预弯曲动力学防斜打快钻具组合动力学模型

Dynamic model of bottom hole assembly used in pre-bending dynamic vertical and fast drilling technology

建立了预弯曲动力学防斜打快钻具组合的动力学模型,对其动力学特性进行的仿真研究。结果表明,这种模型可以较好地反映出钻具组合在井下的涡动轨迹、涡动速度和涡动方向,同时能近似地计算出这种钻具组合的动态相对防斜力大小。钻具组合的涡动使得钻头对下井壁的动态侧向冲击力明显大于对上井壁的动态冲击力,从而使钻头具有较大的动态防斜力。通过合理设计结构参数和施工参数,可以有效地改善预弯曲动力学防斜打快钻具组合的涡动特征,从而使这种钻具组合具有较好的防斜效果。预弯曲动力学防斜打快技术的使用钻压比钟摆极限钻压提高50%以上,相应地提高了机械钻速。

The dynamic model of bottom hole assembly （BHA） used in pre-bending dynamic vertical and fast drilling （PBDVD） technology was established. The simulation of dynamic features of BHA shows that the trace, speed and direction of whirl motion of BHA can be reflected preferably by this model. The dynamic anti-deviation force of BHA can be calculated approximately. The dynamic impact force of bit acted on low side of hole-wall is larger than that on upper side due to the whirl motion of BHA used in PBDVD, which leads to a large dynamic anti-deviation force. The whirl features of BHA can be effectively improved by optimizing the structure parameters and operation parameters. The hole can be controlled vertically with a weight on bit higher 50% than the maximum weight on bit used for pendulum BHA. The mechanical speed of drilling can be enhanced.