Flexible Everting Liner for Hydraulic Head Profiling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for measuring hydraulic head in geologic formations adjacent to boreholes are limited, as they assume constant head distribution and do not accurately account for vertical transmissivity and gradient, which are crucial for understanding contaminant migration and aquifer recharge.
Innovation Solution
A method using a flexible everting/inverting borehole liner to measure hydraulic head distribution by obtaining integrated head measurements while the liner is inverted, allowing for calculation of hydraulic head in incremental intervals based on transmissivity profiles, with optional use of pressure transducers to directly measure borehole pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a constant head distribution is assumed in the formation, then the measurement process is simplified, but the accuracy of vertical transmissivity and gradient determination deteriorates
Solution Approach 1:
The borehole is divided into multiple discrete intervals along its length. A separate pressure measurement is taken at each interval using the everting liner system. This segmentation allows the head distribution to be characterized at multiple discrete points rather than assuming a constant value, thereby improving the accuracy of vertical transmissivity and gradient calculations while maintaining a relatively simple measurement approach.
2Measurement precision
If discrete hydraulic head measurements are taken at multiple intervals, then the accuracy of contaminant migration and aquifer recharge understanding improves, but the device complexity increases
Solution Approach 1:
The everting liner system serves multiple functions: it acts as a seal against the borehole wall, provides a platform for pressure measurement at different intervals, and enables the measurement process itself through its eversion and inversion mechanics. This multi-functionality reduces the need for separate specialized devices for each measurement task, thereby achieving high measurement precision without proportionally increasing device complexity.
Solution Approach 2:
The everting liner system utilizes its own mechanical movement (eversion and inversion) to sequentially expose different borehole intervals for measurement. The system's inherent mechanical action serves the measurement function, eliminating the need for complex external positioning mechanisms or multiple separate measurement devices, thus achieving accurate multi-interval measurements with relatively simple equipment.
3Measurement precision
If incremental liner inversion with pauses is performed to measure tension, then the hydraulic head profile measurement accuracy improves, but the measurement time increases
Solution Approach 1:
The measurement process employs periodic incremental inversion of the liner with pause intervals at each interval. During each pause, tension measurements are taken to determine the hydraulic head at that specific location. This periodic action allows accurate discrete point measurements to be collected systematically along the borehole profile, achieving high measurement precision while organizing the time-consuming process into efficient, repeatable cycles.
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 method provides accurate hydraulic head profiling, enabling better monitoring of aquitards and water quality, and defining long-term vertical gradients, improving the understanding of groundwater flow and contaminant migration.
Implementation Method 1
The liner is everted into the formation using fluid pressure
Implementation Method 2
the tension on the inverted end of the liner is measured to obtain the pressure (head) in the borehole
Implementation Method 3
An optional alternative method uses a pressure transducer below the bottom end the liner to obtain the borehole pressure history directly
Data Source
AI summary
A system for measuring a profile of a hydraulic head. A flexible liner is everted down the borehole. The profile of the transmissivity of the geologic media is obtained during (and indirectly from) the eversion of the flexible liner as it proceeds down the borehole. The liner is then retrieved by inversion from the borehole, while the pressure head in the borehole fluid below the liner is monitored and measured. From the previously obtained transmissivity profile, and the measured head within the borehole, the hydraulic head in the geologic media surrounding the borehole is determined for borehole intervals. A complete hydraulic head profile may be obtained from the collected data.