水下卧式采油树传热特性分析及输油管路保温设计

Thermal Analysis of Subsea Horizontal Xmas Tree and Insulation Design for Flowline

水合物防治是水下采油树流动安全保障需重点考虑的问题,而温降是水合物形成的重要因素;同时,采油树的密封设计、材料选择均与温度密切相关,因此必须对水下采油树进行传热特性分析.针对南海某特定油田环境,并结合水下采油树结构特征,建立了水下采油树本体、出油管的简化传热计算模型,确定了其稳态、非稳态的传热控制方程组及相应边界条件和初始条件.采用Fluent软件对水下采油树进行稳态及非稳态传热模拟,针对不同原油入口温度、海水温度,得出采油树温度分布及出油管内壁温度随时间的变化规律.通过对加装聚氨酯复合材料的采油树出油管模型进行温度场模拟,得到不同原油温度、海水温度下保温层厚度和冷却时间的关系.综合稳态、非稳态分析结果,提出采油树出油管保温层厚度的计算公式.

Hydrate prevention is the key issue for the flow assurance of subsea Xmas tree. And the temperature drop is the crucial factor in hydrate generating. Meanwhile, seal design and material selection of the tree are closely related with the temperature, so thermal analysis of subsea Xmas tree is very important. Simplified thermal analysis model of the tree body aiming at a specific oilfield environment in South China Sea was established. Determining the governing equation and boundary condition relatively, the temperature distribution of the tree in various temperatures of crude oil and sea water is investigated by Fluent and the flowline temperature variation with time is get. Meanwhile, simulation of flowline with polyurethane composites in different temperatures of crude oil and sea water was investigated to get the relationship between the insulation thickness and cooldown time. Through analyzing the results of steady-transient state, calculation formula of insulation layer＇s thickness under different conditions of seawater and crude oil temperatures was put forward.