• Ocean Systems Engineering
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• 제9권2호
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• pp.135-155
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• 2019

One of the safest and the most economical methods to transfer oil and gas is pipeline system. Prediction and prevention of pipeline failures during its assessed lifecycle has considerable importance. The dropped object is one of the accidental scenarios in the failure of the submarine pipelines. In this paper, using Monte Carlo Sampling, the probability of damage to a submarine pipeline due to a box-shaped dropped object has been calculated in terms of dropped object impact frequency and energy transfer according to the DNV-RP-F107. Finally, Reliability sensitivity analysis considering random variables is carried out to determine the effect intensity of each parameter on damage probability. It is concluded that impact area and drag coefficient have the highest sensitivity and mass and add mass coefficient have the lowest sensitivity on probability of failure.

• 한국해양공학회지
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• 제11권2호
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• pp.1-10
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• 1997

The interaction of ground ice features with underlying seabed is one of the major considerations in the design of Arctic pipeline systems. Regarding the development of offshore gas field near Sakhalin Island, which is an ice-infested area, in this paper an ice scour model to determine the burial depth of Arctic offshore pipeline is studied. Using a simplified ice-seabed interaction process, ice scour depth is easily estimated. This nonlinear numerical model can simulate the scouring process for various enviromental parameters such as ice mass, incoming velocity, soil strength. This study also deals with interaction forces during the scouring process in sloping seabed conditions and discusses the ice loads that are transmitted through the seabed soil.

• 플랜트 저널
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• 제5권4호
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• pp.80-85
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• 2009

LNG stevedoring plant offshore pipelines requires human power and the longest construction period in constructing LNG storing terminal and influences on the success of the project absolutely. In this paper, the constructing procedures of LNG stevedoring plant offshore pipeline was established. Establishment of constructing procedures of LNG stevedoring plant offshore pipeline includes procurement of main equipments, iron frame and pipelines. To predict any expectable problems, that may occur by the stage of construction the application to the field works with a base of theoretical and practical contents for the constructing procedures of LNG stevedoring plant offshore pipelines can be established.

• 한국해안해양공학회지
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• 제11권1호
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• pp.1-6
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• 1999

해안 및 해양에 설치되어 있는 해저관로는 원유, 가스, 물과 이들의 혼합된 유체들을 전달하기 위한 수단으로 사용되고 있다. 관로 내부 유체의 열과 압력 차이는 해저관로의 팽찰을 야기시킨다. 해전관로 팽창은 관로와 연결되는 구조물들에 응력을 유발시킨다. 작용 응력이 연결 부재의 항복점을 초과하거나 전체 시스템의 허용변형을 초과할 경우 구조물에 손상이 발생된다. 해안 및 해양에 설치되는 해저관로는 주로 위험 물질이나 유독 유체를 포함하기 때문에 만약 이런 유체의 유출이 발생될 경우 인명 피해는 물론 큰 경제적 손실을 가져온다. 비록 해저관로는 시간적/공간적 제약 없이 유체를 전달할 수 있지만, 이런 관로 설계시 안전하게 그 기능을 수행할 수 있도록 고려되어야 한다. 본 논문에서는 해저관로의 열변형 해석에 사용되는 여러 개의 이론을 조사하였고, 관로의 요소들이 관로 팽창에 미치는 영향에 대해 조사하였다.

• 대한조선학회논문집
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• 제47권2호
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• pp.225-232
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• 2010

The requirement of design of High-Pressure/High-Temperature(HP/HT) pipelines on an seabed increases in recent years. The need of research on the analysis method to improve the design capacity is increasing. The purpose of this study is the development of the analysis method of thermal buckling of subsea pipeline structures. The analysis method of thermal buckling was established by using the commercial FEM code(ABAQUS) which shows the outstanding performance in non-linear static FE analysis. The developed method has been applied to the installation of subsea pipeline on the offshore project. For a validation, the comparative study has been carried out. This application to offshore project demonstrates the superiority of the analysis method of thermal buckling of subsea pipeline structures and testifies the application to detail design.

