<p>The Long Rapids Formation in the Moose River Basin of northern Ontario is Upper Devonian in age and can be correlated with similar shale deposits in the Michigan, Appalachian, and Illinois Basins . The southern Ontario equivalent to the Long Rapids Formation is the Kettle Point Formation. </p> <p> The Long Rapids Formation is a marine black shale deposited predominantly under depleted oxygen conditions. Large amounts of marine organic matter from the water column and from terrestrial sources accumulated in reducing bottom waters with little recycling to produce brown to black, organic-rich sediments . The depositional basin was stratified, and anoxic bottom waters and oxic surface waters were separated by a pycnocline. The position of the pycnocline (or the absence of it) dictated the type of sediment deposited, and the relative depth of the pycnocline to the sediment-water interface was more important than the absolute depth of the water column. The Moose River Basin in Late Devonian times was located on the Laurasian Continent in an area experiencing tropical conditions and was affected by a period of transgression following the Acadian Orogeny. The black shales in the Long Rapids Formation represent a period of transgression of the large epicontinental Catskill Sea, whereas the green-grey mudstones and carbonates represent periods of minor eustatic changes. </p> <p> Dark-coloured facies with abundant bioturbation are overlain by lighter-coloured facies. Bioturbation is variable in the less abundant green-grey mudstone and carbonate facies, and were also low in organic matter. The ichnofauna suite Chondrites-Planolites-Zoophycos-Alcyonidiopsis-(?Teichichnus) represents an oxygen-minimum ichnofacies found predominantly in dark shale facies. As more oxygen was introduced to the sediment-water interface, more permanent burrow structures were constructed such as Teichichnus, Terebellina, ?Cylindrichnus, Skolithos, and Ichnogenus "A" in the green-grey mudstones and carbonates. As well, body fossils were more commonly found in those facies. The Leiorhynchus brachiopod fauna in the dark-coloured shales probably represents a sparse epifauna living in poorly oxygenated or temporarily oxic conditions in a basinal or open-shelf environment. </p> / Thesis / Master of Science (MSc)

[pt] A maioria dos problemas de instabilidade ocorre quando rochas argilosas como folhelhos são perfuradas e o fluido de perfuração interage com a rocha. A interação rocha- fluido é materializada através da troca de íons e moléculas de água entre o fluido de perfuração e a rocha, gerando como conseqüências à variação nas poropressões dentro do folhelho e a alteração na estrutura dos minerais. O presente trabalho tem como objetivo o estudo das mudanças nas propriedades físico-químicas de amostras de folhelhos quando imersas em água e em sais orgânicos e inorgânicos. Um equipamento de imersão foi desenvolvido no qual amostras de folhelho são postas em contato com fluidos. Os resultados eletroquímicos indicam que a imersão dos folhelhos em soluções salinas reduz, quando comparada com a água, as alterações nas propriedades mecânicas, químicas e eletroquímicas dos fluidos. Os resultados mostram também que os folhelhos de origem offshore são mais reativos que os folhelhos originados de plataforma terrestres, devido às propriedades de seus constituintes individuais e de sua microestrutura. Quando imersos, os cloretos e os formiatos reduzem a hidratação das amostras, as mudanças no pH, as alterações nas atividades químicas dos folhelhos e dos fluidos dos poros, na capacidade de troca catiônica, na composição química da matriz da rocha e fluido dos poros, além de diminuir a desintegração superficial das amostras. A microscopia ótica, eletrônica e a espectrometria de dispersão de energia indicam a deposição dos sais nas superfícies das amostras. / [en] Most of borehole instability problems occur when argillaceous rocks such as shales are drilled and the drilling fluid interacts with the rock. The rock-fluid interaction is materialized through the exchange of ions and water molecules between the drilling fluid and the rock, generating pore pressure variation inside the shale and changes in minerals structure. The present work has the objective of studying the changes in the physicochemical properties of shale samples when immersed in the water, inorganic and organic salts. Immersion equipment was developed in which shale samples are put in contact with fluid. The results show that immersion of shale samples in salt solutions reduce, when compared with de-ionized water, the changes in mechanics, chemical and electrochemical of solutions. The results also show that the shales from offshore platform are more reactive than terrestrial basin, in function of shale s individual constituents and microstructure. When immersed, the chlorides and formates reduce the rock water content, the changes in the rock pH, water activity of shale and interstitial water, in the cation exchange capacity, in the chemical composition of rock and interstitial water e reduce the shale s loss of mass. The results indicate that the ions presents in the rock and the fluids flow in the direction of decreasing solute concentration gradient. This result in the alteration the exchangeable bases of shales and the specific surface of clays minerals. The electronic and optic microscopy and energy dispersion spectrometry indicated a deposition of salts in the surface of samples.

