Engineering Commons^™

Investigation Of Local Velocities And Phase Holdups, And Flow Regimes And Maldistribution Identification In A Trickle Bed Reactor, Mohd Fitri Bin Abdul Rahman

Doctoral Dissertations

"Trickle bed reactors are packed beds of catalyst on which gas and liquid reactants flow concurrently downward. In this work, the experimental work was carried out in 0.14 m diameter Plexiglas column using air-water system flowing over a packed bed of 3 mm glass bead particles. The local liquid and gas velocities, phase saturation and their time series have been investigated for the first time by developing, validating, and implementing a new two-tip optical fiber probe technique. It was found the radially and axially the liquid and gas velocities and their saturation vary and they also vary with times. In …

Screening Guidelines And Data Analysis For The Application Of In-Situ Polymer Gels For Injection Well Conformance Improvement, Munqith Naeem Rashak Aldhaheri

Doctoral Dissertations

"Excessive water production represents a major industry challenge because of its serious economic and environmental impacts. Polymer gels have been effectively applied to mitigate water production and extend the productive lives of mature oilfields. However, selecting a proper gel technology for a given reservoir is a challenging task for reservoir engineers because of the associated geological and technical complexities and the absence of efficient screening tools.

A comprehensive review for the worldwide gel field projects was conducted to develop an integrated systematic methodology that determines the applicability of three injection well gel technologies including bulk gels, colloidal dispersion gels, and …

The Effect Of Testing Conditions On Lost Circulation Materials' Performance In Simulated Fractures, Montri Jeennakorn

Doctoral Dissertations

"Lost circulation (LOC) problems increase costs of drilling significantly. It is not only the cost of the drilling fluid that is lost into the formation but also the costs of subsequent problems that can be higher than the cost of the drilling fluids. LOC also possibly leads to a serious risk of blowout incident.

Lost circulation materials (LCM) are regularly added to the drilling fluids with an expectation of plugging the flow path. Due to the difficulties of testing and monitoring LCM sealing processes in the field, LCM evaluation in the laboratory is often used to prove and assure successful …

Experimental Study Of Natural Convection Heat Transfer And Gaseous Dynamics From Dual-Channel Circulation Loop, Ibrahim Ahmed Said Abdallah

Doctoral Dissertations

"This research focuses on establishing a range of scaled separate and integral effects experiments for studying thermal-hydraulic behavior occurring within a component or region of the prismatic very high-temperature reactor (VHTR) such as plenum-to-plenum heat transfer and gaseous dynamics during natural circulation. Natural circulation of the coolant is the leading capability for VHTR to transport the decay heat from the core to the reactor vessel during accident scenarios. To address this need, a scaled-down facility is designed and developed with only two channels with upper and lower plena. The emphasis is placed on high-resolution and high-fidelity experimental data for local …

Numerical Simulation Of Viscoelastic Buckle Folds: Implications For Stress, Fractures, Porosity And Fluid Flow, Xiaolong Liu

Doctoral Dissertations

"Over the past several decades, buckle folds have been exclusively studied by numerous methods. However, lots of assumptions and simplifications are made, which may not result in realistic in-situ stress conditions leading to rock failure. This study represents the first numerical simulation of folding under the consideration of gravity and pore pressure to simulate the structural development of buckle folds.

The first topic covered in this dissertation is the fracture associated to the single layer fold. It is concluded that burial depth, viscosity, and permeability are critical for the initiation of major fracture sets at the hinge zone with varying …

Rock And Fluid Flow Characterization On Unconventional Reservoir Using Confocal-Laser-Microscopy And Micromodels, Songyuan Liu

Doctoral Dissertations

"Unconventional oil reservoirs have become significant sources of petroleum production and have even better potential in the future. Many unconventional oil systems consist of nanoscale pore throats, sub-micro-scale pores and micro-scale fractures that are significantly smaller than those from conventional reservoirs. To understand fluid flow behavior in unconventional reservoir, lab approaches were conducted using lab-on-chip method for the direct visualization of the water/oil flow in sub-micro-scale channels and the flow behavior with influence of surfactant and fractures.

In this work, tight sandstone thin slice was characterized using confocal-laser-microscope. Using designed micromodels, microscopic study of interface and residual oil distribution as …

Atomic/Molecular Layer Deposition Prepared Size-Selective Catalysts And Supported Nickel Catalysts, Zeyu Shang

Doctoral Dissertations

"Heterogeneous catalysts are widely used because of their many advantages. In this dissertation, the application of atomic/molecular layer deposition (ALD/MLD) in heterogeneous catalyst synthesis and modification was examined.

