Shifting Tool Collet with Rolling Members for Seal Bore Protection
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Solution Overview
Problem
Collets used in shifting tools often damage seal bores due to their deflected fingers riding on the bore's edges, leading to scratching or galling, especially when passing through seal bores of lower hardness materials, and existing solutions like hand-grinding or coating are either ineffective or require frequent reapplication.
Innovation Solution
Incorporating sacrificial soft components, such as threaded fasteners with softer heads or rolling members, to protect seal bores from wear, which can be easily replaced, and using EDM methods to create rounded transitions and increased finger counts to minimize contact stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If collet fingers are deflected to pass through seal bores, then the collet can navigate through smaller bore devices, but the fingers can scratch or gall the seal bore surface
Solution Approach 1:
A sacrificial component made of softer material is introduced as an intermediary between the collet fingers and the seal bore. This component contacts the seal bore surface first, preventing direct contact between the harder collet fingers and the bore, thereby eliminating scratching and galling while allowing the collet to pass through
Solution Approach 2:
The sacrificial component is designed as a consumable element that can be easily replaced. Instead of protecting the collet fingers permanently, a cheaper, softer sacrificial material is used that can be replaced after wear, protecting the expensive seal bore in the process
2Manufacturing precision
If hand-grinding or machining is applied to round the outer edges of collet fingers, then edge sharpness is reduced, but the process is inconsistent and may still leave points or ridges
Solution Approach 1:
Instead of attempting to perfectly finish the collet finger edges through manufacturing processes, a sacrificial component is used that absorbs the harmful effect. The sacrificial material compensates for any edge imperfections, making the manufacturing process less critical while still protecting the seal bore
3Object-affected harmful factors
If a coating is applied to collet finger surfaces to reduce damage, then protection is provided, but the coating wears during service and requires frequent reapplication
Solution Approach 1:
The sacrificial component serves as a replaceable protective layer, similar to a coating but designed to be easily removed and replaced. This simplifies maintenance compared to coating processes, as the sacrificial component can be quickly swapped without complex application equipment or curing processes
4Object-affected harmful factors
If a softer material insert is added to protect the seal bore, then protection is provided, but wider slots between collet fingers are required for installation
Solution Approach 1:
The protective function is extracted from the collet finger structure itself and placed into a separate, dedicated sacrificial component. This allows the protective element to be installed independently without requiring modifications to the collet finger geometry, such as wider slots
Solution Approach 2:
The sacrificial component is designed to fit within or alongside the existing collet finger structure, nesting the protective element into the available space without requiring additional clearance or modifying the overall collet geometry
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 sacrificial components effectively reduce wear on seal bores, preventing damage while allowing the collet to maintain functionality and be easily replaced, and the increased finger count distributes contact stress, minimizing the risk of galling and improving the collet's operational reliability.
Implementation Method 1
rolling members such as wheels or balls can be used to keep sharp edges off the seal bore
Data Source
AI summary
A flexible collet on a subterranean tool has sacrificial soft components to protect seal bores through which the collets have to compress to get through. The sacrificial components can be replaced when the tool is removed to the surface. In one embodiment, threaded fasteners are used alone or with washers for height adjustment such that the heads of the fasteners which are softer than the seal bore material ride on the seal bore and take the wear. The tool can ultimately be used to latch into shifting sleeves to move such sleeves to open or close wall ports. Alternatively axial ridges with beveled profile ends can be used or rolling members such as wheels or balls can be used to keep sharp edges off the seal bore. EDM method can be used to create multiple fingers with an axial ridge profile and rounded end transitions.