Swing-Adaptive PDC Drill Bit Cushion for Impact Vibration
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Solution Overview
Problem
PDC drill bits experience premature failure and reduced efficiency due to vibration and torque sensitivity when drilling in complex and difficult formations, particularly in deep and ultra-deep wells, leading to frequent tool damage and increased costs.
Innovation Solution
A PDC drill bit with a swing-adaptive cushion structure that includes a rotatably connected cushion structure on the blade, which swings relative to the drill bit body to absorb impact loads, adjust cutting depth, and reduce vibration, featuring a reset mechanism to return to the initial position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a fixed buffer element is used in the drill bit, then the circumferential impact vibration is reduced, but the biting capacity is reduced when drilling from hard strata into soft formations
Solution Approach 1:
The patent applies the dynamics principle by transforming the fixed buffer element into a movable cushion structure that can swing between different positions. The cushion structure includes a cushioning portion that can move relative to the drill bit body, allowing it to adapt its position based on formation conditions. When encountering hard strata, the cushioning portion moves to a position that reduces circumferential impact vibration; when drilling into soft formations, it moves to a position that maintains biting capacity, thus resolving the contradiction between vibration reduction and productivity.
2Productivity
If the WOB is increased to maintain ROP when cutting teeth are worn, then the ROP is maintained, but the torque increases and the drill bit is more prone to failure
Solution Approach 1:
The patent applies beforehand cushioning by incorporating a cushion structure with a cushioning portion positioned to absorb impact loads before they reach the cutting teeth. This cushioning mechanism reduces the circumferential impact on the cutting teeth, allowing them to maintain effective cutting action longer even as they wear. By providing this protective cushioning in advance, the system can maintain ROP without requiring excessive WOB increases that would otherwise lead to torque-related failures.
3Force
If the cushion structure restricts the biting depth of cutting teeth, then the impact load is reduced, but the ROP is reduced in homogeneous ground
Solution Approach 1:
The movable cushion structure dynamically adjusts its position based on formation conditions. In heterogeneous formations with hard strata, the cushioning portion moves to a position that restricts biting depth to reduce impact loads. In homogeneous ground conditions, the cushioning portion moves to a position that allows greater biting depth, thereby maintaining high ROP. This dynamic adaptability resolves the contradiction between impact load reduction and productivity.
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 cushion structure prolongs the working life of the drill bit by reducing impact forces on cutting teeth, minimizing torque fluctuations, and enhancing drilling efficiency in varying formation conditions.
Implementation Method 1
the cushion structure may swing relative to a rotating portion; when the cushion structure in the initial position is subjected to the impact from the formation rock, the same absorbs the impact load
Implementation Method 2
under the action of a reset mechanism, the same swings toward the initial position of the cushion structure to reset after the cushion structure relieves the impact
Data Source
AI summary
A PDC drill bit has a drill bit body and a blade. The blade is provided with cutting teeth. At least one cushion structure is rotatably connected to the drill bit body. The cushion structure makes contact with bottom hole rock, and the cushion structure swings in a direction opposite to the cutting of the drill bit. Alternatively, a cushioning portion on the cushion structure is eccentrically arranged. Under the action of the normal force of the bottom hole rock, the cushioning portion swings to an offset side. The cushion structure is detached from the bottom hole rock and is reset towards a free state under the action of a reset mechanism. Under complex motion conditions such as compound drilling and drilling into hard or non-uniform stratum conditions, the swing of the cushion structure absorbs an impact load and avoids impact damage to the cutting teeth.