Downhole Tool Slip Member Pivot Mechanism
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Solution Overview
Problem
Downhole tools face challenges with anchor slips that are prone to failure due to concentrated stress and insufficient retraction force, and ratchet systems experience high stress and difficulty in releasing forces without damage.
Innovation Solution
A downhole tool design featuring a slip member with both actuation and brace surfaces that pivot to engage a bore wall, supported by both surfaces for robust anchoring, and a ratchet mechanism with a circumferential ratchet assembly to distribute forces and facilitate controlled extension and retraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a slip is supported only at the point of contact with the cone, then the slip can be actuated to engage the bore wall, but significant stress concentration occurs in both the cone and the slip creating a potential failure point
Solution Approach 1:
The invention transitions from point-contact support (axial dimension only) to surface-contact support by adding a radially extending support surface on the cone. This dimensional expansion distributes the slip reaction forces from a single point across a broader area, reducing stress concentration while maintaining effective slip actuation and engagement capability
2Ease of operation
If an interengaging profile arrangement such as a dovetail arrangement is used between the slips and an actuating cone for retraction, then the slips can be retracted, but the arrangement may be subject to failure by blockage, plastic or complete mechanical failure
Solution Approach 1:
The invention extracts and eliminates the complex interengaging profile arrangement (dovetail mechanism) that caused reliability issues. Instead, it uses a simplified support surface geometry that achieves slip retraction through basic friction and gravitational forces, removing the problematic mechanical interlocking components that were prone to blockage and failure while maintaining effective retraction capability
3Ease of operation
If spring return systems are used for slip retraction, then the slips can be retracted automatically, but the structural arrangements and minimal available space only permit the use of springs with relatively low spring force which may be insufficient to achieve retraction
Solution Approach 1:
The invention eliminates the need for external spring return systems by designing a support surface geometry that enables self-retraction. The slip's own weight and the friction between the slip and support surface provide the retraction force, allowing the system to reset automatically without requiring additional powered components or space-consuming spring mechanisms
4Device complexity
If a ratchet system with minimal dimension curved segments is used due to space restrictions, then the ratchet components can fit within the cylindrical tool, but the forces applied through the ratchet teeth are applied over minimal areas creating significant stresses and possible failure points
Solution Approach 1:
The invention expands the ratchet mechanism from minimal-dimension curved segments to a planar or substantially planar configuration. This dimensional change allows the ratchet teeth to engage over a broader surface area while maintaining compatibility with the cylindrical tool geometry, thereby distributing applied forces more evenly and reducing stress concentrations without significantly increasing overall device complexity
5Ease of operation
If a ratchet system is used to lock-in the setting configuration, then the setting force can be removed, but it is difficult to apply the necessary release force without damaging the ratchet components
Solution Approach 1:
The invention modifies the ratchet tooth geometry parameters, specifically designing teeth with broader contact surfaces and optimized engagement angles. These parameter changes reduce the friction and mechanical interference during release, allowing the ratchet to be opened with lower forces that will not damage the components, while still maintaining secure locking capability during the set configuration
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 design enhances support for anchor slips, reduces stress concentrations, and allows for reliable engagement and release of the tool within the bore, improving the tool's operational reliability and longevity.
Implementation Method 1
a wedge member defining a wedge surface, wherein the wedge member and slip member are configured to move relative to each other such that interengagement between the wedge surface and the actuation surface causes said slip member to pivot
Data Source
AI summary
A downhole tool includes a slip member having an actuation surface, a bracing surface and an engagement surface. The slip member is pivotable about a pivot axis such that it can move between retracted and extended configurations. When the slip member is in the extended configuration, the engagement surface engages a bore wall. The downhole tool also includes a wedge member that has a wedge surface. The wedge member and the slip member are configured to move relative to each other such that the wedge surface of the wedge member engages the actuation surface of the slip member to cause the slip member to pivot about the pivot axis.