The chemistry andphysics involved at the metal/atmosphereinterface is interesting both from a fundamental and an appliedperspective. Since iron is the most important of all metalsthis interface is of particular interest. The objective withthis thesis is to obtain new information on a molecular levelof the iron/atmosphere interface with a special emphasis on theinitial atmospheric corrosion. The work presented herein combines a large variety ofdifferent analytical surface science techniques. Both ultrahigh vacuum and ambient pressure investigations were conductedwith single crystals as well as polycrystalline samples. The interaction of segregated sulfur with a Fe(110) surfacewas investigated by means of atomically resolved scanningtunneling microscopy (STM). A large variety of high and lowcoverage reconstructions were reported. Comparable studies ofoxygen adsorption on the same surface were also completed.Similar to the sulfur experiments, oxygen induced a number oflow coverage reconstructions. At higher coverage, oxideformation was observed and ordered oxides could be fabricatedat elevated temperatures. The oxygen interaction with Fe(110) and Fe(100) surfaces wasalso investigated with synchrotron radiation basedphotoelectron spectroscopy. Detailed information of the initialadsorption and subsequent oxidation was obtained. The Fe 2pcore level of the clean Fe(110) surface was subject to furtherinvestigations because of its complicated line profile that wasinterpreted as an exchange split of the final state. Iron exposed to humidified air with low concentrations ofsulfur dioxide (SO2) shows a surprisingly passive behavior. Themeasured mass gain was significantly lower than that of acopper sample exposed in the same environment. In-situtechniques such as atomic force microscopy (AFM), quartzcrystal microbalance (QCM) and infrared reflection absorptionspectroscopy (IRAS) showed little or no corrosion. Initiationof corrosion was observed upon introduction of additionaloxidants. The conclusion drawn challenge the established modelfor formation and growth of sulfate nests. The condition andformation of sulfate nests are discussed in view of thegenerated in-situ observations. During further experiments, iron was exposed to humid airand sodium chloride aerosols. The surface was investigated within-situ techniques, which provided new useful information. Ahigh corrosion rate was observed and the corrosion attacks formfilaments characteristic of filiform corrosion. A schematicmodel for propagation of the corrosion filaments wasproposed. Filiform corrosion was observed on aluminum surfaces aswell. The corroded surfaces were investigated with synchrotronradiation based photoelectron microscopy and scanning over afiliform head revealed different oxidation states within the Al2p spectrum. The microscopy data was interpreted as anenrichment of aluminum chloride containing compounds within thefiliform corrosion head.

This research is a study of the in-situ upgrading of Jobo crude oil using steam, tetralin or decalin, and catalyst (Fe(acac)₃) at temperatures of 250 °C, 275 °C and 300 °C for 24 hours, 48 hours and 72 hours using an autoclave. Viscosity, API gravity and compositional changes were investigated. We found that tetralin and decalin alone were good solvents for heavy oil recovery. Tetralin or decalin at concentrations of 9% (weight basis) could reduce the Jobo crude oil viscosity measured at 50 °C by 44±2% and 39±3%. Steam alone had some upgrading effects. It could reduce the oil viscosity by 10% after 48 hours of contact at 300°C. Tetralin, decalin or catalyst showed some upgrading effects when used together with steam and caused 5.4±4%, 4±1% and 19±3% viscosity reduction compared with corresponding pre-upgrading mixture after 48 hours of reaction at 300°C. The combination of hydrogen donor tetralin or decalin and catalyst reduced the viscosity of the mixture the most, by 56±1% and 72±1% compared with pre-upgrading mixture. It meant that hydrogen donors and catalyst had strong synergetic effects on heavy oil upgrading. We also found that 300 °C was an effective temperature for heavy oil upgrading with obvious viscosity reduction in the presence of steam, hydrogen donors and catalyst. Reaction can be considered to have reached almost equilibrium condition after 48 hours. The GC-MS analysis of the gas component showed that light hydrocarbon gases and CO₂ were generated after reaction. The viscosity reduction from decalin use is larger than that of tetralin because decalin has more hydrogen atoms per molecule than tetralin. A mechanism of transferring H (hydrogen atom) from H₂O and hydrogen donors to heavy oil, which can lead to structure and composition changes in heavy oil, is explained. The study has demonstrated that in-situ heavy oil upgrading has great potential applications in heavy and extra heavy oil recovery.

