钻杆反转运动及其弯曲频率分析

根据塔里木油田井身结构尺寸、钻井参数,详细地分析了塔里木油田钻杆反转转速、弯曲频率和其环隙比与反转运动的关系.钻杆内不但存在自转转速,而且还存在反转转速,其弯曲频率为钻杆自转转速与其反转转速之和.在钻杆自转转速一定时,钻杆的反转转速与环隙比值β有关.研究结果表明,预防塔里木油田钻杆刺漏失效措施可用:(1) 转盘转速控制在(44.5～92.0)r/min;(2) 在钻杆尺寸不变的情况下,可以增大套管结构尺寸,来降低钻杆的弯曲疲劳应力频率;(3) 采用井底动力钻具.研究的结果为深井、超深井合理的钻井参数选择提供了理论依据.

Analysis of Drill Pipe Reverse Rotation and It's Bending Frequency

Based on the well structure size and the drilling parameters, the characteristic of drill pipe reverse rotation, the calculating formula of the reverse rotation speed and its bending frequency was analyzed in detail. The rotation speed is not only in the drill pipe, but also the reverse rotation speed is in the drill pipe, its bending frequency is the sum of the drill pipe rotation speed and its reverse rotation speed. Under the certain drill pipe rotation speed, the reverse rotation speed of the drill pipe is related to the annulus gap ratio. The results indicated the measures prevented the drill pipe washout of Tarim oil field: 1. the rotation speed of the turntable should be controlled within (44.5-)92.0 r/min; 2. Under the case of the certain drill pipe size, the casing size is increased to decrease the bending stress frequency; 3. The bottom hole dynamical drill tools were adopted. It provides the theoretical supports for the reasonable drill parameter selections of the deep well and extra-deep well.