An innovative combined drilling tool
The project aims to develop a non-conventional, fully fluid driven drilling system, combining 4 main components:
- A High-Pressure Water Jet system able to slot grooves at desired depth and position;
- A pressure intensifier feeding the High-Pressure Mud Jet system, activated preferably by the induced axial drilling vibrations, hence damping at the same time the harmful drilling vibrations;
- A high-power advanced downhole MUDHammer;
- A diamond-enhanced-insert hammer bit.
MUDHammer – High power for hard rock drilling
The Drillstar MUDHammer is the first field-proven hammer drilling solution capable of using most standard, weighted drilling fluids. The fruit of 20 years of research and development, it brings percussion drilling performances all the way down to deeply buried formations. It relies on 2 main components:
1) A high-power, fluid-driven downhole hammer, delivering high-energy impacts dozens of times per second.
2) A range of specific hammer bits, designed to deliver the best rates of penetration (ROP) based on the formation and depth drilled.
Unlike traditional rotary bits, hammer bits rely primarily on impact energy to drill rather than weight & rotation. This means high energy levels can be transmitted to the rock while maintaining lower weight on bit, RPM and torque levels. This higher drilling power translates directly into higher ROP, especially in hard or very hard formations, like the ones encountered at targeted depths for geothermal exploitation.
Intensifier - Utilizing axial vibration energy of drill strings
The intensifier utilizes the axial vibration energy of drill strings, as a substitute of the fluid energy, to drive the plunger. This energy-saving mode not only diminishes the amplitude of the vibration by energy absorption, but pressurizes the fluid to an ultra-high level as an auxiliary power to break the rock. The reciprocating motion driven by the vibration energy of the drill strings, in this way, continuously generates high pressure fluid flow to assist the drill bit to break the rock, increasing the ROP.
The intensifier utilizing axial vibration energy of drilling string (Liao et al. (2015)
