ABSTRACT:

Development of offshore oil and gas fields involved the necessity of installation of multiple underwater pipelines to transport oil and natural gas. In the past intensive research has been conducted in the USSR into various theoretical and practical aspects of the marine pipe line construction. This paper presents the results of experimental studies of hydrodynamic and kinematic behaviour of the marine pipelines. The basic laws are considered of the pipeline hydrodynamic resistance in the process of its towing for different installation methods: from the sea surface and by a submerged method in a broad variety of the pipeline design. A method is suggested to assess the pipeline tow resistance in calm water and in the rough sea. A new pipe string towing technique is considered allowing to reduce the sea wave effects by means of pipeline submersion in the process of its towing. The test results are presented for the alternating stresses in the pipeline under the influence of the sea waves.

INTRODUCTION

At present time the pipeline construction science lacks systematized experimental data evaluating tow resistance of such a complicated from the hydrodynamic point of view system as a pipe string. Stress-strain state of a pipeline in the process of its towing and laying on the sea bottom needs a de tailed study. These problems called for additional research work, which has been conducted by VNIIST and Ukranian Academy of Sciences Hydromechanics Institute. The experimental work was fulfilled in the model basin with the model pipe strings in a broad variety of the pipeline design. Comparison data on pipeline tow resistance were acquired in the full-scale tests carried out in the Caspian Sea. In Fig.1 a general view of model test basin in Kiev is shown. The test basin is used for the present experiment.

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