Aplicações da teoria da percolação à modelagem e simulação de reservatórios de petróleo

In this thesis we study some problems related to petroleum reservoirs using methods and concepts of Statistical Physics. The thesis could be divided percolation problem in random multifractal support motivated by its potential application in modelling oil reservoirs. We develped an heterogeneous and anisotropic grid that followin two parts. The first one introduce a study of the percolations a random multifractal distribution of its sites. After, we determine the percolation threshold for this grid, the fractal dimension of the percolating cluster and the critical exponents ß and v. In the second part, we propose an alternative systematic of modelling and simulating oil reservoirs. We introduce a statistical model based in a stochastic formulation do Darcy Law. In this model, the distribution of permeabilities is localy equivalent to the basic model of bond percolation

Fractais e Percolação na Recuperação de Petróleo

The complex behavior of a wide variety of phenomena that are of interest to physicists, chemists, and engineers has been quantitatively characterized by using the ideas of fractal and multifractal distributions, which correspond in a unique way to the geometrical shape and dynamical properties of the systems under study. In this thesis we present the Space of Fractals and the methods of Hausdorff-Besicovitch, box-counting and Scaling to calculate the fractal dimension of a set. In this Thesis we investigate also percolation phenomena in multifractal objects that are built in a simple way. The central object of our analysis is a multifractal object that we call Qmf . In these objects the multifractality comes directly from the geometric tiling. We identify some differences between percolation in the proposed multifractals and in a regular lattice. There are basically two sources of these differences. The first is related to the coordination number, c, which changes along the multifractal. The second comes from the way the weight of each cell in the multifractal affects the percolation cluster. We use many samples of finite size lattices and draw the histogram of percolating lattices against site occupation probability p. Depending on a parameter, ρ, characterizing the multifractal and the lattice size, L, the histogram can have two peaks. We observe that the probability of occupation at the percolation threshold, pc, for the multifractal is lower than that for the square lattice. We compute the fractal dimension of the percolating cluster and the critical exponent β. Despite the topological differences, we find that the percolation in a multifractal support is in the same universality class as standard percolation. The area and the number of neighbors of the blocks of Qmf show a non-trivial behavior. A general view of the object Qmf shows an anisotropy. The value of pc is a function of ρ which is related to its anisotropy. We investigate the relation between pc and the average number of neighbors of the blocks as well as the anisotropy of Qmf. In this Thesis we study likewise the distribution of shortest paths in percolation systems at the percolation threshold in two dimensions (2D). We study paths from one given point to multiple other points

Ondaletas e movimento browniano fracionário: aplicação à caracterização de poços de petróleo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Fractais e percolação na recuperação de Petróleo

The complex behavior of a wide variety of phenomena that are of interest to physicists, chemists, and engineers has been quantitatively characterized by using the ideas of fractal and multifractal distributions, which correspond in a unique way to the geometrical shape and dynamical properties of the systems under study. In this thesis we present the Space of Fractals and the methods of Hausdorff-Besicovitch, box-counting and Scaling to calculate the fractal dimension of a set. In this Thesis we investigate also percolation phenomena in multifractal objects that are built in a simple way. The central object of our analysis is a multifractal object that we call Qmf . In these objects the multifractality comes directly from the geometric tiling. We identify some differences between percolation in the proposed multifractals and in a regular lattice. There are basically two sources of these differences. The first is related to the coordination number, c, which changes along the multifractal. The second comes from the way the weight of each cell in the multifractal affects the percolation cluster. We use many samples of finite size lattices and draw the histogram of percolating lattices against site occupation probability p. Depending on a parameter, ρ, characterizing the multifractal and the lattice size, L, the histogram can have two peaks. We observe that the probability of occupation at the percolation threshold, pc, for the multifractal is lower than that for the square lattice. We compute the fractal dimension of the percolating cluster and the critical exponent β. Despite the topological differences, we find that the percolation in a multifractal support is in the same universality class as standard percolation. The area and the number of neighbors of the blocks of Qmf show a non-trivial behavior. A general view of the object Qmf shows an anisotropy. The value of pc is a function of ρ which is related to its anisotropy. We investigate the relation between pc and the average number of neighbors of the blocks as well as the anisotropy of Qmf. In this Thesis we study likewise the distribution of shortest paths in percolation systems at the percolation threshold in two dimensions (2D). We study paths from one given point to multiple other points. In oil recovery terminology, the given single point can be mapped to an injection well (injector) and the multiple other points to production wells (producers). In the previously standard case of one injection well and one production well separated by Euclidean distance r, the distribution of shortest paths l, P(l|r), shows a power-law behavior with exponent gl = 2.14 in 2D. Here we analyze the situation of one injector and an array A of producers. Symmetric arrays of producers lead to one peak in the distribution P(l|A), the probability that the shortest path between the injector and any of the producers is l, while the asymmetric configurations lead to several peaks in the distribution. We analyze configurations in which the injector is outside and inside the set of producers. The peak in P(l|A) for the symmetric arrays decays faster than for the standard case. For very long paths all the studied arrays exhibit a power-law behavior with exponent g ∼= gl.

