Browsing by Author "Tutolo, Benjamin Michael"

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    Bulk compositional control on the metamorphism of pelitic rocks with an emphasis on the Whetstone Lake area, Southeastern Ontario
    (2021-12) Forshaw, Jacob Benedict; Pattison, David Robert Maitlan; Ghent, Edward Dale; Nair, Rajeev Kumar Sasidharan; Tutolo, Benjamin Michael; Yakymchuk, Chris
    Metapelites (metamorphosed shales and mudstones) are an important rock type for interpreting metamorphism. This thesis examines the influence of bulk rock composition on the metamorphism of pelites using a two-pronged approach: (i) analysis of large datasets compiled from the literature and (ii) detailed study of an exceptional metamorphic sequence, the Whetstone Lake area in southeastern Ontario. A database of 3225 published whole rock geochemical analyses from the literature was collated, an order of magnitude greater than any previous. Whilst metapelites worldwide appear geochemically similar, there are many metapelites whose composition lies outside the main cluster. Analysis reveals a decrease in volatile content with increasing metamorphic grade, whilst the proportion of the major elements remains relatively constant. The average metapelite from this database is (wt%): SiO2 = 62.24, TiO2 = 0.94, Al2O3 = 19.88, FeOtotal = 7.32, MnO = 0.13, MgO = 2.68, CaO = 0.92, Na2O = 1.57, K2O = 4.19, and P2O5 = 0.15; the average (± 1σ) XMg = MgO/(MgO+FeOtotal) in moles = 0.40 ± 0.09, and the average XFe3+ = Fe3+/(Fe2+ + Fe3+) in moles is 0.27 ± 0.17. A database of 785 published XFe3+ analyses in metapelitic minerals was collated. Average (± 1σ) XFe3+ values in biotite, white mica, chlorite, and staurolite are 0.11 ± 0.08, 0.55 ± 0.18, 0.08 ± 0.07, and 0.07 ± 0.06, respectively. Whilst there is little variation in XFe3+ with pressure and temperature, there is an increase in XFe3+ in both white mica and biotite from ilmenite- to magnetite- to hematite-bearing samples. Metapelites at Whetstone Lake showcase a diversity of mineral assemblages over a small range of grade, a result of wide differences in bulk composition. Whole rock XMg and XFe3+ exert the greatest control on mineral assemblages, whilst MnO, K2O, and Al2O3 have a secondary influence. The observed mineral assemblages, modal proportions, and mineral compositions from both the XFe3+ database and Whetstone Lake were compared with the predictions of thermodynamic modelling. There is acceptable agreement between predicted and observed mineral assemblages and modes, but consistent discrepancies are found for mineral compositions. These include the overestimation of XMg in garnet, staurolite, and cordierite, overestimation of Ti in staurolite and biotite, underestimation of Si in biotite, and overestimation of Al and underestimation of Fe3+, Fe2+, and Mg in muscovite.
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    Dynamics of Viscous Fingering in Porous Media in the Presence of Injected or In Situ Generated Particles
    (2021-01-12) Sabet, Nasser; Hassanzadeh, Hassan; Abedi, Jalal; Mohamad, Abdulmajeed; Hejazi, Hossein; Tutolo, Benjamin Michael; Meiburg, Eckart
    Interfacial instabilities in the form of viscous fingers evolve when a less viscous fluid displaces a more viscous one. Such instabilities occur in a wide range of engineering applications, including subsurface contaminant transport, soil and groundwater remediation, micromixers, enhanced oil recovery, and geological storage of carbon dioxide, to name a few. This thesis focuses on the theoretical study of viscous fingering between two miscible fluids (termed as displacing and displaced fluids) in porous media. In particular, we are interested in investigating the effect of the presence of solid particles on the mixing of fluids for two main scenarios: (i) when the displacing fluid contains solid particles such as nanoparticles and (ii) when the interaction of the displacing and displaced fluids results in the formation of particles (also called precipitates) as is in the case of asphaltene precipitation in mixing of a paraffinic solvent with oil. In this study, we use a combination of theoretical techniques, including the development of analytical solutions, linear stability analysis, and nonlinear numerical simulations to quantify and characterize the effect of particles on fluids mixing. For injected particles, the numerical simulations are based on the stream function vorticity formulation in a moving frame of reference, while for in situ formed particles, a velocity vorticity formulation in a fixed frame is developed to capture the variations of porosity and permeability due to particle deposition. Our results show that non-depositing nanoparticles can be used to fully stabilize an unstable front, whereas depositing nanoparticles might only act as temporary stabilizers. We also quantify the role of each nanoparticle physical property, including their log-viscoity ratio and diffusion coefficient, on the growth of viscous fingers. For miscible viscous fingering in the presence of a nanocatalytic reaction, we show that a higher reaction rate leads to more frontal instability. Also, we define two mechanisms that control the effect of deposition of nanocatalysts on viscous fingering. In the case of in situ formed particles, we investigate the dynamics of viscous fingering in the presence of an infinitely fast and reversible precipitation reaction. Our results reveal that the formed precipitates mostly exist at the interface where the two fluids are mixing actively. Also, we show that the ultimate permeability of porous media can be scaled linearly with the log-viscosity ratio of fluids. Finally, we study the specific case of asphaltene precipitation and deposition in the context of solvent-based recovery of bitumen. In our analysis, we quantify the degree of in situ upgrading of bitumen and shed light on the difference between two commonly used viscosity relations in the literature.
