Downhole Anchor Mechanism Slips for Thin-Walled Casing
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Solution Overview
Problem
Existing downhole anchor mechanisms for refracturing operations face challenges in securing thin-walled tubular sections due to limitations in threaded couplings, which fail to provide sufficient tensile loading, torque ratings, and radial load handling.
Innovation Solution
A downhole tool with a plurality of slips that expand longitudinally to engage the inner casing surface, utilizing a wire or shear pin to secure the slips, allowing for increased radial holding force while reducing radial load on the mandrel, and featuring a ratchet device to maintain the slips in an expanded position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If threaded couplings are used to connect thin-walled tubular sections, then the connection can be assembled, but the coupling fails to provide sufficient tensile loading, torque ratings, and radial load handling
Solution Approach 1:
The coupling is divided into an outer coupling and an inner coupling that work together. The outer coupling engages with the tubular section while the inner coupling provides additional structural support and load-bearing capacity. This segmentation allows the thin-walled construction to achieve sufficient strength by distributing loads across multiple components rather than relying on a single thick-walled structure.
Solution Approach 2:
The coupling system combines different structural elements (outer coupling with engagement features, inner coupling with support features) into a composite assembly. This composite structure provides the necessary mechanical properties (tensile loading, torque ratings, radial load handling) that would be difficult to achieve in a single thin-walled component, effectively creating a composite material solution at the structural level.
2Area of stationary object
If the casing wall thickness is reduced to maximize the internal diameter of the new casing, then the greatest inner diameter is achieved, but the wall is not thick enough to cut normal threads and threaded couplings do not handle radial loads well
Solution Approach 1:
The coupling system separates the functions of engagement and support into outer and inner couplings. The outer coupling provides the engagement interface with the thin-walled tubular section, while the inner coupling provides the structural backbone that can support radial loads and accommodate connection features, eliminating the need for thick walls to cut threads.
Solution Approach 2:
The inner coupling acts as an intermediary structure between the thin-walled tubular section and the required mechanical connections. It provides the necessary structural support and load-bearing capacity that the thin wall cannot provide, while still allowing the thin-walled construction to maintain its maximum internal diameter.
3Area of stationary object
If thin-walled packers are used to maintain the greatest inner diameter possible, then the internal diameter is maximized, but sufficient gripping and sealing capability on the existing casing becomes difficult to achieve
Solution Approach 1:
The coupling system uses an outer coupling with engagement features that interface with the tubular section and an inner coupling that provides structural support. This segmentation allows the thin-walled outer coupling to maintain maximum internal diameter while the combined structure provides sufficient gripping and sealing capability through the coordinated action of both couplings.
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 solution enhances the anchor mechanism's holding capability, allowing for greater loading of the thin-walled mandrel without causing compression damage, and maintains a secure seal with reduced wall thickness, suitable for slim hole applications.
Implementation Method 1
A downhole tool with a plurality of slips that expand longitudinally to engage the inner casing surface
Implementation Method 2
featuring a ratchet device to maintain the slips in an expanded position
Data Source
AI summary
A downhole anchor mechanism for use in downhole tools. The downhole anchor mechanism generally consists of a plurality of sliders that pivot outwardly from a downhole tool body to engage distal ends thereof against a well casing. The sliders are operatively engaged within faceted cavities associated with the tool body, which creates load components that act in a tangential direction, allowing a thin-walled tool body to withstand increased holding force.