南海A气田采用水下生产系统开发,气田井流物经海管输送到附近B综合平台处理,在开发后期,各项参数波动较大,段塞流周期性出现,影响了气田的正常运行。确定南海气田输送系统为典型的下倾管—垂直立管系统,具有严重段塞流的各项特征。通过分析严重段塞流产生原因和实际运行参数变化情况,定义了严重段塞流临界天然气流量。比较常用控制方法后选择流量控制法,运用多相流模拟软件LedaFlow模拟可行,在此基础上,开展实践验证。通过流量控制法有效控制了水下气田严重段塞流的产生,稳定了气田工艺系统的运行,为后续严重段塞流控制提供了实践支持,可作为严重段塞流的有效控制方法在其他气田推广。

Gas field A in the South China Sea is developed using subsea production system, and its multiphase well fluid is tied back via subsea pipeline to the nearby integrated platform for processing. In the later stage of development, slug flow occurs periodically due to big fluctuation in various physical parameters, affecting the normal operation of the gas field. As a first step, it is confirmed that the multiphase well fluid transport system is a typical downdip pipe leading to a vertical riser, and the slug flow demonstrates the characteristics of severe slugging. By analyzing the causes of severe slugging and the effect of changes of actual operating parameters, the critical natural gas flowrate envelop of severe slugging is defined. After comparing the commonly used control methods on slug management, the flow control method is selected. The practical verification of flow control method is carried out using modelling software LedaFlow as the software is found to be feasible for multiphase flow simulation application. The flow control method effectively mitigates the generation of severe slugging in subsea multiphase flowlines, stabilizes the operation of gas processing system on the integrated platform, and provides best practices to support similar severe slugging control issues in the future. It can be promoted for application in other subsea gas field developments as an effective method for severe slugging control.