Down-The-Hole (DTH) percussion tool is recognized for its high average rate of penetration (ROP), when drilling medium hard to very hard rock formations. This ROP which depends on the bit-rock contact conditions at the well bottom to efficiently transfer the impact energy to an intact rock can be ma...

In this paper, we review and analyze published experimental findings in light of the hypothesis that the dependence of bit-rock interface (BRI) pseudo-stiffness on the weight-on-bit (WOB) is the key factor behind the existence of a sweet spot in percussive drilling, i.e., there is an optimal WOB for...

A phenomenological model is proposed to explain the existence of sweet spot in the relationship between the rate of penetration (ROP) and the weight-on-bit (WOB), i.e., the existence of an optimal WOB for which the ROP is maximized. The reasons that have been previously proposed to explain the exist...

Down-The-Hole (DTH) percussion tool is recognized for its high average rate of penetration (ROP), when drilling medium hard to very hard rock formations. This ROP which depends on the bit-rock contact conditions at the well bottom to efficiently transfer the impact energy to an intact rock can be ma...