Multi-angle profile collet for downhole actuation
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Solution Overview
Problem
Existing low load collets used in downhole applications tend to creep open due to uniform shallow sloped surfaces, leading to inaccurate actuation of downhole tools and increased risk of unintended valve operation, as they lack sufficient interference to maintain a neutral position under varying forces.
Innovation Solution
A low load collet with a multi-angle profile is designed, featuring collet springs with protrusions having high-load and low-load ramped surfaces of different angles, ensuring secure actuation and preventing creeping by maintaining strong interference with the actuation mechanism until purposeful activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If uniform shallow sloped surfaces are used on collet protrusions, then low load actuation in one direction is achieved, but the collet creeps in the low load direction during operation
Solution Approach 1:
The collet protrusions are designed with different surface angles at different locations: a first surface with a first angle for low-load actuation and a second surface with a second angle greater than the first angle for preventing creep. This local differentiation allows the same component to provide both low actuation force and positional stability under varying load conditions.
Solution Approach 2:
The ramped surfaces of the collet protrusions are asymmetric in design, with one side having a shallower angle and the other side having a steeper angle. This asymmetry enables the collet to differentiate between intentional actuation forces and operational creep forces, allowing reliable mechanical actuation while preventing unintended movement.
2Force
If shallow angled surfaces are used to reduce actuation force, then low load operation is enabled, but interference with actuation mechanism is insufficient
Solution Approach 1:
Different portions of the collet protrusion surfaces are assigned different angular characteristics: the first ramped surface provides lower interference for reduced actuation force, while the second ramped surface provides higher interference for stronger mechanical engagement. This local quality differentiation resolves the contradiction between low actuation force and sufficient interference strength.
3Ease of operation
If differential opening capability is provided with lower force in one direction, then valve opening is facilitated, but creep potential increases
Solution Approach 1:
The asymmetric ramped surfaces create different interference levels for opening versus closing operations. The shallower first surface facilitates easier valve opening with lower force, while the steeper second surface prevents creep during operation. This asymmetric design enables differential opening capability while maintaining anti-creep performance.
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 multi-angle profile allows for precise and reliable actuation of downhole tools, preventing unintended operation by maintaining a neutral position until the desired force is applied, thus enhancing the differential opening capability of valves and other downhole equipment.
Implementation Method 1
maintaining a strong interference between the collet and the actuation mechanism
Implementation Method 2
The first ramped surface of the first protrusion may be configured to engage a surface of the actuation mechanism
Data Source
AI summary
Systems and methods for actuating a downhole tool using an improved low load collet. The low load collet may include a multi-angle profile that enables the collet to provide a low-load actuation force threshold in one direction, while maintaining a strong interference between the collet and corresponding actuation mechanism. To that end, the collet may include a first protrusion disposed on a first collet spring and a second protrusion disposed on a second collet spring. The first and second protrusions each feature a high-load ramped surface on one side and a low-load ramped surface on an opposite side. The low-load ramped surface of the first protrusion has a shallow angle and the low-load ramped surface of the second protrusion has a steep angle that is larger than the shallow angle.