深水携表层钻井工艺技术

Research on Increasing Drilling Speed for Deepwater Conductor Jetting

深水钻井通常采用喷射法下入表层导管和低压井口头。针对南海深水表层导管喷射钻井速度慢、时效低的问题,通过综合分析影响导管喷射钻井速度的因素,包括地层强度、导管外径、钻头大小、钻头伸出量、钻压、排量、导管上下活动次数和活动幅度等,找出了三个主要关键因素,分别是钻头伸出量、排量和导管上下活动幅度。在确保安全前提下,通过综合考虑钻具配长要求、平台泥浆泵排量和钻井能力情况,优化设计了钻头伸出量、喷射排量和导管上下活动幅度三个作业参数,形成了喷射钻井提速方法。深水作业实践表明,该方法不仅能大幅度提升导管喷射速度、降低作业费用,而且还能增加和保证导管的入泥深度,提高导管喷射成功率,同时,入泥深度的增加也提升了水下井口的稳定性,保障了水下井口作业安全性,为低油价环境下深水钻井降本增效提供了安全有效的方案。

Jetting for conductor and low pressure wellhead is a common method used in the deepwater drilling operation.According to the low drilling speed and efficiency in the deepwater conductor jetting in South Sea,factors affecting jetting speed were analyzed,including formation strength,conductor outer diameter,bit size,bit stick-out,weight on bit,pump displacement and pipe movement,three subjective key factors influencing the jetting speed were found to be the bit stick-out,pump displacement and pipe movement.Under the premise of ensuring safety,by comprehensively considering the requirements of drilling tool length distribution,platform mud pump displacement and drilling capacity,three operating parameters of drill bit stick-out,jetting displacement and pipe movement were optimized to form jetting speed increasing method.Deepwater operation practice shows that not only the drilling speed and jet efficiency was greatly improved,but also the setting depth of the conductor was increased,and the success rate of the jet was improved by the jetting speed increasing method.At the same time,the increasing of conductor setting depth also improves the subsea wellhead stability and ensures the safety of the subsea wellhead,a safe and effective solution for cost reduction and efficiency enhancement of deepwater drilling in the low oil price environment was provided.