井下振动控制技术研究

Study on Downhole Vibration Control Technology

为了获得高的油气钻井投资回报率,必须保证钻井过程安全、快速,以达到减少钻井事故、降低工程成本和尽早获取收益的目的,因此加强钻井过程控制十分必要。井下振动控制技术是保证安全快速钻井的关键技术之一,但是,目前该技术还不够成熟,特别是还未对钻井过程中发生的振动现象进行系统的分析,不能合理、准确地控制钻柱的振动状态和振动强度,以致可能造成能量大量损耗,甚至损坏钻具,无法实现安全、快速钻进。系统分析了振动现象的影响因素,包括:钻头、钻柱系统结构(特别是井底钻具组合,包括钻头类型)、钻井参数(钻压和转速)、已钻井眼几何参数和地层性质等,结合对钻柱固有频率的分析提出了井下振动控制的方法和程序,以最大限度地减小振动的危害,尽可能地提高钻井速度、缩短钻井周期、提高投资回报率。

In order to achieve a high return on investment in oil and gas drilling,we have to ensure the drilling process is safe and fast for the purpose of reducing drilling accidents and project costs,and benefiting as soon as possible.Therefore,enhancing drilling control is very important.Downhole vibration control is one of the key technologies for fast and safe drilling.Currently this technology is not mature,especially the vibration phenomenon of drilling operation was not analyzed systematically.The vibration of the drill string and the vibration strength can not be controlled reasonably and accurately.All these result in waste of energy,even damage the drilling string.Consequently,the safe and fast drilling is almost impossible.After systematic analysis of various factors,such as the structure of drill bit and drilling string system（bottom hole assembly,bit type）,drilling parameters（bit weight,rotary speed）,geometry of drilled trajectory and formation character,combining with analysis of natural frequency of drilling string,vibration control method and procedure are established which can reduce the harm of severe vibration effectively,achieve higher rate of penetration,shorten drilling period and increase return rate.