Injeção de vapor e solvente como um método de recuperação avançada em reservatório avançada em reservatórios de óleo pesado

Currently a resource more and more used by the petroleum industry to increase the efficiency of steam flood mechanism is the addition of solvents. The process can be understood as a combination of a thermal method (steam injection) with a miscible method (solvent injection), promoting, thus, the reduction of interfacial tensions and oil viscosity. The use of solvent alone tends to be limited because of its high cost. When co-injected with steam, the vaporized solvent condenses in the cooler regions of the reservoir and mixes with the oil, creating a zone of low viscosity between the steam and the heavy oil. The mobility of the displaced fluid is then improved, resulting in an increase of oil recovery. To better understand this improved oil recovery method, a numerical study of the process was done contemplating the effects of some operational parameters (distance between wells, injection steam rate, kind of solvent and injected solvent volume)on the accumulated production of oil, recovery factor and oil-steam rate. Semisynthetic models were used in this study but reservoir data can be extrapolated for practical applications situations on Potiguar Basin. Simulations were performed in STARS (CMG, 2007.11). It was found that injected solvent volumes increased oil recovery and oil rates. Further the majority of the injected solvent was produced and can be recycled

Efeitos da deficiência de vitamina A na função pulmonar de crianças após infecção respiratória viral

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Efeito do treinamento resistido na função autônomica cardíaca, nos parâmetros bioquímicos e antropométricos de pessoas vivendo com HIV/AIDS

Introduction: The emergence of High Active Antiretroviral Therapy (HAART) increase the life expectancy of the persons living with HIV/AIDS (PLHIV), therefore the prolonged use cause metabolic implications and influences on body fat distribution and increase the cardiovascular diseases prevalence. Aims: Evaluate the effect of resistance training on heart rate variability, biochemical parameters and somatotype on PLHIV. Methods: Participated this study seven sedentary men, with age above 25 years old, living with HIV/AIDS, under HAART use. Were submitted a 16 week intervention with resistance training. Evaluated the heart rate variability, biochemical parameters and somatotype, before, after 8 weeks and 16 weeks, all in paired form. It was found the data normality by Shapiro-Wilk test and conducted the Anova one way combined with Tukey post hoc to samples in each evaluate moment, adopting significance level p<0,05. Also were calculated percentage change deltas. For somatotype was used the somatotype spatial distance (DES), obeying the significance value DES≥1. Results: Was found significance differences only in variable final heart rate delta 60s (p=0,01), however, is not showed changes on heart rate variability, biochemical parameters and somatotype components. Conclusion: 16 weeks of resistance training showed improvement on heart rate recovery after submaximal effort and, despite is not enough to produce significance differences on biochemical parameters and somatotype components, could be realize improvement on average value of fasting glucose and lipid profile, as well as reducing the endomorphic component

Recuperação e purificação de quitosanases usando adsorção em leito expandido com streamline DEAE com modelagem e simulação usando redes neurais

Expanded Bed Adsorption (EBA) is an integrative process that combines concepts of chromatography and fluidization of solids. The many parameters involved and their synergistic effects complicate the optimization of the process. Fortunately, some mathematical tools have been developed in order to guide the investigation of the EBA system. In this work the application of experimental design, phenomenological modeling and artificial neural networks (ANN) in understanding chitosanases adsorption on ion exchange resin Streamline® DEAE have been investigated. The strain Paenibacillus ehimensis NRRL B-23118 was used for chitosanase production. EBA experiments were carried out using a column of 2.6 cm inner diameter with 30.0 cm in height that was coupled to a peristaltic pump. At the bottom of the column there was a distributor of glass beads having a height of 3.0 cm. Assays for residence time distribution (RTD) revelead a high degree of mixing, however, the Richardson-Zaki coefficients showed that the column was on the threshold of stability. Isotherm models fitted the adsorption equilibrium data in the presence of lyotropic salts. The results of experiment design indicated that the ionic strength and superficial velocity are important to the recovery and purity of chitosanases. The molecular mass of the two chitosanases were approximately 23 kDa and 52 kDa as estimated by SDS-PAGE. The phenomenological modeling was aimed to describe the operations in batch and column chromatography. The simulations were performed in Microsoft Visual Studio. The kinetic rate constant model set to kinetic curves efficiently under conditions of initial enzyme activity 0.232, 0.142 e 0.079 UA/mL. The simulated breakthrough curves showed some differences with experimental data, especially regarding the slope. Sensitivity tests of the model on the surface velocity, axial dispersion and initial concentration showed agreement with the literature. The neural network was constructed in MATLAB and Neural Network Toolbox. The cross-validation was used to improve the ability of generalization. The parameters of ANN were improved to obtain the settings 6-6 (enzyme activity) and 9-6 (total protein), as well as tansig transfer function and Levenberg-Marquardt training algorithm. The neural Carlos Eduardo de Araújo Padilha dezembro/2013 9 networks simulations, including all the steps of cycle, showed good agreement with experimental data, with a correlation coefficient of approximately 0.974. The effects of input variables on profiles of the stages of loading, washing and elution were consistent with the literature

