This study assessed a new experimental model to analyze the effects of sodium hypochlorite solution 2.5% for 10 min and chlorhexidine 2% for 15 s on cones surface alterations. Twenty five gutta-percha and 25 thermoplastic synthetic polymer-based cones had their last 1 mm from the tapered end examined by scanning electron microscopy (SEM) before and after being exposed to the disinfectant solutions. To allow the surfaces to be compared, the samples were not metalized, a voltage of 1 kV was used and the images were captured within standardized angles. The samples were immersed on the test solutions. The comparison of the alterations of the cones was performed using the software program Adobe Photoshop CS. A measurement was taken of the standard deviations of the pixel intensity in this area, higher standard deviations represent more irregular areas. Differences in standard deviation before and after disinfection for each cone were compared between groups by means of analysis of variance supplemented by the Tukey test. Gutta-percha cones showed higher standard deviations than Resilon cones (P < 0.001). In the gutta-percha cones, sodium hypochlorite generated more irregular areas than chlorhexidine and the control group (P < 0.001). The present study has demonstrated the feasibility of using a modified SEM method. This opens opportunities to the use of new and precise tools for evaluating a sample in different moments.

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With today's oil and gas prices, the loss of well production creates a negative financial impact on operating companies, especially in an offshore environment. One of the most common reasons for production loss is the development of scales inside the production strings, blocking the flow of the reservoir fluid to the surface facilities. Barium Sulfate (BaSO4) scale is among the toughest scales to remove, whether mechanically or chemically. Alternatives to remediate this problem are often quite costly. Therefore, under this scenario, a cost-effective intervention mechanism to restore production to previous levels is imperative. One of these mechanisms is the deployment of coiled tubing intervention as it can be done while the well is still live, minimizing further loss of production. The Namorado field in Campos Basin, offshore Brazil, has approximately 60 wells, with most of them presenting deposition of BaSO4 scale throughout their production history. Historically, in this field, the deployment of a down hole motor with coiled tubing has been effective, but limited to restoring the production path's diameter only to the outer diameter of the bit. Results with deploying a down hole motor have been satisfactory. On the other hand, chemical treatments have been extremely ineffective and are, therefore, seldom deployed. This paper presents two case histories of successful Barium Sulfate scale removal from the production tubing by coiled tubing, utilizing a combination of mechanical and hydraulic tools. This process is different from the conventional method (downhole motor) as it provides faster cleanout rates and quicker production restoration. This combination is engineered through software that optimizes the velocity at which the coiled tubing string is run through the scale, as well as the configuration of the hydraulic tool with respect to the pump rate and selection of the jet angle. Introduction One of the most common reasons for production decay in oil and gas wells is scale formation inside the production tubing. In Namorado Field, Campos Basin, Brazil, the management of Barium Sulfate (BaSO4) scales is one of the most challenging objectives for the production maintenance at the field. The Namorado Field suffers, as many oilfields do, from serious scale deposition issues. In particular, the field faces a plague of hard, stubborn Barium Sulfate scale (Figure 1). Despite periodic scale inhibition treatments, many wells still suffer flow restrictions as scale deposits diminish the internal diameter of production tubing. A typical solution has been to remove and replace the production tubing, an expensive proposition because of environmental regulations treating barium sulfate-contaminated tubing as radioactive waste. Since the advent of water injection at the Namorado field, by the middle of the 1980s, laboratory tests indicated the high potential of Barium and Strontium Sulfate precipitation to occur at wells using this technique. During this time, several procedures were analyzed and implemented in order to prevent the occurrence of BaSO4 scale formation and to remove scales already in the tubing as well. In general, scales can have different sources and compositions and can be formed by different factors, such as:Increase or decrease in temperatureIncrease or decrease in pressureIncrease or decrease in salinityIncrease or decrease in pHMixing of two or more different waters

Como forma de melhoria das características mecânicas do solo, o solo-cimento constitui alternativa economicamente viável e de relativa facilidade de aplicação. Portanto, o estudo dos parâmetros de resistência ao cisalhamento, que compõem o entendimento de seu comportamento mecânico, representa fator importante para maior implementação da técnica na prática. O trabalho propõe o estudo comparativo entre o solo natural e o solo com adição de diferentes teores de cimento, a fim de compreender seu comportamento e características geomecânicas. Para tanto, o estudo foi divido em três etapas: realização de ensaios de caracterização e compactação do solo não cimentado, adição de diferentes teores de cimento ao solo e realização de ensaios de compressão triaxial estáticos das amostras de solo e solo-cimento com crescentes teores de cimento (2%, 5% e 10%). Observou-se, por fim, que o material estudado apresentou um comportamento típico de solos cimentados, com aumento da resistência de pico e da rigidez inicial em função do aumento do teor de cimento e da tensão confinante aplicada. Verificou-se um incremento não linear do valor do ângulo de atrito para os solos cimentados de 2,8º, 6,1º e 16,82º, para os teores de 2%, 5% e 10%, respectivamente. Quanto ao valor de coesão, foram obtidos acréscimos de 8.500%, 20.200% e 42.500%. PALAVRAS-CHAVE: Solo-cimento, melhoramento de solos, parâmetros de resistência, ensaio triaxial.ABSTRACT: As a way of improving the mechanical characteristics of the soil, soil-cement is an economically viable and relatively easy to apply alternative. Therefore, the study of the shear strength parameters, which comprise the understanding of its mechanical behavior, represents an important factor for greater implementation of the technique in practice. This work proposes a comparative study between natural soil and soil with the addition of different levels of cement, in order to understand its behavior and geomechanical characteristics. The study was divided into three stages: characterization and compacting tests on cementless soil, adding different levels of cement to the soil and performing static triaxial compression tests on soil and soil-cement samples with increasing levels cement (2%, 5% and 10%). Finally, it was observed that the studied material presented a typical behavior of a soil-cement, with an increase in peak strength and initial stiffness due to the increase in cement content and the confining stress applied. There was a non-linear increase in the friction angle value for soil-cement of 2.8º, 6.1º and 16.82º, for the contents of 2%, 5% and 10%, respectively. As for the cohesion value, it was obtained increases of 8, 500%, 20,200% and 42,500%.

A análise de metodologias de capacidade de carga de estacas do tipo Hélice Contínua Monitorada é de extrema importância para o projetos geotécnicos, tendo em vista que em certas regiões do Brasil, ocorre uma escassez de dados quanto a metodologia que apresenta uma melhor previsão de capacidade de carga para o solo representativo de certas localidades. As 22 estacas apresentadas neste trabalho foram executadas no município de Paulino Neves, região nordeste do Estado do Maranhão. O presente trabalho busca, analisar diferentes metodologias de previsão de capacidade de carga a partir do ensaio SPT, tais como: Aoki-Velloso (1975), Décourt-Quaresma (1978) e Antunes e Cabral (1996). Buscando assim, verificar qual metodologia apresenta as melhores previsões quando comparadas com as 22 provas de carga realizadas nas estacas assentes no solo da região nordeste do Estado do Maranhão. Os métodos semi-empíricos de Antunes e Cabral (1996) e Décourt e Quaresma (1978) foram os que melhor se adaptaram as condições estudadas, apresentando resultados satisfatórios quando comparado com os valores obtidos em provas de carga.