水下采油树油管悬挂器传热计算分析

Calculation and Analysis of Heat Transfer of Subsea Tree Tubing Hanger

水下采油树是深海油气开发的关键设备,油管悬挂器作为采油树核心部件,其传热计算关系到后期油气的流动安全。以传热学理论为基础,分析水下采油树稳态和非稳态条件下传热控制方程及边界条件,对混合天然气比热容、导热系数以及对流换热系数等进行计算。采用数值传热方法建立水下采油树油管悬挂器传热的有限元模型,对油管悬挂器在稳态生产阶段和非稳态停机阶段的温度场分布进行数值模拟。稳态计算结果显示:油管悬挂器内壁温度关于X=0截面对称分布,最高为57℃,为生产的油气温度,最低温度出现在油管悬挂器顶部位置,为21.672℃;停机8 h后,油管悬挂器温度下降到21.66℃;在停机0.5 h内,温降幅度最大,油管悬挂器温度降到25℃,说明内部产出流体在关机初期和采油树本体间的热量交换剧烈;2 h后温度逐渐接近海水温度,最终达到稳态。

Subsea tree is the key equipment for deep-sea oil and gas development.Tubing hanger is the core component of the subsea tree,and its heat transfer calculation is related to the safety of oil and gas flow in the later period.Based on the theory of heat transfer,the heat transfer governing equations and boundary conditions under the steady and unsteady conditions of the subsea tree were analyzed,and the specific heat capacity,thermal conductivity and convective heat transfer coefficient of mixed natural gas were calculated.A finite element model of the heat transfer of subsea tree tubing hanger was established by using the numerical heat transfer method,and the temperature field distribution of the tubing hangers during steady production and unsteady shutdown was numerically simulated.The steady state calculation results show that the temperature of the inner wall of the tubing hanger is symmetrically distributed about the X=0 cross section,the highest is 57℃,which is the temperature of the oil produced,and the lowest temperature appears at the top of the tubing hanger,which is 21.672℃;after 8 hours of shutdown,the temperature of the tubing hanger drops to 21.66℃;within 0.5 h of shutdown,the temperature drop range is the largest,and the temperature of the tubing hanger drops to 25℃,indicating that the heat exchange between the internal produced fluid and the tree body is intense at the initial shutdown stage;after 2 h,the temperature gradually approaches the seawater temperature and finally reaches a steady state.