Scenarios developed by the National Energy Board of Canada predict that Canadian unconventional gas production, including coalbed methane (CBM), may be required to meet Canadian energy demands by the year 2008, and could constitute up to 65% of supply by 2025. Although there has been considerable CBM exploration and development in Alberta in recent years, there has been relatively limited activity in Saskatchewan.<p>The in-situ stress regime can have a strong influence on coal bed methane (CBM) production, coal permeability, hydraulic fracturing pressure, and borehole stability while drilling horizontal wells. A limited number of stress regime analyses have been conducted previously on a regional scale, for the entire Western Canada Sedimentary Basin (WCSB), but none has been conducted with a focus on Saskatchewan. The primary objective of this study was to investigate in-situ stress magnitudes and orientations in southwestern Saskatchewan. The secondary objective was to quantify the influence of in-situ stresses on operational practices that would be used to exploit CBM targets.<p>Analysis of vertical stress magnitudes and gradients were conducted using bulk density data compiled for 257 wells in southwest Saskatchewan. Vertical stress magnitudes calculated at the base of the Belly River Formation in the region where its CBM potential is greatest were found to be in the 6 to 12 MPa range. Vertical stress magnitudes at the top of the Mannville Group in the region where its CBM potential is greatest were found to be in the 12 to 18 MPa range. Data available for interpretation of minimum horizontal stress magnitudes were considerably more limited. A technique was developed to estimate these magnitudes using fracture stimulation data, which were available for the Viking Formation and Mannville Groups. Using this technique, minimum horizontal stress magnitudes at the top of the Mannville Group in the region of greatest interest were estimated to be 10 to 14 MPa. The results of these analyses suggest that depth is a dominant controlling factor for minimum horizontal stress magnitude, but that pore pressures (sub-normal pressures cause lower stresses) and lithology (shaley rocks, and perhaps coals, have higher stresses) also have notable effects. Insufficient data were obtained for direct estimation of minimum horizontal stresses in the Belly River Formation. Minimum horizontal stress magnitudes in this formation might be quite close to vertical stress magnitudes.<p>Borehole breakouts were analyzed to interpret the orientation of maximum horizontal stress (¥òHmax) in the study area. The mean orientation of the mean borehole breakouts gives a 137¨¬ with a circular standard deviation of 12¨¬, which parallels the minimum horizontal stress in the study area with a notable inflection overlying the Swift Current platform. The data is portrayed in a trajectory map. The trajectories indicated on the map can be used for predicting the orientation of induced hydraulic fractures, and the likely orientation of face cleats in coals. Knowledge of the orientations of these features is essential to effective development of CBM resources.<p>Based on the stress and pore pressure data presented in this thesis, it is anticipated that minimum effective stresses in the Belly River coals will typically be a few MPa, and up to 10 MPa in the Mannville coals. A very rough estimate of permeabilities based on the data compiled for various Canadian coals suggests that permeabilities could be in the 0.01 to 10 millidarcy range for the former, and 0.01 to 1 millidarcy range for the latter. <p>Borehole stability analyses were conducted for both the Belly River Formation and the Mannville Group. The results suggest that horizontal drilling of the Mannville coals should be feasible, without the need for high-density drilling muds. Given that the Belly River coals occur in numerous thin seams, they are most likely to be developed using vertical wells. Borehole instability is not likely to be a major problem in these vertical wells.<p>Recommendations are provided for laboratory investigation of coal permeabilities and mechanical properties, field testing for minimum horizontal stress magnitudes in coal seams and adjacent strata, and additional analysis of existing fracture stimulation, log and core data for strata not analyzed in this project.

