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Quantification of dissolution and exsolution dynamics of gaseous solvents in crude oil systems under reservoir conditions
No full textA Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Petroleum Systems Engineering , University of Regina. xxv, 226 p.With a growing demand for fossil fuels, it is of a great importance to improve the oil
recovery factor from both conventional and unconventional reservoirs. Among different
enhanced oil recovery (EOR) methods, injecting gaseous solvents, including CO2, N2, flue
gas, and alkane solvents, is considered as a more effective and efficient method in both
light and heavy oil reservoirs, during which mass transfer is the key underlying recovery
mechanism. In order to optimize the solvent injection method and achieve a higher oil
recovery, it is of fundamental and practical importance to quantify both dissolution and
exsolution dynamics of solvents in light and heavy oils under reservoir conditions.
Firstly, a pragmatic method has been developed and applied to quantify the mutual
mass transfer in different solvent(s)-light oil systems. Experimentally, diffusion
experiments have been conducted for flue gas-light oil systems at constant pressures and
temperatures. The dynamic liquid volume is monitored and recorded continuously during
the experiments, while gas samples are collected at the beginning and end of each test to
measure the gas fractions with gas chromatography (GC) analysis. Theoretically, by
combining the Fick’s law and Peng-Robinson equation of state (PR EOS), the preferential
and mutual diffusion between the flue gas and light oil can be quantified once the
deviations between the measured and calculated parameters (i.e., dynamic swelling factor
and gas composition) are minimized. Both individual diffusion coefficients for each gas
component of a gas mixture in an oil phase and that of the extracted oil components in the
gas phase are increased with pressure and temperature.
Both the experimental and theoretical methods are modified and then extended to
CO2/C3H8-heavy oil systems to quantify the mutual diffusivity between the gaseous
solvents and heavy oil with the consideration of natural convection at high pressures and
elevated temperatures or coupled with heat transfer process. Similarly, diffusion
experiments are conducted with a PVT setup, during which the dynamic swelling factors
of the heavy oil are measured continuously. Both oil and gas samples are collected at end
of each test for oil compositional and GC analyses, respectively. The diffusivities of both
solvents (i.e., CO2 and C3H8) in heavy oil and the extracted oil components in the gas
phase are found to increase with pressure and temperature. Also, there exists an obvious
extraction process from the oil to gas phases at elevated temperatures as light-medium
components have been detected in the collected gas samples at end of the experiments.
While coupling heat and mass transfer to determine the diffusivity of hot solvent in the
heavy oil, thermal equilibrium is found to be achieved earlier than mass equilibrium.
Combined heat and mass transfer will accelerate the oil swelling effect.
Then, experimental and theoretical techniques have been developed to predict gas
exsolution dynamics of CO2/CH4-heavy oil systems on the bubble level to reflect the
physical behaviour of foamy oil. Experimentally, constant-composition-expansion (CCE)
experiments have been performed in a sealed PVT system for a CO2-heavy oil system and
a CH4-heavy oil system, respectively. Theoretically, the classical nucleation theory,
population balance equations (PBEs), Fick’s law, and PR EOS has been integrated to
predict the gas bubble number and size by reproducing the experimentally measured
parameters (i.e., liquid volume and pseudo-bubblepoint pressure). It has been observed
that both temperature and diffusivity of the gas component play an important role in the
foamy oil behaviour. Compared with CO2, CH4 can induce a stronger and more stable
foamy oil since more CH4 bubbles are dispersed in the oil phase.Studentye
Investigating the role of water and nanoparticles in the performance of CO2 and ethane-based cyclic solvent injection process for heavy oil recovery
No full textA Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Petroleum Systems Engineering, University of Regina. XX, 309 p.Cyclic solvent injection (CSI) process is a promising method for enhancing heavy oil
recovery in thin or deep heavy oil reservoirs. Foamy oil flow is a major phenomenon of the CSI
process, but the impact of foam stabilizers like nanoparticle and water on its performance has not
been well understood. Therefore, an in-depth understanding of waterflooding and nanoparticle
affecting CSI performance is a crucial step toward further enhancing oil recovery. In addition,
most studies only focus on one method. In fact, in order to develop an oil reservoir cost-effectively
and efficiently, a variety of methods have to be applied in sequence. In this study, a well-designed
experimental investigation was conducted to determine the role of water and nanoparticle in CSI
process. First, several foundemental live oil depletion tests were applied to investigate the
feasibility of using foamy oil additives in the CSI process, determine the optimum concentration
of the additives, and evaluate the best operation conditions on the performance of the CO2 based
CSI process. Second, three CO2 based CSI tests were performed using a cylindrical sandpack at
different injection pressure. Test 1 conducted a normal CO2 based CSI process for comparison.
