Estudo paramétrico da recuperação de petróleo pesado por aquecimento eletromagnético resistivo

Electrical resistive heating (ERH) is a thermal method used to improve oil recovery. It can increase oil rate and oil recovery due to temperature increase caused by electrical current passage through oil zone. ERH has some advantage compared with well-known thermal methods such as continuous steam flood, presenting low-water production. This method can be applied to reservoirs with different characteristics and initial reservoir conditions. Commercial software was used to test several cases using a semi-synthetic homogeneous reservoir with some characteristics as found in northeast Brazilian basins. It was realized a sensitivity analysis of some reservoir parameters, such as: oil zone, aquifer presence, gas cap presence and oil saturation on oil recovery and energy consumption. Then it was tested several cases studying the electrical variables considered more important in the process, such as: voltage, electrical configurations and electrodes positions. Energy optimization by electrodes voltage levels changes and electrical settings modify the intensity and the electrical current distribution in oil zone and, consequently, their influences in reservoir temperature reached at some regions. Results show which reservoir parameters were significant in order to improve oil recovery and energy requirement in for each reservoir. Most significant parameters on oil recovery and electrical energy delivered were oil thickness, presence of aquifer, presence of gas cap, voltage, electrical configuration and electrodes positions. Factors such as: connate water, water salinity and relative permeability to water at irreducible oil saturation had low influence on oil recovery but had some influence in energy requirements. It was possible to optimize energy consumption and oil recovery by electrical variables. Energy requirements can decrease by changing electrodes voltages during the process. This application can be extended to heavy oil reservoirs of high depth, such as offshore fields, where nowadays it is not applicable any conventional thermal process such as steam flooding

Estudo do comportamento de pastas compósitas cimento/sílica/poliuretana para poços de petróleo HPHT

Os poços HPHT atravessam zonas anormalmente pressurizadas e com altos gradientes de temperatura. Esses poços apresentam elevadas concentrações de tensões produzidas pelas operações de perfuração e fraturamento hidráulico, flutuações da pressão e temperatura, forças dinâmicas geradas durante a perfuração, formações inconsolidadas, entre outros aspectos, podendo resultar em falhas mecânicas na bainha de cimento. Tais falhas comprometem a estabilidade mecânica do poço e o isolamento das zonas produtoras de óleos e/ou gás. Para que operações corretivas não se façam necessárias, é preciso adequar as pastas às condições de cada poço. Sistemas de pastas de cimento para poços HPHT requerem um bom controle de suas propriedades termo-mecânicas. Visto que a temperaturas superiores a 110 oC (230 oF) o cimento, após alcançar um valor máximo de resistência, inicia um processo de perda de resistência (retrogressão). Para prevenir esse efeito substitui-se parcialmente o cimento Portland por sílica com objetivo de incrementar a reação pozolânica. Esta reação modifica a trajetória do processo natural de hidratação do cimento, o gel de silicato de cálcio hidratado (C-S-H) se converte em várias outras fases com maior resistência. Polímeros também são adicionados para proporcionar maior flexibilidade e agir como barreira à propagação de trincas desenvolvidas sob tensão. O presente trabalho teve como objetivo estudar o comportamento do sistema cimento/sílica/polímero quando submetido às condições de alta temperatura e alta pressão. Foram formuladas pastas de cimento puro, pastas contendo 40 % BWOC de sílica flour e pastas com diferentes concentrações de poliuretana (5 % a 25 %) e 40 % BWOC de sílica flour. O peso específico das pastas foi fixado em 1,87 g/cm3 (15,6 lb/gal). Os resultados demonstram que as resistências da pasta contendo 40% de sílica e das com adição de polímero foram muito superiores a da pasta de cimento puro, não ocorrendo o efeito da retrogressão. As pastas com polímero apresentaram um crescente aumento da tenacidade com o aumento da concentração da mesma, sendo assim capaz de suportar as tensões. Além de se manterem estáveis termicamente acima de 180 ºC. O sistema também apresentou excelentes resultados de filtrado, reologia, água livre, estabilidade e permeabilidade. Sendo assim, o mesmo mostrou ser aplicável a poços HPHT

Avaliação da biodegradabilidade de petróleo utilizando microrganismos isolados do estuário do Rio Potengi (RN)