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

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.

Influência da salinidade e temperatura da água nas respotas comportamental e fisiológica de camarões marinhos Litopenaeus vannamei(BOONE 1931)

The shrimp Litopenaeus vannamei has been grown in highly variable environments, especially in relation to salinity and water temperature. The adjustment to such conditions mainly involves changes in behavior, physiology, particularly in the immune response. This may consequently reduce the welfare of these animals. Despite the widespread farming of the species, little is known about their behavioral and physiological responses under stressful conditions. Thus, the objective of this study was to assess the influence of different salinities and temperatures in the behavior of the marine shrimp L. vannamei, and its relation to the total hemocytes count. In the laboratory, juvenile shrimp were kept in glass aquaria with a closed water recirculation system, continuous aeration and filtration, and under a 12:12 h light/dark cycle. Behavioral observations occurred 1, 4, 7 and 10 h after the start of each phase (light or dark). To assess the influence of salinity, shrimp were first acclimated and then observed at 2, 30 or 50 ppm salinity water, while temperatures tested were 18, 28 and 33 ° C. At the end of each experiment (30 days), shrimp hemolymph was collected for subsequent total hemocytes count (THC), a parameter used to assess stress. In general, feeding behavior was modified under lower salinity and temperature, with reduced values in feeding, exploration and digestive tract filling. Inactivity and burrowing were prevalent under extreme conditions water salinity and temperature, respectively: 2 and 50 ppm and 18 and 33 ° C; crawling was also less frequent under these conditions. In regards to light/dark cycle, shrimp were more active during the dark phase (crawling and swimming), while burrowing was higher during the light phase, regardless of salinity or temperature of the water. Inactivity behavior did not vary according to the light/dark cycle. Moreover, the total hemocytes count (THC) was reduced under 2 and 50 ppm salinity and 18 ° C temperature. Farming of L. vannamei under extremely low or high salinities and low temperatures is harmful. This suggests the species must be cultivated in salinities closer to those of the sea as well as at high temperatures, which seems to be ideal for a management focused on animal welfare, therefore, producing healthier shrimp

Relação entre o ciclo sono e vigília e a função cardiorrespiratória em estudantes de medicina

Students, normally, present an irregular sleep pattern characterized by delays in sleep onset and offset from weekdays to weekends, short sleep duration on weekdays and long sleep duration on weekends. The reduction of the necessary sleep and the irregularity in the sleep patterns provoke relevant short- and long-term impairments on performances, for example, in cardiorespiratory function. The cardiorespiratory performance represents, in addition to fitness, traces associated to health conditions and in several studies to pattern and/or individual s sleep quality. The aim of this study was to evaluate the pattern of the sleep-wake cycle and the cardiorespiratory function of medical students under different class schedules. The study was accomplished with two classes of medical students of UFRN, one had classes at 7 am (n = 47) and the second had classes at 8 am (n = 41) during the week. On the first stage of the study all volunteers filled out an anamnesis, the International Physical Activity questionnaire, the Pittsburgh index of sleep quality, the Portuguese version of the Horne and Östberg cronotype questionnaire, the Health and Sleep questionnaire and the Epworth Scale of Somnolence (ESS). On the second stage, 24 students (12 of each class) had their activity rhythm monitored by actimeters set to record activity at a 2-min interval for 14 days concomitant to the completion of the sleep diary. In this same stage, each volunteer performed the effort test (treadmill) only once in the morning period (between 9:00 and 11:00). The students showed an irregular pattern of the sleep-wake cycle and this irregularity is strongly influenced by the class schedules, in addition to the contribution of the academic demand, social activities and endogenous factors. The students who woke up earlier showed greater irregularity in the sleep-wake pattern. The earlier was the class schedule the worse was the sleep quality and the greater was the frequency of students with excessive diurnal somnolence. The classes schedules and the irregular pattern of the sleep-wake cycle did not show effect on the cardiorespiratory performance of the medical students. The performance on the test seems to be affected by other factors, which can be related to the pattern of the sleep-wake cycle or not. Therefore, it is suggested that the late start of classes provokes less irregularity on the pattern of the sleep-wake cycle. However, it was observed that this irregularity and the class schedule seem not to affect the cardiorespiratory performance directly