Test 2 applied a waterflooding process and followed by a CO2 based CSI process. Test 3 was a
hybrid process consisting of the sequence: CSI-waterflooding-CSI-Nanoparticle solution flooding-
CSI. Third, two ethane based CSI tests (A blank test and a similar combination test) were applied
in order to verify and compare CO2 based CSI process. Experimental parameters and results were
monitored and recorded. Comprehensive data analytics were performed to examine the effect of
water and nanoparticle and identify enhancing mechanisms for the CSI process.
Experiment results indicate that using nanoparticles as foam stabilizers in CO2 live oil
pressure depletion tests can enhance oil recovery while reducing gas recovery, with higher
nanoparticle concentrations resulting in even greater oil recovery. An optimal depletion rate of 6
kPa/min was identified, and the waterflooding process had a positive impact on the performance
of both CO2 and ethane based CSI methods, improving mass transfer by expanding gas/oil contact
areas. The nanoparticle solution flooding applied before CSI process were able to effectively
stabilize foamy oil even at high water saturation levels. The integration of CSI, water flooding,
and nanoparticle solution flooding yields an overall oil recovery factor of 69.5% for the combined
CO2 based hybrid EOR process and 76.1% for the ethane based hybrid EOR process. Simulation
results show that the dispersed gas model exhibits strong alignment between oil and gas production
data and pressure distribution in CO2 based live oil pressure depletion tests. For CO2 based CSI
process, by incorporating a modified foamy oil model with separate sets of relative permeability
curves for injection and production stages, and employing the dispersed gas model during
production stage, a robust history-matching of oil, gas, and water production data is achieved
simultaneously.
In the Lloydminster area, thousands of wells have a water cut exceeding 90% after the
waterflooding process and are subsequently abandoned due to the absence of an effective way to
continue development. This study meticulously examines potential enhancements for the CSI
process, which involve utilizing foam stabilizers in combination with synergistic water flooding
methods. The findings of this study provide practical solutions to address the technical challenges
encountered during the subsequent development of heavy oil wells with high initial water
saturation. Additionally, the study highlights the promising prospects of combination approaches
in enhancing heavy oil recovery.Studentye
Geochemical and petrographic studies of accessory minerals in the Athabasca Basin: implications for unconformity-related uranium mineralization
No full textA Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Master of Science in Geology, University of Regina. xvi, 431 p.The unconformity-related uranium (URU) deposits in the Athabasca Basin rank among the world's
largest and highest-grade U deposits, many of which are also characterized by enrichment in rare
earth elements (REE). The source of U and REE for the mineralization, whether from the basin or
the basement, is a subject of scientific debate. This study focuses on the petrographic features and
chemical compositions of detrital and diagenetic accessory minerals within the Athabasca Basin
sandstones to evaluate the potential contributions of the sediments in the basin to the U and REE
budget in the mineralization systems. Employing various analytical methods including
petrographic microscopy, scanning electron microscope – energy dispersive spectroscopy (SEMEDS),
SEM-cathodoluminescence (SEM-CL), Raman spectroscopy, TESCAN integrated mineral
analyzer (TIMA) mapping, and laser ablation inductively coupled plasma mass spectrometry (LAICP-
MS), this study identified the alteration patterns in U- and REE-rich minerals such as zircon,
rutile, and anatase. Alteration patterns indicating depletion of U and REE were observed both at
the mineral rims and deep within their cores, suggesting their release into basinal fluids during
alteration. In contrast, minerals such as aluminum phosphate sulfate (APS) and iron oxide and/or
hydroxide (IOH) demonstrate enrichment of U and REE, primarily in their outer rims, suggesting
their potential roles as "sink" minerals. Some altered zircon and anatase also show local U
enrichment. Petrographic and geochemical analyses indicate that U and REE in detrital minerals
have heterogeneous distribution patterns. Zircon shows a wide range of U concentrations (up to
~6000 ppm), with variable degrees of heavy rare earth elements (HREE) enrichment. The
similarity in REE patterns between detrital zircon, and to a lesser extent the Ti-oxide, in the
sandstone and uraninite in the URU ores suggests that detrital zircon and Ti-oxide in the Athabasca
Basin may be a major contributor of REE, and by inference U, to the URU mineralization. APS
STUDIES OF ACCESSORY MINERALS IN THE ATHABASCA BASIN G. HARMANCI
