It was observed that many hydraulically fractured horizontal shale gas wells exhibit transient linear flow behavior. A half-slope on a type curve represents this transient linear flow behavior. Shale gas wells show a significant skin effect which is uncommon in tight gas wells and masks early time linear behavior. Usually 70-85 percent of frac water is lost in the formation after the hydraulic fracturing job. In this research, a shale gas well was studied and simulated post hydraulic fracturing was modeled to relate the effect of frac water to the early significant skin effect observed in shale gas wells. The hydraulically fractured horizontal shale gas well was described in this work by a linear dual porosity model. The reservoir in this study consisted of a bounded rectangular reservoir with slab matrix blocks draining into neighboring hydraulic fractures and then the hydraulic fractures feed into the horizontal well that fully penetrates the entire rectangular reservoir. Numerical and analytical solutions were acquired before building a 3D 19x19x10 simulation model to verify accuracy. Many tests were conducted on the 3D model to match field water production since initial gas production was matching the analytical solutions before building the 3D simulation model. While some of the scenarios tested were artificial, they were conducted in order to reach a better conceptual understanding of the field. Increasing the water saturation in the formation resulted in increasing water production while lowering gas production. Adding a fractured bottom water layer that leaked into the hydraulic fracture allowed the model to have a good match of water and gas production rates. Modeling trapped frac water around the fracture produced approximately the same amount of water produced by field data, but the gas production was lower. Totally surrounding the fracture with frac water blocked all gas production until some of the water was produced and gas was able to pass through. Finally, trapped frac water around the fracture as combined with bottom water showed the best results match. It was shown that frac water could invade the formation surrounding the hydraulic fracture and could cause formation damage by blocking gas flow. It was also demonstrated that frac water could partially block off gas flow from the reservoir to the wellbore and thus lower the efficiency of the hydraulic fracturing job. It was also demonstrated that frac water affects the square root of time plot. It was proven by simulation that the huge skin at early time could be caused by frac water that invades and gets trapped near the hydraulic fractures due to capillary pressure.

In this proposal, an advanced local oscillator with high resolution, low phase noise and fast switching characteristics is designed for wireless communication applications. The circuit is based on fractional-N frequency synthesis technique in which the use of delta-sigma modulator can remove the fractional spurs effectively. The mechanism in regard to fractional spurs and phase noise for a fractional-N frequency synthesizer will be studied and simulated by developing proper mathematical models. In the implementation of the local oscillator, the analog circuit includes a 1000-1033 MHz VCO, crystal oscillator and loop filter. The digital circuit includes a phase frequency detector, dual modulus divider and 3rd order delta-sigma modulator. At first a FPGA will be used to prototype the digital circuit. The final digital circuit will be implemented in a CMOS process and require 3V operation with low current consumption. The design specifications include that under 1 KHz resolution the phase noise levels are less than -90 dBc/Hz at frequency offets within a loop bandwidth more than 100 KHz. Spurious components are less than -90 dBc/Hz and switching time is less than 1 ms over a 30 MHz tuning range.