Fases magnéticas de sistemas nanoestruturados de terras-raras

There is presently a worldwide interest in artificial magnetic systems which guide research activities in universities and companies. Thin films and multilayers have a central role, revealing new magnetic phases which often lead to breakthroughs and new technology standards, never thought otherwise. Surface and confinement effects cause large impact in the magnetic phases of magnetic materials with bulk spatially periodic patterns. New magnetic phases are expected to form in thin film thicknesses comparable to the length of the intrinsic bulk magnetic unit cell. Helimagnetic materials are prototypes in this respect, since the bulk magnetic phases consist in periodic patterns with the length of the helical pitch. In this thesis we study the magnetic phases of thin rare-earth films, with surfaces oriented along the (002) direction. The thesis includes the investigation of the magnetic phases of thin Dy and Ho films, as well as the thermal hysteresis cycles of Dy thin films. The investigation of the thermal hysteresis cycles of thin Dy films has been done in collaboration with the Laboratory of Magnetic Materials of the University of Texas, at Arlington. The theoretical modeling is based on a self-consistent theory developed by the Group of Magnetism of UFRN. Contributions from the first and second neighbors exchange energy, from the anisotropy energy and the Zeeman energy are calculated in a set of nonequivalent magnetic ions, and the equilibrium magnetic phases, from the Curie temperature up to the Nèel temperature, are determined in a self-consistent manner, resulting in a vanishing torque in the magnetic ions at all planes across the thin film. Our results reproduce the known isothermal and iso-field curves of bulk Dy and Ho, and the known spin-slip phases of Ho, and indicate that: (i) the confinement in thin films leads to a new magnetic phase, with alternate helicity, which leads to the measured thermal hysteresis of Dy ultrathin films, with thicknesses ranging from 4 nm to 16 nm; (ii) thin Dy films have anisotropy dominated surface lock-in phases, with alignment of surface spins along the anisotropy easy axis directions, similar to the known spin-slip phases of Ho ( which form in the bulk and are commensurate to the crystal lattice); and (iii) the confinement in thin films change considerably the spin-slip patterns of Ho.

Efeitos do turno fixo sobre a saúde mental em operadores de petróleo :um estudo de caso em dois ativos produção da Petrobrás

Un conjunto de cambios viene siendo implantado en la Petrobrás procurando que sus unidades de negocios resulten más modernas y competitivas para atender las necesidades del mercado. Dentro de esta perspectiva, un nuevo régimen de trabajo, denominado turno fijo , ha sido implantado en dos activos de producción de la provincia de Rio Grande do Norte. Tal situación originó varios reclamos de los petroleros y, consecuentemente, el interés del SINDIPETRO-RN en obtener una evaluación más precisa de las consecuencias de los mismos. Este estudio, realizado a partir de la demanda sindical de esos trabajadores, ha tenido como objetivo central analizar los efectos del turno fijo sobre la salud mental de los operadores de producción, actualmente lotados en los referidos activos. El estudio ha sido realizado con 39 operadores que representan el 82,9% de la población objeto de este estudio. La muestra ha sido homogénea en cuanto al género, grado de instrucción, edad y tiempo de servicio en la compañía, lo que ha posibilitado un mayor control de las variables y un estudio comparativo entre los dos activos. Para el desarrollo del estudio, se han aplicado los siguientes instrumentos de colecta de datos: una escala de medida probada y validada (QSG-12), un cuestionario abierto, entrevistas individuales y una ficha socio-demográfica. Las respuestas del cuestionario abierto han sido categorizadas mediante la aplicación de análisis de contenido. Los resultados de ese tratamiento y las respuestas del QSG-12 han sido registradas en la forma de banco de datos del SPSS for Windows (Statical Package for social sciense for Windows) para luego procederse con el desarrolllo de los análisis estadísticos. Los principales resultados encontrados en el estudio han sido que la mitad de los participantes de la muestra han presentado resultados de deteriorización de la autoeficacia más elevado que 1,44 (un una escala de 0 a 3) y, en tensión emocional y depresión, el resultado es más elevado que 1,67; la mayoría se da cuenta del aumento de carga de trabajo, revela acentuado sufrimiento con el distanciamiento de la familia, y 58,8% presenta enfermedades psicosomáticas crónicas. La percepción de los operadores sobre el turno fijo e el análisis de éste, conforme el modelo vitamínico de Warr, conducen a la conclusión de que el turno fijo es uno de los factores que está influyendo negativamente en la salud mental de esos trabajadores