minerals display the highest concentrations of REE (up to 10,000 ppm), also characterized by
LREE enrichment, primarily around their rims. The IOH minerals also show LREE-enriched REE
patterns. It is inferred that the APS and IOH minerals as well as diagenetic anatase acted as sink
minerals that preferentially retained LREE and certain amounts of U that were leached from zircon
and Ti-oxide. Mass balance calculations based on the data from this study and bulk sandstone
compositions reported in the literature suggest that as much as approximately 88 million tonnes of
U and 355 million tonnes of REE could be released from detrital zircon and Ti-oxide in the
sandstone into the basinal fluids. These results suggest that detrital accessory minerals, especially
zircon and Ti-oxide, in the sandstones may be a major source for U and REE in the URU deposits
in the Athabasca Basin and that there is still great potential to discover more U and REE resources
in the Athabasca Basin.
Keywords: Athabasca Basin, accessory minerals, zircon, uranium, rare earth elements, REE,
leaching, source of uranium, unconformity-related, URUStudentye
Adults’ perceptions of child eyewitness credibility: multiple independent lineups
No full textA Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Bachelor of Arts (Honours) in Psychology, University of Regina. 58 p.Eyewitness testimony is a powerful piece of evidence in criminal cases (O’Neill et al., 2011; Neal et al., 2012), but this can be problematic as eyewitness testimony is a leading cause of wrongful convictions (Innocence Project, 2023). Mistaken eyewitness testimony is prominent in children, as children identify innocent suspects more frequently than adults (Fitzgerald & Price, 2015). Age-appropriate lineup techniques have been explored to reflect child eyewitness accuracy, such as the multiple independent lineups technique (MIL; Carr & Bruer, 2023). Although Carr & Bruer (2023) found promising results using the MIL technique with children, how adults perceive child eyewitness credibility through MIL was unstudied. This study aimed to fill this gap in how adults perceive child eyewitness credibility on the MIL. To do so, juryeligible participants (N =176. 73% female, 24% male, 3% identified as other [i.e., nonbinary], Mage = 23.26, SD = 7.85) read a mock trial transcript where the child eyewitness made their identification(s) of the suspect through the traditional lineup or the MIL technique. Perceived credibility for the participants was measured through several different dimensions (i.e., identification, overall credibility, honesty, and cognitive ability). Largely, the results did not indicate any significant differences across lineup techniques (traditional lineup or MIL), nor the age of the child eyewitnesses (younger or older). This indicates that adults perceive child eyewitness credibility similarly regardless of technique used and age of the child eyewitness. Implications and future directions are discussed
Examining how organizational leaders perceive internet-delivered cognitive behavioural therapy for public safety personnel using the RE-AIM implementation framework
No full textWithin Canada, internet-delivered cognitive behavioural therapy (ICBT) has recently been tailored
by PSPNET to meet the needs of public safety personnel (PSP) to help address high rates of mental health
problems within this population. Perceptions and outcomes of ICBT among PSP are promising, but it remains
unknown how PSPNET is perceived by PSP organizational leaders. It is important to assess this gap because these
leaders have significant potential to influence the uptake of ICBT.
Methods: In the current study, PSP leaders (n = 10) were interviewed to examine their perceptions of PSPNET and
opportunities to improve ICBT implementation. The RE-AIM evaluation framework was used to assess PSP
leaders' perceptions of PSPNET in terms of reach, effectiveness, adoption, implementation, and maintenance.
Results: The results evidenced that leaders perceived PSPNET as effective in reaching and serving PSP and PSP
organizations. PSP leaders reported perceiving ICBT as effectively implemented, especially for being freely
offered to individual PSP and for improving PSP's access to experienced therapists specifically trained to work
with PSP. Participants indicated organizations have promoted and will continue promoting PSPNET longer-term,
facilitating adoption and maintenance. Factors perceived as facilitating successful service delivery included
building relationships and trust with PSP organizations and general support for PSP leadership mental health
initiatives. PSP leaders identified perceived areas for improving ICBT implementation (e.g., ensuring leaders
have access to data on PSPNET uptake and outcomes, creating promotional videos, expanding availability of
PSPNET to other provinces, offering additional options for receiving therapist support).