[pt] A perfuração de poços de petróleo através de folhelhos, que se constituem na maioria das rochas da coluna estratigráfica, pode apresentar problemas de instabilidade devido às interações fisico-químicas entre os fluidos de perfuração e estas rochas. Os custos associados à solução destes problemas são muito altos e dependendo da intensidade destes problemas, poços podem ser perdidos. Nesta tese, um novo equipamento, capaz de reaplicar parte das tensões que estão atuando na amostra de rocha, foi desenvolvido. Uma metodologia de testes para avaliar os mecanismos de interação rocha-fluido e para determinar os parâmetros de transporte de massa, necessários para análises de estabilidade de poços, é proposta. Especificamente, parâmetros que descrevem o transporte de água e íons devido a gradientes hidráulicos e químicos são determinados. O conhecimento destes parâmetros contribui para compreender a eficiência do fluido de perfuração no controle de instabilidades durante a perfuração. Testes realizados em dois folhelhos de plataformas offshore usando diferentes fluidos demonstraram a eficiência do equipamento e da metodologia de testes. Os parâmetros de transporte obtidos são consistentes com valores obtidos em outros trabalhos. / [en] The drilling of oil wells through shales, which constitute the majority of rocks in the stratigraphic column, may present instability problems due to physico-chemicals interactions between the drilling fluids and these rocks. The costs associated to the solution of these problems are very high and, depending upon the intensity of these problems, wells can be lost. In this thesis, a new equipment was developed which is capable of reapplying part of the stresses that were acting upon the rock sample. A testing methodology to evaluate rock-fluid interaction mechanisms and to determine the mass transport parameters, needed for wellbore stability analyses, is proposed. Specifically, parameters that describe the transport of water and ions due to hydraulic and chemicals gradients are determined. The knowledge about these parameters is instrumental to understand the efficiency of the drilling fluid in controlling instabilities during drilling. Tests carried out in two shales from offshore platforms using different fluids demonstrated the efficiency of equipment and of the testing methodology. The transport parameters obtained are consistent with values obtained elsewhere.

No description available.

Shale oil is an attractive, alternative fuel source for a world in which there is an increasing demand for energy. However, it is necessary to assess the environmental impacts of the shale oil industry before widescale production is begun. Diversity of retorting processes, the subsequent variability in waste products and the possible waste management schemes makes assessment of these impacts complicated. Waste treatment and disposal are areas which must be researched thoroughly. To properly evaluate the environmental risks associated with the disposal of processed shales and process wastewaters, an appreciation for the sorption/desorption (S/D) characteristics of oil shales is required. The overall objective of this research was to evaluate the S/D capacity of four types of shale: Antrim (spent, eastern shale), Anvil (raw, western shale), Oxy 6 and Run 16 (spent, western shales). Batch and continuous-flow, column experiments were performed in which the S/D behavior of five cations (As, Ca, Cd, Fe, and K) and three anions (F, SO₄, and HCO₃/CO₃) was monitored. The conductivity, redox potential, and pH of the eluent fluids were also determined. This study showed that retort temperature and porosity of the various shales had a significant effect an their S/D characteristics. Batch elution trials with spent shales produced eluents having a characteristic pH in the range 8.5 to 11.5. In these experiments, the shales retorted at lower temperatures (660°C and 793°C) released higher levels of Ca, K, and SO₄ than did a higher temperature, retorted shale (800 to 1000°C) and raw shale. The shales retorted at lower temperatures also had the highest porosities of the four shales and exhibited a greater capacity for sorption of As and F than did the other shales. Continuous-flow, elution trials showed that most inorganics monitored were flushed from the columns of shale in the first 5 to 8 pore volumes of effluent. / Master of Science

