Estudo da segrega����o gravitacional do processo de inje����o de vapor em reserv��t��rios heterog��neos

Due to reservoirs complexity and significantly large reserves, heavy oil recovery has become one of the major oil industry challenges. Thus, thermal methods have been widely used as a strategic method to improve heavy oil recovery. These methods improve oil displacement through viscosity reduction, enabling oil production in fields which are not considered commercial by conventional recovery methods. Among the thermal processes, steam flooding is the most used today. One consequence in this process is gravity segregation, given by difference between reservoir and injected fluids density. This phenomenon may be influenced by the presence of reservoir heterogeneities. Since most of the studies are carried out in homogeneous reservoirs, more detailed studies of heterogeneities effects in the reservoirs during steam flooding are necessary, since most oil reservoirs are heterogeneous. This paper presents a study of reservoir heterogeneities and their influence in gravity segregation during steam flooding process. In this study some heterogeneous reservoirs with physical characteristics similar those found in the Brazilian Northeast Basin were analyzed. To carry out the simulations, it was used the commercial simulator STARS by CMG (Computer Modeling Group) - version 2007.11. Heterogeneities were modeled with lower permeability layers. Results showed that the presence of low permeability barriers can improve the oil recovery, and reduce the effects of gravity segregation, depending on the location of heterogeneities. The presence of these barriers have also increased the recovered fraction even with the reduction of injected steam rate

An��lise param��trica da simulação composicional do processo de Drenagem Gravitacional Assistida por G��s (GAGD)

In Brazil and around the world, oil companies are looking for, and expected development of new technologies and processes that can increase the oil recovery factor in mature reservoirs, in a simple and inexpensive way. So, the latest research has developed a new process called Gas Assisted Gravity Drainage (GAGD) which was classified as a gas injection IOR. The process, which is undergoing pilot testing in the field, is being extensively studied through physical scale models and core-floods laboratory, due to high oil recoveries in relation to other gas injection IOR. This process consists of injecting gas at the top of a reservoir through horizontal or vertical injector wells and displacing the oil, taking advantage of natural gravity segregation of fluids, to a horizontal producer well placed at the bottom of the reservoir. To study this process it was modeled a homogeneous reservoir and a model of multi-component fluid with characteristics similar to light oil Brazilian fields through a compositional simulator, to optimize the operational parameters. The model of the process was simulated in GEM (CMG, 2009.10). The operational parameters studied were the gas injection rate, the type of gas injection, the location of the injector and production well. We also studied the presence of water drive in the process. The results showed that the maximum vertical spacing between the two wells, caused the maximum recovery of oil in GAGD. Also, it was found that the largest flow injection, it obtained the largest recovery factors. This parameter controls the speed of the front of the gas injected and determined if the gravitational force dominates or not the process in the recovery of oil. Natural gas had better performance than CO2 and that the presence of aquifer in the reservoir was less influential in the process. In economic analysis found that by injecting natural gas is obtained more economically beneficial than CO2

Modelagem e simulação de um sistema de bombeio mec��nico em po��os direcionais utilizando par��metros concentrados

This work aims presenting the development of a model and computer simulation of a sucker rod pumping system. This system take into account the well geometry, the flow through the tubing, the dynamic behavior of the rod string and the use of a induction motor model. The rod string were modeled using concentrated parameters, allowing the use of ordinary differential equations systems to simulate it s behavior

Estudo param��trico do processo de inje����o de solventes em po��os horizontais para reservat��rios de ��leos pesados

The world has many types of oil that have a range of values of density and viscosity, these are characteristics to identify whether an oil is light, heavy or even ultraheavy. The occurrence of heavy oil has increased significantly and pointing to a need for greater investment in the exploitation of deposits and therefore new methods to recover that oil. There are economic forecasts that by 2025, the heavy oil will be the main source of fossil energy in the world. One such method is the use of solvent vaporized VAPEX which is known as a recovery method which consists of two horizontal wells parallel to each other, with a gun and another producer, which uses as an injection solvent that is vaporized in order to reduce the viscosity of oil or bitumen, facilitating the flow to the producing well. This method was proposed by Dr. Roger Butler, in 1991. The importance of this study is to analyze how the influence some operational reservoir and parameters are important in the process VAPEX, such as accumulation of oil produced in the recovery factor in flow injection and production rate. Parameters such as flow injection, spacing between wells, type of solvent to be injected, vertical permeability and oil viscosity were addressed in this study. The results showed that the oil viscosity is the parameter that showed statistically significant influence, then the choice of Heptane solvent to be injected showed a greater recovery of oil compared to other solvents chosen, considering the spacing between the wells was shown that for a greater distance between the wells to produce more oil

