Composite Shock Absorber for PDC Bit Vibration Protection
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Solution Overview
Problem
Polycrystalline diamond compact bits in petroleum drilling suffer from impact resistance issues, leading to damage from lateral and axial vibrations, which significantly reduces their service life and increases drilling costs.
Innovation Solution
A composite shock absorber comprising a drilling tool body, an impact body, a disc spring group, a torsion bar spring, and an annular pressing sleeve, where the torsion bar spring absorbs torsional vibrations and the disc spring group absorbs axial vibrations, with a sealing mechanism to mitigate damage to the cutting teeth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a polycrystalline diamond compact bit is used for drilling, then the anti-abrasive ability is improved, but the impact resistance deteriorates
Solution Approach 1:
The patent applies beforehand cushioning by introducing a shock absorption device comprising spring components (first spring and second spring) that are pre-installed in the drilling tool. These springs are positioned to cushion the impact between the polycrystalline diamond compact bit and the rock formation before the impact occurs, thereby protecting the cutting teeth from shock damage while maintaining their anti-abrasive properties
Solution Approach 2:
The patent uses an intermediary approach by introducing a shock absorption device as a mediator between the drilling tool body and the polycrystalline diamond compact bit. This intermediary device absorbs and dampens the impact forces transmitted to the cutting teeth, protecting them from shock damage while allowing the bits to maintain their inherent anti-abrasive capabilities
2Productivity
If the polycrystalline diamond compact bit operates under normal conditions, then continuous cutting is achieved, but actual drilling conditions cause violent vibrations that damage the cutting teeth
Solution Approach 1:
The patent applies dynamics by making the drilling tool structure movable and adaptable through the shock absorption device. The spring components can dynamically adjust their compression and extension to accommodate the violent vibrations and lateral movements encountered during actual drilling, allowing the bit to maintain continuous cutting while protecting against damage from irregular motions
3Duration of action of stationary object
If the shock absorption device is added to protect the cutting teeth, then the service life is extended, but the device complexity increases
Solution Approach 1:
The patent applies universality by designing a shock absorption device that performs multiple functions: the first spring absorbs axial vibrations, the second spring absorbs lateral vibrations, and both springs work together to protect the cutting teeth from various types of impact. This multi-functional approach extends service life while keeping the overall device complexity manageable by consolidating protection against multiple vibration types into a single integrated system
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 composite shock absorber effectively extends the service life of polycrystalline diamond compact bits by reducing damage from vibrations, enhancing drilling speed and efficiency.
Implementation Method 1
the torsion bar spring absorbs torsional vibrations
Implementation Method 2
the disc spring group absorbs axial vibrations
Implementation Method 3
a sealing ring is arranged between the sealing shaft section at the lower end of the torsion bar spring and the inner wall of the impact body
Data Source
AI summary
The invention relates to a composite shock absorber for a polycrystalline diamond compact bit, comprising a drilling tool body having a water inlet, an impact body having a water outlet and forming a shock absorption cavity, a disc spring group having an annular pressing sleeve, a cylindrical torsion bar spring which has an external thread and a spline, is connected to the drilling tool body through threads and extended into an impactor and connected thereto through the spline, and the annular pressing sleeve, wherein bit vibration impact force is transmitted therebetween through a torsion transmission joint, and a bearing group is arranged between the lower end surface of the annular pressing sleeve and an annular step of the impact body. The composite shock absorber can weaken damage of the slippage effect to polycrystalline diamond compact cutting teeth, absorb axial vibration from a drill stem and prolong the service life of the bit.