[pt] Este trabalho desenvolve uma metodologia para obter experimentalmente a pressão capilar de diferentes fluidos em contato com folhelhos, comparando-a com valores obtidos analiticamente a partir da caracterização dos fluidos e dos folhelhos individualmente. Foram realizados ensaios numa célula de difusão a qual permite simular as condições de pressão aplicadas no campo, avaliar a interação físico- química entre fluidos e rochas, além de determinar os parâmetros de transporte de massa devido a gradientes químicos e hidráulicos. Verifica-se que os valores de pressão capilar obtidos diretamente na célula de difusão são inferiores aos obtidos a partir da equação de pressão capilar utilizando a tensão interfacial, o ângulo de contato e o raio de poros do folhelho. Desta forma, conclui-se que caso seja realizada uma análise de estabilidade considerando a pressão capilar do fluido, este parâmetro deve ser determinado experimentalmente na célula de difusão. Caso contrário, valores superestimados poderão ser encontrados. / [en] A methodology was developed to experimentally obtain the capillary pressure of different fluids in contact with shales and compare these values with analytical results from individual characterization of fluids and shales. Tests were carried out in a diffusion cell, which allows the simulation of in-situ pressure conditions, the evaluation of physical-chemical interactions between fluids and rocks and the determination of mass transport parameters due to hydraulic and chemical gradients. It is observed that the values of capillary pressure directly obtained in the diffusion cell are inferior to the ones obtained from the capillary pressure equation using the interfacial tension, the contact angle and the pore radius of shales. Thus, it can be concluded that, if a stability analysis considering the capillary pressure of the fluid is carried out, this parameter should be experimentally determined in the diffusion cell. Otherwise, overestimated values can be found.