• International Journal of Naval Architecture and Ocean Engineering
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• 제10권3호
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• pp.348-359
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• 2018

A series of indoor simulation tests on a large-sized shaking table was performed, which was used to simulate the earthquake ground motion for the pipe-soil interaction system to be tested. The purpose of this study is to examine the dynamic characteristic and seismic response of a length of PVC pipeline lay on a clay seabed under seismic load. The pipeline was fully instrumented to provide strain and acceleration responses in both transverse and in-line. Dynamical modal tests show that corresponding mode shapes vertically and horizontally are basically the same. But the absolute values of the natural frequencies vertically are all higher than those corresponding values in transverse. It turned out that the geometry configuration of riser affects its stiffness. Seismic response of pipeline depends significantly on the waveform, and Peak Ground Acceleration (PGA). As the seismic loading progressed, the strain response was severe around both TDZ and catenary zone. Additionally, strain responses in top and bottom positions were more severe than the result in left or right side of the pipeline in the same section.

• Structural Engineering and Mechanics
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• 제41권6호
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• pp.805-822
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• 2012

Offshore pipelines have to withstand combined actions of tension and bending during deepwater installation, which can possibly lead to elliptical buckle and even catastrophic failure of whole pipeline. A 2D theoretical model initially proposed by Kyriakides and his co-workers which carried out buckling response analysis of elastic-plastic tubes under various load combinations, is further applied to investigate buckling behavior of offshore pipelines under combined tension and bending. In association with practical pipe-laying circumstances, two different types of loadings, i.e., bent over a rigid surface in the presence of tension, and bent freely in the presence of tension, are taken into account in present study. In order to verify the accuracy of the theoretical model, numerical simulations are implemented using a 3D finite element model within the framework of ABAQUS. Excellent agreement between the results validates the effectiveness of this theoretical method. Then, this theoretical model is used to study the effects of some important factors such as load type, loading path, geometric parameters and material properties etc. on buckling behavior of the pipes. Based upon parametric studies, a few significant conclusions are drawn, which offer a theoretical reference for design and installation monitoring of deepwater pipelines.

• 한국해양환경ㆍ에너지학회지
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• 제19권1호
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• pp.52-61
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• 2016

대용량의 $CO_2$를 지중에 저장하기 위한 CCS(Carbon Capture and Storage)는 고압의 파이프라인 수송공정을 수반한다. 또한, 사고 및 유지보수와 같은 비정상상태가 발생할 경우 고압의 $CO_2$를 대기 중으로 방출시키는 감압공정이 필요하다. 본 연구에서는 고압 $CO_2$ 파이프라인에서의 감압현상을 수치해석적 방법을 이용하여 분석하였다. 수치계산 결과를 실험데이터와 비교분석함으로써 수치해석의 예측 능력을 검증하였다. 수치모델이 기체-액체 혼합 구간에서의 2상 감압현상을 잘 예측하였다. 그러나 초임계 액체 단상 감압과 기체 단상 감압현상에 대해서는 온도변화 등을 예측하는데 한계가 있음을 밝혔다.

• 대한조선학회논문집
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• 제55권2호
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• pp.93-102
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• 2018

Quantitative Risk Assessment (QRA) has been used in shipping and offshore industries for many years, supporting the decision-making process to guarantee safe running at different stages of design, fabrication and throughout service life. The assessments of a risk perspective are informed by the frequency of events (probability) and the associated consequences. As the number of offshore platforms increases, so does the length of subsea pipelines, thus there is a need to extend this approach and enable the subsea industry to place more emphasis on uncertainties. On-board operations can lead to objects being dropped on subsea pipelines, which can cause leaks and other pipeline damage. This study explains how to conduct hit frequency analyses of subsea pipelines, using historical data, and how to obtain a finite number of scenarios for the consequences analysis. An example study using probabilistic methods is used.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.905-910
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• 2003

In this paper, we develop real-time monitoring system to detect third-party damage on natural gas pipeline by using sound propagation model. Since many third-party incidents cause damage that does not lead to immediate rupture but can grow with time, the developed real-time monitoring system can execute a significant role in reducing many third-party damage incidents. The developed system is composed of three steps as follows: i) DSP based system, ii) wireless communication system, iii) the calculation and monitoring software to detect the position of third-party damage using the propagation speed of acoustic wave. Furthermore, the developed system was set at practical offshore pipeline between two islands in Korea and it has been operating in real time.