Quantitive Risk Evaluation Of Subsea Pipelines Under The Operation Of Trawling

With the fast development of ocean exploitation, offshore pipeline which is animportant means of transporting oil and gas is subjected to all kinds of risks due to thecomplex environment in ocean. The risk is mainly due to external occasionaldisturbance, including impact from other objects. this kind of risk can damage thepipeline, it is not convenient to check,maintain and operate the damaged offshorepipelines underwater. Once an accident happens, it can cause great loss in economy,environment and human safety. However, it violates the goal of greatest profit toenhance protection measurements excessively. Therefore it is very necessary to carrythe safe analysis under accidental loads.This paper analyzes the problem that trawl equipment interferes in subseapipelines. Consequently, we describe three kinds of interferences in the pipelines:impact,pull-over and hooking. Specific formula and dynamic analysis model aregiven, which are used to calculate the energy and response of pipelines. This paperdevelops the model of failure probability after confirm the breakage grade of pipelines.Finally, this paper relates the failure probability to breakage grade by using riskmatrix, and gives risk assessment quantitively.