Comportamento mec��nico de um agregado reciclado a partir de res��duos de constru����o e demoli����o submetido a carregamentos c��clicos

Tese (doutorado)���Universidade de Bras��lia, Faculdade de Tecnologia, Programa de P��s-Gradua����o em Geotecnia, 2016.

Sistema inteligente para apoio �� decis��o na opera����o de uma malha de escoamento de petr��leo

The petroleum production pipeline networks are inherently complex, usually decentralized systems. Strict operational constraints are applied in order to prevent serious problems like environmental disasters or production losses. This paper describes an intelligent system to support decisions in the operation of these networks, proposing a staggering for the pumps of transfer stations that compose them. The intelligent system is formed by blocks which interconnect to process the information and generate the suggestions to the operator. The main block of the system uses fuzzy logic to provide a control based on rules, which incorporate knowledge from experts. Tests performed in the simulation environment provided good results, indicating the applicability of the system in a real oil production environment. The use of the stagger proposed by the system allows a prioritization of the transfer in the network and a flow programming

Simulação estoc��stica da transmissividade em forma����es gran��ticas alteradas e fracturadas

Considerando como caso de estudo o do maci��o envolvente e subjacente �� antiga mina de ur��nio de Quinta do Bispo (Concelho de Mangualde), composto essencialmente por granitos herc��nicos e metasedimentos do Complexo Xisto-Grauv��quico, estabeleceu-se uma metodologia que permitiu a constru����o de modelos 3D de transmissividade, equiprov��veis, mediante o cruzamento de propriedades intr��nsecas do maci��o rochoso ��� neste caso particular, a litologia, o grau de altera����o e a densidade de fractura����o - pass��veis de modela����o estoc��stica a 3D, com propriedades hidrogeol��gicas do meio, medidas in situ e avaliadas deterministicamente, por via da realiza����o e interpreta����o de ensaios de bombagem direcionados. A interpreta����o dos resultados dos ensaios de bombagem realizou-se por patamares, recorrendo-se aos métodos de ���Porosidade Dupla��� e de ���Theis com correc����o de Jacob���, tendo-se processado curvas cumulativas de valores de transmissividade em fun����o da litologia e do grau de altera����o, conforme os distintos sectores comportamentais do maci��o. A metodologia adoptada levou a que os valores de transmissividade de cada c��lula dos modelos 3D tenham sido simulados com condicionamento aos valores experimentais dos ensaios de bombagem, ponderados de acordo com as probabilidades dessa mesma c��lula representar, numa dada localiza����o no espa��o, uma certa Litologia, sob um determinado Grau de Altera����o que possui, quando aplic��vel, um certo N��mero de Fracturas n��o preenchidas. As vari��veis representativas dos atributos geol��gicos Litologia, Grau de Altera����o e N��mero de Fracturas, foram simuladas em cadeia pelo que os modelos de transmissividades integram a variabilidade e heterogeneidade locais destes atributos, os quais condicionam o fluxo tridimensional da ��gua.

Produ����o e avalia����o de materiais de refer��ncia para nutrientes e contaminantes inorg��nicos em amostras agron��micas.