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    Investigating Groundwater Impacts and Sulfur Cycling in Urban Stormwater Ponds
    (2023-04-25) Ogrins, Lucas; Cey, Edwin; Mayer, Bernhard; Tutolo, Benjamin Michael
    Stormwater ponds have been used to manage water quality and quantity during high flow events. Groundwater can potentially impact the operations of stormwater ponds by altering pond water chemistry, although this influence is poorly understood. This study was undertaken to improve understanding of groundwater and surface water interactions and sulfur cycling in a stormwater system. A pair of interconnected stormwater ponds were investigated at an airport in Calgary Alberta where one pond, Pond M, was known to generate noticeable quantities of hydrogen sulfide. A site investigation was carried out to evaluate groundwater flow directions, groundwater and surface water chemical compositions, sulfur sources and fate through stable isotope analysis, and water budgets. At both ponds, groundwater accounted for a minor fraction of the total water budget and surface water flows dominated. While groundwater contributions were low, elevated sulfate was seen in groundwater samples in the study area, which was attributed to evaporative concentration, with concentrations being the highest around Pond M. Sulfate was shown to enter the pond bottom by diffusion at an estimated rate of 8.9 to 17 kg per day and is the main sulfur source for bacterial sulfate reduction. Other possible sulfate inputs into Pond M are groundwater leakages into stormwater pipes above the pond and preferential flow paths in fractured till adjacent to the pond. Groundwater with high dissolved solid content contributes to stratification at Pond M and likely enhances hydrogen sulfide generation by reducing oxygenation of the water column. Hydrogen sulfide generated in Pond M oxidizes into elemental sulfur and contributes to turbidity encountered at the second pond, Pond E. Stormwater at Pond E was found to exit the study area by seeping into the ground, potentially bypassing the outlet control structure. Groundwater interactions with stormwater ponds have the potential to alter pond structure and can contribute to hydrogen sulfide generation by diffusion of sulfate into pond sediments where bacterial sulfur reduction can occur.
