An Overview of Deepwater Pipeline Laying Technology

The technology and methods involved in pipeline laying in shallow water have evolved to the level of routine and commonplace. However, regarding the unexpected deepwater complexity, the traditional pipeline laying techniques have to confront many new challenges arisen from the increase of the water depth, diameter of the pipe and the welding difficuhy, all of which should be modified and/or innovated based on the existed mature experiences. The purpose of this investigation is to outline the existing and new engineering laying techniques and the associated facilities, which can provide some significant information to the related research. In the context, the latest deepwater pipeline laying technology and pipe laying barges of the renowned companies from Switzerland, Norway, Italy etc., are introduced and the corresponding comparison and discussion are presented as well.

Some Considerations in Design and Construction of the Wei-Liu Water Supplying Submarine Pipeline

The Wei- Liu water supplying submarine pipeline is at present the longest one of the kind in China. It is about 4 kilometers long from Weihai City to Liugong Island in Shandong province. It took only half a year to design and construct it. The project was of a high economic efficiency and some practical experiences were achieved. In this paper a general introduction to the design and construction of this pipeline is presented and such problems as the stability of the pipeline in very soft clay, design of curved slide for launching and estimation of dragging forces are expounded.

Numerical Study and Economy Analysis of Two Heated Crude Oil Pipelines Laid in One Ditch

In this paper,the transportation economy of two heated crude oil pipelines laid in one ditch is analyzed by taking into account the influence of operating temperature,interval between two pipelines,and distance between two heating stations on the heating energy consumption.To analyze the transportation economy,the two heated crude oil pipelines laid in one ditch are simulated under four operating conditions based on an unstructured finite volume method.Compared with laying two crude oil pipelines separately in two ditches,the results attest notably higher soil temperature,meaning reduced heat dissipation of each pipeline by laying two pipelines in one ditch.It is inferred that for the same desired oil temperature at the inlet of the next heating station,laying two pipelines in one ditch requires lower oil temperature at the outlet of heating station,indicating decreased energy cost at the heating station and improved transportation economy.Then economy analysis of four configurations of laying two pipelines in one ditch is performed.By comparing the results of four conditions,the interval between two pipelines of 1.2 m is found to save the energy most efficiently,which is as large as 26.6%compared with that of laying two pipelines in two separate ditches.In addition,narrowing the pipeline interval and extending the distance between heating stations is beneficial to save heating energy.This study is expected to provide valuable guidance for operation optimization of heated crude oil pipelines.