Formation Tester Seal Pad Stabilizer Load Sharing
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Solution Overview
Problem
Existing formation tester tools face challenges in maintaining seal integrity due to high borehole fluid pressure, leading to compromised pressure measurements and non-representative samples, as the stabilization load is entirely transferred to the seal pad, making it susceptible to compressive loads and misalignment issues.
Innovation Solution
A formation tester tool design where a hydraulically actuated probe piston serves as a stabilizer, sharing radially directed forces with a separate seal member, allowing the seal pad to be displaced hydraulically and maintain sealing contact with the borehole wall, reducing compressive loads and enhancing seal longevity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stabilization load is entirely transferred to the seal pad, then the seal pad can maintain sealing contact with the borehole wall, but the seal pad becomes susceptible to high compressive loads and misalignment issues, reducing seal integrity and longevity
Solution Approach 1:
The tool divides the stabilization function into two separate components: a stabilizer that contacts the borehole wall for mechanical support, and a seal pad that provides sealing without bearing the full stabilization load. This segmentation reduces the compressive stress on the seal pad and improves overall reliability.
Solution Approach 2:
The stabilizer acts as an intermediary component between the tool body and the borehole wall, absorbing the stabilization load and preventing it from being fully transmitted to the seal pad. This mediator protects the seal pad from excessive compressive forces while maintaining sealing effectiveness.
2Reliability
If the seal pad is subjected to high compressive loads to maintain sealing, then sealing contact is achieved, but the seal life is reduced and misalignment sensitivity increases
Solution Approach 1:
By separating the stabilizer and seal pad into distinct components with different functions, the seal pad is relieved of excessive compressive loads, extending its operational life while maintaining effective sealing contact with the borehole wall.
Solution Approach 2:
The system changes the load distribution parameters by introducing a stabilizer that bears the mechanical stabilization load, thereby reducing the compressive stress parameter on the seal pad and extending its service life.
3Reliability
If the seal pad must be perfectly aligned with the borehole wall for effective sealing, then sealing integrity is maintained, but the device becomes highly sensitive to misalignment and requires higher precision
Solution Approach 1:
The stabilizer serves as an intermediary that provides mechanical support and positioning, allowing the seal pad to maintain effective sealing contact without requiring perfect alignment. The stabilizer compensates for misalignment while the seal pad focuses on providing the sealing function.
Solution Approach 2:
Dividing the function into a stabilizer for mechanical support and a seal pad for sealing allows each component to be optimized independently, reducing the overall alignment precision requirements while maintaining seal integrity.
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
This configuration prolongs seal life, reduces sensitivity to misalignment, and ensures effective sealing even when the seal pad is not perfectly aligned with the borehole wall, resulting in more accurate pressure measurements and representative samples.
Implementation Method 1
A formation tester tool includes a tool body, a probe assembly located within the tool body. The probe assembly includes a probe piston reciprocating within a cylinder, a seal pad mounted on the probe piston, and a hydraulic system configured to actuate the probe piston radially to a deployed position in which the stabilizer stabilizes the tool against the borehole wall
Implementation Method 2
The seal pad forms a sealing interface with the borehole wall to prevent fluid leakage and maintain pressure isolation
Data Source
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AI summary
A formation tester tool assembly includes a seal member mounted on rigid stabilizer that contacts a borehole wall separately from the seal member, so that seal exposure to a stabilization load that presses the tool against the borehole wall is limited or reduced by contact engagement of the stabilizer with the borehole wall. The stabilizer is provided by a hydraulically actuated probe piston reciprocally movable relative to a tool body on which it is mounted. The seal member is in some embodiments movable relative to the probe piston, for example being configured for hydraulic actuation to sealingly engage the borehole wall while the tool body is stabilized by action of the probe piston.