This work shows that toughness (resistance) to fracture propagation is an inherent characteristic of cohesionless particulate materials, which is significant for understanding hydraulic fracturing in geotechnical, geological, and petroleum applications. We have developed experimental techniques to quantify the initiation and propagation of fluid-driven fractures in saturated particulate materials. The fracturing liquid is injected into particulate materials, where the fluid flow is localized in thin crack-like conduits. By analogy, we call them 'cracks' or 'hydraulic fractures'. Based on the laboratory observations and scale analysis, this work offers physical concepts to explain the observed phenomena. When a fracture propagates in a solid, new surfaces are created by breaking material bonds. Consequently, the material is in tension at the fracture tip. In contrast, all parts of the cohesionless particulate material (including the tip zone of hydraulic fracture) are likely to be in compression. In solid materials, the fluid front lags behind the front of the propagating fracture, while the lag zone is absent for fluid-driven fractures in cohesionless materials. The compressive stress state and the absence of the fluid lag are important characteristics of hydraulic fracturing in particulate materials with low, or no, cohesion. Our experimental results show that the primary factor affecting peak (initiation) pressure is the magnitude of the remote stresses. The morphology of fracture and fluid leak-off zone, however, changes significantly not only with stresses, but also with other parameters such as flow rate, fluid rheology, and permeability. Typical features of the observed fractures are multiple off-shots and the bluntness of the fracture tip. This suggests the importance of inelastic deformation in the process of fracture propagation in cohesionless materials. Similar to solid materials, fractures propagated perpendicular to the least compressive stress. However, peak injection pressures are significantly greater than the maximum principle stresses in the experiments. Further, by incorporating the dominate experimental parameters into dimensionless form; a reasonable power-law fit is achieved between a dimensionless peak injection pressure and dimensionless stress. Scaling indicates that there is a high pressure gradient in the leak-off zone in the direction normal to the fracture. Fluid pressure does not decrease considerably along the fracture, however, due to the relatively wide fracture aperture. This suggests that hydraulic fractures in unconsolidated materials propagate within the toughness-dominated regime. Furthermore, the theoretical model of toughness-dominated hydraulic fracturing can be matched to the experimental pressure-time dependences with only one fitting parameter. Scale analysis shows that large apertures at the fracture tip correspond to relatively large 'effective' fracture (surface) energy, which can be orders of magnitude greater than typical for hard rocks.

Cette thèse a pour objet l’étude de l’origine et de la création des fonds régionaux d’art contemporain (FRAC) entre 1981 et 1986. Le plan se divise en trois grandes parties. La première partie analyse les modes d’acquisitions et d’expositions qui, au cours du XX° siècle en France, ont été des modèles pour la constitution des FRAC. La seconde partie étudie l’engagement du ministère de la culture dans une politique ambitieuse qui aboutit à la création des FRAC après l’arrivée de la gauche au pouvoir en 1981. La troisième partie, à proprement parlée d’histoire de l’art, porte sur les collections des FRAC. Cette étude des collections a constitué l’essence de la recherche établie à partir de données informatiques de videomuseum qui a opéré un recensement de toutes les acquisitions. La thèse s’appuie également sur des documents d’archives, des travaux existants, une étude sur le terrain dans chaque collection de FRAC, d’entretiens et d’un dépouillement de la presse artistique. Issus des revendications politiques formulées dans le programme de la gauche1 pour les élections présidentielles de mai 1981, les FRAC, financés à parité par l’Etat et par les régions, constituent un exemple fort de la réussite d’une politique culturelle décentralisée. Entre 1983 (date des premières acquisitions) et mars 1986 (date de la défaite de la gauche aux élections législatives) les vingt et un FRAC en activité ont acquis un total de 5 438 oeuvres provenant de 1 377 artistes. Fonds d’exception dans le paysage culturel français, les FRAC sont l’aboutissement d’une volonté de démocratisation revendiquée depuis les années 60. Jusqu’en 1986, la croissance constante des crédits d’acquisition - autant du côté de l’Etat que des conseils régionaux - aurait pu conduire à l’établissement d’une esthétique officielle. Nous verrons qu’il y a eu tout au plus des « zones d’influence » qui sont apparues pour compenser de réelles absences dans les collections des musées en région. Toutefois, malgré cet incontestable investissement institutionnel, la puissance publique ne pouvait prétendre à devenir un acteur majeur dans l’histoire de l’art. / This thesis studies in depth, the origin and the creation of theRegional Contemporary Art Collection (FRAC) between 1981 and 1986. The plan is divided into three main parts. The first part analyses the patterns of acquisitions and eexhibitions, which were models for the formation of the FRAC during the twentieth century in France. The second part examines the commitment of the Ministry of Culture in an ambitious policy that led to the creation of the FRAC after the arrival of the labour party who came to power in 1981. The third part, strictly concerning the history of art, focuses on the collections of the FRAC. This study of the collections has been the core of the research, established from computer data created by Videomuseum, who made a census of all acquisitions. The thesis is also based on archival documents, existing works, an onsite study of each collection of the FRAC, interviews and a literature of artistic media. Included in the labour party’s political program for the presidential elections of May 1981, the FRAC, funded equally by the State and the Regions, is a strong example of the success of a decentralized cultural policy. Between 1983 and March 1986 twenty-one FRAC in activity acquired a total of 5,438 works of art from 1,377 artists.Since the 1960s, the FRAC is an exception in French cultural funding and the result of a desire for democratisation. Until 1986, the continued growth of acquisition loans - offered by the State and regional councils - could lead to the establishment of a formal aesthetic. “Zones of influence" emerged to compensate for absences in the museum collections in the region. However, despite this undeniable institutional investment, public power was not entitled to become a major player in the history of art .

