基于FTA定性的简易水下井口设计可靠性分析

水下井口作为水下生产系统的核心装备,下端连接导管和套管,上端支撑防喷器组和水下采油树等水下装备,是整个水下生产系统的重要组成部分。特别是在浅海作业环境中,外部易受到风浪影响,一旦发生失效,将会造成严重的后果。基于浅水水下井口的结构特点,建立了水下井口失效事故树模型(FTA),划分了基本事件和最小割集,分析了基本事件结构重要度,对水下井口装置关键部件的风险程度进行了评估。结果表明:低压井口头、环形密封总成、高压井口头、套管悬挂器、防磨补芯装置和导向基座是水下井口设备发生失效的关键部件。针对失效关键部件提出设计优化建议,从而提高海洋油气生产的整体安全可靠性。为建立一套适用于浅水简易水下井口及采油树风险评估与安全可靠性技术体系提供了重要参考依据。

The Reliability Evaluation of Simple Subsea Wellhead Design Based on FTA

As the core equipment of the subsea production system, the subsea wellhead is an important part of the entire subsea production system, connecting the catheter and casing at the bottom and supporting the BOP set and subsea tree at the top. Especially in the shallow sea operating environment, the outside is easily affected by wind and waves, and once it fails, it will cause serious consequences. Based on simple structure characteristics of the shallow subsea wellhead, the subsea wellhead failure accident tree model(FTA)was established, the basic event and the minimum cut set were divided, the importance of the basic event structure was analyzed, and the risk degree of the key components of the subsea wellhead device was evaluated. The results show that the key components of subsea wellhead failure are low-pressure wellhead, annular seal assembly, high-pressure wellhead, casing hanger, anti-wear mending device, and guide base. The design optimization suggestions for the key failure parts were put forward, to improve the overall safety and reliability of offshore oil and gas production and provide an important reference for the establishment of a technical system for risk assessment and safety reliability of shallow water simple subsea wellheads, and Christmas tree.