A intensa busca por confiabilidade de resultados torna cada vez mais importante o papel dos materiais de refer��ncia, principalmente em qu��mica anal��tica, pois fornecem refer��ncias metrol��gicas visando assegurar a rastreabilidade de medi����es e ainda s��o fundamentais para a valida����o de métodos anal��ticos. O aumento da demanda por novos materiais de refer��ncia �� gradativo em todas as ��reas do conhecimento, por��m os setores agropecu��rios e de alimentos est��o entre os mais carentes. No Brasil, essa demanda �� atendida somente pela importa����o do material a custos elevados, sendo freq��ente a inexist��ncia de materiais adequados ��s necessidades do pa��s. Nesse contexto, o presente trabalho visou �� produ����o de material de refer��ncia para nutrientes e contaminantes inorg��nicos em fosfato de rocha, mat��ria-prima utilizada para a fabrica����o de fertilizantes. O material foi produzido seguindo as seguintes etapas, estabelecidas internacionalmente pelas ISO GUIAS 30 a 35: preparo e envase do material, avalia����o da homogeneidade, teste de estabilidade a curto e a longos per��odos e na caracteriza����o pr��via, que consistiu na montagem do ensaio colaborativo, com a distribui����o do material preparado a laborat��rios que se dispuseram a colaborar com o projeto. Ainda foram realizados estudos voltados ao preparo da amostra visando a rapidez e redu����o de uso de reagentes. A avalia����o da estimativa da massa m��nima, da homogeneidade e da estabilidade do material foi realizada utilizando-se como t��cnica de determina����o a espectrometria de emiss��o ��ptica com plasma indutivamente acoplado (ICP OES). Para a determina����o de f��sforo foi avaliado o emprego de espectrometria de emiss��o com plasma induzida por laser (LIBS). Os resultados foram submetidos �� an��lise de vari��ncia de fator ��nico (ANOVA) e a homogeneidade e a estabilidade do material apresentaram m��dias dentro do intervalo de confian��a de 95%. Os resultados obtidos durante o preparo e atrav��s do ensaio colaborativo possibilitaram a caracteriza����o qu��mica e o calculo das incertezas relativas a cada etapa do preparo do material, sendo elaborada a carta controle com os resultados do material de refer��ncia e as incertezas expandidas para cada um dos analitos em estudo. Parte do trabalho foi desenvolvido junto ao National Research Council Canada (NRCC) em Ottawa no Canad��, onde foi avaliada a aplicabilidade do sistema de combust��o iniciada por radia����o microondas no preparo de amostras de materiais de refer��ncia nacionais anteriormente preparados, f��gado bovino (RM-Agro E3001a) e forrageira (RM-Agro E1001a), para a determina����o de As, Cd, Cu e Pb por espectrometria de massas com plasma indutivamente acoplado (ICP-MS), sendo obtidos resultados que poder��o ser aplicados em outros materiais org��nicos e inorg��nicos.

Esp��cies reativas de oxig��nio e de nitrog��nio, antioxidantes e marcadores de dano oxidativo em sangue humano: principais métodos anal��ticos para sua determina����o

We review here the chemistry of reactive oxygen and nitrogen species, their biological sources and targets; particularly, biomolecules implicated in the redox balance of the human blood, and appraise the analytical methods available for their detection and quantification. Those biomolecules are represented by the enzymatic antioxidant defense machinery, whereas coadjutant reducing protection is provided by several low molecular weight molecules. Biomolecules can be injured by RONS yielding a large repertoire of oxidized products, some of which can be taken as biomarkers of oxidative damage. Their reliable determination is of utmost interest for their potentiality in diagnosis, prevention and treatment of maladies.

Aplica����o de métodos de calibra����o multivariada para a determina����o simult��nea de riboflavina (VB2), tiamina (VB1), piridoxina (VB6) e nicotinamida (VPP)

In this work, the artificial neural networks (ANN) and partial least squares (PLS) regression were applied to UV spectral data for quantitative determination of thiamin hydrochloride (VB1), riboflavin phosphate (VB2), pyridoxine hydrochloride (VB6) and nicotinamide (VPP) in pharmaceutical samples. For calibration purposes, commercial samples in 0.2 mol L-1 acetate buffer (pH 4.0) were employed as standards. The concentration ranges used in the calibration step were: 0.1 - 7.5 mg L-1 for VB1, 0.1 - 3.0 mg L-1 for VB2, 0.1 - 3.0 mg L-1 for VB6 and 0.4 - 30.0 mg L-1 for VPP. From the results it is possible to verify that both methods can be successfully applied for these determinations. The similar error values were obtained by using neural network or PLS methods. The proposed methodology is simple, rapid and can be easily used in quality control laboratories.

