胎体耐损性弱化孕镶金刚石钻头的试验及碎岩机理分析

Experiment and rock fragmentation mechanism of impregnated diamond bit with weakening matrix

为了提高孕镶金刚石钻头在坚硬致密弱研磨性地层的钻进效率,将胎体耐磨损性弱化理论引入钻头设计中,对胎体耐磨损性弱化孕镶金刚石钻头碎岩机理进行探讨并对胎体进行扫描电镜分析。研究结果表明:与普通孕镶金刚石钻头相比,胎体耐磨损性弱化孕镶金刚石钻头的机械钻速提高了64%;经弱化处理的钻头在钻进过程中,弱化颗粒易于从胎体表面脱落,使其表面形成非光滑形态,减少了钻头唇面与孔底岩石面之间的接触面积,提高了钻头唇面与岩石的单位面积压力,改善了金刚石颗粒的冷却效果,降低了金刚石颗粒的热损耗;脱落的弱化颗粒在孔底参与磨损钻头胎体,增加了孔底岩粉的研磨能力,促进了胎体中新颗粒金刚石的出刃。

Weakening matrix theory was applied to design of the drilling bit to improve the drilling efficiency of impregnated diamond bit in hard compact rock formation. The rock fragmentation mechanism was studied and the matrix was analyzed by SEM. The results show that drilling efficiency increases by 64% compared with that of the conventional impregnated diamond bit. Under the process of drilling, the weakening particle can easily drop from matrix developing non-smooth surface, the working surface area in contact with the rock is reduced, the pressure between surface and rock increases, and the cooling effect of diamond is improved. The weakening particle participates in wearing matrix, which increases the abrasive power of rock powder, and promotes the speed of diamond metabolism.