Most of the earth’s surface is covered by seas. Deep underwater reservoirs have abundant resources of oil and gas. In the development of offshore oil and gas reservoirs, oil and gas transportation is performed by a pipe system combining a deep-water pipeline and a riser. In the process of transportation, differences in phase properties of the gas and liquid phases can cause severe slugging accidents. Therefore, studying the characteristics and influencing factors of the severe slugging phenomenon is important for the effective development of deep underwater fields. In this paper, the authors have established a three-dimensional numerical model of a deep-water pipeline-catenary riser. Based on the model, simulation of the transient multiphase is performed using the COMSOL simulation software. Applying the controlling variable method, we analyzed the flow characteristics, fluid velocity field, and bottom pressure of the riser for different types of severe slugging phenomenon and the influence of the angle and pressure in the inclined pipe on slugging. The results show that with decrease in the angle of the inclined pipe or with increase in the pipe diameter, the severe slugging period will increase; with increase in the angle of the pipe or decrease in the pipe diameter, the bottom pressure of the riser will also increase. The results of the research provide a theoretical basis for ensuring safe operation and maintenance of submarine pipelines.

地球表面的大部分被海洋覆盖。深部水下储层具有丰富的油气资源。在海上油气藏开发中，油气输送是通过深水管道和立管相结合的管道系统进行的。在运输过程中，气相和液相的相性质差异会导致严重的段塞事故。因此，研究严重段塞现象的特征及影响因素对于深水领域的有效开发具有重要意义。在本文中，作者建立了深水管道-悬链线立管的三维数值模型。基于该模型，使用 COMSOL 仿真软件对瞬态多相进行仿真。应用控制变量法，针对不同类型的严重段塞现象，分析了立管的流动特性、流体速度场、底部压力以及斜管内倾角和压力对段塞的影响。结果表明，随着斜管倾角的减小或管径的增大，严重段塞周期会增加；随着管子角度的增加或管径的减小，立管的底部压力也会增加。研究结果为保障海底管道的安全运行和维护提供了理论依据。结果表明，随着斜管倾角的减小或管径的增大，严重段塞周期会增加；随着管子角度的增加或管径的减小，立管的底部压力也会增加。研究结果为保障海底管道的安全运行和维护提供了理论依据。结果表明，随着斜管倾角的减小或管径的增大，严重段塞周期会增加；随着管子角度的增加或管径的减小，立管的底部压力也会增加。研究结果为保障海底管道的安全运行和维护提供了理论依据。