Flexible Borehole Liner Eversion Under High Artesian Pressure
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Solution Overview
Problem
The installation of flexible borehole liners is limited by high artesian pressures and shallow water tables, which often require extensive scaffolding, posing safety risks and operational challenges, especially when the artesian head is above the ground surface.
Innovation Solution
A method and apparatus that reduce the effective water table beneath the liner by using a bypass pipe and weighted mud to create a higher pressure within the liner, allowing eversion without extending the surface casing, thereby bypassing artesian flow and enabling liner installation in conditions with artesian heads up to 20 feet above the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If extensive scaffolding is used to achieve the needed higher water level within the liner, then the liner installation can be accomplished, but the installation personnel are exposed to freezing winter winds and safety risks increase
Solution Approach 1:
The invention extracts the harmful element (scaffolding) from the system by replacing it with a submersible pump that can be operated from within the borehole or from the surface without requiring external support structures. This eliminates the safety risks and exposure to freezing winds while maintaining the ability to achieve the necessary water level for liner installation.
Solution Approach 2:
The submersible pump acts as an intermediary device that transfers water into the liner from the borehole, eliminating the need for scaffolding to achieve the required water level. The pump mediates between the available water in the borehole and the need for pressurized water in the liner, solving the contradiction without exposing personnel to harmful external conditions.
2Ease of operation
If the surface casing is extended above the surface to obtain the necessary driving pressure within the liner, then the liner can be installed, but the device complexity and installation difficulty increase
Solution Approach 1:
The invention removes the need for casing extension by extracting the water pressurization function and placing it within the existing casing structure using a submersible pump. This eliminates the complexity of extending the casing while maintaining the driving pressure needed for liner installation.
Solution Approach 2:
The invention replaces the mechanical solution of extending the casing (which requires additional materials, labor, and structural support) with a hydraulic solution using a submersible pump. This substitution reduces device complexity while achieving the same functional outcome of generating sufficient driving pressure for liner installation.
3Reliability
If a bypass pipe is installed to allow artesian flow to bypass the liner, then liner collapse is prevented, but the device complexity increases
Solution Approach 1:
The invention merges the function of the bypass pipe with the existing water flow path in the borehole. The submersible pump creates a controlled water level that naturally directs artesian flow around the liner through the annular space, combining the pressurization function and the bypass function into a single integrated system rather than requiring separate bypass infrastructure.
4Ease of operation
If the water level inside the liner is significantly higher than the water table in the formation, then the liner can be everted into the borehole, but the loss of energy and water increases
Solution Approach 1:
The invention applies partial action by pumping water only to the extent necessary to achieve the minimum required water level for liner eversion, rather than maintaining a significantly higher water level. The submersible pump provides just enough pressure head to overcome the artesian pressure and enable liner installation, reducing unnecessary energy consumption and water loss while still achieving the installation objective.
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 safe and efficient installation of flexible borehole liners in challenging conditions, preventing liner collapse and allowing normal artesian flow to bypass the liner during installation, thus extending the applicability of everting flexible liners beyond previous limitations.
Implementation Method 1
the installation of everting flexible liners into boreholes was limited to situations of less than approximately five feet of artesian head above the ground surface
Implementation Method 2
A method and apparatus that reduce the effective water table beneath the liner by using a bypass pipe and weighted mud to create a higher pressure within the liner
Implementation Method 3
A method and apparatus that reduce the effective water table beneath the liner by using a bypass pipe and weighted mud to create a higher pressure within the liner
Data Source
AI summary
An apparatus and method for facilitating eversion of a flexible liner down a borehole when an artesian head condition is producing a rate of water flow out of the top of the borehole. A bypass pipe channels artesian flow, moving upward in the borehole and/or well casing, past an everting flexible liner to a wellhead fixture. Artesian flow arriving at the wellhead fixture is pumped away to ameliorate resistance to liner eversion otherwise presented by the water flow. A heavy mud may be disposed inside the everting liner further to promote its downward eversion past the artesian flow.