Modeling transient streaming potentials in falling-head permeameter tests

Area of Science:

• Geophysics
• Hydrogeology
• Physical Chemistry

Background:

• Falling-head permeameter tests are standard for measuring soil hydraulic conductivity (K).
• Streaming potential measurements offer insights into fluid flow and porous media properties.
• Electrokinetic coupling coefficients (Cl) quantify the relationship between fluid flow and electrical potential.

Purpose of the Study:

• To estimate hydraulic conductivity (K) and electrokinetic coupling coefficients (Cl) of sand samples using transient streaming potential data.
• To validate the streaming potential method against traditional head-based measurements.
• To explore the potential of streaming potential as a proxy for hydraulic head in hydrogeology.

Main Methods:

• Collected transient streaming potential data during falling-head permeameter tests on two distinct sand samples.
• Employed a semi-empirical model integrating falling-head permeameter flow and electrokinetic coupling principles.
• Analyzed streaming potential versus time and head data to estimate K and Cl.

Main Results:

• Hydraulic conductivity (K) estimates from streaming potential data showed less than 10% deviation compared to head data.
• Electrokinetic coupling coefficient (Cl) values derived from streaming potential versus time and head data were in close agreement.
• Demonstrated the feasibility of using temporal streaming potential responses for estimating both K and Cl.

Conclusions:

• Transient streaming potential measurements in falling-head permeameter tests are effective for determining hydraulic conductivity and electrokinetic coupling coefficients.
• The streaming potential method provides a reliable alternative for estimating K, closely matching traditional methods.
• Transient streaming potential data show promise as a valuable proxy for hydraulic head in hydrogeological applications.