Horizontal drilling and hydraulic fracture stimulation have enabled the economic development of unconventional resource plays. An average horizontal well in the Barnett Shale requires 3 to 4 million gallons of fresh water, 90% of which is used for hydraulic fracture stimulation. While the water consumption of Barnett Shale operations is less than 1% of total Region C consumption, extended drought conditions and competing demands for water resources are placing pressure on operators to reduce terminal water consumption. Strategies which reduce water requirements associated hydraulic fracture stimulation without compromising the efficiency and cost of energy production are essential in developing a comprehensive policy on energy-water management. Recycling and reuse technologies were evaluated on the basis of performance, cost, and capacity to treat reclaimed flowback water and oilfield brine. Recycling flowback fluids for future hydraulic fracture applications is the most practical repurposing of oilfield waste. The low TDS content of flowback derived from water-based fracs permits multiple treatment options. Mobile thermal distillation technology has emerged as the prevailing technique for recycling flowback water, yielding maximum water savings and reduced operating costs. The estimated cost of recycling flowback water by thermal distillation is $3.35/bbl. Compared to the current cost of disposal, recycling provides an opportunity to minimize waste and reduce the fresh water requirements of hydraulic fracture stimulation at an incremental cost. The stewardship role of the Texas Legislature is to protect the water resources of the state and to facilitate the Regional Water Planning Process, ensuring future water needs are met. The support and participation of the Legislature and other planning entities is critical in advancing the energy-water nexus. As operators pursue innovative water management practices to reduce terminal water consumption in the oilfield, the Barnett Shale positions itself as a model for sustainable water use in the development of unconventional shale resources. The cost of recycling and reuse technology limits the participation of small and mid-size operators who possess the greatest market share of the Barnett Shale. Funding for research and implementation of water-conscious strategies such as shared recycling facilities, CO2 capture and storage, and pipeline infrastructure would create multi-user opportunities to promote conservation and reduce net consumption of fresh water supplies. Through the integration of technology and policy, terminal water consumption in the Barnett Shale can be greatly diminished. / text

In the post-operational phase of a Low/Intermediate-Low radioactive waste repository, gas will be generated in the caverns due to anaerobic corrosion of metals, and also chemical and microbial degradation of organic substances. Previous investigations on gas migration have indicated that discrete water conducting features (e.g. shear zones) are mainly responsible for gas transport from the caverns through the geosphere. Two phase flow processes occur in these water conducting features; the continuity and spatial distribution of pore spaces, the pore size distribution and the interfacial forces of the three phases gas-water-rock have a significant influence on gas transport.The main difficulties to be resolved when simulating two-phase flow processes in fractured rock are:- The description of the internal heterogeneity of the individual water conducting features. The influence of channelling along preferential flow paths is even more important than for single phase fluid flow, because gas transport takes place more or less exclusively along the most transmissive channels. - The determination of effective mass exchange coefficients of the relevant components of the system. Mass exchange may occur between three phases (gas-water-rock). It depends on the spatial distribution of water and gas along the water conducting features (i.e. specific surface of contact areas between phases), and on the solubility and diffusivity of the different components, but also on a couple of state variables of liquid phase (initial content of dissolve/free gas, initial pressure).The work presented in this thesis aims to improve the understanding of the physics of single and multiphase transport phenomena, to be able to develop a quantitative description of gas transport in shear zones to overcome in a satisfactory way the problems described above.

