导向钻具振动特性分析

Analysis of steering drilling vibration characteristics

在钻进过程中,钻具振动是一个无法避免且信号复杂的现象,并伴有横向、纵向和扭转等多种振动形式。剧烈的纵向偏转振动、大幅度的粘滑扭转振动以及剧烈的横向振动等现象不仅会影响钻井速度,还容易使钻柱疲劳破坏,诱发钻井事故,大大增加了钻井成本和风险。通过分析钻具振动产生机理以及产生振动的原因,对钻柱振动信号进行实时监测和分析,利用钻具产生的振动可以传输井下钻具情况和岩层信息这一特点,有效控制钻柱振动,判断井下工况,预防钻井事故,优化钻井以及识别地层岩性。通过实钻井实验验证了对于垂直钻进过程中,由于钻柱在井下复杂情况下的振动信号的影响,使得导向钻具系统的姿态参数测量误差较大,特别是井斜角和方位角。钻进中根据实际井斜情况,可以按照理论设计及时调整姿态参数,对系统进行防斜纠错。因此,对钻具振动信号特性进行分析,有利于识别钻具损坏、降低钻进成本。

During the drilling process,the drill tool vibration is unavoidable and generates complex signals.It is accompanied by transverse,longitudinal and torsional vibrations.Severe longitudinal deflection vibration,large stick⁃slip torsional vibration and severe transverse vibration not only affect the drilling speed,but also be prone to causing fatigue damage to the drill string and leads to drilling accidents,which greatly increases drilling costs and risks.In view of the above,the drill string vibration signals are monitored in real time and analyzed by analyzing the vibration generation mechanism of the drill tools and its vibration causes.The vibration generated by drilling tools is used to transmit the information of down⁃hole drilling tools and rock formation,so as to effectively control the vibration of drilling string,judge down⁃hole conditions,prevent drilling accidents,optimize drilling and recognize the lithology.It is verified by the actual drilling experiment that,due to the influence of the vibration signal of the drill string under the complicated underground conditions,the measurement error of attitude parameter of the steerable drilling system is large during the vertical drilling process,especially the inclination angle and azimuth angle.In the drilling process,according to the actual well inclination,the attitude parameter can be adjusted in time according to the theoretical design to perform system inclination prevention.Therefore,the characteristic analysis of the drill tool vibration signals is beneficial to the identification of the damage of the drilling tools and reducing the drilling cost.