Browsing by Author "Wong, Ronald C. K."
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Item Open Access 1d compression creep behaviour of kaolinite and bentonite clay(2011) Varatharajan, Sivarajan; Wong, Ronald C. K.Creep mechanisms and factors influencing the creep in clay soils are not yet well understood due to the complex structure of clay matrix. An experimental program was conducted to investigate the parameters affecting the creep behaviour. One-dimensional single stage, stepwise and overloaded-unloaded compression creep tests were conducted using standard oedometer apparatus on kaolinite and bentonite clay samples. Single and radial drainage conditions with different pore fluids were considered. Required creep stress levels were achieved using instantaneous loading increments. Effects of stress level, stress history, pore fluid chemistry, fabric structure, drainage condition and mineral compositions of clay on creep behaviour were studied based on the experimental results. Drainage condition exhibited insignificant influence on creep. Creep mechanisms were explained as a combined effect of sliding of clay particles at their contacts and deformation of particle itself. Compression of micro pores during the creep is negligible. Developed model successfully describes the creep behaviour interims of viscosity.Item Open Access Acidifying emissions in Alberta: managing the gap(2000) Schmitz, Ronald A.; Wong, Ronald C. K.Item Open Access Anisotropy in deformations and hydraulic properties of Colorado shale(2004) Gautam, Rajeeb; Wong, Ronald C. K.The structural integrity of Colorado shale, a natural cap rock for the Clearwater Formation reservoir is of prime importance from both operational management and geoenvironmental perspectives. This research was focused on the anisotropic investigation of deformation and hydraulic properties of the Colorado shale. Development of local strain measurement devices along with the confined torsion testing technique and triaxial testing technique on horizontally drilled shale core samples enabled the determination of static stiffness parameters over a wide range of strains. The results from the triaxial tests conducted on vertically and horizontally drilled core samples (E_v, v_vh, Eₕ, vₕₕ) were combined with the results from the confined torsion tests (G_vh) to evaluate all five independent transversely isotropic elastic parameters. At small strain, the Poisson's ratios are found to be zero. The anisotropy ratios Eₕ / E_v for the Second White Specks (SWS) and Westgate (WG) Formation shales are about 1.98. Likewise, the anisotropy ratios Gₕₕ/G_vh for those formations are about 1.86 and 1.50, respectively. Anisotropic hydraulic properties of the Colorado shale have been investigated by conducting steady and transient state water displacement tests on the vertically and horizontally drilled shale core samples. The results show that the permeability of the Westgate Formation shale is higher than that of the SWS shale (k_v(WG) =7k_v(sws) ). Similarly, the permeability along the horizontal direction is greater than that along the vertical direction (k_(h(sws)) = 5k_(v(sws))). The values of pore pressure parameters B and A_v for the Westgate Formation and SWS shale samples range from 0.30-0.72 and 0.20-0.35, respectively. The theoretical analysis and the test results further show that the Colorado shale samples are not at their full pore fluid saturations. The results from the confined creep tests and the unconfined creep tests conducted on the vertically and horizontally aligned shale samples show that the creep strain along the vertical direction (perpendicular to bedding) is much higher than that along the horizontal direction (parallel to bedding). Similarly, higher creep was observed in the Westgate Formation shale than that in the SWS shale. The numerical and experimental investigation of borehole heating of low-permeability shale indicated high propensity for formation fracturing in such shales.Item Open Access Applications of micromechanics in granular sand and swelling clay(1994) Zhong, Xiaoxiong; Wong, Ronald C. K.Item Open Access Behaviour of unsaturated soils under direct shear and triaxial compression(2005) Lun, Martin C.H.; Wong, Ronald C. K.Item Open Access Behavioural characteristics and constituitive modelling of Athabasca tar sand at low effective stresses(1995) Samieh, Ahmed Mosalem; Wong, Ronald C. K.In this thesis, the behaviour of Athabasca oil sand at low effective stresses is investigated. A series of consolidated drained triaxial tests was performed on undisturbed specimens at a confining pressure range of 30 kPa to 750 kPa. The influence of testing conditions, namely slenderness ratio and end conditions, on the behavioural characteristics of the material is investigated. The results of the shear tests revealed that the use of short specimens with free ends promotes the homogeneity of the sheared specimens. This homogeneity has been attested by the results of magnetic resonance imaging. The results of the shear tests exhibited that at low effective stresses, Athabasca oil sand does not reach to the critical state by the end of the tests. Thus, it is not possible to determine the critical state characteristics from these experimental results. The critical state characteristics of the material were determined from consolidated drained tests on reconstituted oil-free Athabasca sand specimens. A new algorithm is developed to determine the homogenous stress-strain and volume change responses of the material until the critical state is approached. A constitutive model, based on the generalized disturbed state concept, is established to model the response of Athabasca oil sand at low effective stresses. The response of Athabasca oil sand is expressed in terms of the responses of its reference states, namely the virgin and the fully disturbed states, through a disturbance function. A generalized single surface plasticity model is incorporated for modelling the virgin state of the material, whereas the fully disturbed state is assumed to be the critical state. The model parameters required to simulate both the experimental and the homogenous responses of Athabasca oil sand are identified and evaluated. The model is verified against both the experimental and the homogenous responses of the material.Item Open Access Biodegradation and electrical conductivity of amine contaminated soil: a laboratory study(2001) Ndegwa, Anne W.; Wong, Ronald C. K.Item Open Access Bioremediation and fracturing of soil(1996) Wibowo, Rinaldi; Wong, Ronald C. K.Item Open Access Bioremediation of crude oil in cold-climates(1999) Gibb, Angela; Wong, Ronald C. K.Item Open Access Chemically and electrically induced swelling in clays and shales(2012) Deriszadeh, Mohammad; Wong, Ronald C. K.