Downhole Shock Assembly Dual-Spring Stiffness Vibration
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Solution Overview
Problem
Downhole drilling operations face challenges in effectively managing and absorbing various forces such as weight on bit, torque, and pressure, which can lead to inefficiencies and tool wear, particularly in the interaction between the drill string and the wellbore.
Innovation Solution
A shock assembly is introduced, comprising a mandrel and a housing with first and second springs of different stiffnesses, positioned between the conveyance and the motion tool, to selectively engage and absorb these forces, creating vibration and reducing friction by slidingly moving the housing about the mandrel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single spring is used in the shock assembly, then the structure is simpler, but it cannot selectively engage under different force conditions leading to reduced adaptability
Solution Approach 1:
The shock assembly divides the spring system into multiple segments (first spring and second spring) with different stiffness characteristics. Each spring segment engages under specific force conditions, allowing the system to adapt to varying downhole forces while maintaining manageable structural complexity through modular design.
Solution Approach 2:
The system changes the stiffness parameter by engaging different springs based on force magnitude. The first spring (higher stiffness) engages under high forces, while the second spring (lower stiffness) engages under lower forces, enabling the shock assembly to adapt its mechanical properties dynamically without complex control systems.
2Adaptability or versatility
If multiple springs of different stiffness are used, then force absorption adaptability is improved, but device complexity increases
Solution Approach 1:
The shock assembly employs a dynamic spring selection mechanism where the housing slides along the mandrel to engage different springs based on applied forces. This dynamic engagement allows the system to adapt to varying force conditions without requiring complex active control systems, maintaining mechanical simplicity while achieving adaptability.
Solution Approach 2:
The mandrel acts as an intermediary element that mediates between the housing and multiple springs. Through the sliding interaction between the housing and mandrel, the system selectively engages appropriate springs based on force conditions, simplifying the control mechanism while maintaining adaptability.
3Stability of the object's composition
If the housing is fixed relative to the mandrel, then structural stability is improved, but vibration generation capability is reduced
Solution Approach 1:
The shock assembly intentionally introduces mechanical vibration by allowing controlled sliding movement between the housing and mandrel. The engagement and disengagement of different springs creates vibratory motion that enhances drilling efficiency by preventing stick-slip conditions and improving cuttings removal, while the overall structural stability is maintained through the constrained sliding mechanism.
Solution Approach 2:
The sliding interaction between the housing and mandrel creates periodic engagement and disengagement of springs, generating controlled vibrations at specific frequencies. This periodic action improves drilling performance by continuously disrupting the drill string-stabilized formation interface, enhancing penetration efficiency without compromising structural integrity.
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 shock assembly effectively manages downhole forces, enhancing drilling efficiency by reducing friction and tool wear through controlled engagement of springs, thereby improving the drilling process.
Implementation Method 1
a first spring and a second spring slidably positionable in the housing between the mandrel and the housing. The first spring has a first spring stiffness and the second spring has a second spring stiffness. The second spring stiffness is less than the first spring stiffness such that the first and second springs selectively engage as the housing slidingly moves about the mandrel
Implementation Method 2
the first and second springs selectively engage as the housing slidingly moves about the mandrel in response to forces applied to the system to selectively restrict movement between the mandrel and the housing whereby the motion tool is vibrated
Data Source
AI summary
A shock assembly for use with a motion tool deployable into a wellbore by a conveyance. The motion tool includes a mandrel operatively connectable to the conveyance or the motion tool, a housing operatively connectable to the motion tool or the conveyance (the housing having an opening to slidingly receive the mandrel and including a first and a second spring portion), a first spring slidably positionable in the first spring portion and having a first spring stiffness, and a second spring slidably positionable in the second spring portion having a second spring stiffness. The second spring stiffness being less than the first spring stiffness such that the first and second springs selectively engage as the housing slidingly moves about the mandrel in response to forces applied to the system to selectively restrict movement between the mandrel and the housing whereby the motion tool is vibrated.