In order to test the hypothesis that fractures in outcrops are equivalent to subsurface fracture systems I compare fracture cement morphology, texture, mineralogy and geochemistry from a suite of outcrop samples from Union Springs, NY, with fractures in four cores from a currently producing reservoir in southwest Pennsylvania. Transmitted light-microscope petrography and cold cathodoluminescence of calcite of outcrop and core samples reveals a variety of cement morphologies including crack-seal and blocky fracture cement textures that are interpreted as a record multiple repeated stages of fracture opening and sealing, as well as fibrous calcite fill and other mineral phases. The stable isotopic composition of calcite fracture cements from different fracture types in cores and outcrop range from -21.5 to +4.4‰ δ13C PDB and -8.0 to -12.0 ‰ δ18O PDB and indicate calcite precipitation temperatures between 46 and 89°C. Fluid inclusion microthermometry from secondary fluid inclusions indicates trapping temperatures between 110 and 120°C. Microprobe analysis of fracture calcite cement indicates a range in Fe, Mn, and Mg composition, with subsurface and outcrop cement of similar composition. Assuming burial history predicts thermal history, isotopic compositions together with fluid inclusions suggest calcite precipitated in vertical fractures during prograde burial, during the Acadian to early Alleghanian orogenies. These findings indicate that fractures in outcrops of the Marcellus Formation can be used as a proxy for those in the subsurface. / text

La réutilisation à grande échelle de composants logiciels se révèle être un challenge pour la conception de nouvelles applications. Dans la grande majorité des cas, pour être intégrés à une application, les composants disponibles ont besoin d'être adaptés afin de faire face à la multiplicité des environnements de déploiement dotés de caractéristiques variables. Ainsi, pour éviter le redéveloppement de nouveaux composants et favoriser la réutilisation, de nombreuses approches ont proposé des techniques permettant d'adapter le comportement de composants existants. Cependant, adapter le comportement de composants n'est pas suffisant pour permettre leur réutilisation : il faut également adapter leur structure. Or, aucune approche existante ne permet de répondre pleinement à ces besoins en adaptation structurelle. Ainsi, notre objectif est de proposer une approche, appelée Scorpio, permettant d'adapter la structure de composants. Nous nous focalisons plus particulièrement sur des composants existants. Dans un premier temps, nous nous sommes intéressés à l'adaptation structurelle de composants existants en proposant un processus permettant leur ré-ingénierie vers de nouvelles structures. Puis, pour répondre aux besoins liés à une adaptation sans interruption de l'exécution, nous avons proposé des mécanismes permettant de prendre en charge l'adaptation dynamique de ces composants. Partant du constat qu'un certain nombre d'environnements, tels que les environnements ubiquitaires, nécessite une automatisation du processus d'adaptation, nous avons proposé alors de prendre en charge ces besoins à travers une approche permettant l'auto-adaptation structurelle de composants logiciels. Enfin, nos propositions ont été mises en œuvre d'une part par la réalisation du prototype Scorpio-Tool implémenté en Fractal et d'autre part, par la définition et le développement d'un scénario ubiquitaire permettant l'expérimentation de ces propositions.

