Drill Bit Induced Unloading and Abrasive Jet Generation
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Solution Overview
Problem
Current drill bit technologies fail to efficiently release bottom-hole stress and generate abrasive jets underground, limiting drilling speed and rock breaking efficiency, as they require additional tools or complex rig modifications.
Innovation Solution
A drill bit with a joint function of induced unloading and abrasive jet, featuring an annular and central drill bit design where the central bit is recessed and non-rotatable, allowing for in-situ abrasive jet generation by mixing drilling fluid with rock debris, enhancing rock breaking efficiency without additional tools or rig complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydraulic energy methods (pulse cavitation jet, ultra-high-pressure pulse jet, abrasive jet) are used to release bottom-hole stress, then drilling speed is improved, but device complexity increases due to requiring special tools above the drill bit and consuming hydraulic energy
Solution Approach 1:
The patent combines the stress release function and abrasive jet generation function into a single integrated drill bit structure. The annular drill bit with rock pillar through hole and central drill bit configuration merges the induced unloading mechanism with the abrasive jet generation system, eliminating the need for separate special tools above the drill bit while maintaining improved drilling speed
Solution Approach 2:
The drill bit generates its own abrasive jet using the drilling fluid and rock debris produced during the drilling process itself. The rock debris from rock pillar breaking is automatically collected and mixed with drilling fluid to form the abrasive jet, making the system self-sufficient without requiring external abrasive supply systems or additional hydraulic energy input
2Productivity
If abrasive jet is generated above ground with special equipment, then rock breaking efficiency is improved, but drilling costs increase and drill strings are eroded
Solution Approach 1:
The patent replaces the above-ground mechanical abrasive jet generation system with an underground generation system that uses the drill bit itself as the generator. The abrasive jet is created in-situ by mixing drilling fluid with rock debris through the drill bit's internal channels and nozzles, eliminating the need for external equipment that causes drill string erosion and increases costs
3Productivity
If underground abrasive jet generation is implemented with an underground generator, then rock breaking efficiency is improved, but bottom-hole drill rig combination complexity increases
Solution Approach 1:
The patent merges the abrasive jet generation function directly into the drill bit structure itself. The annular drill bit with rock pillar through hole and central drill bit configuration integrates the rock breaking mechanism with the abrasive jet generation system, using the drill bit's own structure (channels, nozzles, rock debris collection) to generate the jet without requiring separate underground generator equipment
Solution Approach 2:
The drill bit performs multiple functions simultaneously: it breaks rock through the annular and central bit configuration, generates abrasive jet through its internal channels and nozzles, and releases bottom-hole stress through the induced unloading mechanism. This multi-functionality eliminates the need for additional specialized equipment in the bottom-hole drill rig combination
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 design enables simultaneous stress unloading and abrasive jet generation, improving drilling speed and rock breaking efficiency across various well types with a simplified structure and operation, applicable to both vertical and directional wells.
Implementation Method 1
The abrasive jet may fully exert the hydraulic energy at the drill bit to realize high efficient rock breaking
Implementation Method 2
one method of releasing the stratum stress based on hydraulic energy, represented by pulse cavitation jet speed-up technique, ultra-high-pressure pulse jet speed-up technique
Data Source
AI summary
A drill bit performs pilot rock-breaking using an outer annular drill bit and breaks a central rock pillar using a central drill bit mounted in the middle of the annular drill bit and located inside a drill bit body to induce unloading of a bottom hole stress. A method mixes rock debris produced by rock breaking of the central drill bit as abrasive with the drilling fluid flowing into the entire drill bit as abrasive jet liquid phase to form an abrasive jet. The method includes obtaining an annular borehole by braking, and breaking the rock pillar at the inner side of the annular borehole to induce unloading of the bottom hole stress, mixing the rock debris produced by breaking the rock pillar at the inner side of the annular borehole as abrasive with the drilling fluid entering the drill bit to form an abrasive jet.