Double Rotary Drill Drive for Precise Toolface Azimuth Adjustment
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Solution Overview
Problem
Existing directional drills lack a mechanism for accurate and efficient toolface azimuth adjustment due to reliance on a single rotary power source, leading to poor control accuracy, high inertia, and frequent thread loosening during drilling, which complicates automated drilling operations.
Innovation Solution
A combined drilling system with double rotary driving devices, incorporating a main motor, gearbox, and a rotary speed reducer with a self-locking function, allows for precise toolface azimuth adjustment by engaging and disengaging toothed disks to control rotation speed and direction, reducing reliance on a single power source and enhancing control accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single main motor is used to drive drill pipes rotation, then high-speed rotation can be achieved, but toolface azimuth adjustment accuracy deteriorates due to high rotation speed and large moment of inertia
Solution Approach 1:
The patent divides the rotary driving function into two independent parts: the main motor for high-speed rotation and the downhole motor for low-speed precise adjustment. This segmentation allows each motor to operate in its optimal speed range, resolving the contradiction between high-speed rotation capability and precise azimuth adjustment.
Solution Approach 2:
The downhole motor acts as an intermediary device between the drill pipes and the driving force. It receives power from the mud pump and provides controlled low-speed rotation for precise toolface azimuth adjustment, mediating between the high-speed main motor and the requirement for accurate positioning.
2Power
If the main motor drives drill pipes rotation for toolface azimuth adjustment, then rotation power is provided, but control accuracy deteriorates due to large moment of inertia of transmission system
Solution Approach 1:
The patent segments the power delivery system into two paths: one through the main motor for high-power rotation, and another through the downhole motor for low-power precise control. This allows the system to have both high power capability and high control accuracy simultaneously.
Solution Approach 2:
The system changes the rotational speed parameter by using two different motors. The main motor operates at high speed for power-intensive operations, while the downhole motor operates at low speed for precision control, changing the operational parameters to match the required function.
3Productivity
If main motor drives drill pipes at high speed, then drilling speed requirement is met, but thread connection loosening occurs during reverse rotation
Solution Approach 1:
Instead of using the main motor for both forward rotation and reverse adjustment, the patent inverts the approach by using the downhole motor specifically for reverse rotation and azimuth adjustment. This prevents the high-speed main motor from causing thread loosening during reverse operations.
4Strength
If power head transmission system has large mass and inertia, then structural strength is maintained, but adjustment efficiency deteriorates due to inability to accurately stop
Solution Approach 1:
The patent segments the rotation control into two independent systems: the main motor-driven transmission system for high-speed rotation, and the downhole motor-driven system for precise positioning and stopping. This allows the heavy transmission system to maintain its strength while the lighter downhowe motor system provides precise control.
Data Source
AI summary
The present invention relates to a combined drilling system with double rotary driving devices and a control method, belonging to the technical field of coal mine drills. The other end of a driving shaft in the gearbox connects to an adjuster, which includes a transmission shaft, fixed toothed disk, moving toothed disk, rotary seat, end cover, and a rotary speed reducer with a self-locking function. One end of the transmission shaft is fixedly connected to the driving shaft. The fixed and moving toothed disks are sheathed on the transmission shaft, with the fixed toothed disk engaged with the moving toothed disk through skewed teeth. The moving toothed disk is rotationally connected and can slide axially along the transmission shaft. The rotary seat is fixedly connected to the moving toothed disk, while the rotary speed reducer's output disk is coaxially fixed to the rotary seat, enabling controlled rotation.