Self-Adjusting Drill Bit Pads for Vibration Control
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Solution Overview
Problem
Drill bits experience fluctuations and vibrations due to changes in rock formations, leading to inefficient drilling and premature damage, as existing control methods for rate of penetration and depth of cut require surface-based actions with non-immediate effects.
Innovation Solution
A downhole rotary drilling tool with extendable and retractable pads controlled by a rate control device that adjusts the depth of cut based on force and pressure applied during drilling, allowing for automatic adjustment of the drill bit's aggressiveness and reducing vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drill bit aggressiveness is increased to improve drilling speed, then productivity increases, but vibrations and fluctuations increase causing premature damage
Solution Approach 1:
The pad is made movable rather than fixed, allowing it to dynamically adjust its position relative to the drill bit body. The pad can extend and retract based on real-time drilling conditions, enabling the system to optimize between aggressiveness and stability automatically during operation
Solution Approach 2:
The depth of cut parameter is dynamically changed by adjusting the pad position. By controlling how much the pad extends from the drill bit body, the system can modify the effective depth of cut to match formation hardness variations, thereby maintaining productivity while reducing harmful vibrations
2Ease of operation
If surface-based control methods are used to control rate of penetration and weight-on-bit, then drilling parameters can be adjusted, but the impact on drill bit fluctuations is not substantially immediate
Solution Approach 1:
The drill bit system performs self-regulation through the movable pad mechanism that automatically responds to drilling conditions. The pad's movement is controlled by forces generated during drilling itself, eliminating the need for external surface-based control systems and providing immediate autonomous adjustment
Solution Approach 2:
The system incorporates inherent feedback through the force and pressure applied to the pad during drilling. The pad position automatically adjusts in response to the forces generated by the drilling process itself, creating a closed-loop control system that provides immediate response to changing conditions
3Productivity
If the depth of cut is increased to improve drilling efficiency, then productivity increases, but vibrations and fluctuations increase causing premature damage
Solution Approach 1:
The pad position is made dynamic rather than fixed, allowing continuous adjustment of the depth of cut during drilling operations. This enables the system to optimize drilling efficiency while automatically reducing depth of cut when vibrations occur, thereby eliminating the need to choose between productivity and vibration control
Solution Approach 2:
The depth of cut parameter is continuously adjusted by changing the pad extension distance. By modifying this critical parameter in real-time based on drilling conditions, the system can maintain high productivity during normal operation while reducing depth of cut to minimize vibrations when encountering hard formations or abnormal conditions
Data Source
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AI summary
In one aspect, a drill bit is disclosed, including: a bit body; a pad associated with the bit body; a rate control device coupled to the pad that extends from a bit surface at a first rate and retracts from an extended position to a retracted position at a second rate in response to external force applied onto the pad, the rate control device including: a piston for applying a force on the pad; a biasing member that applies a force on the piston to extend the pad at the first rate; a fluid chamber associated with the piston; and a pressure management device for controlling a fluid pressure within the fluid chamber.