bluuebunny/crossref_metadata_2025 huggingface dataset:
Emotionen in mittelalterlicher Anthropologie, Naturkunde und Medizin
Authors: Riha Ortrun
Published: April 2009

In medieval medical anthropology, emotions are closely tied up with humoral pathology, e.g. joy with blood, anger with yellow bile, and sorrow with black bile. The face and body are external signs of a person's constitutional emotionality. Health is based on mental stability: Rage should be channelled into something constructive; love-sickness can even cause death. The use of drugs must respect emotional side effects: While some herbs and gems can brighten the mind, others cause sadness und discomfort. Inadequate emotions not only cause mental illnesses, but can also be mental illnesses in themselves, e.g. raving madness or deep depression. Thus, calming and cheering psychotherapy complements dietary, physical, medicinal, and surgical treatment.
Darstellungsmuster und Typen von Zorn in der Historiographie. Die ‚Antapodosis‘ Liudprands von Cremona
Authors: Freudenberg Bele
Published: April 2009

In this article, I propose to see the emotion of anger in the ‘Antapodosis’ by Liudprand of Cremona as an important means of assessing characters. By depicting the anger of the Ottonian kings as just and predictable, Liudprand shows how the ideal ruler should behave. He uses various examples from the Old Testament and especially the Deuterocanonical books of the Maccabees to present the anger of the Ottonian kings in the same fashion. In his vision, the negative counterpart to the Ottonians is played by the Italic kings, who show their unworthiness precisely through the inept and tyrannical use of anger. In addition to this, Liudprand writes about aristocratic anger-management as well as the anger of women. Although a man of the church, Liudprand shows himself to understand and to use the code of honour which applied to noblemen in conflicts. Women do not, on the contrary, show unmediated anger. Their emotion is mixed with grief and tears.
Negative Emotionen in neulateinischen Tragödien des 14. und 15. Jahrhunderts. Kontinuität und Modifikation des Motivs furor
Authors: Beyer Hartmut
Published: April 2009

The depiction of negative emotions in neo-Latin tragedies of the 14th and 15th centuries is to a great extent influenced by the Younger Seneca, whose works of the same genre furnished numerous descriptions of the highly destructive emotion furor (conceived as an aggravation of ira) and its physical effects on the characters on stage. This accords strongly with Seneca's philosophical doctrines on anger described especially in ‘De ira’. On the basis of three texts – Albertino Mussato's ‘Ecerinis’ (Padua 1315), Leonardo Dati's ‘Hyempsal’ (Florence 1440) and Carlo and Marcellino Verardi's ‘Fernandus servatus’ (staged in Rome 1493) – this essay examines the reception and modification of the theme of furor, taking into account especially the tragedies' contexts and their intended effect. In none of the cases presented was the author's main interest directed towards emotions per se. They rather act as a means of morally classifying the characters on stage. There is also (compared to Seneca's tragedies) an increased interest in the remedies against negative emotions. The Stoic theory of affects, according to which emotions are always negative and act as a kind of illness of the soul, is not fully adopted. Rather, many passages imply an Aristotelian or Christian understanding of emotions, which involve both justified anger and damnable apathy.
Polycentric Polytheism and the Philosophy of Religion
Authors: Butler Edward P.
Published: April 2009

The comparison drawn by the Neoplatonist Olympiodorus between the Stoic doctrine of the reciprocal implication of the virtues and the Neoplatonic doctrine of the presence of all the gods in each helps to elucidate the latter. In particular, the idea of primary and secondary “perspectives” in each virtue, when applied to Neoplatonic theology, can clarify certain theoretical statements made by Proclus in his Cratylus commentary concerning specific patterns of inherence of deities in one another. More broadly, the “polycentric” nature of Neoplatonic theology provides a theoretical articulation for henotheistic practices within polytheism without invoking evolutionist notions of “monotheistic tendencies.” The Neoplatonic distinction between the modes of unity exhibited by divine individuals (“henads”) and ontic units (“monads”), which is integral to the polycentric theology, also provides a theoretical basis for the non reductive crosscultural comparison between deities. The polycentric theology thus offers a promising foundation for a polytheistic philosophy of religion.
Tag Retention and Effects of Tagging on Movement of the Giant Red Sea Cucumber Parastichopus californicus
Authors: Cieciel Kristin , Pyper Brian J. , Eckert Ginny L.
Published: April 2009