Proposta de Intervenção para Auxiliar a Reabilitação Motora e Cognitiva de Pacientes com Acidente Vascular Cerebral

Stroke is the leading cause of combined motor and cognitive disability worldwide. The rehabilitation of stroke patients is mostly directed towards motor recovery through the training of the affected member under supervision of a Physical Therapist. In the present study we introduce a new approach for both cognitive and motor therapy, which relies on motor imagery of the upper limbs and working memory training. This therapy should be utilized as an adjuvant to physical therapy. Ten individuals (5 men and 5 women) were selected for the pilot study, all of them in the acute phase of the first ischemic stroke episode. The control group had 5 individuals who were submitted to physical therapy only, whilst the other 5 patients in the experimental group also performed the cognitive and motor training with a video game specially built for this study. Two patients left the experimental group before the end. Total training lasted for 9 weeks, 2 times a week, for half an hour. Patients reported they enjoyed playing the game, even though it required a lot of mental effort, according to them. Plus, they considered it had a beneficial influence in their activities of daily living. No side effects were reported. Preliminary results suggest there is a difference between groups in cognitive and upper limb motor evaluation following the intervention. It is important to notice that our conclusions are limited due the small sample number. Overall, this work is supported by other studies in literature focused in rehabilitation with motor imagery and working memory and indicate a continuity of the research, increasing total training hours

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

Vegetação dunar: caracterização estrutural de dunas do município de Natal-RN como subsídio para implantação de técnicas de reflorestamernto, recuperação e conservação do ecossistema

The Brazilian coast has a wide variety of complex environments and ecosystems along the coast, about 80% are represented by sandbanks and dunes. The coastal ecosystems were the first to suffer the impacts man and places, as the very fragile ecosystems, are somehow altered. Are few areas of restinga well as natural features, very few protected in conservation units. Only in the last two decades the Brazilian restinga have been studies that are showing their importance for biodiversity of the country, though its economic importance remains largely unknown. In Rio Grande do Norte in the restinga vegetation and dune environments extend for almost the entire coast. The dunes are distinguished in the coastal landscape of the state due to the exuberance of its forms, heights and coating plants. The dune system is of fundamental importance for the maintenance of coastal urban settlements, especially for the city of Natal, acting on the hydrological dynamics of water table and reducing the effect of wind and movement of grains of sand to the interior and thus avoiding the burial City. However, the ecosystem of restinga and dune environments have been weakened and destroyed according to the intense urbanization and the knowledge of the vegetation of restinga installed on the dunes are still scarce. Thus, the objective of this study was to characterize the structure and floristic composition of vegetation established on a dune in the Dunes State Park Christmas and gather information to develop a model of recovery of the dune ecosystem. This dissertation is composed of 2 chapters, the first being: Structure of the vegetation of the dunes Dunes State Park in Natal, RN with the objective of describing the structure and composition of species of tree-shrub vegetation of restinga dunes of the Parque das Dunas and second: Recovery of degraded areas in a sand dune, which aimed to review the terms and concepts used in the theme of recovery and the techniques for recovery of degraded areas with emphasis on sandy environments and poor in nutrients, reporting some experiences within and external to Brazil the country, mainly in the Northeast and dunes positive and negative aspects that should be followed in building a model to be adopted for the recovery of local dunes

Caracterização hidrodinâmica e morfo-sedimentar do estuário Potengi e áreas adjascentes: subsídios para controle e recuperação ambiental no caso de derrames de hidrocarboneto