Abstract In-situ remediation using reactive zones is a promising groundwater contaminant treatment technology that involves the injection of a reagent(s) into the subsurface to destruct harmful target chemicals. For efficient and effective treatment the reagent has to be delivered into a specific contaminated zone for the desired chemical reaction(s) to occur. The most commonly used delivery method is a conventional well where the distribution of injected reagent is mainly controlled by the surrounding hydraulic conductivity field. In this case, the reagent is easily delivered into the higher hydraulic conductivity zones but the lower hydraulic conductivity zones are missed. The goal of this research effort is to investigate a novel delivery method involving a single well vertical recirculation system or a dipole well. The configuration of this single dipole well is that injection and extraction occurs from two chambers separated by an impermeable central packer. Thus, this dipole well system can induce predominantly vertical flow across bedding plane features and it is therefore hypothesised that this delivery system can overcome physical heterogeneities creating a more uniform reactive zone. The objective of this research was to demonstrate that the dipole well is a useful delivery tool compared to the commonly used single injection well. Mathematical simulations were used to investigate the delivery performance of a dipole well using steady-state and transient approaches. A simple analytical model was used to determine the steady-state dipole flow field and observe the impact of system parameters on reagent delivery behaviour. The size of coverage area (the area swept by the injected reagent) was used as the performance metric to assess the impact of each system parameter on the dipole well performance. Numerical simulations were used to extend this investigation to homogeneous and heterogeneous (structured or randomly correlated hydraulic conductivity) aquifers under pulsed operation to identify those situations where the dipole delivery system is more efficient or effective. Both forward and backward particle path lines were used to identify reagent coverage areas around the injection well and down gradient. The impact of each system parameters on the dipole well performance was studied. The shoulder length and the injection cost are characteristic parameters that affect dipole delivery performance. A relationship between the down gradient coverage area vs. characteristic system parameters was developed and can be used to predict the dipole well performance in homogenous aquifers. The impact of the hydraulic conductivity distribution on dipole well performance is consistent with either a structured hydraulic conductivity field or randomly correlated hydraulic conductivity fields. Regions of lower hydraulic conductivity can be swept by the dipole well and the dipole well outperforms a single injection well, which is analyzed as a base case in terms of the shape of down gradient coverage area. However, the advantage of dipole well over a single well delivery is small if the degree of heterogeneity is large or the horizontal extent of the bedding plane is small.

Abstract In-situ remediation using reactive zones is a promising groundwater contaminant treatment technology that involves the injection of a reagent(s) into the subsurface to destruct harmful target chemicals. For efficient and effective treatment the reagent has to be delivered into a specific contaminated zone for the desired chemical reaction(s) to occur. The most commonly used delivery method is a conventional well where the distribution of injected reagent is mainly controlled by the surrounding hydraulic conductivity field. In this case, the reagent is easily delivered into the higher hydraulic conductivity zones but the lower hydraulic conductivity zones are missed. The goal of this research effort is to investigate a novel delivery method involving a single well vertical recirculation system or a dipole well. The configuration of this single dipole well is that injection and extraction occurs from two chambers separated by an impermeable central packer. Thus, this dipole well system can induce predominantly vertical flow across bedding plane features and it is therefore hypothesised that this delivery system can overcome physical heterogeneities creating a more uniform reactive zone. The objective of this research was to demonstrate that the dipole well is a useful delivery tool compared to the commonly used single injection well. Mathematical simulations were used to investigate the delivery performance of a dipole well using steady-state and transient approaches. A simple analytical model was used to determine the steady-state dipole flow field and observe the impact of system parameters on reagent delivery behaviour. The size of coverage area (the area swept by the injected reagent) was used as the performance metric to assess the impact of each system parameter on the dipole well performance. Numerical simulations were used to extend this investigation to homogeneous and heterogeneous (structured or randomly correlated hydraulic conductivity) aquifers under pulsed operation to identify those situations where the dipole delivery system is more efficient or effective. Both forward and backward particle path lines were used to identify reagent coverage areas around the injection well and down gradient. The impact of each system parameters on the dipole well performance was studied. The shoulder length and the injection cost are characteristic parameters that affect dipole delivery performance. A relationship between the down gradient coverage area vs. characteristic system parameters was developed and can be used to predict the dipole well performance in homogenous aquifers. The impact of the hydraulic conductivity distribution on dipole well performance is consistent with either a structured hydraulic conductivity field or randomly correlated hydraulic conductivity fields. Regions of lower hydraulic conductivity can be swept by the dipole well and the dipole well outperforms a single injection well, which is analyzed as a base case in terms of the shape of down gradient coverage area. However, the advantage of dipole well over a single well delivery is small if the degree of heterogeneity is large or the horizontal extent of the bedding plane is small.

