Overshot Tool Stacked Piston Expansion Mechanism
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Solution Overview
Problem
Existing overshot tools face reliability issues in maintaining a mechanical interconnection and fluid-tight seal between lower and upper tubulars, often resulting in fluid leakage or separation over time.
Innovation Solution
An overshot tool design featuring a tubular expander sleeve and axially movable stacked pistons that radially expand the lower tubular to secure the connection with the overshot sleeve, utilizing an anchor to fix the tool housing and generate cumulative axial force for a secure mechanical and fluid-tight engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional overshot tools are used to interconnect lower and upper tubulars, then the mechanical interconnection is initially achieved, but the connection reliability deteriorates over time due to separation and fluid leakage
Solution Approach 1:
The tool employs a dynamic expansion mechanism where the expander sleeve is initially compressed during setting, then expands radially to grip the lower tubular. This dynamic transition from compressed to expanded state creates a reliable mechanical interconnection that maintains connection reliability over time by continuously applying radial force through the elastic element.
Solution Approach 2:
The invention changes the physical state of the expander sleeve from compressed to expanded, transforming the mechanical properties to achieve reliable connection. The elastic element's deformation from compressed to expanded state creates sustained radial force, changing the parameter of mechanical force application to ensure long-term connection reliability.
2Reliability
If the lower tubular is expanded radially to secure connection, then mechanical interconnection is improved, but the complexity of the expansion mechanism increases
Solution Approach 1:
The invention uses hydraulic principles by employing a fluid-filled chamber that transmits pressure uniformly to the expander sleeve. The piston applies axial force to the fluid, which then converts to radial expansion force on the lower tubular. This hydraulic mechanism achieves reliable mechanical interconnection while keeping the device complexity manageable through fluid pressure transmission.
Solution Approach 2:
The expander sleeve acts as an intermediary element between the piston and the lower tubular. It receives axial compressive force from the piston and converts it to radial expansion force on the tubular. This intermediary mechanism simplifies the overall system by using a single component to perform the force transformation, reducing the need for multiple complex mechanical elements.
3Force
If stacked pistons are used to generate cumulative axial force, then the expansion force is sufficient, but the device complexity and space requirements increase
Solution Approach 1:
The invention merges multiple pistons into a stacked configuration within a single housing, combining their individual forces to create cumulative axial force. The pistons are arranged in series, allowing their forces to add together while occupying a compact volume. This merging approach achieves sufficient expansion force while minimizing the overall device size and complexity.
Solution Approach 2:
The stacked piston arrangement utilizes the axial dimension to accumulate force, stacking multiple pistons along the length of the housing rather than arranging them radially. This dimensional arrangement allows the forces from multiple pistons to be combined in the axial direction, achieving sufficient expansion force while maintaining a compact radial profile.
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 solution provides a reliable mechanical and fluid-tight connection between the lower and upper tubulars, ensuring a secure interconnection and preventing fluid leakage, with the ability to maintain a 'full bore' connection.
Implementation Method 1
fluid pressure applied to stacked pistons to force the expander sleeve downward
Implementation Method 2
radially expand the lower tubular to connect with an upper tubular
Implementation Method 3
An anchor engages an inner surface of the lower tubular and axially fixes the position of the tool housing in the well
Implementation Method 4
A plurality of sealing members may be positioned on a radially inward surface of the overshot sleeve
Data Source
AI summary
An overshot tool is provided for interconnecting and sealing between a lower tubular (C) in a well and an upper tubular (30). A tubular expander sleeve (36) and an overshot sleeve (26) are supported in a well on an upper tubular. The tool housing (60) encloses a plurality of axially stacked pistons (58, 68, 74), which generate an axial force to move the expander sleeve downward and radially expand a portion of a lower tubular to seal between an outer diameter of the lower tubular and an inner diameter of the overshot sleeve.