The oil activity in the Rio Grande do Norte State (RN) is a permanent threat to coastal ecosystems, particularly mangroves, with the possibility of oil spills. In this context, the objective of this study was to evaluate the potential resistance of the mangrove environment of a possible spill. Were selected and isolated microorganisms degrading oil by the technique of enrichment cultures and formation of a bacterial consortium. The kinetic study of the consortium was held in rotary incubator shaken at 150 rpm and 30° C. Samples were taken at intervals of 4 hours for analysis of cell concentration and surface tension. The biodegradation was monitored using two methods of respirometry: manometric (OxiTop-C ®) and conductivimetry, where the biodegradation of oil was estimated indirectly by oxygen consumption and CO2 production, respectively. Furthermore, it was used a full 2² factorial design with triplicate at central point to the runs that used the conductivimetric methodology.. The technique of enrichment cultures allowed to obtain thirteen bacterial strains. Kinetic study of the consortium, we can showed the absence of the lag phase, reaching a maximum cell concentration of 2.55 g / L at 16 h of cultivation and a reduction on surface tension. When we adopted the methodology of OxiTop-C was detected a band indicating biodegradability (1% oil v/v), however when we used the conductivimetry methodology did not observe any band that would indicate effective biodegradation. By monitoring a process of biodegradation is necessary to observe the methodology will be adopted to evaluate the biodegradation process, since for the same conditions adopted different methodologies can produce different results. The oil-degrading isolates from soils of the mangrove estuary Potengi / RN are largely to be used in bioremediation strategies of these places, in the case of a possible oil spill, or it can be used in the treatment of waste oil generated in saline environments, since they are optimized the conditions of the tests so that the efficiency of biodegradation reach the minimum level suggested by the standarts

Efeito da perda de carga e calor no poço injetor no processo de drenagem gravitacional assistido com vapor e solvente

Nowadays, most of the hydrocarbon reserves in the world are in the form of heavy oil, ultra - heavy or bitumen. For the extraction and production of this resource is required to implement new technologies. One of the promising processes for the recovery of this oil is the Expanding Solvent Steam Assisted Gravity Drainage (ES-SAGD) which uses two parallel horizontal wells, where the injection well is situated vertically above the production well. The completion of the process occurs upon injection of a hydrocarbon additive at low concentration in conjunction with steam. The steam adds heat to reduce the viscosity of the oil and solvent aids in reducing the interfacial tension between oil/ solvent. The main force acting in this process is the gravitational and the heat transfer takes place by conduction, convection and latent heat of steam. In this study was used the discretized wellbore model, where the well is discretized in the same way that the reservoir and each section of the well treated as a block of grid, with interblock connection with the reservoir. This study aims to analyze the influence of the pressure drop and heat along the injection well in the ES-SAGD process. The model used for the study is a homogeneous reservoir, semi synthetic with characteristics of the Brazilian Northeast and numerical simulations were performed using the STARS thermal simulator from CMG (Computer Modelling Group). The operational parameters analyzed were: percentage of solvent injected, the flow of steam injection, vertical distance between the wells and steam quality. All of them were significant in oil recovery factor positively influencing this. The results showed that, for all cases analyzed, the model considers the pressure drop has cumulative production of oil below its respective model that disregards such loss. This difference is more pronounced the lower the value of the flow of steam injection

Efeito antibacteriano de tecidos têxteis revestidos por prata através da técnica de deposição por plasma

In this study, it has been investigated the influence of silver film deposition onto 100% polyester woven and non-woven, on the survival of Escherichia coli and Staphylococcus aureus in contact with these surfaces. The treatment was performedin a chamber containing the working gas at low pressure (~ 10-2 mbar). Some process parameters such as as voltage: 470 V; pressure: 10-2 mbar; current : 0.40 A and gas flow: 6 and 10 cm3/min were kept constant. For the treatments with purêargon plasma using a flow of 6 and 10 cm3/min, different treatment times were evaluated, such as, 10 , 20, 30, 40, 50 and 60 minutes. Contact angle (sessile drop), measurements were used to determine the surface tension of the treated fabrics and its influence on the bacteria grow as weel as the possibilities of a biofilm formation. The formation of a silver film, as well as the amount of this element was verified byEDX technique. The topography was observed through scanning electron microscopy (SEM) to determine the size of silver grains formed on the surfaces of the fabric and assess homogeneity of treatment. The X-ray diffraction (XRD) was used to analyze the structure of silver film deposition. The woven fabric treatments enabled the formation of silver particulate films with particle size larger than the non-woven fabrics. With respect to bacterial growth, all fabrics were shown to be bactericidal for Staphylococcus aureus (S. aureus), while for the Escherichia coli (E. coli), the best results were found for the non-woven fabric (TNT) treated with a flow of 10 cm3/min to both bacteria

