渤海某探井152.4 mm井段钻进过程中发生井漏,井筒液柱压力降低导致地层流体侵入,造成喷漏同存的复杂情况,存在钻具埋卡、井喷等风险。为解决喷漏同存问题,通过DrillBench软件分析气体在稠塞中的运移特性。研究结果表明:稠塞在低转速下的流变参数值对防气窜的效果影响较大;在保证井筒内压力平衡的前提下,应尽量使用密度较低的稠塞以减缓气窜速度。进一步指导现场稠塞设计及环空挤注方案的制定,应用效果显著,为后续压井以及注水泥塞提高下部地层承压能力争取了安全时间窗口。结论表明,稠塞技术能够有效延缓气窜,为喷漏同存的复杂井况处置提供科学依据和实例参考,对提升海洋钻井井控安全具有重要意义。

A certain exploration well in the Bohai region experienced a wellbore leak during the drilling process of the 152.4 mm section. The decrease in wellbore fluid column pressure caused the formation fluid to invade the wellbore, resulting in a complex situation of simultaneous blowout and leakage. The well control disposal is challenging, with additional risks such as drill string sticking and well kick. To address the above issue, this study uses the Dynamic Well Control module of DrillBench software to simulate and analyze the migration characteristics of gas in the viscous plug. It is concluded that: the rheological parameters of the viscous plug at low rotational speeds have a significant impact on its gas channeling prevention effect; while ensuring wellbore pressure balance, viscous plug with lower density should be used as much as possible to slow down gas channeling rate. Based on this, further guidance was provided for the on-site design of viscous plugs and the formulation of annular squeeze cementing plans. The application achieved significant effectiveness, securing a safe time window for subsequent well killing and cement plug injection to enhance the pressure-bearing capacity of the lower formation. The results demonstrate that the viscous plug technology can effectively delay gas channeling, providing scientific evidence and practical reference for handling complex well conditions of simultaneous blowout and leakage, which is of great significance for improving well control safety in offshore drilling.