Downhole Tool Stop Device Shear Pin Release Mechanism
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Solution Overview
Problem
Existing downhole-tool stop devices face challenges in allowing further axial travel when releasing a downhole tool, as grippers can be difficult to disengage, especially when activated by conical pressing elements that require rotation or axial movement, potentially leading to issues with loosening or overtightening threaded connections and making it hard to release the tool.
Innovation Solution
A downhole-tool stop device featuring a first and second stop collar with the second collar being displaceably attached via shear pins, allowing it to break upon impact with the casing, enabling further axial travel and facilitating the release of the downhole tool by breaking the shear pins when the tool is pulled back into the well.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stop collar is permanently attached to the pipe string, then the stop device provides stable positioning, but it prevents further axial travel when the downhole tool needs to be released
Solution Approach 1:
The stop collar is designed with a dynamic attachment system using shear pins that can transition from a fixed state during insertion to a released state during tool retrieval. The shear pins allow the collar to move axially relative to the pipe string when subjected to sufficient pull force, enabling the collar to travel further than its initial position and expose the tool for release.
Solution Approach 2:
The attachment between the stop collar and pipe string is segmented into discrete shear pins rather than being a monolithic permanent connection. This segmentation allows the connection to fail in a controlled manner under specific load conditions, enabling the collar to detach and move axially when needed for tool release.
2Ease of operation
If the shear pins are designed to break upon impact during insertion, then the collar can move further for tool release, but the shear pins may weaken or break prematurely during insertion
Solution Approach 1:
The shear pins are pre-loaded with a specific axial force during assembly that is insufficient to break them during normal insertion operations. The pins are designed with a break strength that exceeds the insertion impact forces but is less than the pull force applied during tool release, ensuring they remain intact during insertion and only fail when intended.
Solution Approach 2:
The shear pins are designed with specific material properties and dimensional parameters that create a break strength threshold between insertion forces and release forces. By carefully selecting the pin diameter, material strength, and length, the design ensures the pins withstand insertion impacts but break under the higher tensile loads applied during tool retrieval.
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
This solution allows for effective release of the downhole tool by enabling further axial movement and preventing the shear pins from weakening or breaking during insertion, ensuring reliable operation and preventing the second stop collar from falling off the pipe string.
Implementation Method 1
The at least one rupture body is taken from the group consisting of shear screws and shear pins
Implementation Method 2
the at least one rupture body is taken from the group consisting of shear screws and shear pins
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
The present invention relates to a downhole-tool stop device (1) and a method of using the same, the stop device (1) comprising a first collar (4) attached to an elongated body (9), characterized by the stop device (1) including a second collar (6) attached to the elongated body (9), and the second collar (6) being displaceably attached to the elongated body (9), and the first collar (4) and the second collar (6) being placed a distance (A1) apart.