Chemically and electrically induced swelling in clays and shales
Date
2012
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Abstract
The swelling behavior of shale formations is of importance from both operational management and geo-environmental perspectives. This research program was concentrated on the investigation of deformation of shales and clays in response to the variations of pore fluid chemistry. Development of a mathematical framework describing the swelling behavior of clay-based materials along with experimental study of swelling geomaterials enabled for simulating the swelling process.
A new experimental setup featured with electrical elements was developed to accelerate the conventional swell test on argillaceous materials by applying the electrical potential gradient. Based on the results of swell tests on several clay and shale samples, the application of electrical potential gradient was identified as an effective method to accelerate the rate of ionic extraction and the swelling process. X-ray CT scanning technique was applied as a non-destructive method to qualitatively investigate the profile of swelling through the test materials under conventional and accelerated swell tests. In addition, the influence of specific surface area, cation exchange capacity, Atterberg limits, and grain size distribution was assessed on the amount of swelling. Applicability of coefficients of volume change obtained from consolidation-rebound tests was examined in simulating the swelling behavior.
Coefficients of hydraulic and electro-osmotic permeability were identified as key material properties controlling the rate of swelling. Comparison between the numerical and experimental results showed that the hydraulic and electro-osmotic permeability could vary with the changes in the pore fluid concentration. Applying the numerical model along with the experimental results of swell tests resulted in the determination of hydraulic and electro-osmotic permeability as functions of pore fluid concentration. These material properties were determined for clay and shale samples investigated in this research program.
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Bibliography: p. 250-259
A few pages are in colour.
A few pages are in colour.
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Citation
Deriszadeh, M. (2012). Chemically and electrically induced swelling in clays and shales (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/4801