A fluid pulse apparatus for down hole drilling having a turbine assembly actuated by a flow of drilling fluid. The apparatus has a narrowed fluid flow section that cooperates with a piston that moves between an open and a fluid flow restricting position. The apparatus has a turbine assembly that rotates in response to a flow of drilling fluid. The turbine apparatus has upper and lower cam surfaces that cooperate with fixed cam followers such that rotation of the turbine assembly and cam action between the cam surfaces and the fixed followers causes the turbine assembly to reciprocate axially. The piston is fixed to either of the upper or the lower cam surfaces such that as the turbine assembly reciprocates axially, the piston moves between the open and the flow restricting positions to create a pulsed fluid flow.

The present invention relates to a drilling device. The device comprises at least one drill rod, the or each drill rod having a first cylindrical wall defining an elongate chamber for receiving a working fluid to form a fluid column, the length of the fluid column being equal to a total length of the elongate chambers of the or each drill rod. The device also comprises a displacement excitation device arranged at a proximal end of the fluid column and configured to excite the fluid column to cause the working fluid in the fluid column to oscillate, wherein the excitation device is configured to excite the fluid column at an excitation frequency at or within 10% of a natural frequency of the fluid column determined based on the fluid column having a fixed boundary condition at a proximal end thereof. The device further comprises a tool piston moveably mounted at a distal end of the fluid column and a drilling tool connected to the tool piston such that the oscillation of the working fluid in the fluid column imparts an oscillating force to the drilling tool.