Electrohydraulic Drill Bit Pads for Depth of Cut Control
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Solution Overview
Problem
Drill bits often experience high fluctuations in rate of penetration and aggressiveness, making it difficult to control drilling efficiency and avoid bit damage, as surface-controlled methods to adjust weight-on-bit and rotational speed are not immediately effective.
Innovation Solution
A drill bit with extendable and retractable pads controlled by a force application device, which adjusts the depth of cut and axial aggressiveness in response to drilling parameters such as vibration, lateral movement, and stick-slip, using a motor-driven mechanism to extend and retract pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surface-controlled methods are used to adjust weight-on-bit and rotational speed, then drilling parameters can be controlled, but the control is not immediately effective and drill bit fluctuations cannot be quickly reduced
Solution Approach 1:
The drill bit incorporates movable pads that can dynamically adjust their position relative to the cutters in real-time during drilling operations. This dynamic adjustment allows immediate modification of drill bit aggressiveness and depth of cut without waiting for surface commands, directly addressing the delayed response issue of traditional surface-controlled methods
Solution Approach 2:
The system includes sensors that detect drill bit fluctuations and aggressiveness, providing real-time feedback to a controller that automatically adjusts pad position. This closed-loop feedback mechanism enables immediate corrective action to reduce fluctuations, eliminating the time delay inherent in surface-controlled adjustment methods
2Productivity
If drill bit aggressiveness is increased to improve rate of penetration, then drilling efficiency improves, but drill bit fluctuations increase
Solution Approach 1:
The movable pads enable real-time dynamic adjustment of drill bit aggressiveness. When fluctuations are detected, the pads automatically adjust to reduce aggressiveness and stabilize drilling, allowing the system to maintain high ROP while preventing excessive fluctuations that would occur with fixed high-aggressiveness configurations
Solution Approach 2:
The system changes the physical parameter of pad position relative to the cutters to control drill bit aggressiveness. By varying this parameter in real-time based on drilling conditions, the system optimizes the balance between rate of penetration and drill bit stability, achieving high productivity without excessive fluctuations
3Productivity
If depth of cut is increased to improve drilling efficiency, then rate of penetration increases, but drill bit fluctuations and aggressiveness become difficult to control
Solution Approach 1:
The dynamic pad adjustment system allows the depth of cut to be modified in real-time without changing the overall drill bit design. Even with increased depth of cut for higher efficiency, the movable pads provide continuous controllability by adjusting their position to fine-tune aggressiveness and reduce fluctuations, maintaining ease of operation throughout the drilling process
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 solution allows for real-time control of drill bit aggressiveness, improving drilling smoothness, reducing vibrations, and enhancing steerability and efficiency by dynamically adjusting the pad extension and retraction based on drilling conditions.
Implementation Method 1
Each pad has an electrohydraulic actuator configured to apply a force to the pad to extend and retract the pad from the drill bit surface
Data Source
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AI summary
A drill bit is disclosed that in one embodiment includes a pad configured to extend and retract from a surface of the drill bit, a motor, a linearly movable member coupled to the motor, a hydraulic unit configured to apply force on the pad, and wherein motion of the motor in a first direction causes the linearly movable member in a first direction to cause the hydraulic unit to exert a force on the pad to extend the pad,