同轴双向回转钻进破岩效率研究

Research on rock-breaking efficiency of coaxial contra-rotary drilling

摘要:

国内外相关研究均显示同轴双向回转可有效降低钻具振动和提高破岩效率，但双向回转相对传统单向回转的钻进效率的提升水平研究较少。据此，本文建立双向回转钻头以及单向回转钻头与岩石相互作用的有限元模型，以破岩比功作为评价指标量化比较分析了2种钻头的破岩效率。通过定义双向钻头内外壁尺寸差、内外钻头的间隙、内钻头壁厚与双向钻头内外壁尺寸差之比、内外钻头转速比和内外钻头底部高度差5种核心参数，并设计正交试验完成了仿真分析。结果显示，内外钻头高度差与内外钻头间隙对于破岩比功影响比较小，内外钻头尺寸差、内外钻头转速比和内钻头壁厚与双向钻头内外尺寸差之比对破岩比功影响显著。

Abstract:

Related research at home and abroad have shown coaxial contra-rotary drilling can effectively reduce drilling tool vibration and improve the rock breaking efficiency. There are few researches on the improvement level of drilling efficiency of coaxial contra-rotary drilling compared with traditional drilling. In view of the above， the finite element model of interaction between coaxial contra-rotary bit and rock is established and the finite element model of interaction between conventional bit and rock is established. The rock breaking efficiency of the two kinds of drill bits is compared quantitatively with rock breaking specific work as evaluation index. The orthogonal experiment is designed by defining five core parameters， the size difference between the inner and outer wall of the coaxial contra-rotary bit， the gap between the inner and outer wall of the coaxial contra-rotary bit， the ratio of the inner and outer wall thickness to the size difference between the inner and outer wall of the coaxial contra-rotary bit， the rotating ratio of the inner bit and outter bit and the bottom height difference of the inner and outer bit. The simulation analysis is completed according to the orthogonal experiment. The result show that the height difference between the internal and external bit and the internal and external bit clearance have little influence on the rock breaking specific work， while the size difference between the inner and outter bit， the rotating ratio of the inner and outter bit and the ratio of the wall thickness of the inner bit to the size difference between the inner and outer wall of the coaxial contra-rotary bit have significant influence on the rock breaking specific work.