Flexible Liner Eversion Steering via Asymmetric Reinforcement
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Solution Overview
Problem
Flexible liners used in subsurface boreholes often become entrapped in enlargement voids due to uneven borehole diameters and asymmetrical tensile strength, causing them to deviate from a straight path and fail to propagate into enlarged sections.
Innovation Solution
The method involves selectively controlling the circumferential longitudinal tensile strength of the liner by adding a reinforcement tendon diametrically opposite the seam and using weight or buoyant mechanisms to guide the liner in a desired direction, allowing it to propagate in a straight path or non-linear paths, even when unconstrained by the borehole wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the liner is installed in a borehole with enlargement voids, then the liner can seal the borehole, but the liner becomes entrapped on ledges and cannot propagate into enlarged sections
Solution Approach 1:
The patent applies asymmetry by adding a reinforcing tendon diametrically opposite the seam, creating intentional asymmetry in the liner's circumferential tensile strength distribution. This asymmetric reinforcement pattern allows the liner to maintain structural integrity while controlling its eversion path to navigate enlargement voids and ledges effectively
2Ease of manufacture
If the liner has variable longitudinal tensile strength due to the seam, then the liner can be constructed, but the liner curves as it propagates and deviates from the proper path
Solution Approach 1:
The patent intentionally introduces asymmetry by placing a reinforcing tendon diametrically opposite the seam. This creates a controlled asymmetric tensile strength distribution that counteracts the natural curvature caused by the seam, enabling the liner to propagate in a straighter path while maintaining construction feasibility
Solution Approach 2:
The reinforcing tendon provides localized reinforcement at specific circumferential positions. This local quality enhancement allows the liner to maintain its natural seam construction while adding targeted strength in specific regions to control propagation behavior and reduce unwanted curvature
3Ease of operation
If the liner is constrained by the borehole wall, then the liner propagates in the axial direction, but the liner cannot navigate non-vertical boreholes or large caverns
Solution Approach 1:
The patent makes the liner's mechanical properties dynamic by incorporating a reinforcing tendon that can be selectively engaged. The tendon provides rigid support when needed for axial propagation through boreholes, while allowing the liner to flex and adapt when navigating non-vertical sections or large caverns, thus achieving both axial propagation and navigation capabilities
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 approach enables the flexible liner to steerably evert into non-vertical boreholes and navigate through large caverns, maintaining orientation and avoiding entrapment, thereby ensuring effective deployment in various subsurface environments.
Implementation Method 1
selectively controlling the circumferential longitudinal tensile strength of the liner by adding a reinforcement tendon diametrically opposite the seam
Implementation Method 2
using weight or buoyant mechanisms to guide the liner in a desired direction
Data Source
AI summary
A method and system for steering the direction of propagation of a flexible liner everting under a driving fluid pressure. There is provided a method for controlling and guiding directionally the eversion of the flexible liner into a borehole that penetrates a subsurface (e.g., subterranean) void with a diameter substantially exceeding the nominal diameter of the borehole. Further, liner propagation by eversion can be controlled outside of a borehole and when unconstrained by a borehole, such as on or beneath the surface of a body of water.