We examined tag retention and the effects of tagging on short-term movements of the giant red sea cucumber Parastichopus californicus. Retention rates were monitored for six different tag types (Floy banner FTSL-73, cinch FT-4C, fingerling FTF-69, garment, single T-bar FD-94, and the coded wire tag), which were applied to 30 individuals under laboratory conditions. The single T-bar and coded wire tag had the highest retention rates: 70% and 60% after 16 weeks, and 40% and 37% after 32 weeks. To assess the effects of tagging and handling on movement, a field study was conducted in Amalga Harbor, Alaska, in which giant red sea cucumbers were tagged with T-bar tags and monitored for 24 h. Tagged and handled animals moved significantly farther than control animals. The median (linear) distance moved by control animals over 24 h was 1.8 m (range, 0.2–4.2 m), whereas the median distance for tagged animals was 4.2 m (range, 0.4–22.7 m). Short-term behavior was affected by both tagging and handling; therefore, we recommend that researchers minimize handling and wait at least 24 h after tagging before monitoring giant red sea cucumber movements.
Development and Evaluation of Methods for Osmotic Induction Marking of Golden Perch Macquaria ambigua with Calcein and Alizarin Red S
Authors: Crook David A. , O'Mahony Damien J. , Sanger Andrew C. , Munro Andrew R. , Gillanders Bronwyn M. , Thurstan Stephen
Published: April 2009

We conducted a series of osmotic induction procedures for marking golden perch Macquaria ambigua with calcein and alizarin red S (ARS), evaluated the factors that influenced mark quality, and tested for any effects on fish growth and mortality. Three aspects of the marking protocols were considered: immersion time in a 5% salt solution (0, 5, or 10 min), immersion time in the fluorescent dye (5 or 10 min), and concentration of the dye (low or high). Quantitative estimates of mark intensity using photographs of marked fish were made with image analysis software. Although there were some significant interactions between factors, salt immersion was generally the primary determinant of mark intensity, followed by dye concentration and dye immersion time. Fish marked with calcein did not have higher mortality rates than unmarked fish and had significantly higher growth rates. The highest-exposure ARS treatments resulted in higher mortality and lower growth rates than for unmarked fish. Following this result, a lower-exposure ARS marking protocol was tested, which resulted in no detectable effects on mortality or growth rates while still producing high-quality marks. Although further study of the long-term retention of marks under field conditions is required to understand the limitations of the chemical marking methods examined in this study, our results suggest that the methods would greatly enhance our knowledge of the outcomes of fish stocking.
Use of Parentage Assignment and DNA Genotyping to Validate Scale Analysis for Estimating Steelhead Age and Spawning History
Authors: Seamons Todd R. , Dauer Michael B. , Sneva John , Quinn Thomas P.
Published: April 2009

Sound fisheries management depends on understanding life history characteristics, such as age at maturity, migration, and spawning history; hard parts, such as scales and otoliths, are commonly used to estimate values for these traits. Validation of these techniques is often difficult but critical because errors in mean values for a population can result in erroneous estimates of sustainable exploitation rates. In this study, we compared information on age and spawning history derived from genetic analysis with information from scale analysis for 1,836 individual steelhead Oncorhynchus mykiss representing two life history stages (smolt and mature adult); these fish were of hatchery and wild origin and were sampled from two rivers in Washington State over a period of 19 years. Aging error rates were less than 5% for both wild smolts and hatchery adults, but the error rate for wild adults was much higher (13%; 95% confidence interval [CI] = 1.82–29.22%). Adult scale ages were biased; scale readers typically overestimated the ages of younger fish and underestimated the ages of older fish. In addition to the errors in age estimation, repeat spawners were misclassified as virgin spawners 6.5% of the time (95% CI = 0.79–20.26%). The higher error rates obtained in using scales for aging and identifying repeat spawning in wild adults may partly stem from the more complex life history relative to that of smolts or hatchery-origin adults; these results highlight the need for verification of scale analysis, especially for wild steelhead populations.
Relationship between plasma and red blood cell concentrations of quinine in Brazilian children with uncomplicated Plasmodium falciparummalaria on oral therapy
Authors: Vieira José L.F. , Gomes Andreza L.S. , Borges Larissa M.G. , Guimarães Erika R.
Published: April 2009