Implications: Overall, the study provides insights into PSP leaders' perceptions of the implementation of ICBT
among PSP and ideas for optimizing implementation efforts.This research was conducted by PSPNET, which is funded by the Canadian Government's Ministry of Public Safety and Emergency Preparedness
Future nostalgia in the twenty-first century: Hauntology, hermeneutics, and historicity in contemporary popular music
No full textA Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Master of Arts in Interdisciplinary Studies, University of Regina. v, 91 p.This thesis offers a critical analysis and discussion of the philosophical and popular culture
concept of hauntology and its application to popular music and theory of history, arguing that
hauntology is limited in ways that make it unequipped for understanding popular music’s
historicity as the form develops into the 2020s. Drawing on UK artist Dua Lipa’s 2020 album
Future Nostalgia as a case study, the argument suggests that recent developments in music
production and consumption challenge the hauntological understanding of pop’s historicity. It
concludes that instead of looking at the historical in pop through the lens of hauntology, popular
music’s relationship to historicity can be better understood through the framework of
philosophical hermeneutics.Studentye
Fabrication of PLA-hemp 3D printing filaments
No full textA Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Master of Applied Science in Industrial Systems Engineering, University of Regina. xvi, 153 p.This thesis focuses on the development and evaluation of polylactic acid (PLA) composites
infused with hemp fibers for 3D printing applications. The project aims to leverage the intrinsic
properties of hemp fibers and PLA to create a material that mitigates brittleness and enhances
biodegradability while maintaining mechanical performance and printability. The methodology
involves fabricating composite filaments from 2 mm PLA pellets and 0.4 mm hemp fiber particles.
Hemp fiber at varying weight ratios (5 wt%, 10 wt%, and 15 wt%) was extruded using a single
screw extruder. The optimal ratio was determined among these blends for maximum tensile and
flexural strength, and the structures on the fractured surfaces were observed under low
magnification. The filaments were studied under flexural and tensile mechanical testing, optical
microscopy analysis, Fourier Transform Infrared thermal profiling, moisture absorption, and
biodegradability analysis. The blends were compared with a commercial PLA filament for 3D
printing applications.
As a summary of the results, the composition of 5 wt% and 10 wt% hemp powder had
lower Ultimate Tensile Strength (UTS) than 100 wt% PLA filaments; however, this blend had
higher elongation and toughness. The highest tensile strength of 35 MPa occurred with the 95 wt%
PLA-5 wt% hemp fiber composition. Similarly, the flexural strength for the 95 wt% PLA-5 wt%
hemp fiber composition was 86 MPa, which was the highest among the composites, but lower than
100 wt% PLA. This composition showed a higher flexural modulus of 4 GPa which was greater
than 100 wt% PLA. For water absorption, all the composite filaments showed the greatest rate of
absorption during the first 1 hour. After the initial hour, no notable changes occurred. The 85 wt%
PLA-15 wt% hemp fiber had the highest absorption rate; indicating that increasing the fiber
percentage increases the water absorption. The biodegradability was studied using an enzyme-rich
FABRICATION OF 3D PRINTING FILAMENTS M. UDDIN
detergent which showed that 90 wt% PLA-10 wt% hemp fiber had the highest weight loss
percentage across all three concentrations which was over 20% which indicates that this
composition was more prone to biodegradability using this method than the other compositions.
The printability of the filaments was analyzed qualitatively using a commercial 3D printer.
A simple design for a “paper clip” was printed which requires both tensile and flexural strength.
The products were printed with ease whereby the filaments melted and flowed through nozzles of
0.8 mm diameter for fused filament printing.Studentye
Progressive partition-based granular computing and complexity measures
No full textA Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Master of Science in Computer Science, University of Regina. x, 77 p.Granular computing has received much interest over the past few decades due to its
effectiveness and practicality in managing complexity. While it is intuitively believed
that complexities in granular computing are linked to granularities, there do not
exist any studies to show they have a direct connection. This suggests the need
to investigate complexity from a different perspective. Simon’s concept of nearly
decomposable systems, which describes complexity from a hierarchical perspective,
aligns closely with the hierarchical nature of granular structures. Thus, granular
structures can provide a foundation for exploring complexities in granular computing.