O presente trabalho consistiu na realização de um estudo geológico na porção norte da Bacia intracratônica do Paraná. O estudo buscou avaliar o potencial gerador e de exploração de shale gas e shale oil dos folhelhos negros da Formação Irati na região de Goiás e Mato Grosso, Centro-Oeste do Brasil, através da caracterização de geoquímica orgânica dos folhelhos, determinação do potencial gerador e grau de maturação da matéria orgânica dos folhelhos, caracterização das relações geológicas da formação, espessuras, áreas de ocorrência, alternância de camadas com carbonatos, profundidade de ocorrência, padrões de fraturamento, composição mineralógica e estimativa de reservas de shale gas tecnicamente recuperáveis. O trabalho contribui com uma metodologia que permite avaliar o potencial de geração e exploração de recursos de shale gas e shale oil. O estudo na temática de recursos energéticos não convencionais, com destaque para o shale gas, principal fonte de gás natural não convencional explorada no mundo, é de extrema importância, pois o gás natural é considerado um combustível de transição de uma matriz energética baseada em energias fósseis para uma matriz com predominância de energias renováveis, considerando-se os seus benefícios, tanto ambientais quanto em aspectos estratégicos e econômicos. Os valores de COT variam de 0,04 a 3,52% com média de 1,31%, o que lhes confere um bom potencial gerador de hidrocarbonetos na área de estudo. Foram encontrados valores no pico S2 que variam de 5,13 a 63,13 mg HC/g de rocha para a maioria das amostras estudadas pela pirólise Rock-Eval, conferindo-lhes um bom a excelente potencial petrolífero. Os folhelhos apresentam querogênio do tipo I, II e IV, com predomínio do querogênio do tipo II e IV. Estudos de maturidade térmica da matéria orgânica (querogênio) com base nos valores de Tmax, IH, IP e Ro, indicam seu grau como imaturo (com baixo nível de conversão em hidrocarbonetos) a supermaturo (zona de gás seco). Amostras que alcançaram a janela de geração de gás seco não possuem potencial para geração de hidrocarbonetos, uma vez que apresentam querogênio do tipo IV, que evidencia baixo poder de preservação da matéria orgânica durante o intenso magmatismo ocorrido no Mesozóico (Jurássico/Cretáceo). A maioria das amostras analisadas apresentam bom potencial para shale gas e/ou shale oil, porém as condições de temperatura e pressão durante a diagênese não foram suficientes para a maturação da matéria orgânica nos folhelhos. Os folhelhos possuem altos teores de quartzo e quantidades significativas de outros minerais tais como, o feldspato plagioclásio (albita), mica e carbonatos (calcita e dolomita), podendo responder favoravelmente à fraturamento hidráulico. A estimativa de reservas indica que a área de estudo poderia ter um potencial para cerca de 23 Trilhões de Pés Cúbicos de reservas de gás natural não comprovadas tecnicamente recuperáveis. / The present work consisted in the accomplishment of a geological study in the northern portion of the Intracratonic Basin of Paraná. The study aimed to evaluate the potential for shale gas and shale oil exploitation of the Irati Formation black shales in the region of Goiás and Mato Grosso, Mid-West of Brazil, through the characterization of organic geochemistry of shales, determination of the generating potential and degree of maturation of the organic matter of the shales, characterization of the geological relations of the formation, thicknesses, areas of occurrence, alternation of layers with carbonates, depth of occurrence, fracturing patterns, mineralogical composition and estimation of technically recoverable shale gas reserves. The work contributes with a methodology that allows to evaluate the potential of generation and exploitation of shale gas and shale oil resources. The study on the subject of unconventional energy resources, especially shale gas, the main source of unconventional natural gas explored in the world, is extremely important because natural gas is considered a transition fuel of a energy matrix based on energies fossils for a matrix with predominance of renewable energies, considering its benefits, both environmental and strategic and economic aspects. The TOC values vary from 0.04 to 3.52% with an average of 1.31%, which gives them a good hydrocarbon potential in the study area. S2 peak values ranging from 5.13 to 63.13 mg HC / g of rock were found for most of the samples studied by Rock-Eval pyrolysis, giving them a good excellent oil potential.The shales present type I, II and IV kerogen, with predominance of type II and IV kerogen. Thermal maturity studies of organic matter (kerogen) based on the values of Tmax, HI, PI and Ro, indicate their degree as immature (with low conversion level in hydrocarbons) to supermature (dry gas zone). Samples that reached the window of dry gas generation do not have potential for hydrocarbon generation, since they present type IV kerogen, which evidences low preservation power of organic matter during the intense magmatism occurring in the Mesozoic (Jurassic / Cretaceous). Most of the analyzed samples present good potential for shale gas and / or shale oil, but the conditions of temperature and pressure during diagenesis were not sufficient for the maturation of the organic matter in the shales. The shales have high quartz contents and significant amounts of other minerals such as plagioclase feldspar (albite), mica and carbonates (calcite and dolomite), and can respond favorably to hydraulic fracturing. The reserve estimate indicates that the study area could have a potential for about 23 trillion cubic feet of unproved technically recoverable natural gas reserves.

