应用事故树法对深水井控进行风险评估

深水井喷事故危害极大，严重时可导致井眼报废、船毁人亡等恶性后果，预防和控制深水井喷是国内外石油界的一个技术难题。文中利用风险树分析引发深水钻井工程事故的顶事件，重点讨论各底事件的相互联系及对系统的影响程度，分析顶事件的发生概率，为最大程度地减少深水井控事故的发生提供理论依据。通过对深水钻井过程中存在的风险进行分析，构建了深水井控风险分析事故树，并对其进行了定性与定量分析。通过风险分析，认为深水井控最主要的影响因素是关井及压井时设备故障、设计方法及操作失误的影响超过安全极限。分析表明，降低基本事件的发生概率对预防井喷作用明显，基本事件发生概率提高1倍，井喷发生概率提高近10倍。针对深水井控过程中存在的风险因素，从工艺、装备及人员要求方面提出了预防深水井喷的措施。

Risk assessment on well control in deepwater drilling based on fault tree analysis

The harm of deepwater blowout is extremely serious, which may lead to useless wellbore and the disaster of rigs and staff. At present, the well blowout precaution and control technology in deepwater drilling is still a world-class technical problem for the petroleum industry both at home and abroad. Based on the fault tree analysis, the top events resulting in the accidents in deepwater drilling are discussed. Emphasis is laid on the discussion of the correlation between bottom events and their effect on the system. The probability of top events is also analyzed. All provides theoretical basis for reducing the deepwater well control accidents to the greatest extent. Based on the analysis on risks in deepwater drilling, the fault tree for the analysis of well control in deepwater is established, for which both qualitative analysis and quantitative analysis are conducted. Risk analysis shows that the critical factors affecting deep water well control are that the negative effect of design methods and operating failures exceeds the safety limits. It is significantly helpful to prevent blowout by reducing the occurrence probability of elementary events. The occurrence probability of elementary events is enhanced by one time, while that of blowout is increased by 10 times. In view of the risk elements in deepwater well control, measures of preventing blowout are put forward from the perspectives of technologies and equipments as well as the requirements on operating personnel.