水下采油树生产通道流动安全分析与应用

Flow Safety Analysis and Application of Production Fairway of Subsea Christmas Tree

目前对油气井生产期间水下采油树生产通道内温压场动态缺乏精细表征,对生产通道内部和节流阀后水合物的生成和防治,以及对生产通道的出砂冲蚀等研究均较少。为此,采用数值模拟方法建立水下采油树生产通道有限元模型,对油气井生产期间的温度场动态进行精细表征,对水合物生成风险进行预测,对生产通道进行冲蚀特性研究,并进行了现场应用验证。研究结果表明:为避免水下采油树生产通道生产期间节流阀后出现-40℃的低温,推荐节流阀下游预充填压力≥8 MPa;在节流阀上游2~3 h后、下游6~10 h后,温度可以升至水合物相平衡温度点以上,当产量较低时水合物抑制剂需持续注入12 h以上。研究结论可为水下采油树的正常运行和油气井的安全生产提供技术支持。

At present,there is a lack of fine characterization on the temperature and pressure field performance in the production fairway of subsea Christmas tree during the production of oil and gas wells,and there is a lack of research on the generation,prevention and control of hydrates inside the production fairway and after the throttle valve,as well as sand erosion in the production fairway.Therefore,in the paper,the numerical simulation method was used to build a finite element model of production fairway of subsea Christmas tree to conduct fine characterization on the temperature field performance during the production period of oil and gas wells,prediction on the risk of hydrate generation,and research on the erosion characteristics of production fairway.The research results show that in order to avoid a low temperature of-40℃after the throttle valve in the production fairway of subsea Christmas tree during the production period,it is proposed to allow the prefill pressure at downstream of throttle valve to be higher or equal to 8 MPa;the temperature can rise above the phase equilibrium temperature point of hydrate after 2-3 h at upstream of throttle valve and 6-10 h at downstream of throttle valve,and when the production rate is low,the hydrate inhibitor needs to be continuously injected for more than 12 h.The research conclusions provide technical support for the normal operation of subsea Christmas trees and the safe production of oil and gas wells.