Slip Pad Insert Structure to Prevent Downhole Slip Rotation
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Solution Overview
Problem
Existing downhole tools face challenges in securely engaging and holding onto the casing during operations due to issues with slip rotation and disengagement of inserts, which can lead to unwanted movement and failure.
Innovation Solution
The design incorporates slip assemblies with inserts featuring serial wide axial teeth on a long shelf embedded in a slip pad, where the insert's base extends to the cone, and the slip body is configured to accept and maintain the insert, with guidance lugs and fins preventing slip rotation, ensuring secure engagement and resistance to disengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional inserts are used in slip assemblies, then the downhole tool can engage the casing, but the inserts may disengage, rotate, or shear during setting and operations
Solution Approach 1:
The insert is segmented into multiple functional zones: a base portion for radial engagement with the cone, a shelf portion for axial positioning within the slip body, and teeth extending outward for casing engagement. This segmentation allows each portion to perform its specific function optimally while working together as an integrated component.
Solution Approach 2:
The insert is nested within the slip body, with the base portion extending radially to engage the cone, the shelf portion embedded in the slip body's outer surface, and teeth extending outward. This nested configuration secures the insert against disengagement, rotation, and shearing while maintaining engagement functionality.
2Ease of operation
If the slip assembly is designed to allow insert movement for setting, then the tool can be deployed, but the slip may rotate about the cone causing unwanted movement
Solution Approach 1:
The insert base portion has an asymmetric geometry with a first side and second side that interface differently with the cone's outer surface. This asymmetric design, combined with the cone's inclined surface, prevents the slip from rotating about the cone while allowing axial movement for setting operations.
Solution Approach 2:
The insert base portion is pre-configured with specific geometric features that engage the cone's outer surface before setting occurs. This preliminary geometric engagement prevents rotational movement during the setting process and subsequent operations, ensuring stability from the outset.
3Ease of manufacture
If the insert base is made thin for easier manufacturing, then manufacturing cost decreases, but the insert may be sheared during setting
Solution Approach 1:
The insert design transitions from a purely radial thickness dimension to a multi-dimensional structure with axial extension (shelf portion) and radial engagement (base portion). This dimensional change allows the base to be thinner while the overall insert length provides the necessary structural strength to resist shearing during setting.
Solution Approach 2:
The insert base portion features a curved lower surface that matches the cone's outer surface curvature. This curved geometry distributes contact forces more evenly across the base, reducing stress concentrations that could lead to shearing, while allowing the base to remain relatively thin for manufacturing efficiency.
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 described structure provides enhanced resistance to unwanted movement and secure holding of the downhole tool within the casing by directly translating vertical setting forces into radial engagement, improving the tool's stability and durability during operations.
Implementation Method 1
The cone has an incline on its outer face relative to the mandrel and facing toward the slip. The slip has a similar matching incline on its inner face toward the cone. In operation, setting the downhole tool compresses the slip and cone along the mandrel toward one another. This forces the slip up the cone's incline, radially outward away from the mandrel and toward the casing.
Data Source
AI summary
A downhole tool slip assembly having slip pad inserts with serial wide axial teeth on a long, wide shelf. The insert's base extends to the cone and is narrower than the teeth and shelf. An axial groove facilitates drilling out the insert. Inner slip pad fingers within cone grooves control slip pad separation and rotation.