This study presents the Environmental Sensibility Mapping to oil spillings on the Potengi estuary - RN and neighboring coastline through remote sensing data, collecting, treatment and integration of the geomorphologic, oceanographic (temperature, salinity, density, direction and intensity), meteorological (wind speed and direction) and high resolution seismic (bathymetry and sonography) data. The Potengi river estuary is located on the eastern coastline of the Rio Grande do Norte State, being inserted in the geological context for the coastal Pernambuco-Paraíba basin and spreading over 18 km; it shelters the Natal harbor zone and an oil terminal, centralizing, therefore, important oil transport operations that can cause accidental spillings. Under the oceanographic point of view, the Potengi estuary is characterized by the absence of any expressive thermic stratification, being classified as partially mixed, B type according to Pritchard (1955), and 2 type in conformity to the stratification-circulation diagram by Hansen & Rattray (1966). Two main wind systems are responsable for the formation of wave sets that occur in the area. The dynamic tide presents, in the Natal Harbor, mean amplitude in spring and quadrature tides, with around 2.8 and 2m, respectively. The mechanism of saline tide mixing was defined through the salinity which is the main parameter for the identification of this mechanism. Important variations of the salinity mean values (36.32 psu), temperature (28.11ºC) and density (22.96 kg/m3) in the estuarine waters presented features belonging to low latitude regions. The water temperature follows the air temperature variations, in the region, with expressive daily amplitudes. In this study, the identification of the estuarine bed morphology through bathymetric and sonographic analysis, had the purpose to evaluate the influence of the superficial and bottom currents for the bottom shaping. In this way, the use of the side scan sonar showed, to be very useful in the identification of the bottom morphology and its relationship with the predominant action of the tidal currents in the Potengi estuary. Besides, it showed how the sonograms can be a support to the comparison of the several patterns derived from the local hydrodynamic variations. The holocene sediments, which fill the estuarine channel, are predominantly sandy, varying from selected, sometimes silty. The sedimentation is controlled by the environmental hydrodynamic conditions, being recognized two important textural facies: Muddy Facies and Sandy Facies. The distribution of these textural facies apparently oscillates owing to the tidal cycle and flow intensity. Each one of the above mentioned data was integrated in a Geographic Information System (GIS), from which was produced the Environmental Sensibility Map to oil spillings with Coastal Sensibility Index (CSI) to the Potengi estuary. The integrated analysis of these data is essential to oil spilling contingency plans, in order to reduce the spilling environmental consequences and to make efficient the endeavours of contention and cleaning up/removal on the Natal Harbor. This study has the aim to collaborate for the increase of informations about the estuarine environment and contribute to a better management of the question: environment/polluting loads

Correlação entre força muscular do assoalho pélvico, função sexual e qualidade de vida em mulheres de meia idade

Introduction: Menopause is characterized by the depletion of ovarian follicles and the gradual decline in estradiol levels, which ends with the definitive cessation of menstrual periods (menopause). As a result of hypoestrogenism, characteristic symptoms, such as hot flashes, night sweats, vaginal dryness, dyspareunia, insomnia, mood swings and depression can be observed. There is also the weakening of the pelvic floor muscles (MAP) as a result of progressive muscle-aponeurotic and connective atrophy with consequent decreased sexual function. Objective: To evaluate the strength of MAP, sexual function and quality of life of menopausal women. Methodology: This is an observational, analytical, cross-sectional design. The sample consisted of 55 women (35 postmenopausal and 20 perimenopausal), aged between 40 and 65, who were assessed by muscle strength and perineometry test. For the assessment of sexual function and quality of life, used the Female Sexual Function Index (FSFI) and Utian Quality of Life (UQOL), respectively. Statistical analysis was performed using Pearson's correlation and multivariate analysis. Results: The mean age was 52.78 (± 6.47 years). Sexual dysfunction presented, 61.8% of participants (43.62% of postmenopausal and perimenopausal 18.17%). Muscle strength test and the maximum perineometry had a median of 3.00 (Q25: 2 e Q75: 4) and 33,50 cmH20 (Q25: 33,5 e Q75: 46,6), respectively. No correlation was found between sexual function and muscle strength (r = 0.035; p = 0.802) and between sexual function and perineometry (r = 0.126; p = 0.358). The mean total score of UQOL was 74.45 (± 12.23). Weak positive correlation was found between sexual function and quality of life (r = +0.422 p = 0.001). Multivariate analysis identified associations between sexual function and variables: quality of life, climacteric symptoms, physical activity and education level. Conclusions: These results suggest that the climacteric symptoms, quality of life, physical activity and level of education are associated with sexual function in menopausal women. However, the muscular component of sexual function needs to be further investigated in this context.

