基于CFD的水下采油树生产通道流动数值模拟

Flow Numerical Simulation for Production Channel in Subsea X'mas Tree based on CFD

水下采油树生产通道是海洋油气井井底油气产出的通道,通过对通道进行开启和关闭以及节流实现对油气生产的控制。在介绍水下卧式采油树结构的基础上,运用CFD软件对水下采油树生产通道进行流体动力学三维数值模拟,研究液压驱动生产主阀开启和关闭的流动特性,并对生产通道的设计提出建议。建模时入口条件设置为速度入口边界条件,出口为压力出口边界条件,壁面为无滑移边界条件。分析结果表明,流体在直角拐弯处有较大的压降,设计时应尽量增大弯道角度和半径,合理布置采油树各部件,减少流道拐弯次数;闸阀开关过程中上游形成暂时的压力舱,应尽量减小主阀开闭对压力的影响。

Serving as an oil and gas production channel for the subsea wells, the subsea X＇ mas tree controls the oil and gas production through opening, closing and choking the flow channel. The structural composition of subsea horizontal X＇ mas tree is introduced. To identify the flow characteristics when the hydraulic main valve is opened and closed and provide recommendations for the design of production channels, the CFD software is used for the three-dimensional fluid dynamics numerical simulation of subsea X＇ mas tree production channel. In the mod- el, the inlet is applied with speed inlet boundary, the outlet is applied with pressure-outlet boundary, and the wall is set as no-slip boundary. The analysis results show that there is a greater pressure drop in the right-angle bend. Thus, in the design, the bend angle and radius should be maximized and the components of the tree should be arranged rationally to reduce the number of channel bends. A temporary pressure tank will be formed upstream during switching the valve, so that the impact of opening and closing the main valve on the pressures should be minimized.