Pipeline Laying Research Articles

Scaled Model Simulation and Experimental Verification of Submarine Flexible Pipeline Laying System

In order to adapt to the complex and changeable marine environment such as wind, wave, and current, the physical simulation experiment is usually needed in the design of a deep-sea flexible pipeline-laying system. In reality, the flexible pipeline-laying system is very large, and the experimental cost is huge. Therefore, when analyzing this system, it is necessary to carry out scaled model experiments to verify the rationality of it. Taking the flexible pipeline-laying system working under four-level sea conditions as an example, this paper deduces the similarity criteria of the scaled model according to the similarity theory. According to the required experimental site, the sizes and materials of the model are selected, and then the physical quantities of the model and their similarity ratio corresponding to the prototype are determined. According to the physical quantities of the experimental model, the similarity of dynamic characteristics and structural strength between the model and the prototype are verified by Adams and ANSYS Workbench. The research shows that the scaled model and prototype based on similarity theory can meet the established similarity relationship, and the scaled model experiment is an effective way to verify the rationality of the design of a flexible pipeline-laying system.

Zhoushan City Mainland Water Diversion Phase III Project Key Technologies of Cross-sea Pipeline Laying Construction

This paper introduces the cross-sea water transmission pipeline project from Zhenhai to Mamu section of Zhoushan Continental Water Diversion Project Phase III, and summarizes the towing method of the nearshore section of the pipeline laying, the S-Lay, Post-trenching technology and concrete chain row installation construction techniques. Through the summary of the paper, it is expected to provide help for the construction of the sea bottom pipeline for island water supply in the future.

Test Analysis and Pipeline Risk Assessment of Oil and Gas Pipeline Laying in Typical Loess Area

In recent years, with the development of oil and gas storage and transportation technology, pipelines have been successfully laid and safely operated in areas with various geological and geographical characteristics. However, for pipelines in particular sections such as collapsible loess areas and landslide ones, oil and gas pipelines will be restricted by conditions. Different problems may even occur during laying and operation. On the basis of mechanical analysis and calculation, this paper establishes a mechanical model. Combined with similar simulation experiments, the influence of water flow erosion on oil and gas pipelines under different slope laying conditions is analyzed. At the same time, the risk assessment methods of special pipe sections in loess areas are established, which have certain guiding significance and reference value for pipeline laying in loess areas.

多级水站间的自来水管道铺设问题

多级水站间的自来水管道铺设问题

赵楼煤矿管道敷设分析研究

赵楼煤矿管道敷设分析研究

Stress Analysis of Pipeline Laying on Thrust Fault

It is taken one project of pipe installment in tunnel of China-Central Asia Line as one case. Set up one FEM contact element pairs, it simulates the relationship of pipe and thrust fault. With the thrust fault happening, the laying pipe occur large displacement, stress, and gap or pressure. Compare the maximum stress to 90% of allowable yield strength, it determines damage occurs or not about the pipe. Dislocation of ground face leads to pipe local shrinking, and then large tensile strain happens to local damage. To avoid that bad consequence, horizontal Compensators will be installed on tunnel both sides to coordinate deformation.

A New Routing Algorithm Based on Adjacent Matrix in Pipeline Laying

With the development of economy, higher requirements for pipeline laying are raised. Among them, how to choose path for laying effectivelyand cheaply is the most important. Compared with ‘Dijkstra’, ‘Bellman-Ford’, ‘Floyd’ and ‘Dynamic planning model’, a new routing algorithm based on adjacent matrix is proposed and detailed processes and rules are designed. Additionally the effectiveness of the algorithm is proved through being applied to an example.

