing contacts between the pipeline and the stinger rollers and pipe-seabed interactions are considered particularly. The numerical analysis of an illustrative case for a gas export pipeline being installed to a water depth of 1500 m in the South China Sea is carried out in the time domain using the commercial computer code OrcaFlex. The influences of seabed soil models, soil characteristics, submerged self-weight of the pipe, surface waves, and pipelay vessel motions on the dynamic behaviour of the pipeline in the TDZ have been quantitatively studied in view of non-linear hysteretic soil model. The results indicate that the soil characteristics and the pipelay vessel motions induced by the surface wave have great influence on the bending moment and embedment of the pipeline, and the seabed resistance.

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Section: Introductionmentioning

confidence: 99%

Influences of pipe–soil interaction on dynamic behaviour of deepwater S-lay pipeline under random sea states

Gong

2016

Ships and Offshore Structures

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“…In this paper, it is assumed that the rollers are cylindrical, and that the support acts in directions that are mutually perpendicular towards the pipelines' longitudinal axes and all supporting rollers. The contact forces of the roller acting on the pipeline can be calculated by linear stiffness k s [33]:…”

Section: Roller: Simplifying Assumptionsmentioning

confidence: 99%

Numerical Simulations of Dynamic Pipeline-Vessel Response on a Deepwater S-Laying Vessel

et al. 2018

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The dynamic action induced on offshore pipelines by deepwater S-laying is significant, and directly determines how the pipeline structures are designed and installed. Existing research has not fully investigated the benefits of coupling models of pipeline and pipelaying vessel motions. Therefore, this paper presents a coupled time-domain numerical model for examining the effect of coupled dynamic reactions. The coupled model takes into account the motion of the pipelaying vessel, surface waves, ocean currents, wind forces, pipeline dynamics, and contact between the rollers and the pipeline. A proportional, integral, derivative (PID) controller was used for simulating the control of the pipelaying vessel. The hydrodynamic forces that the pipeline experiences were modeled using the Morison equation. The model was solved using Newmark's method and verified using OrcaFlex software. The model was then used to analyze practical operations: the laying of a 22" gas export pipeline on the seabed by the pipelaying vessel HYSY201 in the Pingbei-Huangyan gas fields in the East China Sea. The effects of coupled factors on pipelaying vessel motions and pipeline dynamics were approximated. These effects included configurations, axial tensions, and bending moments. The results show a significant connection between the dynamic responses of the pipelines and pipelaying vessel motions.S-laying method, the pipeline is supported using a stinger and passes over a regular roller sequence forming an S-shaped trajectory before landing on the seabed, as illustrated in Figure 1. The upper curved S-shaped parts that rest on stingers are called overbends and are followed by inflection points where the pipeline curvature is zero. Before approaching the seafloor, the pipeline is reversed into a sagbend. Horizontal tension in the pipeline is maintained by mounted tensioner devices on the top of the pipeline. Consequently, S-laying operations depend on roller configuration and stinger radius. Large plastic deformation occurs when pipes pass over stingers. The plastic deformation is caused by the combined effects of the pipelaying vessel motion, roller reaction forces, axial tensions, and bending moments [5,6].Processes 2018, 6, x FOR PEER REVIEW 2 of 22 the S-laying method, the pipeline is supported using a stinger and passes over a regular roller sequence forming an S-shaped trajectory before landing on the seabed, as illustrated in Figure 1. The upper curved S-shaped parts that rest on stingers are called overbends and are followed by inflection points where the pipeline curvature is zero. Before approaching the seafloor, the pipeline is reversed into a sagbend. Horizontal tension in the pipeline is maintained by mounted tensioner devices on the top of the pipeline. Consequently, S-laying operations depend on roller configuration and stinger radius. Large plastic deformation occurs when pipes pass over stingers. The plastic deformation is caused by the combined effects of the pipelaying vessel motion, roller reaction forces, axial tensions, an...

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“…As a consequence, numerical techniques are preferred for modeling systematical behaviors of offshore pipelines in the S-lay process [13][14][15]. Gong et al [16] and Gong and Xu [17] developed a full FEM on the basis of OrcaFlex to simulate the structural behaviors of pipeline installation and explored the influence of normal sea states on the pipeline responses. Ivić et al [18,19] established a pipeline laying model by the use of non-linear elastic beam elements to analyze the static behaviors of the S-laying pipe and formulated a specialized A reasonable wave generation method is necessary to simulate freak waves and explore their impact on marine structures.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation into Freak Wave Effects on Deepwater Pipeline Installation

Gong

2020

JMSE

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Freak waves are an extreme marine environment factor in offshore structure design and become a potential risk, particularly for laying oil-gas pipelines in deep waters. The objective of this study was to reveal the freak wave effects on dynamic behaviors of offshore pipelines for deepwater installation. Thus, a dedicated finite element model (FEM) for deepwater pipeline installation by the S-lay method was developed with special consideration of freak waves. The FEM also took pipelay vessel motions, pipe–stinger roller interactions, and the cyclic contacts between the pipeline and seabed soil into account. Real vessel and stinger data from an actual engineering project in the South China Sea were collected to obtain an accurate simulation. Moreover, an effective superposition approach of combined transient wave trains and random wave trains was introduced, and various types of freak wave trains were simulated. Extensive numerical analyses of a 12 inch gas pipeline being installed into a water depth of 1500 m were implemented under various freak wave conditions. The noticeable influences of freak waves on the pipeline and seabed responses were identified, which provides significant awareness of offshore pipelines for deepwater installation design and field operation monitoring.

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The influence of sea state on dynamic behaviour of offshore pipelines for deepwater S-lay

Cited by 40 publications

References 30 publications

Influences of pipe–soil interaction on dynamic behaviour of deepwater S-lay pipeline under random sea states

Influences of pipe–soil interaction on dynamic behaviour of deepwater S-lay pipeline under random sea states

Numerical Simulations of Dynamic Pipeline-Vessel Response on a Deepwater S-Laying Vessel

Numerical Investigation into Freak Wave Effects on Deepwater Pipeline Installation

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