Efeito do treinamento muscular inspiratório com diferentes cargas na força e função de músculos respiratórios

Background: The inspiratory muscle training (IMT) has been considered an option in reversing or preventing decrease in respiratory muscle strength, however, little is known about the adaptations of these muscles arising from the training with charge. Objectives: To investigate the effect of IMT on the diaphragmatic muscle strength and function neural and structural adjustment of diaphragm in sedentary young people, compare the effects of low intensity IMT with moderate intensity IMT on the thickness, mobility and electrical activity of diaphragm and in inspiratory muscles strength and establish a protocol for conducting a systematic review to evaluate the effects of respiratory muscle training in children and adults with neuromuscular diseases. Materials and Methods: A randomized, double-blind, parallel-group, controlled trial, sample of 28 healthy, both sexes, and sedentary young people, divided into two groups: 14 in the low load training group (G10%) and 14 in the moderate load training group (G55%). The volunteers performed for 9 weeks a home IMT protocol with POWERbreathe®. The G55% trained with 55% of maximal inspiratory pressure (MIP) and the G10% used a charge of 10% of MIP. The training was conducted in sessions of 30 repetitions, twice a day, six days per week. Every two weeks was evaluated MIP and adjusted the load. Volunteers were submitted by ultrasound, surface electromyography, spirometry and manometer before and after IMT. Data were analyzed by SPSS 20.0. Were performed Student's t-test for paired samples to compare diaphragmatic thickness, MIP and MEP before and after IMT protocol and Wilcoxon to compare the RMS (root mean square) and median frequency (MedF) values also before and after training protocol. They were then performed the Student t test for independent samples to compare mobility and diaphragm thickness, MIP and MEP between two groups and the Mann-Whitney test to compare the RMS and MedF values also between the two groups. Parallel to experimental study, we developed a protocol with support from the Cochrane Collaboration on IMT in people with neuromuscular diseases. Results: There was, in both groups, increased inspiratory muscle strength (P <0.05) and expiratory in G10% (P = 0.009) increase in RMS and thickness of relaxed muscle in G55% (P = 0.005; P = 0.026) and there was no change in the MedF (P> 0.05). The comparison between two groups showed a difference in RMS (P = 0.04) and no difference in diaphragm thickness and diaphragm mobility and respiratory muscle strength. Conclusions: It was identified increased neural activity and diagrammatic structure with consequent increase in respiratory muscle strength after the IMT with moderate load. IMT with load of 10% of MIP cannot be considered as a placebo dose, it increases the inspiratory muscle strength and IMT with moderate intensity is able to enhance the recruitment of muscle fibers of diaphragm and promote their hypertrophy. The protocol for carrying out the systematic review published in The Cochrane Library.

Injeção de vapor e solvente como um método de recuperação avançada em reservatório avançada em reservatórios de óleo pesado

Currently a resource more and more used by the petroleum industry to increase the efficiency of steam flood mechanism is the addition of solvents. The process can be understood as a combination of a thermal method (steam injection) with a miscible method (solvent injection), promoting, thus, the reduction of interfacial tensions and oil viscosity. The use of solvent alone tends to be limited because of its high cost. When co-injected with steam, the vaporized solvent condenses in the cooler regions of the reservoir and mixes with the oil, creating a zone of low viscosity between the steam and the heavy oil. The mobility of the displaced fluid is then improved, resulting in an increase of oil recovery. To better understand this improved oil recovery method, a numerical study of the process was done contemplating the effects of some operational parameters (distance between wells, injection steam rate, kind of solvent and injected solvent volume)on the accumulated production of oil, recovery factor and oil-steam rate. Semisynthetic models were used in this study but reservoir data can be extrapolated for practical applications situations on Potiguar Basin. Simulations were performed in STARS (CMG, 2007.11). It was found that injected solvent volumes increased oil recovery and oil rates. Further the majority of the injected solvent was produced and can be recycled