Research on the Overall Heat Transfer Coefficients of Crude Oil Pipeline and Product Pipeline Laid in One Ditch

Crude oil pipelines and product pipelines laid in one ditch is a new construction technology, which not only saves construction costs but protects the environment. Overall heat transfer coefficients of the crude oil pipeline and product pipeline laid in one ditch are important parameters that are used to calculate the oil temperature along the pipeline and influence the design and operation of the whole pipeline. Formulas regarding soil temperature field, heat emission coefficient between the pipeline and the soil, as well as overall heat coefficients of the crude oil pipeline and product pipeline laid in one ditch are deduced by conformal mapping. Then the oil temperatures along the pipeline are calculated. Comparing the temperatures for double-pipeline and single-pipeline conditions, the results calculated by the overall heat transfer coefficient formulas with pipelines laid in one ditch are more accurate than those with a single pipeline.

Numerical Model for Pipeline Laying During S-lay

The S-lay method has been widely used in pipeline installation from shallow water to deep water for decades. In this paper, a novel numerical model for analyzing pipelines in the S-lay problem is proposed to investigate the overall configuration, internal forces, and strain of the pipeline taking into account the influence of ocean currents and seabed stiffness. The influence of many important factors, including the variation position of the liftoff point, the change of stinger radius, ocean currents, seabed stiffness are investigated in detail. Some useful results are obtained: the stress state of the pipeline is found to vary greatly during the whole laying process; the train of the pipeline at both the upper and the lower sides is very important; ocean currents have negligible influence on the pipeline; traditional “touchdown factor” is not suitable to predict the real pipe embedment; and soil stiffness plays an important role in pipeline behavior on the seabed. The illustrative examples and comparison with a previous work demonstrate the widespread applicability of this model. Moreover, the solution process of this model is easy and fast, so it is suitable for engineering applications.

Underground Hollow Space Surveys After Pipeline Laying Works by Pipe Jacking Method

Underground Hollow Space Surveys After Pipeline Laying Works by Pipe Jacking Method

Increase in Productivity of Pneumatic Impact Devices for Trenchless Underground Pipeline Laying

The disadvantages of devices for cyclic cleanup of a pipe from soil core during trenchless underground pipeline laying are shown. Three variants of the cleanup device movement towards the borehole bottom are analyzed. The methods are proposed for increase in haulage velocity.

Submerged Pipeline Laying by TPP (Taisei Pipe in Pipe) Method

Submerged Pipeline Laying by TPP (Taisei Pipe in Pipe) Method

Automatic Welding System for Offshor Pipeline Laying

Automatic Welding System for Offshor Pipeline Laying

Influence of Lay Barge Motions on a Deepwater Pipeline Laid Under Tension

Tensioning is a prime requirement for laying deepwater pipelines. Of the several new or improved pipe laying methods which have been proposed, or even utilized, all require tensioning of the pipeline to minimize stress in the critical area. In these methods the use of a stinger is optional. Dixon and Rutledge produced charts by which the minimum tension and angle of inclination could be determined for laying pipelines in intermediate and deep waters. The pipeline is freely suspended from the sea floor up to the stinger, or to the lay barge if no stinger is used. It takes a shape over its unsupported length which differs from a natural catenary at its ends due to the pipeline stiffness. In the present work the authors have employed the same mathematical technique to study the sensitivity of a tensioned pipeline to lay barge motions, i.e., surge, heave, and pitch. Two general trends emerge from the results which are presented both in the form of graphs for several sizes of the pipeline and for water depths up to 1000 ft, and in the form of dimensionless charts. Surge, and to a lesser degree heave, is influential in shallow or intermediate water depths. Pitch becomes a critical parameter in deep waters where the tension is large. The influence of a sloping rather than horizontal sea floor is also studied in this work. It is shown that for a practical range of slopes the prior analysis gives a satisfactory description of the configuration. However, additional curves which have been provided are required to make application of the previous results.

Stiffened Catenary Calculations in Pipeline Laying Problem

According to a granted U. S. Patent, it is contemplated that deep water pipelines be laid on the sea floor from an inclined derrick on a lay barge without the aid of a stinger. Means are presented in this paper for calculation of required tension and inclination of pipeline at the lay barge. Charts giving necessary tension and inclination, taking pipeline stiffness into consideration, are presented.