Clay shales are currently being assessed as possible host rock formations for the deep geological disposal of radioactive waste. However, one main concern is that the favourable long-term isolation properties of the intact rock mass could be negatively affected by the formation of an excavation damaged zone (EDZ) around the underground openings. This thesis investigated the deformation and failure process of a clay shale, namely Opalinus Clay, with particular focus on the influence of anisotropy on the short-term response of circular tunnels. To achieve this goal, a hybrid continuum-discontinuum numerical approach was used in combination with new field measurements from the Mont Terri underground research laboratory. The response of Opalinus Clay during the excavation of a full-scale emplacement (FE) test tunnel was characterized by geodetic monitoring of wall displacements, radial extensometers and longitudinal inclinometers. The deformation measurements indicated strong directionality induced by the combined effect of in situ stress field and presence of bedding planes striking parallel to the tunnel axis, with the most severe deformation occurring in the direction approximately perpendicular to the material layering. Computer simulations were conducted using a newly-extended combined finite-discrete element method (FEM/DEM), a numerical technique which allows the explicit simulation of brittle fracturing and associated seismicity. The numerical experimentation firstly focused on the laboratory-scale analysis of failure processes (e.g., acoustic activity) in brittle rocks, and on the role of strength and modulus anisotropy in the failure behaviour of Opalinus Clay in tension and compression. The fracturing behaviour of unsupported circular excavations in laminated rock masses was then analyzed under different in situ stress conditions. Lastly, the modelling methodology was applied to the aforementioned FE tunnel to obtain original insights into the possible EDZ formation process around emplacement tunnels for nuclear waste. The calibrated numerical model suggested delamination along bedding planes and subsequent extensional fracturing as key mechanisms of the damage process potentially leading to buckling and spalling phenomena. Overall, the research findings may have a potential impact on the constructability and support design of an underground repository as well as implications for its long-term safety assessment procedure.

Clay shales are currently being assessed as possible host rock formations for the deep geological disposal of radioactive waste. However, one main concern is that the favourable long-term isolation properties of the intact rock mass could be negatively affected by the formation of an excavation damaged zone (EDZ) around the underground openings. This thesis investigated the deformation and failure process of a clay shale, namely Opalinus Clay, with particular focus on the influence of anisotropy on the short-term response of circular tunnels. To achieve this goal, a hybrid continuum-discontinuum numerical approach was used in combination with new field measurements from the Mont Terri underground research laboratory. The response of Opalinus Clay during the excavation of a full-scale emplacement (FE) test tunnel was characterized by geodetic monitoring of wall displacements, radial extensometers and longitudinal inclinometers. The deformation measurements indicated strong directionality induced by the combined effect of in situ stress field and presence of bedding planes striking parallel to the tunnel axis, with the most severe deformation occurring in the direction approximately perpendicular to the material layering. Computer simulations were conducted using a newly-extended combined finite-discrete element method (FEM/DEM), a numerical technique which allows the explicit simulation of brittle fracturing and associated seismicity. The numerical experimentation firstly focused on the laboratory-scale analysis of failure processes (e.g., acoustic activity) in brittle rocks, and on the role of strength and modulus anisotropy in the failure behaviour of Opalinus Clay in tension and compression. The fracturing behaviour of unsupported circular excavations in laminated rock masses was then analyzed under different in situ stress conditions. Lastly, the modelling methodology was applied to the aforementioned FE tunnel to obtain original insights into the possible EDZ formation process around emplacement tunnels for nuclear waste. The calibrated numerical model suggested delamination along bedding planes and subsequent extensional fracturing as key mechanisms of the damage process potentially leading to buckling and spalling phenomena. Overall, the research findings may have a potential impact on the constructability and support design of an underground repository as well as implications for its long-term safety assessment procedure.

Thesis (Ph.D.); Submitted to the University of California, Berkeley, CA (US); 18 Dec 2003. / Published through the Information Bridge: DOE Scientific and Technical Information. "LBNL--54280" Garcia, Julio Enrique. USDOE Director. Office of Science. Basic Energy Sciences (US) 12/18/2003. Report is also available in paper and microfiche from NTIS.