基于弹塑性分析的海底管道拆除数值模拟

Numerical Simulation of Decommissioning Offshore Pipeline Using Elasto-plastic Analysis

海洋平台到了服役期,经检测评估需要拆除时,周围的管道也必须拆除。海底管道一般是埋设在海底以下一定深度,可以先将管道从海底提到泥面以上,然后再将管道拖到岸上进行废弃处理。为了计算需要的提升力,运用有限元分析方法对管道进行了弹塑性分析。以胜利埕岛油田某段双层管为例,在提升过程中,由于管道在泥面下、海水中和空气中不同位置管段的受力不同,采用了数值模拟和人工迭代相结合的方法,计算了将管道从海底提出一定高度所需要施加的作用力,为海底管道拆除施工提供理论依据。

Offshore oil and gas facilities will be decommissioned after their life span. When the jacket platform is dismantled, the subsea pipeline near the offshore structure should also be removed. The pipeline was generally buried under the mudline. When dismantled, the pipeline should be elevated above the sea, then to be handled easily and carried to shore. The Elasto-plasticity of the material was considered in order to analyze the elevation force finit element method was used. Taking the example of a double layer pipeline in Shengli Oil Field, in lifting period because the loads at different sections of the pipeline were different, numerical simulation and manual iteration were combined to calculate the force. The conclusion can be used in the practice of dismantling of the subsea pipeline.