超高速下单粒金刚石与岩石相互作用响应的研究

Research on the response of single diamond particles and rock interaction at ultra-high speed

摘要:

随着钻进深度的加深，破碎硬岩地层愈发困难，提高转速成为硬岩地层快速有效破碎的可行方法之一。孕镶金刚石钻头在硬岩层中具有较好的应用效果，常规转速下孕镶钻头与岩石之间相互作用机理较为完善，超高转速下也有相应的应用和研究基础，但碎岩机理尚未完全清晰。为探究常规速度至超高速下单粒金刚石对岩石的切削力和硬岩的破碎变化情况，以孕镶钻头和岩石相互作用界面响应模型为基础，利用ABAQUS软件建立单粒金刚石切削岩石的二维模型，并提出一种近似分析方法，并进一步推导单粒金刚石受力表达式。结果表明：（1）单粒金刚石对岩石的切削作用主要集中在切削具与岩石接触界面的中上部，高速下比常规切削速度下单粒金刚石受切削力减小，且主要作用部位受到切削速度改变的影响。（2）金刚石颗粒作用岩石中存在塑性破坏和脆性破坏且两种破坏模式交替产生，超高速下岩石产生脆性破坏的比例相比于常规切削速度有所增加，且超高速下切削力波动范围更小，岩石破碎所需的能量更少。（3）提出一种孕镶金刚石钻头碎岩响应近似分析方法，将产生碎岩作用的金刚石颗粒等价为具有“刀尖”和“前、后刀面”的切削具进行分析，推导得到单粒金刚石受力表达式，其受力与切削速度、切削深度等因素有关。研究结果可以为提高转速切削硬岩地层的进一步研究及应用提供依据和参考。

关键词:孕镶金刚石钻头;单粒金刚石;超高速;碎岩模式转变;名义“刀尖”;碎岩响应

Abstract:

With the deepening of drilling depth， breaking hard rock formations became more difficult， and increasing rotational speed has become one of the feasible methods to break hard rock formation rapidly and effectively. The impregnated diamond bit has a good application effect in the hard rock formation， the interaction mechanism between the impregnated bit and rock is relatively perfect at conventional speed， and there is also a corresponding application and research basis at high speed and ultra-high speed. However， the rock fragmentation mechanism at high speed to ultra-high speed is not completely clear. Based on the interface laws for impregnated diamond and rock， a two-dimensional model of single diamond cutting rock is established by using ABAQUS software， and an approximate analysis method is proposed to define and calculate the nominal “tool tip” position， and further derive the force expression of single diamond， in order to explore the rock cutting force and changes of hard rock breaking from conventional speed to high speed and ultra-high speed by single diamond. The result shows that the cutting action of single diamond on rock is mainly concentrated in the middle and upper part of the interface between the cutting tool and the rock. The cutting force of a single diamond at high speed is lower than that under conventional cutting speed， and the main action part is affected by the change of cutting speed. There are plastic fracture and brittle fracture in the interaction between diamond particles and rock， and the two failure modes occur alternately. The proportion of brittle fracture at high speed increases compared with conventional speed， and the fluctuation range of cutting force at high speed is smaller， and the he energy required for rock breaking is much less. An approximate analysis method of rock-breaking response of the impregnated diamond bit is proposed， which equals the diamond particles as a cutting tool with “tip” and “front and rear” through analysis， the force expression of single diamond which is related to factors such as cutting speed and cutting depth is derived， and force is. The research results can provide a basis and reference for further research and application of breaking hard rock formations with increased rotational speed.

Key words:impregnated diamond bit;single diamond particles;ultra-high speed;transformation of rock fragmentation mode;nominal “tool tip”;response of rock breaking