Saúde mental em operadores de petróleo do Rio Grande do Norte

The importance of identifying the consequence of the hours worked on people in society has been well recognized within Organizational and Work Psychology. From this point of view, the present research had the objective of analysing the effects of work regimes on the mental health of petroleum operators of Petrobrás. The sample totaled 144 subjects, corresponding to 27% of the work population. The mental health of the participants was evaluated using the following instruments of measurement: QSG-12, Scale of self-esteem, Scale of Positive and Negative Affections and the Scale of Valuable Attributes of IMST, each representing an empirical factor used to indicate and measure the five dimensions of mental health. The subjects perceptions of their work regime and the rest of their conditions of work were evaluated using scales of descriptive attributes of IMST, by applying a semi-structured questionnaire and by use of interviews. A socio-demographic file was used to collect information related to the biographical and socio-occupational profile of the worker sample. The answers to the questionnaire were inserted into the data bank of SPSS (Statistical Package for Social Science), for statistical analysis, and the interviews were analised based on the technique of Contents Analysis recommended by Bardin (1995). The main results revealed that one third of the worker sample were tense; however, the mental health of the majority was preserved. Cluster Analysis applied to the group of seven factors which measured the five dimensions of mental health identified four profiles of psychological well-being shared between members of the sample. It was observed that the people working in the system of Continuous Shift Alternation (TIR) and in the system of Pre-advising tended to present balanced and satisfactory profiles, while the ones which worked in the Administrative Field tended to present anxious and oscillating profiles, and thus were more affected psychologically. These were also the ones that also perceived the more negative aspects of their laborious conditions (reduced chances of self-improvement, physically stressful and financial resources below expectations with which to supply family and personal necessities. In agreement with the ecological model formulated by Warr (1987), the present study concluded that the positive and negative effects on the psychological well-being tended to occur as a consequence of the perceptions the petrol operators developed to face their work conditions

Síntese enzimática de biosurfactante e sua aplicabilidade na indústria do petróleo

Enzymes have been widely used in biosynthesis/transformation of organic compounds in substitution the classic synthetic methods. This work is the first writing in literature of enzymatic synthesis for attainment the biossurfactants, the use glucose sucrose, ricinoleic acid e castor oil as substratum, and as biocatalyst, used immobilized lipase Thermomyces lanuginose, Rhizomucor miehei and the Candida antarctica lipase B; alkaline protease and neutral protease from Bacillus subtillis and yeast Saccharomyces cerevisiaeI. The analysis of HPLC (high performance liquid chromatography) showed that highest conversions were reached of used the alkaline protease from Bacillus subtillis. Laboratory tests, to evaluate the applicability, indicated that the produced biosurfactantes had good stability in presence of salts (NaCl) and temperature (55 e 25°C), they are effective in the reduction of the superficial tension and contac angle, but they have little foaming capacity, when compared with traditional detergents. These results suggest that the prepared surfactants have potential application as wetting agent and perforation fluid stabilizer

Obtenção e aplicação de sistemas microemulsionados na recuperação avançada de petróleo

Due to the need of increasing production in reservoirs that are going through production decline, methods of advanced recovery have frequently been used in the last years, as the use of conventional methods has not been successful in solving the problem of oil drifting. In this work, the efficiency of different microemulsionated systems in the flow of oil from cores from Assu and Botucatu formations. Regarding drifting tests, cores were calcinated at a temperature of 1000°C, for 18 hours, with the aim of eliminating any organic compound present in it, increasing the resultant permeability. Following, the cores were isolated with resin, resulting in test specimens with the following dimensions: 3.8 cm of diameter and 8.7 cm of length. Cores were saturated with brine, composed of aqueous 2 wt % KCl, and oil from Guamaré treatment station (Petrobras/RN). A pressure of 20 psi was used in all tests. After core saturation, brine was injected again, followed by oil at constant flow rate. The system S3 - surfactant (anionic surfactant of short chain), isoamillic alcohol, pine oil, and water - presented the best drift efficiency, 81.18%, while the system S1E commercial surfactant, ethyl alcohol, pine oil, and distilled water presented low drift efficiency, 44,68%

