Self-Retaining Shear Pin for Downhole Tubular Separation
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Solution Overview
Problem
Existing shear pin tools used to connect downhole tubulars in wellbores do not effectively retain separated parts under high axial loading, which can lead to equipment malfunction due to debris entering downhole equipment.
Innovation Solution
A self-retaining shear pin tool design that includes a cap and a shear pin with swage dies, which expands and locks into the tubular aperture upon axial loading, preventing the separated parts from falling or moving freely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing shear pin tools are used to connect downhole tubulars, then the tubulars can be connected and separated under axial loading, but the separated parts of the shear pin tool fall into downhole equipment causing equipment malfunction
Solution Approach 1:
The harmful parts (separated shear pin tool components) are extracted from the downhole environment by designing them to remain in the tubular aperture after separation, preventing them from entering and damaging downhole equipment
Solution Approach 2:
The tubular aperture serves as an intermediary containment space that captures and retains the separated shear pin tool parts, acting as a barrier between the separation zone and the downhole equipment
2Reliability
If additional retention mechanisms are added to prevent shear pin parts from falling, then equipment malfunction is prevented, but device complexity increases
Solution Approach 1:
The shear pin tool design enables self-retention through the dimensional change of its body under axial loading, which automatically locks the components in place without requiring external retention mechanisms
Solution Approach 2:
The body of the shear pin tool undergoes dimensional changes under axial loading that transform its geometry to create a locking effect, retaining the separated parts within the tubular aperture
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 self-retaining shear pin tool effectively separates downhole tubulars while retaining tool parts, preventing equipment malfunction and reducing the need for additional retention mechanisms, thus simplifying design and operation.
Implementation Method 1
Upon application of the force, the swage die causes the body portion of the shear pin to expand and to change dimension. The dimensional change of the body locks the shear pin into the aperture of the tubular
Data Source
Figure 1~2
Figure 3A
Figure 3B
AI summary
A self-retaining shear pin tool and methods for connecting downhole tubulars in a wellbore are disclosed. The self-retaining shear pin tool includes a cap having an inner side and an outer side opposite the inner side, the cap defining a first recess formed in the inner side of the cap, the first recess of the cap having a cylindrical portion and a frustoconical portion extending from the cylindrical portion towards the outer side of the cap, and a shear pin disposed partially in the first recess of the cap and extending out of the first recess of the cap. The shear pin includes a body, a first recess extending inward from a first end of the body, a second recess extending inward from a second end of the body, a first swage, and a second swage die.