Shifting Tool Collet With Sacrificial Soft Components
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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 that contact the seal bore wall to absorb wear, such as threaded fasteners with softer heads or rolling members like wheels or balls, 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
1Strength
If the collet fingers are made harder to withstand bending stresses, then the collet can better withstand repetitive bending stresses, but the harder collet fingers will scratch or gall the seal bore more easily
Solution Approach 1:
A sacrificial insert made of softer material is placed between the collet finger and the seal bore. This insert acts as a mediator that contacts the seal bore first, preventing the harder collet finger from directly scratching or galling the seal surface while still allowing the collet to perform its function of engaging the sleeve.
Solution Approach 2:
The sacrificial insert is designed to be replaceable and is made of a softer material that wears preferentially. When the insert becomes worn, it can be easily replaced without replacing the entire collet assembly, providing a cost-effective solution that protects the seal bore during service.
2Object-affected harmful factors
If the collet fingers are rounded to reduce edge contact, then the likelihood of scratching the seal bore is reduced, but hand-grinding or machining creates inconsistent results with potential points or ridges
Solution Approach 1:
Instead of attempting to achieve perfect edge rounding through machining, the patent uses a sacrificial insert that is simpler to manufacture and replace. The insert's soft material naturally conforms to the seal bore without creating inconsistent edges, and when worn, can be easily replaced.
Solution Approach 2:
The patent changes the material parameter of the insert to be softer than both the collet finger and the seal bore. This material parameter change allows the insert to deform slightly during installation and operation, ensuring consistent contact without creating sharp edges or ridges that could damage the seal.
3Object-affected harmful factors
If a coating is applied to the collet finger surfaces to protect the seal bore, then wear is reduced, but the coating must be reapplied frequently as it wears during service
Solution Approach 1:
The sacrificial insert is designed as a replaceable component that can be easily removed and replaced when worn. This eliminates the need for frequent reapplication of coatings, as the entire insert can be swapped out in a single operation, saving time and effort.
Solution Approach 2:
The sacrificial insert serves as a permanent intermediary protection layer that can be easily replaced when worn, unlike coatings that degrade over time and require frequent reapplication. The insert provides consistent protection throughout its service life until wear becomes excessive.
4Object-affected harmful factors
If a brass insert is added to protect the seal bore, then temporary protection is provided, but wider slots are required between collet fingers reducing contact area and tensile strength
Solution Approach 1:
The patent optimizes the insert material properties to be softer than both the collet finger and seal bore, allowing the insert to conform to the seal bore surface without requiring excessive slot width. This material parameter change enables better protection while maintaining adequate contact area and tensile strength in the collet finger.
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 protect seal bores from damage by absorbing wear and reducing contact stress, allowing the collet to pass through without impairing the seal's functionality, while the increased finger count and rounded transitions minimize the risk of galling and scratching.
Implementation Method 1
sacrificial soft components to protect seal bores through which the collets have to pass in a compressed state before reaching the tool that they ultimately engage for operation thereof. A sacrificial softer material is disposed to contact the seal bore wall so that if there is to be any wear, the sacrificial material wears down.
Implementation Method 2
The sacrificial material needs to be inserted in a way that it is retained for functionality without limiting the number of fingers just to accommodate the insertion or fixation technique.
Implementation Method 3
threaded fasteners with softer heads or rolling members such as wheels or balls can be used to keep sharp edges off the seal bore
Implementation Method 4
rolling members such as wheels or balls can be used to keep sharp edges off the seal bore
Implementation Method 5
EDM methods can be used to create multiple fingers with an axial ridge profile and rounded end transitions
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.