Integrated Drill Rod for Coal Seam Gas Drainage
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Solution Overview
Problem
Current gas drainage methods for deep low-permeability coal seams are inefficient due to poor permeability increasing effects, low gas drainage efficiency, complex operation procedures, and high production costs, requiring multiple boreholes and repeated drill bit operations.
Innovation Solution
A deep low-permeability gassy seam drilling-slitting-sealing-fracturing device and method that integrates drilling, slitting, sealing, and fracturing processes using a single device, featuring a drilling control system, high-pressure water power system, water pressure grading control system, and fracturing and sealing control system, allowing for real-time adjustments of drilling direction, water pressure, and operation sequences to enhance gas drainage efficiency and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple boreholes are constructed for gas drainage, then gas drainage coverage is improved, but construction efficiency decreases and production costs increase
Solution Approach 1:
The patent combines multiple boreholes into a single integrated borehole that performs drilling, slitting, sealing, and fracturing operations sequentially. The drill rod is equipped with multiple functional components (slitting water outlet, sealing capsule, fracturing water outlet) that can operate in sequence without removing the drill bit, effectively merging what would traditionally require multiple separate boreholes into one integrated structure.
Solution Approach 2:
The drill rod is designed as a universal tool that performs multiple functions: drilling the borehole, creating slits in the coal seam, sealing the borehole with an inflatable packer, and performing hydrofracturing. This multi-functional design eliminates the need for separate specialized equipment for each operation, reducing the total number of boreholes needed while maintaining comprehensive gas drainage capability.
2Ease of operation
If repeated drill bit operations are performed for drilling, slitting, sealing and fracturing, then operational flexibility is improved, but working time increases and efficiency decreases
Solution Approach 1:
The drill rod is pre-equipped with all necessary functional components (slitting water outlet, sealing capsule, fracturing water outlet) before the drilling operation begins. This preliminary preparation allows all subsequent operations (slitting, sealing, fracturing) to be performed continuously without removing or replacing the drill bit, eliminating the time loss associated with repeated drill bit operations while maintaining operational flexibility through controlled water pressure adjustments.
Solution Approach 2:
The patent enables continuous useful action by maintaining the drill bit in the borehole and sequentially activating different functional components through water pressure control. The slitting water outlet, sealing capsule, and fracturing water outlet operate in sequence without interrupting the drilling operation, ensuring continuous productive work rather than repeated cycles of drilling, removing, and repositioning the drill bit.
3Productivity
If single borehole operations are used for gas drainage, then construction efficiency is improved, but permeability increasing effect is insufficient
Solution Approach 1:
The patent segments the coal seam treatment into distinct functional zones within a single borehole: the slitting water outlet creates fractures in the coal seam, the sealing capsule isolates the borehole section, and the fracturing water outlet performs hydrofracturing. This segmentation allows each component to perform its specific function effectively while all functions operate within the same borehole structure, maintaining construction efficiency while achieving reliable permeability increase.
Solution Approach 2:
The patent utilizes parameter changes in water pressure to activate different functions of the drill rod. By controlling water pressure at different levels (slitting pressure, sealing pressure, fracturing pressure), the system transitions between different operational modes without changing the physical structure. This parameter-based control enables a single borehole to achieve multiple treatment effects, including sufficient permeability increase through controlled hydrofracturing.
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
The integrated device simplifies operations, improves gas drainage efficiency, and ensures safety by allowing single-device operation without repeated drill bit movements, enhancing permeability and reducing dust, while maintaining flexible and convenient drilling operations.
Implementation Method 1
the high-pressure water power system supplies high-pressure water with a pressure of 0-50 MPa
Implementation Method 2
hydrofracturing and permeability increasing are performed for a coal mass by injecting high-pressure water
Implementation Method 3
adjusts a water pressure for flushing of drill cuttings to less than 5 MPa
Implementation Method 4
adjusts a water pressure for sealing with a borehole sealing capsule to 35-40 MPa
Data Source
AI summary
A deep low-permeability gassy seam drilling-slitting-sealing-fracturing drilling device includes a drilling control system, a high-pressure water power system, a water pressure grading control system and a fracturing and sealing control system. The drilling control system adjusts a drilling direction a water supply pressure of the drill rod, the high-pressure water power system supplies high-pressure water with different pressures to the device, and the water pressure grading control system ensures that a water pressure for flushing drill cuttings is less than 5 MPa, a water pressure for slitting in a direction perpendicular to a length of the drill rod is 25-35 MPa, a water pressure for sealing with a borehole sealing capsule is 35-40 MPa, and a water pressure for further pressure relief and permeability increasing of a coal seam is 40-50 MPa. The fracturing and sealing control system controls borehole sealing and hydrofracturing operations.