Study On Safety Evaluation Technology Of BZ34-1 To Friendship Number Submarine Pipeline

The submarine pipeline is likely to face with corrosion dangling fatigue and third-party damage due to the complex marine environment. The failure in oil and gas transmitting pipeline will bring bad environmental impact and economic damage. So it is necessary to give management and maintenance measures after safety assessment. How to scientifically and quantitatively evaluate the potential risk of submarine pipeline in service and forecast its residual life is an important project.In the paper basic parameters of BZ34-1to Youyi submarine pipeline are collected. Based on the principles of the pipeline section, the pipeline is divided into three sections: vertical pipe, buried pipe and suspended span pipe.(1) This paper makes nonlinear finite element analysis of the buried section for single point corrosion defect and composite defect. Besides, the result of finite element calculation has been compared with several common standard predictions. The pipeline’s residual strength assessment has been complete and the safety of a buried pipeline is determined. The factors which control and affect the dangerous degree of a submarine pipeline are complex and uncertain. It is necessary to make safety evaluation of buried pipeline based on the reliability theory. The Monte Carlo simulation method is used to solve the failure probability and assesse the residual life.(2) Fatigue analysis yield evaluation and resonance evaluation are conducted in suspended span pipe. The value of lift coefficient is solved by FLUENT software and transient dynamics analysis is further conducted combined with ANSYS. Vortex-induced vibration fatigue evaluation is finished based on DNV standard. In the evaluation process, vibration characteristics and stress amplitude of tube cross section are considered and the stress concentration factor is introduced based upon the S-N curve. According to the finite element analysis result and theoretical calculation method, yield evaluation of the cross section of the tube containing corrosion defects is made(3) Finally safety evaluation of vertical pipe is conducted based on load coefficient method. Due to the load specialization, the safety evaluation under combined loads (Internal pressure, temperature and wave flow) is complete through force analysis of vertical pipe.Based on the study of the three sections, the safety evaluation of BZ34-1to Youyi submarine pipeline is completed. Submarine pipeline is divided and evaluation result of different pipeline is given. It provides the direct basis for management and maintenance. In this paper, governance and detection measures which are suitable for evaluation pipeline are put forward.