Laser-Mechanical Drill Bit for Hard Rock Drilling
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Solution Overview
Problem
Conventional drilling methods face challenges in efficiently advancing boreholes in hard and ultra-hard rock formations due to excessive weight-on-bit (WOB) leading to rapid bit wear and economically unviable drilling rates.
Innovation Solution
The development of laser-mechanical drill bits that combine high power laser energy with mechanical forces to remove material from borehole surfaces, allowing for reduced WOB and increased drilling efficiency by maintaining cutter temperatures below thermal degradation levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional mechanical drilling is used to advance boreholes in hard and ultra-hard rock, then drilling can be performed, but excessive weight-on-bit causes rapid bit wear and economically unviable drilling rates
Solution Approach 1:
The patent combines laser energy delivery with mechanical drilling by integrating a laser beam delivery system with a drill bit assembly. The laser beam is delivered through the drill bit to the borehole surface, creating a fusion of optical and mechanical drilling methods that work together to remove rock material.
Solution Approach 2:
The patent replaces pure mechanical drilling with a hybrid system where laser energy is used to heat and soften the rock, reducing the mechanical forces required. The laser beam delivers thermal energy to the borehole surface, substituting part of the mechanical cutting process with thermal softening, thereby reducing weight-on-bit requirements and bit wear.
2Productivity
If high power laser energy is delivered to the borehole surface to soften rock, then material removal is facilitated, but cutter temperature increases which can lead to thermal degradation
Solution Approach 1:
The patent extracts harmful thermal energy from the cutter region by providing dedicated cooling passages. These passages allow cooling fluid to flow through the drill bit, specifically removing heat from the cutter area to prevent thermal degradation while maintaining the high power laser energy delivery to the borehole surface for effective material removal.
Solution Approach 2:
The patent introduces a cooling fluid as an intermediary substance that transfers heat away from the cutters. The cooling fluid flows through cooling passages in the drill bit, absorbing excess heat and acting as a thermal intermediary between the heat source (laser) and the sensitive components (cutters), thereby maintaining operational temperatures below degradation thresholds.
3Strength
If conventional mechanical drilling is used, then drilling can be performed, but excessive weight-on-bit is required leading to rapid bit wear
Solution Approach 1:
The patent changes the physical state of the rock from a cold, hard state to a warmed, softened state by delivering high power laser energy to the borehole surface. This parameter change in temperature reduces the rock's resistance to mechanical removal, allowing drilling to proceed with significantly reduced weight-on-bit and thereby extending bit life.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly extends bit life, reduces friction, and enables faster and more economical drilling through hard rock formations with lower weight-on-bit, maintaining cutter temperatures below 400°C and achieving drilling rates of up to 20 ft/hr in 35 ksi rock.
Implementation Method 1
delivering high power laser energy in conjunction with mechanical forces to a surface, such as the end of a borehole
Implementation Method 2
laser beam to a surface, such as the end of a borehole, to remove material from the surface
Implementation Method 3
mechanical forces to advance a borehole
Implementation Method 4
remove material from the surface
Implementation Method 5
cooling fluid flow paths that provide for cooling of the cutters
Data Source
AI summary
An apparatus with a high power laser-mechanical bit for use with a laser drilling system and a method for advancing a borehole. The laser-mechanical bit has a beam path and mechanical removal devices that provide for the removal of laser-affected rock to advance a borehole.