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    Scale Up of Pore Level Flow Properties; Application in Wellbore Modelling Containing Inflow Control Devices
    (2021-08-31) Bashtani, Farzad; Kantzas, Apostolos; Clarkson, Christopher; Maini, Brij; Tutolo, Benjamin Michael; Gostick, Jeffrey
    Prediction of reservoir production using different technical scenarios and designs is essential for optimization of a reservoir development plan. Due to the scale of a reservoir, simulators use simplified discretized equations to predict the production and other properties of the reservoir. Therefore, they cannot observe complicated physical phenomena that occur at the pore scale. Such phenomena have a significant effect on the relative permeability of the fluids which is an important factor for predicting multiphase flow behavior at the reservoir scale. Commercial reservoir simulator software use correlations to calculate relative permeability of the fluids. Even though such method is proven practical for conventional reservoirs, it is not accurate for unconventional and tight reservoirs if not calibrated and matched using SCAL data and can lead to erroneous predictions. The objective of this research is to calculate the single-phase and immiscible two-phase flow properties including porosity, permeability, capillary pressure, and relative permeability using random-network modelling technique at the pore scale and then scale up the results to macro scale, and core scale using analytical and numerical methods available in the literature and develop new scale up methods when the current methods prove to be inaccurate. The scaled-up flow properties are then used to construct a comprehensive near well bore model with complex well completion setups which contain tubing-deployed and liner-deployed flow control devices (FCDs). The effect of various completion designs such as open-hole, single and parallel tubing, liner-deployed FCD, and retrofitted tubing-deployed FCD setups in conjunction with the scaled-up flow properties obtained from pore level modelling is incorporated in a comprehensive software package. The application of the coupled scaled-up micro-scale simulation and near well bore modelling is illustrated in two aspects: Control of gas coning in horizontal wells with tubing deployed FCDs and application of PNM in simulation of black oil reservoirs. Control of gas coning in horizontal wells using tubing deployed FCDs is studied and the scaled-up relative permeability curves were incorporated during simulation. In this study, a new formulation is also developed to capture the phase-change normal to the well. In this model a modified version of boundary-element-method (BEM) is implemented, and the pressure is used as a tracer and all the properties such as saturation and mobility variation are calculated normal to the well bore. This is a new semi-analytical method where all the integration terms are calculated numerically. Application of PNM and its corresponding scaled-up results in near well bore simulation is also studied. We explain the variability of pore structure on its relative-permeability and capillary pressure curves, and for a similar formation and identical permeability how other factors can vary the characteristic curves. By using a boundary-element-method we also incorporate such variations into well/reservoir interaction. As a result of such modelling one may evaluate the performance of the well on different gas cresting/coning scenarios. The results show that such variability in the pore network has less than 10% on production gas rates, but its effect on oil production can be extensive. The results of such work show the importance of PNM in well completion design and probabilistic analysis of the performance and can be extended on different factors of the reservoir in the future works.
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    The Controls of Porosity on Mineral Alteration Processes in the Shallow Oceanic Lithosphere at Slow-Spreading Ridges
    (2023-03-20) Pujatti, Simone; Tutolo, Benjamin Michael; Lecumberri-Sanchez, Pilar; Pattison, David Robert Maitlan; Nair, Rajeev Kumar Sasidharan; Lauer, Rachel Mollie; Tutolo, Benjamin Michael; Shugar, Daniel H
    Porosity exerts strong controls on mineral replacement and alteration processes mediated by the action of fluids. These processes are ubiquitous in the Earth’s crust, but even more so within the oceanic lithosphere, an environment saturated by infiltrating fluids that can range in composition from hot hydrothermal fluids to low-temperature seawater. This thesis presents examples of fluid-rock interactions that affect mafic and ultramafic lithologies recovered via drilling from the subseafloor of the slow-spreading Mid-Atlantic Ridge. These reactions are enabled by the presence of pores that provide flow pathways for fluids to reach the reaction front of altering minerals. Chapter 2 explores the genesis of petrographic textures observed in samples recovered from the Trans-Atlantic Geotraverse, a hydrothermal sulfide mound that shows black smoker activity. The textures form due to the replacement of anhydrite by pyrite under the action of hot hydrothermal fluids generated via heating of seawater entrained within the oceanic crust, and involved growth of quartz into open space. Intensive investigation of the observed textures detailed in this Chapter provides a mechanistic explanation for the attainment of the sulfur isotopic signatures found in sulfide precipitate within the hydrothermal mound. In Chapter 3, tomographic analysis of serpentinized peridotite at nanometer and micrometer scales reveals the presence of dissolution pores located at the grain boundaries of olivine, which show significant connectivity, suggesting that soluble Mg and Si sourced from the dissolution of olivine are exported to seawater, affecting its chemical budget, alkalinity, and consequently the coupled carbonate-silicate cycle. Chapter 4 tests the hypothesis that the porosity and Fe3+ contents of serpentinized peridotite increase with increasing serpentinization degree, suggested by correlations between density and magnetic susceptibility of serpentinites established in earlier work. The hypothesis was tested by applying statistical analysis to geochemical and porosity data collected on serpentinite samples recovered from 10 different drilling sites, revealing complex alteration patterns that involve seafloor weathering processes and thus extend beyond the transformation imparted by serpentinization reactions. Together, the scientific investigations conducted in this thesis demonstrate the importance and complexities of porosity generation and evolution during alteration of the shallow oceanic lithosphere.