Este estudo apresenta ao Departamento de Engenharia de Minas e Petróleo (PMI) da Escola Politécnica da USP, e também a toda a sociedade, a importância que os oceanos têm com relação às suas riquezas minerais. Pretende ainda mostrar a grande responsabilidade que um empreendimento mineiro no fundo do mar precisa ter, com relação aos impactos ambientais, sendo possível minerar em regiões profundas no oceano promovendo a sustentabilidade. A ideia da mineração oceânica/submarina está ainda sendo amadurecida, este é o momento adequado para se propor metodologias de trabalho submarino sustentáveis; mitigar seus impactos. Este trabalho abrange o tema de maneira ampla, abordando o aspecto histórico, legal, ambiental, bem como questões técnicas de engenharia de minas, como sondagem submarina, caracterização tecnológica, lavra submarina, beneficiamento de minério oceânico e descarte de rejeitos. O trabalho apresenta os passos e resultados de um caso real de exploração oceânica. Trata-se de um estudo para viabilizar economicamente a extração e o beneficiamento de areia marinha, para fins industriais, proveniente da Baía de Guanabara (RJ). O trabalho apresenta desde o planejamento da amostragem no fundo do mar, execução destes trabalhos, caracterização tecnológica, simulação de processo e estudos específicos do uso industrial da areia após beneficiamento. Apresenta ainda uma proposta de rota de processo para a areia marinha e questões ligadas à lavra e ao descarte de rejeitos. / This study aims to show the importance of the oceans and its mineral wealth. It intends also to show the big responsibility that an undersea enterprise must bear concerning the environmental impact. It shows the availability to minein a sustainable way in the bottom of the sea. The undersea mining is still raising, now is the auspicious time to suggest sustainably submarine work methodologies; to mitigate its impact. This study covers the historic, legal and environmental aspects, as well as technical issues of mining engineering such as undersea survey, process mineralogy, undersea mining, mineral beneficiation for marine ores and tailings disposal. This study presents the steps and results of a real subsea exploration case. The studied ore is a marine sand from Baía de Guanabara (Rio de Janeiro), aiming to supply industrial market. This is a feasibility and technical study to show how to exploit and process this kind of ore. The study shows the undersea survey planning and its execution, the process mineralogy planning and its results, process simulation and some specific studies to industrial uses for this sand, after its beneficiation. Besides these subjects, the study proposes an industrial process route for process and tailings disposal.

Este estudo apresenta ao Departamento de Engenharia de Minas e Petróleo (PMI) da Escola Politécnica da USP, e também a toda a sociedade, a importância que os oceanos têm com relação às suas riquezas minerais. Pretende ainda mostrar a grande responsabilidade que um empreendimento mineiro no fundo do mar precisa ter, com relação aos impactos ambientais, sendo possível minerar em regiões profundas no oceano promovendo a sustentabilidade. A ideia da mineração oceânica/submarina está ainda sendo amadurecida, este é o momento adequado para se propor metodologias de trabalho submarino sustentáveis; mitigar seus impactos. Este trabalho abrange o tema de maneira ampla, abordando o aspecto histórico, legal, ambiental, bem como questões técnicas de engenharia de minas, como sondagem submarina, caracterização tecnológica, lavra submarina, beneficiamento de minério oceânico e descarte de rejeitos. O trabalho apresenta os passos e resultados de um caso real de exploração oceânica. Trata-se de um estudo para viabilizar economicamente a extração e o beneficiamento de areia marinha, para fins industriais, proveniente da Baía de Guanabara (RJ). O trabalho apresenta desde o planejamento da amostragem no fundo do mar, execução destes trabalhos, caracterização tecnológica, simulação de processo e estudos específicos do uso industrial da areia após beneficiamento. Apresenta ainda uma proposta de rota de processo para a areia marinha e questões ligadas à lavra e ao descarte de rejeitos. / This study aims to show the importance of the oceans and its mineral wealth. It intends also to show the big responsibility that an undersea enterprise must bear concerning the environmental impact. It shows the availability to minein a sustainable way in the bottom of the sea. The undersea mining is still raising, now is the auspicious time to suggest sustainably submarine work methodologies; to mitigate its impact. This study covers the historic, legal and environmental aspects, as well as technical issues of mining engineering such as undersea survey, process mineralogy, undersea mining, mineral beneficiation for marine ores and tailings disposal. This study presents the steps and results of a real subsea exploration case. The studied ore is a marine sand from Baía de Guanabara (Rio de Janeiro), aiming to supply industrial market. This is a feasibility and technical study to show how to exploit and process this kind of ore. The study shows the undersea survey planning and its execution, the process mineralogy planning and its results, process simulation and some specific studies to industrial uses for this sand, after its beneficiation. Besides these subjects, the study proposes an industrial process route for process and tailings disposal.