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钻柱失稳对钻井作业造成诸多不利影响，钻压传递困难，易发生卡钻以及对井壁稳定和井眼轨迹控制不利。石油大学采用水平井“九五”课题组自行设计的钻柱稳定性实验台进行了钻柱稳定性试验。试验中采用内径３０ｍｍ、外径４０ｍｍ的透明有机玻璃管模拟井壁，采用 １４ｍｍ、 １２ｍｍ、 １０ｍｍ、 ８ｍｍ等不同尺寸的紫铜管模拟不同外径、刚度、单位长度重量的受压钻杆，分别对各种试件在９０°、６０°、３０°、０°倾角的不同条件下进行了试验。试验表明：１．各试件基本上遵循相同的规律，即非失稳状态、初始失稳及准螺旋失稳状态、准螺旋失稳及螺旋失稳状态３个阶段。２．摩阻力对钻柱失稳具有迟滞作用，在一定程度上起到增加钻柱稳定性的作用。３．改变试件的倾角．在试件自重的影响下随着与竖直方向夹角的增大，试件的失稳载荷增加，证明了与理论分析的一致性。还证明了现有理论结果预测值大都高于试验值，其中准螺旋理论结果与试验值较为接近，可供实际钻井作业参考。
Drill string instability caused a lot of adverse effects on drilling operations, WOB pressure transmission difficulties, prone to sticking and borehole stability and well trajectory control adverse. The University of Petroleum conducted a drill string stability test using a drill string stability test bench designed by a group of horizontal wells in the Ninth Five-Year Plan. In the experiment, a transparent plexiglass tube with an inner diameter of 30mm and an outer diameter of 40mm was used to simulate the borehole wall. Pressure-controlled drill rods with different outer diameters, stiffness and unit length weights of 14mm, 12mm, 10mm, Various specimens were tested under different conditions of 90 °, 60 °, 30 ° and 0 ° inclination. Tests show that: 1. The test specimens basically follow the same rule, that is, three stages: non-steady state, initial instability and quasi-helical instability, quasi-helical instability and spiral instability. 2. Frictional resistance hysteresis on the drill string instability, to a certain extent, play an increasing role of the stability of the drill string. 3. Change the inclination of the specimen. Under the influence of specimen self-weight, with the increase of the included angle with the vertical direction, the instability load of the specimen increases, which proves the consistency with the theoretical analysis. It is also proved that the predictions of the existing theoretical results are mostly higher than the experimental values, and the quasilinear theory results are close to the experimental values, which can be used for actual drilling operations.