Downhole Cleaning Element Magnetic Retention System
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Solution Overview
Problem
Existing downhole cleaning apparatuses face reliability issues due to premature activation of shear pins, which can lead to failure or incorrect deployment of cleaning elements, especially in deviated or unlined wells.
Innovation Solution
A downhole cleaning apparatus with a cleaning element that is selectively movable from a retracted to an extended position, utilizing a retention system with a protrusion and recess mechanism that prevents premature extension, ensuring reliable activation only under controlled conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shear pins are used to retain cleaning elements in a retracted position, then the cleaning elements can be selectively activated, but the shear pins are prone to premature activation or failure due to metal fatigue and g-forces
Solution Approach 1:
The patent replaces the shear pin mechanical retention system with a magnetic retention system. Magnets are used to hold the cleaning elements in the retracted position, and the cleaning elements are activated by moving the magnets away, allowing the cleaning elements to extend under spring force. This substitution eliminates the metal fatigue and shearing issues associated with shear pins while maintaining reliable selective activation.
Solution Approach 2:
The patent changes the retention mechanism from a mechanical shear-based system to a magnetic field-based system. By utilizing magnetic attraction forces instead of mechanical shear strength, the system avoids the limitations of metal fatigue and g-force susceptibility inherent in mechanical shear pins, while still providing controllable retention and release.
2Productivity
If cleaning elements are extended to clean the wellbore, then cleaning effectiveness is improved, but the cleaning elements may be prematurely activated during tool run-in or drilling operations
Solution Approach 1:
The magnetic retention system provides more precise and reliable control over cleaning element activation compared to shear pins. The magnetic force can be reliably switched on and off by moving the magnets, ensuring that cleaning elements are activated only when intended, not during tool run-in or drilling operations.
Solution Approach 2:
The patent introduces magnets as an intermediary mechanism between the control system and the cleaning elements. The magnets act as a controllable intermediary that can reliably engage and disengage to control the extension and retraction of cleaning elements, providing precise control over activation timing.
Data Source
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AI summary
Disclosed herein is a downhole cleaning apparatus and a method of cleaning a wellbore. The downhole cleaning apparatus has a body and a cleaning element coupled to the body. The cleaning element is selectively moveable in relation to the body from a retracted position to an extended position. When the cleaning element is in the retracted position it is retained by retention formations internal to the tool that are coupled together. The retention formations can be slideably released from one another to enable the cleaning element is able to move to the extended position. The force required to slideable release the retention formations exceeds any forces encountered when the apparatus is run in, preventing premature extension of the cleaning element.