绳索取心复合钻柱的动力学行为研究

Dynamics Behavior of Compound Drill String for Wireline Coring

摘要:

绳索取心复合钻柱在岩心钻探“满眼钻进”过程中，钻杆易出现不同程度的划痕、压痕及磨痕等情况。本文利用非线性有限元方法，采用三维管单元对绳索取心复合钻柱拉压两处截面的涡动轨迹、涡动速度、横向振动、纵向振动规律进行了分析。结果表明：转速的增加和钻压的增大会显著增加钻柱与井壁的碰撞次数；在相同钻压条件下，随着钻柱回转速度的增大，钻柱与井壁的碰撞机率增加、接触轨迹增长，致使钻柱与孔壁的滑动摩擦机会增多；钻柱的涡动速度均值将随钻压和转速的增加而增大，转速大于钻压的影响；转速的增加则会加大钻柱的横向振荡频率，钻压的增大会增加钻柱横截面的纵向振荡幅值。

Abstract:

During full-hole core drilling, wire-line coring compound drill string is easy to have scratch, indentation and wear marks. Based on nonlinear finite element method and using three-dimensional pipe unit, two composite sections of compound drill string were analyzed about its dynamics behavior including whirl orbit, whirl speed, lateral vibration and longitudinal vibration. The results showed that with the increase of rotary speed and WOB, the collision time of the drill string and the well wall significantly increased; under the same WOB, along with the increase of the rotary speed, the collision probability of drilling string and well wall increased and the contact trajectory became lengthened, which led to more sliding friction between the drill string and the well wall; with the increase of WOB and rotary speed, the mean value of whirl speed increased, the effect of rotary speed was larger than WOB; the increase of rotary speed would increase the lateral oscillation frequency of drill string, the increase of WOB would increase the longitudinal oscillation amplitude of drill string cross section.