INTEGRATED SUBMARINE PIPELINE INVESTIGATION TECHNIQUES AND DF1-1 PIPELINE UNSAFETY FACTOR ANALYSIS

Submarine pipelines play an important role in offshore oil and gas industries. It is necessary to investigate submarine pipelines regularly or timely to insure their safety. This paper introduces the fundamental principle of an integrated surveying system (including a dual-frequency side-scan sonar,a high resolution sub-bottom profiler,and a swath sounder system) and its application to investigating DF1-1 submarine pipeline. Some factors that threatened the safety of the pipeline were also analyzed. It was realized that both of moving sand waves and seabed scour around the pipeline ould cause the spanning of the pipeline,which severely threatens the safety of the pipeline.