水平井施工中的钻具安全

The Safety of Drilling Tools in Horizontal Well Construction

水平井施工中钻具不同于直井的钻具组合,采用滑动钻进方式,钻柱不旋转,钻柱与井壁间的摩阻完全有钻柱轴向力克服,钻柱发生屈曲,产生托压甚至自锁,容易卡钻,使水平钻进无法进行。在水平井施工中由于井斜角和水平位移的增加,摩阻和扭矩增大是非常突出的问题。特别是深井水平段较长时,对钻具安全提出了更高的要求,需要保证较高的安全系数;另外深井长水平段施工中,水平段钻柱的屈曲也是一个无法回避的问题。

The drilling tools, which be used in horizontal well construction, are different from the drilling tools which be used in vertical well drilling. It uses the slide drilling method so that the drills stems cannot rotate. The friction which generates between the drills stems and well walls is totally overcome by the axial force of drills stems. As a result, the drills stems will easily bend and generate pressure even become self-locking. At the same time, the drill bit is easily stuck so that the horizontal well drilling cannot be proceeded. During the process of horizontal well construction, the friction and torque increasing will he very serious because of the increasing of hole drift angle and horizontal displacement, especially when the horizontal segment is longer in a deep well, because the higher security factor must he guaranteed since there are higher requirement to the drilling tools safety. Moreover, during the construction process of horizontal segment in deep wells, the drill stem bend in horizontal segment is cannot he avoided.