Scenarios developed by the National Energy Board of Canada predict that Canadian unconventional gas production, including coalbed methane (CBM), may be required to meet Canadian energy demands by the year 2008, and could constitute up to 65% of supply by 2025. Although there has been considerable CBM exploration and development in Alberta in recent years, there has been relatively limited activity in Saskatchewan.<p>The in-situ stress regime can have a strong influence on coal bed methane (CBM) production, coal permeability, hydraulic fracturing pressure, and borehole stability while drilling horizontal wells. A limited number of stress regime analyses have been conducted previously on a regional scale, for the entire Western Canada Sedimentary Basin (WCSB), but none has been conducted with a focus on Saskatchewan. The primary objective of this study was to investigate in-situ stress magnitudes and orientations in southwestern Saskatchewan. The secondary objective was to quantify the influence of in-situ stresses on operational practices that would be used to exploit CBM targets.<p>Analysis of vertical stress magnitudes and gradients were conducted using bulk density data compiled for 257 wells in southwest Saskatchewan. Vertical stress magnitudes calculated at the base of the Belly River Formation in the region where its CBM potential is greatest were found to be in the 6 to 12 MPa range. Vertical stress magnitudes at the top of the Mannville Group in the region where its CBM potential is greatest were found to be in the 12 to 18 MPa range. Data available for interpretation of minimum horizontal stress magnitudes were considerably more limited. A technique was developed to estimate these magnitudes using fracture stimulation data, which were available for the Viking Formation and Mannville Groups. Using this technique, minimum horizontal stress magnitudes at the top of the Mannville Group in the region of greatest interest were estimated to be 10 to 14 MPa. The results of these analyses suggest that depth is a dominant controlling factor for minimum horizontal stress magnitude, but that pore pressures (sub-normal pressures cause lower stresses) and lithology (shaley rocks, and perhaps coals, have higher stresses) also have notable effects. Insufficient data were obtained for direct estimation of minimum horizontal stresses in the Belly River Formation. Minimum horizontal stress magnitudes in this formation might be quite close to vertical stress magnitudes.<p>Borehole breakouts were analyzed to interpret the orientation of maximum horizontal stress (¥òHmax) in the study area. The mean orientation of the mean borehole breakouts gives a 137¨¬ with a circular standard deviation of 12¨¬, which parallels the minimum horizontal stress in the study area with a notable inflection overlying the Swift Current platform. The data is portrayed in a trajectory map. The trajectories indicated on the map can be used for predicting the orientation of induced hydraulic fractures, and the likely orientation of face cleats in coals. Knowledge of the orientations of these features is essential to effective development of CBM resources.<p>Based on the stress and pore pressure data presented in this thesis, it is anticipated that minimum effective stresses in the Belly River coals will typically be a few MPa, and up to 10 MPa in the Mannville coals. A very rough estimate of permeabilities based on the data compiled for various Canadian coals suggests that permeabilities could be in the 0.01 to 10 millidarcy range for the former, and 0.01 to 1 millidarcy range for the latter. <p>Borehole stability analyses were conducted for both the Belly River Formation and the Mannville Group. The results suggest that horizontal drilling of the Mannville coals should be feasible, without the need for high-density drilling muds. Given that the Belly River coals occur in numerous thin seams, they are most likely to be developed using vertical wells. Borehole instability is not likely to be a major problem in these vertical wells.<p>Recommendations are provided for laboratory investigation of coal permeabilities and mechanical properties, field testing for minimum horizontal stress magnitudes in coal seams and adjacent strata, and additional analysis of existing fracture stimulation, log and core data for strata not analyzed in this project.