Qu��mica forense: perspectivas sobre novos métodos anal��ticos aplicados �� documentoscopia, bal��stica e drogas de abuso

In this review recent methods developed and applied to solve criminal occurences related to documentoscopy, ballistic and drugs of abuse are discussed. In documentoscopy, aging of ink writings, the sequence of line crossings and counterfeiting of documents are aspects to be solved with reproducible, fast and non-destructive methods. In ballistic, the industries are currently producing ''lead-free'' or ''nontoxic'' handgun ammunitions, so new methods of gunshot residues characterization are being presented. For drugs analysis, easy ambient sonic-spray ionization mass spectrometry (EASI-MS) is shown to provide a relatively simple and selective screening tool to distinguish m-CPP and amphetamines (MDMA) tablets, cocaine and LSD.

Métodos probabil��stico e determin��stico para diagn��stico da necessidade de subsolagem de solos agr��colas

This paper presents two techniques to evaluate soil mechanical resistance to penetration as an auxiliary method to help in a decision-making in subsoiling operations. The decision is based on the volume of soil mobilized as a function of the considered critical soil resistance to penetration in each case. The first method, probabilistic, uses statistical techniques to define the volume of soil to be mobilized. The other method, deterministic, determines the percentage of soil to be mobilized and its spatial distribution. Both cases plot the percentage curves of experimental data related to the soil mechanical resistance to penetration equal or larger to the established critical level and the volume of soil to be mobilized as a function of critical level. The deterministic method plots showed the spatial distribution of the data with resistance to penetration equal or large than the critical level. The comparison between mobilized soil curves as a function of critical level using both methods showed that they can be considered equivalent. The deterministic method has the advantage of showing the spatial distribution of the critical points.

Modelo din��mico de simulação e otimiza����o da for��a normal de rea����o do solo para um mecanismo de corte basal

The physical model was based on the method of Newton-Euler. The model was developed by using the scientific computer program Mathematica��. Several simulations where tried varying the progress speeds (0.69; 1.12; 1.48; 1.82 and 2.12 m s-1); soil profiles (sinoidal, ascending and descending ramp) and height of the profile (0.025 and 0.05 m) to obtain the normal force of soil reaction. After the initial simulations, the mechanism was optimized using the scientific computer program Matlab�� having as criterion (function-objective) the minimization of the normal force of reaction of the profile (FN). The project variables were the lengths of the bars (L1y, L2, l3 and L4), height of the operation (L7), the initial length of the spring (Lmo) and the elastic constant of the spring (k t). The lack of robustness of the mechanism in relation to the variable height of the operation was outlined by using a spring with low rigidity and large length. The results demonstrated that the mechanism optimized showed better flotation performance in relation to the initial mechanism.

Simulação da varredura da superf��cie por um cortador de base segmentado

Base cutting and feeding into harvesters of plants lying close to the ground surface require an efficient sweeping action of the cutting mechanism. It is not the case of conventional sugarcane harvesters which have rigid blades mounted on discs capable to contaminate the cane with dirt as well as damage the ratoons. The objective of this work was to simulate the sweeping performance of a segmented base cutter. The model was developed using the laws of dynamic. Simulation included two rotational speeds (400 and 600 rpm), two cutting heights (0.12 and 0.13 m) and two disk tilting angles (-10�� and -12��). The simulated sweeping angle varied between 56�� and 193��, which are very promising as a mean to cutting and feeding cane sticks lying on the ground. Cutting height was the variable that affected sweeping action the most. This behavior indicates the need to have an automatic control of the cutting disk height in order to keep good sweeping performance as the harvester moves forward.

Transfer��ncia de massa e secagem em leitos vibrofluidizados: uma revis��o

Development of processing technology and equipments requires new methods and better quality of the processed product. In the continuous drying process, utilization of equipments that promotes an increment in the transfer coefficients becomes of the major interest. The use of vibrational energy has been recommended to the dispersed materials. Such method is based on the use of vibrational energy applied to disperse media. Thus, a literature review on the mass transfer and drying in vibro-fluidized beds was carried out, showing experimental results and mathematical modeling.