Downhole Slip Deployment Control Using Asymmetric Keyway and Shear Pin
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Solution Overview
Problem
Prior art well bore packing devices face issues with uneven deployment and alignment of slips, leading to incomplete sealing and restricted use in applications with high expansion ratios, due to the tendency of slips to fracture irregularly and separate from the mandrel, causing friction and drag during deployment.
Innovation Solution
A downhole apparatus with a mandrel, radial shoulder, and concentrically disposed slips and cones, featuring alignment pins and a stroke limiter to control the deployment and alignment of slips, ensuring even fracture and alignment, and a tapered design allowing higher expansion ratios and controlled elastomer engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If one-piece segmented slip assembly is used, then the slip can be anchored to the tubular member, but the slip segments may rotate off axis and deploy irregularly
Solution Approach 1:
The patent introduces asymmetric features including a keyway in the slip assembly and a corresponding key on the cone, along with an asymmetric retention member that engages these features. This asymmetric design prevents rotation of the slip segments by providing a mechanical interlock that maintains fixed orientation, thereby ensuring symmetric deployment while preserving anchoring reliability.
2Reliability
If slip is retained on the plug mandrel, then the slip assembly is anchored, but the slip segments accelerate away from the mandrel independently during setting
Solution Approach 1:
The retention member is pre-configured to engage the slip assembly with the cone through asymmetric keyway-key interaction before the setting operation begins. This preliminary mechanical interlock ensures that during the setting operation, the slip segments cannot accelerate independently away from the mandrel, as they are pre-constrained to move together as a unified assembly, thereby improving both anchoring stability and deployment control.
3Reliability
If upper slips set first, then the sealing sequence is maintained, but the lower slips create friction and drag during deployment
Solution Approach 1:
The patent employs a dynamic retention member that can transition between engaged and disengaged states. During deployment, the retention member is engaged to maintain the asymmetric positioning and reduce drag on the lower slips. As the upper slips set and seal, the retention member can be disengaged to allow the lower slips to deploy freely, thereby maintaining the sealing sequence while minimizing deployment drag through dynamic adaptation.
4Adaptability or versatility
If the annular space between plug and tubular inner diameter increases, then higher expansion ratio is achieved, but irregular slip deployment is more likely
Solution Approach 1:
The asymmetric keyway-key-retention member mechanism provides a mechanical constraint that maintains fixed orientation of the slip assembly relative to the cone, regardless of the annular space size. This asymmetric mechanical interlock prevents rotation and ensures symmetric deployment even when the expansion ratio is high and the annular space is large, thereby enabling adaptability to various tubular diameters while maintaining deployment precision.
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 apparatus ensures even slip deployment and alignment, maintaining effective sealing across a wider diameter range, reducing friction and drag, and allowing for higher expansion ratios compared to prior art packers.
Implementation Method 1
an alignment pin selectively connecting the sub member with the upper slip means, and wherein the alignment pin is selected to shear at a predetermined force
Implementation Method 2
an elastomeric member operatively associated with the upper cone means, and wherein the elastomeric member is disposed about the mandrel
Data Source
AI summary
An apparatus for use in a well. The apparatus comprises a mandrel containing a radial shoulder, a sub member concentrically disposed about the mandrel, and an upper slip, concentrically disposed about the mandrel, for engaging the well. The apparatus further comprises an upper cone abutting an underside of the upper slip, and wherein the upper cone is disposed about the mandrel, and an elastomer operatively associated with the upper cone, and wherein the elastomer is disposed about the mandrel. The apparatus further includes a lower slip, concentrically disposed about the mandrel, for engaging with the internal portion of the well, and lower cone abutting an underside of the lower slip, and wherein the lower cone is disposed about the mandrel, and wherein the lower cone is operatively associated with the elastomer. The apparatus further contains a first alignment member selectively connecting the sub with the upper slip, and wherein the first alignment pin is selected to shear at a first predetermined force.