<p>The chemistry andphysics involved at the metal/atmosphereinterface is interesting both from a fundamental and an appliedperspective. Since iron is the most important of all metalsthis interface is of particular interest. The objective withthis thesis is to obtain new information on a molecular levelof the iron/atmosphere interface with a special emphasis on theinitial atmospheric corrosion.</p><p>The work presented herein combines a large variety ofdifferent analytical surface science techniques. Both ultrahigh vacuum and ambient pressure investigations were conductedwith single crystals as well as polycrystalline samples.</p><p>The interaction of segregated sulfur with a Fe(110) surfacewas investigated by means of atomically resolved scanningtunneling microscopy (STM). A large variety of high and lowcoverage reconstructions were reported. Comparable studies ofoxygen adsorption on the same surface were also completed.Similar to the sulfur experiments, oxygen induced a number oflow coverage reconstructions. At higher coverage, oxideformation was observed and ordered oxides could be fabricatedat elevated temperatures.</p><p>The oxygen interaction with Fe(110) and Fe(100) surfaces wasalso investigated with synchrotron radiation basedphotoelectron spectroscopy. Detailed information of the initialadsorption and subsequent oxidation was obtained. The Fe 2pcore level of the clean Fe(110) surface was subject to furtherinvestigations because of its complicated line profile that wasinterpreted as an exchange split of the final state.</p><p>Iron exposed to humidified air with low concentrations ofsulfur dioxide (SO2) shows a surprisingly passive behavior. Themeasured mass gain was significantly lower than that of acopper sample exposed in the same environment. In-situtechniques such as atomic force microscopy (AFM), quartzcrystal microbalance (QCM) and infrared reflection absorptionspectroscopy (IRAS) showed little or no corrosion. Initiationof corrosion was observed upon introduction of additionaloxidants. The conclusion drawn challenge the established modelfor formation and growth of sulfate nests. The condition andformation of sulfate nests are discussed in view of thegenerated in-situ observations.</p><p>During further experiments, iron was exposed to humid airand sodium chloride aerosols. The surface was investigated within-situ techniques, which provided new useful information. Ahigh corrosion rate was observed and the corrosion attacks formfilaments characteristic of filiform corrosion. A schematicmodel for propagation of the corrosion filaments wasproposed.</p><p>Filiform corrosion was observed on aluminum surfaces aswell. The corroded surfaces were investigated with synchrotronradiation based photoelectron microscopy and scanning over afiliform head revealed different oxidation states within the Al2p spectrum. The microscopy data was interpreted as anenrichment of aluminum chloride containing compounds within thefiliform corrosion head.</p>

Thèse de doctorat : Sciences et environnement. Sciences des sols : Bordeaux 1 : 2009. / Titre provenant de l'écran-titre.

Thesis (M.Med.Sc.)--University of Hong Kong, 2009. / Includes bibliographical references (p. 63-68).

Thesis (Ph. D.)--University of Texas at Austin, 2003. / Supervisors: Lynn E. Katz and Gerald E. Speitel Jr. Vita. Includes bibliographical references. Also available from UMI.