Estudo da modificação de bentonita para a remoção de fenol em águas produzidas na indústria de petróleo

This study evaluates the inclusion of quaternary ammonium salt, bromide hexadecyl trimethyl ammonium (HDTMA-Br) on sodium bentonite to evaluate their performance on the adsorption of phenol present in produced water. It was observed an increase in d001 samples modified with HDTMA-Br by diffraction of X-rays, showing the intercalation of quaternary ammonium cations in the interlamellar layers of clay. Through the adsorption isotherms could be abserver adsorption behavior of sodium bentonite and organophilic bentonite produced in three different concentrations of HDTMA-Br for adsorption of phenol, which is the main phenolic compound found in the product water. Different concentrations of synthetic solutions of phenol were placed in contact with these adsorbents under the same conditions of agitation and temperature. The adsorbent showed adsorptive favorable, especially the clay modified with the highest concentration of HDTMA-Br, 150% CEC of clay, BEN30-14, with higher amounts of phenol adsorbed per gram of adsorbent (mg.g-1)

Análise química de produtos de incrustação em dutos de petróleo por espectometria de fluorescência de raios X

The quantitative chemical characterization of the inorganic fraction of scale products is very relevant in studying, monitoring and controlling corrosive processes of oil pipelines. The X-ray fluorescence spectrometry (XRF) is a very versatile analytical technique, which can be used in quantitative analysis in solid samples at low concentrations of the chemical element, in the order of few ppm. A methodology that involves sample preparation diluted in the proportion of 1:7 (one portion of the sample for seven of wax), pressed as pellets was used in the XRF calibration for chemical analysis of scale products from oil pipelines. The calibration involved the preparation of reference samples from mixtures of P.A. reagents, aiming to optimize the time consumed in the steps of sample preparation and analysis of Al, Ba, Ca, Fe, K, Mg, Mn, Na, P, S, Si, Sr and Ti, using the same pressed pellet for trace and major elements analysis

Síntese, caracterização e aplicação do MCM-41 e A1-MCM-41 na pirólise do resíduo atmosférico de petróleo

In present work, mesoporous materials of the M41S family were synthesized, which were discovered in the early 90s by researchers from Mobil Oil Corporation, thus allowing new perspectives in the field of catalysis. One of the most important members of this family is the MCM-41, which has a hexagonal array of mesopores with pore diameters ranging from 2 to 10 nm and a high surface area, enabling it to become very promising for the use as a catalyst in the refining of oil in the catalytic cracking process, since the mesopores facilitate the access of large hydrocarbon molecules, thereby increasing the production of light products, that are in high demand in the market. The addition of aluminum in the structure of MCM-41 increases the acidity of the material, making it more beneficial for application in the petrochemical industry. The mesoporous materials MCM-41 and Al-MCM-41 (ratio Si / Al = 50) were synthesized through the hydrothermal method, starting with silica gel, NaOH and distilled water. CTMABr was used as template, for structural guiding. In Al-MCM-41 the same reactants were used, with the adding of pseudoboehmite (as a source of aluminum) in the synthesis gel. The syntheses were carried out over a period of four days with a daily adjustment of pH. The optimum conditions of calcination for the removal of the organic template (CTMABr) were discovered through TG / DTG and also through analysis by XRD, FTIR and Nitrogen Adsorption. It was found that both the method of hydrothermal synthesis and calcination conditions of the studies based on TG were promising for the production of mesoporous materials with a high degree of hexagonal array. The acidic properties of the materials were determined by desorption of n-butylamine via thermogravimetry. One proved that the addition of aluminum in the structure of MCM-41 promoted an increase in the acidity of the catalyst. To check the catalytic activity of these materials, a sample of Atmospheric Residue (RAT) that is derived from atmospheric distillation of oil from the Pole of Guamaré- RN was used. This sample was previously characterized by various techniques such as Thermogravimetry, FTIR and XRF, where through thermal analysis of a comparative study between the thermal degradation of the RAT, the RAT pyrolysis + MCM-41 and RAT + Al- MCM-41. It was found that the Al-MCM-41 was most satisfactory in the promotion of a catalytic effect on the pyrolysis of the RAT, as the cracking of heavy products in the waste occurred at temperatures lower than those observed for the pyrolysis with MCM-41, and thereby also decreasing the energy of activation for the process and increasing the rates of conversion of residue into lighter products

