Opposing Piston Actuation for Subterranean Tool Release
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Solution Overview
Problem
Existing hydraulic actuators for subterranean tools, such as liner hangers, are insensitive to tubing pressure, making it difficult to set and release the tool without premature activation, and lack a clear method for reversing the actuation mechanism for tool release.
Innovation Solution
An actuation assembly with opposing pistons and sequentially straddled ports allows for the application of predetermined pressure to set and release the tool, using a collet to retain the actuating sleeve and a straddle device to isolate ports for controlled movement, enabling multiple cycles of setting and releasing the tool in a single trip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic actuators are made insensitive to tubing pressure using opposed pistons, then premature setting is prevented, but the ability to release the tool becomes unclear and difficult to achieve
Solution Approach 1:
The actuation system is segmented into two independent piston chambers (first and second pistons) that can be independently activated. This segmentation allows one piston to be used for setting the tool while the other is used for releasing it, resolving the contradiction by providing both reliability during setting and ease of operation for release through separate control mechanisms
Solution Approach 2:
The release mechanism uses the opposite approach from the setting mechanism. While setting is achieved by isolating the first piston from tubing pressure, release is achieved by isolating the second piston from tubing pressure. This inversion of the control strategy enables both reliable setting and easy release operations
2Device complexity
If a single piston is used for tool setting, then the structure is simpler, but the tool cannot be released and repositioned for multiple cycles
Solution Approach 1:
The actuation system divides the single-piston design into two distinct pistons (first and second pistons) with separate control ports. This segmentation enables the tool to perform multiple cycles of setting and releasing by independently controlling each piston, thereby achieving adaptability for multiple operations without excessive complexity
Solution Approach 2:
The dual-piston system provides multi-functionality where the first piston handles setting operations and the second piston handles release operations. This universal design allows the same actuator to perform both setting and releasing functions, enabling multiple cycles in a single trip
3Speed
If ports are continuously open to tubing pressure, then the actuator responds quickly to pressure changes, but premature activation occurs during pressure surges
Solution Approach 1:
The system prepares both pistons in advance with ports that can be selectively isolated. Before pressure surges cause premature activation, the isolation mechanism is ready to seal off the appropriate port, preventing harmful pressure transmission while maintaining the capability for quick response when properly activated
Solution Approach 2:
The isolation mechanism acts as an intermediary between the tubing pressure and the pistons. It mediates the pressure transmission by selectively allowing or blocking pressure reach to each piston, thereby preventing premature activation while enabling controlled response to legitimate actuation signals
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
Enables reliable setting and releasing of subterranean tools like liner hangers, preventing premature activation and allowing for multiple uses in the same wellbore trip, while maintaining insensitivity to tubing pressure and mechanical shocks.
Implementation Method 1
elevating the pressure to one of the pistons that has access to tubing pressure above the seated object so that one piston creates a net force in the setting direction for setting the tool
Implementation Method 2
isolation of an opposing piston to tubing pressure to reverse the movement of an actuation mechanism for release of the tool
Data Source
Figure 1~5
Figure 3~4
AI summary
An actuator for a subterranean tool is releasably retained by a collet. The actuation system features opposing actuation pistons with ports communicating to the tubing. The spaced ports are sequentially straddled for initial setting and a subsequent release using a predetermined applied pressure. The applied pressure overcomes the retaining force of the collet and actuates a one of two opposed pistons to set the tool, which is preferably a liner hanger. Upon shifting the actuation tool to communication to another port leading to an actuating piston pushing in another direction with applied pressure releases the tool and re-latches a retaining collet. The tool can be set, released and repositioned for another cycle in the same trip in the hole.