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.Item Open Access Consolidation and shear behaviour of kaolinite-bentonite clay mixtures(2009) Inparajah, Delakshan; Wong, Ronald C. K.This thesis consisted of three parts: consolidation characteristics variation, shear strength behaviour and resistivity analysis of different kaolinite-bentonite clay mixtures with various pore fluid salinity levels. The 1-D oedometer tests were performed to determine the consolidation characteristics of kaolinite-bentonite clay mixtures with different pore fluid salinity levels. The samples were prepared at a moisture content level of 2% above the respective liquid limit of each clay sample mixture. The behavioural pattern of the measured coefficient of consolidation (Cv) and the compression index (Cc) of the clay mixtures with the key influencing factors such as salinity level of pore fluid (pore fluid chemistry) and mineral composition were analyzed in detail. Direct shear box tests were also conducted to study the shear behaviour of different clay mixtures. For the simple direct shear test, thin disk samples of 2 to 3 mm thicknes and 60 mm diameter were prepared by mixing different kaolinite-bentonite clay mixtures with different pore fluid s. The clay samples were sheared back and forth until they reached a residual stress state. The peak, residual stress values and the residual friction angle variations were analyzed in detail. Resistance variations of different clay mixtures were measured using the inductance-capacitance-resistivity meter (LCR meter) at a higher frequency level of I O kHz and the results were used to study the porosity variation of the clay mixtures using Archie's equation.Item Open Access Development of a geotechnical asset management system(2011) Waiguru, Moses Maina; Cowe Falls, Lynne; Wong, Ronald C. K.Item Open Access Development of finite element models for thermal multiphase flow in deformable porous media with anisotropic full permeability tensor(2006) Du, Jiancheng; Wong, Ronald C. K.Item Open Access Dnapl-water two-phase flow in rock fractures(2010) Weerakone, Weerakone M. S. B.; Wong, Ronald C. K.Item Open Access Effects of material strength, confining pressure and joint configuration on the shear behavior of brittle materials(2000) Ma, Stevenson Ka Yiu; Wong, Ronald C. K.Item Open Access Evaluation of embankment failure at Canadian Pacific Railway mile 34.1 Kaministiguia subdivision(1998) Choi, Eddie Sing Chuen; Wong, Ronald C. K.Item Open Access Finite element analysis of straight shaft cast-in-place concrete pile set in oil sand(2011) Barr, Lucas Allister; Wong, Ronald C. K.Item Open Access Finite element simulation of hydraulic fracturing in unconsolidated sands(2010) Xu, Bin; Wong, Ronald C. K.Fluid injection into reservoirs; such as waste disposal, steam or water flooding and well testing, is a common practice in oil and gas industry. The injection of large volumes of fluid into an unconsolidated sands reservoir can result in significant changes to the in-situ stress distributions which may lead to the hydraulic fractures initiation and propagation. Hydraulic fracturing can be broadly defined as a process by which a fracture initiates and propagates due to hydraulic loading (i.e., pressure) applied by a fluid inside the fracture[l]. Although hydraulic fracturing in hard rock has been comprehensively studied both experimentally and numerically, some fundamental mechanisms of hydraulic fracturing in unconsolidated formation have not been well understood. The hydraulic fracture in unconsolidated sand reservoir can be represented as an anisotropic area of dilation zone or a net of micro-cracks, inside which the formation has low effective stresses and high hydraulic conductivity values. In this thesis, w present a 3D finite element model for simulating the hydraulic fracture initiation and propagation in unconsolidated sands reservoir due to large volumes of fluid injection at high injection rate. To simulate this strong anisotropy in mechanical and hydraulic behaviour induced by fluid injection, a poro-elasto-plastic constitutive model together with a strain-induced anisotropic permeability model are formulated and implemented into a 3D finite element simulator, which is used to match the field injection data. Several case studies, which include the field produced water re-injection into deep unconsolidated formation and well testing in oil sands formation, are conducted using the developed finite element model. The bottom-hole-pressures predicted by the developed finite element codes are used to history match the field bottom-hole-pressures. The numerical calculations clearly show that the presented numerical model can capture the physical mechanism of hydraulic fracture initiation and propagation in unconsolidated sand formation and matches the field pressure versus time curve very well.Item Open Access Geomechanical effects of cyclic stream simulation on casing integrity(1997) Smith, Richard James; Wong, Ronald C. K.Item Open Access Geotechnical behaviour of bentonitic clay seam(2005) Kumar, Deepak; Wong, Ronald C. K.Thin layers of soft clay seam exist beneath the earth surface at several locations in Western Canada. They were formed out of volcanic eruptions in the past and were buried due to geological depositions on them from the top. Over the years, they have undergone several fabric and mineralogical transformations due to in situ pressure and existing physicochemical environment. Relative shearing of soil layers above and below a clay seam is always possible in the presence of a source of shearing. Several casing (meant for extracting oil) failures have been reported from the oil fields of Alberta due to such relative shearing of soil layers above and below the existing clay seam. At these sites, cyclic steam stimulation (a thermal process) technique is used to extract oil. In the mentioned technique, steam at high pressure and temperature is injected in oil bearing formations to reduce their viscosity before extraction, and it also acts as an excitation source of shearing along the clay seam. Beforehand knowledge of relative shear displacement along clay seam caused by a certain steam pressure can help reduce the number of casing failures. In the present work, an analytical elastic model has been developed to estimate the shear displacement along the clay seam due to steam injection. Concepts of elastic fracture mechanics were used to estimate the relative displacement. Several laboratory tests including creep test, direct shear box test, mineralogical and fabric analyses were conducted on samples of clay seam for their complete characterization.