Novo método para estimativa do gradiente de fratura para poços de petróleo

The development of oil wells drilling requires additional cares mainly if the drilling is in offshore ultra deep water with low overburden pressure gradients which cause low fracture gradients and, consequently, difficult the well drilling by the reduction of the operational window. To minimize, in the well planning phases, the difficulties faced by the drilling in those sceneries, indirect models are used to estimate fracture gradient that foresees approximate values for leakoff tests. These models generate curves of geopressures that allow detailed analysis of the pressure behavior for the whole well. Most of these models are based on the Terzaghi equation, just differentiating in the determination of the values of rock tension coefficient. This work proposes an alternative method for prediction of fracture pressure gradient based on a geometric correlation that relates the pressure gradients proportionally for a given depth and extrapolates it for the whole well depth, meaning that theses parameters vary in a fixed proportion. The model is based on the application of analytical proportion segments corresponding to the differential pressure related to the rock tension. The study shows that the proposed analytical proportion segments reaches values of fracture gradient with good agreement with those available for leakoff tests in the field area. The obtained results were compared with twelve different indirect models for fracture pressure gradient prediction based on the compacting effect. For this, a software was developed using Matlab language. The comparison was also made varying the water depth from zero (onshore wellbores) to 1500 meters. The leakoff tests are also used to compare the different methods including the one proposed in this work. The presented work gives good results for error analysis compared to other methods and, due to its simplicity, justify its possible application

Influência na qualidade final de metais retificados através da variação da velocidade de mergulho

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A saúde psíquica de quem faz saúde: uma análise crítica sobre a humanização direcionada ao profissional de saúde

It is noticeable that pressure, tension and overwork are frequent in health professionals routine. The work related to the ward area demands deep attention and surveillance. Because of that, it is essential to have a specific look at the humanization directed at health professionals, considering that taking care of other human beings is the essence of their job. This study has analyzed the psychic health levels, as well as the stress health professionals are submitted to, providing a debate about the humanization in 06 public hospitals (03 of them awarded by actions of humanization, and 03 not awarded) in Rio Grande do Norte state, Brazil. A study with 126 active health professionals (doctors, nurses, psychologists, nutritionists and social workers) in ward areas in their respective institutions was carried out. The thesis presented, with multi-disciplinary characteristic, counted on the support of statisticians (to calculate samples and data analysis), psychologists, social workers and administrators (linked to the human resources sector in each hospital). A cross-sectional study was performed, taking into consideration both quantitative and qualitative factors. The tools used for that were a semistructured questionnaire with socio-demographic characteristics, work and humanization; Lipp's Stress Symptoms Inventory for Adults (ISSL), and the Goldberg s General Health Questionnaire (QSG). The workers are predominantly women (84,9%), married (54,8%), between 46 and 55 years old (40,5%), working in the same institution for more than 20 years (22,2%), and between 16 and 20 years (20,6%), respectively. They work 40 hours a week (71,4%) and have multiple jobs (61,9%). Although most of these individuals global psychic health is in a good level, there are a significant number of people that is gradually getting worse concerning psychic stress (F1) showed by QSG (54,7%), and stress showed by ISSL(42,1%). Observing the categories, nurses (41,5%). Nutritionists (20,8%), doctors and social workers (18,9%), were among the most affected. About general health (F6), 63% of the awarded hospitals and 70% of the not awarded ones, presented good health levels (ranging from 5 to 50%). It was also noticed that, in the groups mentioned above, 25 and 20% respectively, were inserted in scores between 55 to 90%, what means that they are in worsening phase. The fact that the hospital is awarded or well recognized doesn t interfere in health professionals stress level and in their psychic health. Through what was heard from these individuals, it was possible to verify that they know little about humanization, once few of them identify or know that the service they offer is in an adoption process by Ministerial Policies. It was also detected the necessity of developing actions aimed at worker s health. Such results showed the importance of have more investments in programs that are directed to workers well-being, because they deal with other people s health and it is known that it is difficult for them to offer high-quality assistance if there are not suitable physical, psychological and material conditions to help them develop their jobs. As a warning, it is fair to say that investments in actions that provide humanized care to health professionals, mainly concerning preventive care for their health and life quality in their work

Morte como desafio afetivo para o profissional da saúde: ansiedade e sentimentos de quem lida com o paciente terminal com câncer