Estudo da água produzida em diferentes zonas de produção de petróleo, utilizando a hidroquímica e a análise estatística de parâmetros químicos

Over exploitation of oil deposits on land onshore or offshore, there is simultaneous generation of waste water, known as produced water, which represents the largest waste stream in the production of crude oil. The relationship between the chemical composition of oil and water production and the conditions in which this process occurs or is favored are still poorly studied. The area chosen for the study has an important oil reserve and an important aquifer saturated with freshwater meteoric. The aim of this work is to study some chemical parameters in water produced for each reservoir zone of production in mature oil fields of Açu Formation, using the hydrochemical and statistical analysis to serve as a reference and be used as tools against the indicator ranges water producers in oil producing wells. Samples were collected from different wells in 6 different areas of production and were measured 50 parameters, which can be classified into three groups: anions, cations and physicochemical properties (considering only the parameters that generated values above detection limits in all samples). Through the characterization hydrochemistry observed an area of water and chlorinated sodium, chlorinated calcium or magnesium (mixed) in well water in different areas of Açu, by applying a statistical treatment, we obtained a discriminant function that distinguishes chemically production areas. Thus, it was possible to calculate the rate of correct classification of the function was 76.3%. To validate this model the accuracy rate was 86%

Análise dos Processos de Flotação e Oxidação Avançada para o Tratamento de Efluente Modelo da Indústria do Petróleo

The generation of wastes in most industrial process is inevitable. In the petroleum industry, one of the greatest problems for the environment is the huge amount of produced water generated in the oil fields. This wastewater is a complex mixture and present great amounts. These effluents can be hazardous to the environmental without adequate treatment. This research is focused in the analysis of the efficiencies of the flotation and photo-oxidation processes to remove and decompose the organic compounds present in the produced water. A series of surfactants derivated from the laurilic alcohol was utilized in the flotation to promote the separation. The experiments have been performed with a synthetic wastewater, carefully prepared with xylene. The experimental data obtained using flotation presented a first order kinetic, identified by the quality of the linear data fitting. The best conditions were found at 0.029 g.L-1 for the surfactant EO 7, 0.05 g.L-1 for EO 8, 0.07 g.L-1 for EO 9, 0.045 g.L-1 for EO 10 and 0.08 g.L-1 for EO 23 with the following estimated kinetic constants: 0.1765, 0.1325, 0.1210, 0.1531 and 0.1699 min-1, respectively. For the series studied, the most suitablesurfactant was the EO 7 due to the lower reagent consumption, higher separation rate constant and higher removal efficiency of xylene in the aqueous phase (98%). Similarly to the flotation, the photo-Fenton process shows to be efficient for degradation of xylene and promoting the mineralization of the organic charge around 90% and 100% in 90 min

Hidrólise e caracterização de poliacrilamida hidrofobicamente modificada: avaliação da aplicabilidade na recuperação de petróleo

The hydrolysis reaction in alkaline conditions of the commercial polymer poly(acrylamide-co-metacrylate of 3,5,5-trimethyl-hexane) called HAPAM, containing 0.75 % of hydrophobic groups, was carried out in 0.1 M NaCl and 0.25M NaOH solutions, varying the temperature and reaction time. The polymers were characterized by 1H and 13C Nuclear Magnetic Resonance (NMR), Elemental Analysis and Size Exclusion Chromatography (SEC). The values of the hydrolysis degree were obtained by 13C NMR. The viscosity of HAPAM and HAPAM-10N-R solutions was evaluated as a function of shear rate, ionic strength and temperature. At high polymer concentration (Cp), the viscosity of HAPAM solutions increased with the ionic strength and decreased with the temperature. The viscosity of HAPAM-10N-R solutions increased significantly in distilled water, due to repulsions between the carboxylate groups. At high Cp, with the increase of ionic strength and temperature, occurred a decrease of viscosity, due to mainly the high hydrolysis degree and the low amount of hydrophobic groups. These results indicated that the studied polymers have properties more suitable for the application in Enhanced Oil Recovery (EOR) in low salinity and moderate temperature reservoirs