Downhole Tool Actuator Piston Hydraulic Lock Resolution
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Solution Overview
Problem
Downhole systems can become hydraulically locked, preventing the piston from moving to a second axial position and necessitating manual intervention, which risks overshooting and bypassing the intended position.
Innovation Solution
A tool actuator with a fluid chamber and circumferential seals, an actuation arm, and a locking mechanism that allows controlled movement of the piston out of the locked position by equalizing fluid pressure and using an actuation arm to apply force, ensuring precise movement without overshooting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the actuator seals the first region from the second region to maintain pressure differential, then the piston can be held in position, but the piston becomes hydraulically locked and cannot move to the second axial position
Solution Approach 1:
The actuator piston serves as an intermediary device between the fluid pressure system and the downhole piston. It receives pressurized fluid in its fluid chamber, which then acts upon the actuator piston to move it axially. The actuator piston in turn applies force to the downhole piston through contact, providing controlled movement while maintaining hydraulic sealing when needed.
Solution Approach 2:
The actuator piston automatically responds to fluid pressure changes in its fluid chamber. When pressurized fluid is introduced, the pressure differential across the actuator piston automatically moves it axially without requiring additional control mechanisms. The system uses the fluid pressure itself to drive the actuation process.
2Ease of operation
If manual intervention is used to push the piston downward, then the piston can be moved past the locked position, but the piston may overshoot and bypass the second axial position
Solution Approach 1:
The actuator piston provides feedback-based control through its fluid chamber pressure system. As the actuator piston moves axially and contacts the downhole piston, the fluid pressure in the actuator piston's fluid chamber can be modulated to control the movement rate and stop position, preventing overshoot of the second axial position.
Solution Approach 2:
The invention replaces manual mechanical pushing with a fluid-pressure-driven actuator piston system. Instead of direct mechanical force application that is difficult to control, the system uses hydraulic pressure acting on the actuator piston to provide smooth, controllable movement of the downhole piston to the precise second axial position.
3Adaptability or versatility
If additional actuators are dropped from the surface to shift the piston, then the piston may be moved to further positions, but the actuators cannot be pumped to the piston due to hydraulic lock
Solution Approach 1:
The actuator piston is designed to perform multiple functions: it can be pumped downhole through the conduit, it can seal hydraulically to hold position, it can be actuated by fluid pressure to move the downhole piston, and it can provide controlled contact to prevent overshooting. This multi-functionality eliminates the need for multiple separate actuator devices.
4Ease of operation
If the actuator piston moves downward to actuate the downhole piston, then fluid below the piston must be displaced upward, but hydraulic lock prevents this displacement
Solution Approach 1:
The system segments the fluid communication paths using the actuator piston with its fluid chamber and circumferential seals. The seals divide the fluid space into isolated regions, allowing the actuator piston to move within its fluid chamber without causing uncontrolled fluid displacement in the downhole region, while still enabling controlled actuation when needed.
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 controlled and precise movement of the downhole piston from a hydraulically locked state to the intended operational position, preventing unintended bypassing and ensuring successful completion of downhole operations.
Implementation Method 1
flowing fluid from the chamber to an inner annular region between the housing and the pipe through the first and second ports such that downward movement of the piston terminates
Implementation Method 2
The actuator piston also includes an actuation arm for actuating the downhole piston. The actuation arm includes a shaft extending from the receptacle wall and through an opening of the housing and a contact member disposed at an end of the shaft
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A downhole tool actuator (100) includes a housing (102) defining an axial bore and a first port (110) extending radially from the axial bore, as well as a piston (106) disposed and movable within the axial bore of the housing. The piston (106) includes a receptacle wall (116), a shaft (126) extending axially from the receptacle wall, and a contact member (130) extending across the shaft. The receptacle wall (116) defines a chamber (118) and a second port (120) extending radially from the chamber. The contact member (130) is positioned outside of the housing (102) and is configured to engage a downhole tool.