A novel nanostructured size-selective catalyst was synthesized by depositing ultra-thin porous shells on the surface of catalysts. The ultra-thin porous shells were formed by oxidation of aluminum alkoxide films deposited by MLD. The catalytic activity of the size-selective catalyst was improved by introducing gaps between the porous shell and catalytic metal nanoparticles. The introduction of gaps greatly reduced the catalyst activity loss, which resulted from the contact areas between the active sites …

Experimental Investigations Of Natural Circulation In A Separate-And-Mixed Effects Test Facility Mimicking Prismatic Modular Reactor (Pmr) Core, Mahmoud M. Taha

Doctoral Dissertations

"After the Fukushima Daiichi nuclear power plant accident in 2011, significant attention was directed to investigate natural circulation thermal-hydraulics in Prismatic Modular Reactors (PMRs). Natural circulation is employed as a passive safety feature that passively removes the decay heat released after the loss of flow accidents (LOFA). Several computational studies have addressed such phenomena, however, validation of Computational Fluid Dynamics (CFD) is needed by providing high-quality data obtained from separate test facilities designed with reference to the corresponding reference PMRs. To address this need, a separate effects Plenum-to-Plenum Facility (P2PF) was designed and developed with dual channels and plena for …

Impact Of Vertical Internals On The Hydrodynamics And Heat Transfer Coefficient In A Gas-Solid Fluidized Bed, Haidar Moafaq Taofeeq

Doctoral Dissertations

"This research studied the impact of the dense vertical immersed heat exchanging tubes on the gas and solids hydrodynamic characteristics, flow regime, pressure drop, and heat transfer in a 0.14 m inside diameter gas-solid fluidized bed column of. Two sizes of vertical internal tube bundles (0.0127 and 0.0254 m) of circular arrangement have been implemented to represent the heat exchange tubes covering 25% of the column cross-sectional area. The experimental work was achieved at different operating conditions and various solids particle types that differ in average particle size, solids density, particles shape, and particles sphericity. The experimental measurements were performed …

Mass Transfer Studies In Heavy Oil Recovery Using Solvents, Vijitha Mohan

Doctoral Dissertations

"Heavy oil, sometimes called bitumen, is known for its high viscosity (above 100 cp) and low API gravity (below 22⁰). In most cases, viscosity reduction is needed for the final product. There is a considerable amount of heavy oil in Alberta, Canada and the world's largest heavy oil deposit is in Venezuela. Yet less than 1% of it can be recovered because of its high viscosity. For shallow reservoirs, it is possible to resort to open cast mining. For deeper reservoirs, steam is used at ~ 350 ⁰C which gets the oil viscosity reduced to 1cp, which can now be …

Engineering Advanced Adsorbent Materials For Co₂ Capture Applications, Harshul Thakkar

Doctoral Dissertations

"Global climate change due to the increasing CO₂ concentration in the atmosphere is primarily associated with anthropogenic CO₂ emissions. CO₂ capture technologies using adsorbents have not been implemented commercially due to lack of scalable, practical and cost-effective strategies and are still under development. Moreover, the use of conventional configurations such as pellets and beads for the removal of CO₂ from enclosed environments have been shown to impose limitations to the removal efficiency and system performance. In this dissertation, engineering of advanced and efficient structured adsorbents for practical and scalable CO₂ capture technologies and their use …

Investigation Of Hydraulic Fracture Complexity And The Benefits Of Maximizing Or Minimizing Complexity In Unconventional Resources, Rashid Sheikh Kassim

Doctoral Dissertations

"This dissertation discusses two separate, yet inter-related studies. The first study was an extension of historical work comparing transversely fractured versus longitudinally fractured horizontal wells in multiphase flow environment. The second study investigated hydraulic fracture complexities and the benefits of maximizing or minimizing complexities in unconventional resources and tight reservoirs.

The main objective of this research was to investigate fracture complexity and its impact on well performance and economics. To achieve that objective, three different integrated completions and reservoir models were built. Two of the three models, a hybrid reservoir model and micro-seismic based SRV (stimulated reservoir volume) model, were …

Data Analysis And Application Guidelines Of Particle Gel Treatments, Yue Qiu

Doctoral Dissertations

“Water production is a severe worldwide issue in mature oilfields, which results in shortening the economic life of oil and gas wells. Particle gel have been widely applied in mature oilfields to improve reservoir sweep efficiency and control water production. To date, more than 10,000 injection wells were successfully treated by particle gels. However, considerable uncertainty still exists regarding to where and how particle gel treatments can be best applied.

The main objective of this study is to provide application guidelines and prediction model for particle gel treatments through data analysis. In this study, four particle gel treatment datasets have …