基于模糊事故树的水下井口回收风险分析

Analyzing the risks in subsea wellhead recovery based on fuzzy fault tree

刘书杰 黄熠 孟文波 黄亮 李磊 付光明

LIU Shujie HUANG Yi MENG Wenbo HUANG Liang LI Lei FU Guangming

中海石油(中国)有限公司湛江分公司 非常规油气开发教育部重点实验室∙中国石油大学(华东)

Zhanjiang Branch of CNOOC (China) Co., Ltd., Zhanjiang 524005, Guangdong, China MOE Key Laboratory of Unconventional Oil and Gas Development, China University of Petroleum (East China), Qingdao 266580, Shandong, China

水下井口系统回收过程中操作风险较高,易发生回收工具失效、操作失误等风险事件，进而导致水下井口回收失败。结合水下井口系统回收操作流程和专家现场经验，梳理导致水下井口系统回收失效的基本事件，基于基本事件和逻辑关系建立以水下井口系统回收失效为顶事件的事故树；通过引入专家评价机制，对基本事件的发生概率进行语言评价；利用模糊数学算法将专家对基本事件的语言评价转换为基本事件发生的概率；基于基本事件概率的敏感性分析识别水下井口系统回收过程中的高风险因素。结果表明，表层套管与导管回收刀片损坏失效概率最大，此外割刀卡死、刀片损坏、切割位置不准、人为操作失误对水下井口系统回收失效的影响也较大，需要针对上述因素提出相应的预防和改进措施，研究结果可以为水下井口系统的安全回收提供重要参考。

In the process of subsea wellhead system recovery, the operation risks are great, and risk events tend to happen easily, such as recovery tool failure and operation failure, which lead to the failure of subsea wellhead recovery. In this paper, the basic events leading to the failed recovery of subsea wellhead system were sorted out based on the operation process and expert’s field experience of subsea wellhead system recovery, and the fault tree with subsea wellhead system recovery failure as the top event was established based on basic events and logical relations. The expert evaluation mechanism was introducing to carry out linguistic evaluation on the occurrence probability of basic event. The expert’s linguistic evaluation on basic event was converted into the occurrence probability of basic event by using the fuzzy mathematics algorithm. And the high risk factors in the process of subsea wellhead system recovery were identified based on the sensitivity analysis of basic event probability. It is indicated that the damage failure probability of the cutting blade for surface casing and conductor pipe recovery is the highest, and cutter knife freezing, cutting blade damage, inaccurate cutting position and human operation error have greater influences on the failure of subsea wellhead system recovery, so it is necessary to put forward the corresponding prevention and modification measures. The research results can provide an important reference for the safe recovery of subsea wellhead system.

10.13639/j.odpt.2023.02.018