Drilling apparatus and method

摘要

The present disclosure provides a drilling method and drill. According to a disclosed method, multiple reciprocating rock-breaking elements, including a hammer drill bit, are used. The elements are moved in alternation to each other such that the net volume displacement by the moving parts is reduced for reducing compression work and thus for losing useful energy from the available amount from the drill bit engine for rock breaking. If desired, a small component of the net volume displacement is kept for enhancing PVW for enhancing rock chipping by tensile strength. The method also includes synchronizing the peak of the pressure depression wave with that of the impact moment of the drill bit's reciprocating motion to enhance, rather than hamper, rock breaking by the creation of PVW.

主权项

1. A drilling method comprising, in a downhole environment:
actuating a reciprocating rock-breaking element including at least one drill bit to impact a rock formation; manipulating pressure waves in a downhole environment as the at least one drill bit of the reciprocating rock-breaking element impacts the rock formation, actuating a pressure-cycling member to decompress wellbore fluid proximate the rock-breaking element in the downhole environment; actuating the reciprocating rock-breaking element away from the rock formation; and as the at least one drill bit of the reciprocating rock-breaking element is moved away from the rock formation, actuating the pressure-cycling member to compress the wellbore fluid proximate the rock-breaking element; wherein the reciprocating rock-breaking element impacting the rock formation creates pressure and velocity waves to enhance rock breaking.