This study investigates the complexity of the progressive partition-based model of
granular computing. We formally define the progressive partitioning tree (PPT),
which is the structure used in the progressive partition-based model, and provide a
general method that recursively measures the complexity of PPTs. Additionally, we
propose a class of interaction-based complexity measures by treating interactions as
the source of complexity. These measures can quantitatively explain the complexity
differences between structures and the complexity reduction offered by the progressive
partition-based model of granular computing.Studentye
Examining the gut microbiota in aging
No full textA Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Master of Science in Interdisciplinary study, University of Regina. xi, 123 p.The human gut microbiome, comprised primarily of bacteria, plays a crucial role in
overall health and physiology by regulating metabolism, immunity, and behavior through the
microbiota-gut-brain axis (MGBA). Key functions include fermenting complex carbohydrates
into short-chain fatty acids (SCFAs) that maintain gut integrity, modulating inflammation, and
influencing energy homeostasis (i.e., food intake regulation). For example, SCFAs can play a role
in food intake regulation by directly or indirectly influencing episodic appetite signals (ghrelin,
glucagon-like peptide 1 [GLP-1]) and tonic appetite signals (leptin, insulin). Gut dysbiosis, or an
imbalance in the gut microbiome, leads to altered metabolic processes, increased epithelial
permeability, and systemic inflammation that contribute to health issues like metabolic
dysfunction (type 2 diabetes [T2D]), cardiovascular disease, and neuropsychiatric conditions.
Aging is associated with gut dysbiosis, which can affect energy homeostasis and increase the
risk for age-associated comorbidities. Regular physical activity has been shown to improve gut
health and food intake regulation in young adults. This project aimed to characterize gut
microbial communities in active older adults (60 years +) (GUMS) compared to a sedentary
cohort with type 2 diabetes (T2D) (DMP) and investigate how gut bacteria may be influenced by
physical activity/cardiorespiratory fitness (CRF), body composition, appetite hormones,
cardiometabolic health, and mental health.
Data was analyzed from n=22 GUMS (active older adults) and n=6 DMP (sedentary older
adults with T2D). Gut bacterial diversity and composition were assessed by sequencing of 16S
amplicon DNA from participant stool samples. In-person data was collected to assess CRF (via
peak oxygen consumption [VO2peak] test), body composition (via air displacement
plethysmography), appetite hormones (from plasma blood samples), and cardiovascular health
(blood pressure, arterial stiffness). Mental health was assessed using standardized
questionnaires administered through Qualtrics.
Diversity measures were not significantly different between physically active older
adults (GUMS) and sedentary older adults with type 2 diabetes (DMP); however compositional
differences were observed. A nonsignificant increased proportion of opportunistic pathogens is
apparent in DMP, suggestive of gut dysbiosis in T2D. Further, lower CRF and higher body fat
[observed in DMP] were linked to decreased gut microbial diversity and increased opportunistic
pathogens. Fasted appetite hormones ghrelin and GLP-1 did not differ between groups, but
insulin and glucose levels were higher in DMP, reflecting their diabetic condition. No
correlations were found between gut microbial diversity and appetite hormones, though
positive correlations were observed between appetite hormones and SCFA-producing taxa.
Dietary patterns showed higher fat intake and lower fiber consumption in DMP, potentially
contributing to dysbiosis and metabolic issues. It was also observed that hypertension
medication was associated with reduced gut microbial diversity and increased opportunistic
pathogens, indicating a potential dysbiotic effect of hypertension treatment.
Future research should recruit a larger number of participants and conduct long-term
studies comparing older and younger populations to further understand the impact of aging
and habitual physical activity on the gut microbiome. Additionally, exploring broader ranges of
appetite hormone values could clarify their associations with gut microbial composition.
Further research is also required to confirm the dysbiotic effects of hypertension medication.Studentye
New Light on the Mystery of Count Esterhazy
No full textDive into the enigmatic world of Count Esterhazy, an immigration agent who brought Hungarians to settle in Saskatchewan. This exhibition unveils their early immigration history while revealing the scandals and questions about Esterhazy’s aristocratic origins