栅格胎体孕镶金刚石钻头的破岩机理分析

Analysis on rock fragmentation mechanism of impregnated diamond bit with grids matrix

从岩石宏观裂纹变化出发,研究孕镶金刚石钻头在钻进过程中由于岩体裂纹的影响而造成的断裂问题。运用岩石断裂力学理论,结合钻头实际工作条件,简化应力、水力及裂纹条件,建立了简化的岩石断裂等效模型,从理论上分析了一种新型栅格胎体孕镶金刚石钻头的破岩机理。研究结果表明:与常规的钻头相比,新型钻头的特殊栅格结构能有效提高钻压,比压由原来的68.03 kgf/cm^2增加到了113.33 kgf/cm^2,提高了将近67%,使钻头能更有效地压入岩体,产生破碎穴及裂纹;特殊的栅格结构有利于冲洗液的储存,改善了金刚石颗粒的冷却效果,从而以更加有利的拉裂破坏方式破碎岩石。

Based on the change of rock macroscopic crack,fracture problem caused by rock crack during the drilling with impregnated diamond bit was studied.A simplified rock fracture equivalent model was established with simplified stress and crack by using the rock fracture mechanics theory combining practical working conditions in the process of drilling,a new rock fragmentation mechanism of impregnated diamond bit with grids matrix was analyzed theoretically.The results indicated that special grid structure can effectively increase drilling pressure to press into rock to induce crushing cavity and crack compared with that of the conventional impregnated diamond bit,pressure per unit area increased by 67%,from 68.03 kgf/cm^2 to 113.33 kgf/cm^2.Special grid structure is conducive for the flushing fluid to store,better to improve the cooling effect of diamond particles,and to break rock matrix in a more beneficial way of tensile crack.