It is a Cross-sectional and multi-disciplinary study whose population selection was made by department of human resources (composed by a Manager, an Oncologist and a Psychologist) from the hospital where this research was realized. They also collaborated with important information about the work of that professionals in the hospital. We also counted on a Statistic who made study design calculating the sample and analyzing data. This research issued Evaluating health professionals anxiety levels who care for cancer terminally ill and their feelings about that work as well as identifying the factors which have influence on it. 100 health professionals from the Hospital which is a reference on cancer caring in Brazil situated in the city of Natal, state of Rio Grande do Norte, participated of this research. There was a sample loss of 21%. Data were collected through a questionnaire and State-Trait Anxiety Inventory (STAI). Results showed that 15% of the professionals have low State Anxiety levels, 70% Medium State Anxiety levels and 15% high State anxiety levels. The Number of Patients and Working in another Institution have interfered in the anxiety levels. Doctors and Nursing Assistants and Technicians have got the highest high State Anxiety percentage (25%). 73% of them declare to feel some sort of different behavior and/or feelings in caring for terminally ill. The most remarkable professionals feelings were Suffering and Sadness, and Terminally ill Children was the most difficult age group to care for. We conclude that work overload and having more than one job can interfere in professional stress levels and anxiety. Dealing with terminally ill, specially children one, can cause on the professionals psychological suffering. It s recommended the development of supporting and training strategies to reduce and/or to prevent Stress and Anxiety high levels

Ensaio clínico randomizado sobre a prática da atenção farmacêutica nas farmácias comunitárias

Introdução: A criação de programas de equipe multiprofissional de saúde desponta como uma alternativa eficiente para controlar a evolução dos pacientes portadores de diabetes, e a inserção do farmacêutico em tais programas tem contribuído para melhorar o acompanhamento desses pacientes. Objetivo: Avaliar o impacto da intervenção do farmacêutico no acompanhamento dos pacientes diabéticos tipo 2, em farmácias comunitárias. Métodos: Ensaio clínico randomizado, uni-cego envolvendo 100 pacientes diabéticos tipo 2 de ambos os gêneros, usuários de farmácia comunitária, com idade igual ou superior a 30 anos, em uso de hipoglicemiantes orais com adição ou não de insulina e foram acompanhados por 6 meses. Os pacientes do grupo controle receberam o tratamento habitual existente em qualquer farmácia, e os de intervenção receberam o acompanhamento do farmacêutico incluindo intervenções aos problemas relacionados aos medicamentos. Os desfechos primários avaliados foram os valores da hemoglobina glicada (HbA1c), glicose basal e um questionário de qualidade de vida validado denominado de Diabetes Quality of Life Measure (DQOL) - Brasil; e como desfechos secundários as dosagens dos triglicérides, colesterol total, (HDL) colesterol, (LDL) colesterol, tensão arterial e a satisfação do usuário com o serviço prestado. Essa pesquisa contou com a colaboração de vários profissionais das diferentes áreas do conhecimento a seguir nominados: médico, farmacêutico bioquímico, enfermeiro, nutricionista e estatístico. Resultados: Finalizaram o estudo 89 pacientes. Durante o acompanhamento 95,7% (45/47) dos pacientes no grupo intervenção apresentaram problemas relacionados aos medicamentos (PRM), perfazendo um total de 141, com uma média de 3 eventos por paciente, ocorrendo uma resolutividade de 61,7% (87/141). A categoria que mais apresentou PRM foi a de efetividade com 34,1% (48/141) e a classe farmacológica mais utilizada foi a dos hipoglicemiantes orais com 35% (49/141). As variáveis de desfechos primários como hemoglobina glicada (HbA1c) e a glicose basal não apresentaram valores estatisticamente significantes quando comparadas o final com o inicial do acompanhamento nos grupos intervenção e controle considerando um p<0,05, mas o questionário de qualidade de vida DQOL Brasil apresentou resultados estatisticamente significante com um p=0,000. Os desfechos secundários, com exceção da satisfação do usuário, não apresentaram valores xi estatisticamente significantes quando comparados o final com o início do acompanhamento nos grupos de intervenção e controle. Conclusão: Os resultados indicam que as modificações das variáveis clínicas não apresentaram valores significativos no controle da enfermidade e comorbidades, enquanto que na avaliação da qualidade de vida os pacientes afirmaram que melhoraram; portanto, pode-se postular que a intervenção farmacêutica é uma atividade necessária, mas que a prática do Pharmaceutical Care trará benefícios com sustentabilidade para os pacientes se houver uma efetiva integração do farmacêutico numa equipe multiprofissional de saúde, o que está indisponível nas Farmácias Comunitárias

