Downhole Hydraulic Lock Release Using Piston and Shear Assembly
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Solution Overview
Problem
Existing downhole tools face challenges in securely locking and unlocking mechanisms to prevent premature actions during well-related operations, necessitating a reliable and efficient method for releasing tools after completion.
Innovation Solution
A locking mechanism that includes a piston and shear assembly, where hydraulic pressure or a shifting tool is used to shear the shear assembly, allowing the piston to shift and unlock the mechanism, enabling axial movement and disengagement of components for tool release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking mechanism is used to secure downhole tools, then reliability is improved, but device complexity increases
Solution Approach 1:
The locking mechanism is divided into distinct functional segments: a locking component with locking surfaces, a piston element, and a shear assembly. This segmentation allows each component to perform its specific function independently while maintaining overall system reliability without excessive complexity.
Solution Approach 2:
The shear assembly acts as an intermediary element between the piston and the locking component. It provides a controlled failure mode that transitions the mechanism from locked to unlocked state, simplifying the overall control logic while maintaining reliability through a defined release pathway.
2Ease of operation
If a shear assembly is used for unlocking, then ease of operation is improved, but manufacturing precision requirements increase
Solution Approach 1:
The shear assembly is pre-configured in a stressed state during assembly, with the shear surface positioned to fail at a predetermined location when hydraulic pressure is applied. This preliminary positioning simplifies the unlocking operation to a simple pressure application, while the manufacturing precision is concentrated in the initial assembly process rather than operational control.
3Productivity
If hydraulic pressure is used to actuate the piston, then productivity is improved, but reliability risks increase due to premature unlocking
Solution Approach 1:
The locking surfaces are designed with geometric features that create mechanical interference, preventing the locking component from moving in the unlock direction until the shear assembly fails. This preliminary anti-action counteracts the hydraulic pressure on the piston, ensuring that premature unlocking cannot occur even if hydraulic pressure is applied inadvertently.
Solution Approach 2:
The shear assembly is designed to fail in a controlled manner that gradually transitions the locking mechanism from the locked to unlocked state. This cushioning effect prevents sudden, uncontrolled release while maintaining the high productivity benefit of hydraulic actuation by ensuring the unlocking process is smooth and predictable.
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 mechanism provides secure locking during operations and efficient unlocking through hydraulic pressure, ensuring reliable tool release without premature action, facilitating seamless downhole tool management.
Implementation Method 1
The locking mechanism is shifted to an unlocked position by applying a pressure within a bore of the locking mechanism
Implementation Method 2
A locking mechanism that includes a piston and shear assembly, where hydraulic pressure or a shifting tool is used to shear the shear assembly
Data Source
AI summary
An improved downhole locking mechanism which may include a housing releasably connected to a downhole tool. The housing includes a first housing connected to a second housing. A sleeve disposed within the second housing. A coupling connecting the sleeve and a completion or another assembly. A piston disposed within the sleeve and retained in a locked position via a shear assembly. The piston maintains a retainer in the locked position, where the retainer engages both the sleeve and the lower housing. Hydraulic pressure within the bore of the locking mechanism causes the piston to shear the shear assembly and axially shift the piston towards the upper housing. Shifting the piston causes the retainer to move radially inward to an unlocked position and disengaging the sleeve from the lower housing and unlocking the locking mechanism.