【摘要】 为进一步完善瓦斯抽采钻进过程中的孔壁失稳机理,提高钻进过程中的成孔率,以钻杆为研究对象,建立钻杆横向应力数学模型。用数值模拟求解结果分析钻杆横向应力对孔壁稳定性的影响。结果表明:(1)在速度上,钻杆横向初始速度越大,钻杆横向应力越容易造成孔壁失稳;(2)在结构上,在外径一定的条件下,钻杆内外径比值越接近1,钻杆横向应力越容易引起孔壁失稳、钻进在20米以内时,钻杆横向应力对孔壁的影响显著,但是随着钻杆钻进长度的增加,孔壁越不容易发生失稳;(3)在载荷上,轴向力越大,钻杆横向应力越容易引起孔壁失稳;(4)在空间位置上,钻杆与孔壁的间距越大,孔壁越容易发生破坏失稳。更多还原

【Abstract】 In order to improve borehole failure mechanism in the gas drainage drilling process and ratio of finishing gas hole,the drill pipe mass element can be considered to establish the mathematical model of drill pipe’s lateral stress. The method of numerical simulation is used to analyze the influence of drill pipe’s lateral stress on the stability of borehole. The research shows that(a)when it comes to the speed,the larger the initial velocity is,the easier the borehole failure happens.(b)When it com es to the structure,the closer of the diameter ratio is,the less stable of borehole will be. When the length of drill pipe changes within 20 m,the lateral stress of drill pipe has a significant effect on the stability of borehole.(c) When the outside diameter of drill pipe is given,the smaller the inside diameters is,the easier the borehole loses stability.(d)When it comes to the space,the wider the space between drill pipe and borehole,the greater the lateral stress,the easier borehole loses stability.更多还原