Morbimortalidade perinatal associada à infecção clamidiana: uma revisão sistemática

Universidade Federal do Rio Grande do Norte

Caracterização de superfícies de titânio modificado por oxidação à plasma

Recent years have seen a significant growth in surface modifications in titanium implants, resulting in shorter healing times in regions with low bone density. Among the different techniques, subtraction by chemical agents to increase oxidation has been applied for surface treatment of dental implants. However, this technique is generally unable to remove undesirable oxides, formed spontaneously during machining of titanium parts, raising costs due to additional decontamination stages. In order to solve this problem, the present study used plasma as an energy source to both remove these oxides and oxidize the titanium surface. In this respect, Ti disks were treated by hollow cathode discharge, using a variable DC power supply and vacuum system. Samples were previously submitted to a cleaning process using an atmosphere of Ar, H2 and a mixture of both, for 20 and 60 min. The most efficient cleaning condition was used for oxidation in a mixture of argon (60%) and oxygen (40%) until reaching a pressure of 2.2 mbar for 60 min at 500°C. Surfaces were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscopy (AFM), adhesion and cell proliferation. SEM showed less cell spreading and a larger number of projections orfilopodia in the treated samples compared to the control sample. AFM revealed surface defects in the treated samples, with varied geometry between peaks and valleys. Biological assays showed no significant difference in cell adhesion between treated surfaces and the control. With respect to cell proliferation, the treated surface exhibited improved performance when compared to the control sample. We concluded that the process was efficient in removing primary oxides as well as in oxidizing titanium surfaces

A influência do sorriso gengival no vedamentos labial

Ideally the smile should expose minimal gingival, therefore patients with gummy smile and passive eruption altered or excessive marginal gingivae, usually excessive gingival display because incomplete anatomical crown exposure is present. If the maxillary incisor show at rest is optimal, active upper incisor intrusion should not be iniciated. To achieve a smile with minimal gingival exposure, the anatomic crown should be fully exposed by surgical crown lengthening. Precise determination of the location of cementoenamel junction prior to surgery, precise placement of incisions and correct establish of biological width are necessary in order to achive this goal. One protocol is decribed and clinical results from 15 brazilian subjects, after three years post surgery are showed

Atenção ao usuário em um centro de referência HIV/Aids: perspectiva de profissionais e usuários

We study the health care focused on care in an intercessor and dialogical relationship with the User, which involves the construction of therapeutic projects essential to the quality of the treatment of the user in health services, and it is necessary individual and collective actions. It is intended to acknowledge and analyze the perception of social subjects, users and professionals on the treatment given to a user of a Specialized Outpatient Service (Serviço Ambulatorial Especializado SAE) in STD/HIV/AIDS state reference in Natal, RN. The study is structured in a transdisciplinary vision of science and knowledge, theoretical and methodological principles that give meaning to the expression of the institutional features of care and health care reconnecting them to the social context. As a research strategy we seek the expressions of 56 subjects of social research, which agreed to participate in the sample, from a symbolic map of the attention, coupled with the techniques of observation and semi-structured interview. For the analysis of the results, five categories of analysis were established: the meaning of the service, care perception, process of communication and interaction, treatment perception and organization and evaluation of the service. It is argued that the attention and care are developed in a technical health care assistance to the disease, focusing on attention based on treatment, on diagnostic and drug therapy of antiretroviral drugs, reflecting the traditional biomedical paradigm of attention to the disease. This is also the mode of organization of practical actions in daily SAE: the therapy proves to be fragmented in several specialties, vertical and feeds the same model, generating tension and overload for professionals; showing impersonal care focused on structured and informative technology, unrelated to an interactive dialogic. From the speech of the subjects, the SAE is understood as the place of confrontation with the disease, but also enables greater elaboration of the illness by meeting their peers. Living with HIV and AIDS is living with concern, apprehension and fear, but mainly with the stigma, prejudice and exclusion, which require that the disease is kept in secret. There is a movement of forces and power, expressed in the knowledge-power of those who dominate the technical and administrative capabilities, devices that concentrate the maintenance of the medicalization of care, rapid consultations and with little attention, making it difficult to interact with and listen to, combined with structural failures, organizational and inadequate management of the service. We conclude that there are dimensions that are not considered in the internal dynamics of the care service multiple forms, characterized by care conflicting models, marked by individual interventions related to the disease. The subject is not considered together with his speech as technical discourse is imposed and care production based on material technology is observed