水改气海底管道输送高压天然气可行性研究

Study on feasibility of high pressure natural gas transported by water subsea pipeline

为了满足油气输送需求,现将一输水管线改输高压天然气,需对该管线改输的可行性进行研究论证,通过ANSYS建模分析得到腐蚀缺陷处在4.75MPa高压下所受到的最大等效应力小于管道的设计抗力273.6MPa,满足安全标准。利用OLGA模拟出管道输送高压天然气时的压力和温度曲线满足实际工况要求,OLGA模拟出的预测腐蚀速率最大处为0.04mm/y,对管道的剩余寿命影响较小。应用DNV腐蚀因素失效概率模型计算得到该管道的失效概率小于1.5×10-3,安全等级介于"一般"和"很高"之间。经研究论证得该管道改输高压天然气是可行的。该研究提出了针对管线改输可行性分析的一般方法和步骤,能够为其他改输管线提供一定的参考。

In order to meet the transport needs of oil and gas, a water pipeline pressure natural gas pipeline, and the feasibility should be demonstrated. By needs to be changed into the high- ANSYS modeling and analysis, it showed that the maximum equivalent stress at corrosion defect position of the pipeline under high pressure 4.75MPa was less than the designed resistance of pipeline 273.6MPa, which could meet safety standards. The pressure and temperature curves of the pipeline transporting high-pressure natural gas were simulated by using OLGA software, which could meet the actual working conditions. The maximum corrosion rate was 0.04mm/y by OLGA simulation, which caused little impact on the remaining lifetime of the pipeline. The failure probability of the pipeline was less than 1.5 ~ 10-3 by using DNV corrosion factor failure probability model, and the mal＂ and ＂very high＂. The conclusion was concluded that changing the pipeline security level was between ＂norto transport high-pressure natural gas is feasible. The study presents the general feasibility analysis method and steps for pipeline transport switchover, and it can provide a reference for other transport switchover pipelines.