We determined the relationship between plasma and red blood cell concentrations of quinine in children with uncomplicated falciparum malaria from an endemic area of Amazonian region. Quinine was determined by high performance liquid chromatography with ultraviolet detection. In the steady state the ratio between plasma and red blood cell quinine concentration was 1.89 ± 1.25 ranging from 1.05 to 2.34. This result demonstrated that quinine do not concentrate in red blood cell of Brazilian children and characterize the absence of interracial difference in this relationship.
A postura no trabalho dos operadores de checkout de supermercados: uma necessidade constante de análises
Authors: Batiz Eduardo Concepción , Santos Andréia Fuentes dos , Licea Olga Elena Anzardo
Published: April 2009

As condições de trabalho nas quais os operadores de checkout de supermercados realizam suas atividades têm sido uma preocupação dos especialistas nos últimos tempos. Essa pesquisa foi realizada em oito supermercados de duas cidades do Brasil com o objetivo de conhecer as condições em que os operadores realizam suas atividades, detectando os fatores de risco para propor medidas que eliminem ou minimizem o aparecimento de efeitos adversos nos trabalhadores. Foi aplicado um questionário e o método RULA a uma amostra de 80 trabalhadores. O estudo mostrou que o mobiliário não está adaptado às características antropométricas da população, a maioria das posturas analisadas é inadequada, não existem revezamento nem pausas que poderiam ajudar a minimizar a situação, existência de sobrecarga, mental e física, entre outras. Conclui-se que a atividade pode representar riscos à saúde dos operadores de caixa de supermercados.
Determinación de la densidad de entrecruzamiento de poliuretanos obtenidos a partir de aceite de ricino modificado por transesterificación
Authors: Valero Manuel F. , Pulido Jorge E. , Ramírez Álvaro , Cheng Zhengdong
Published: April 2009

Se obtuvo una gama de polioles a partir del aceite de ricino modificado por transesterificación con pentaeritriol y glicerina. Los productos resultantes fueron caracterizados físico-químicamente. Se sintetizaron elastómeros de poliuretano a partir de los polioles derivados del aceite de ricino modificado. La densidad de entrecruzamiento se determinó por ensayos de hinchamiento a partir de la ecuación de Flory-Rehner apoyada en la espectroscopia MALDI TOF MS para determinar la estructura química de la unidad repetitiva promedio del poliuretano. Se estudió la variación de la densidad de entrecruzamiento de los poliuretanos con base en el índice de hidroxilo del poliol utilizado en la síntesis. Los resultados muestran que los PU obtenidos a través de la modificación del aceite con pentaeritriol tienen una mayor densidad de entrecruzamiento que los PU obtenidos a partir del aceite original y de los polioles derivados de la reacción de transesterificación del aceite con glicerina, debido a que estos polioles poseen una mayor funcionalidad hidroxílica.
Rentabilidade e eficiência no setor bancário brasileiro
Authors: Ceretta Paulo Sergio , Niederauer Carlos Alberto Pittaluga
Published: April 2009

As transformações na economia internacional vêm atingindo em grande escala o setor bancário brasileiro. Para verificar o nível de competição no setor, e para investigar o desempenho comparativo entre os bancos brasileiros, aplicou-se o método da análise por envoltória de dados. Foram utilizados dados sobre o montante de capital dos proprietários, capital de terceiros, receita total e resultado do semestre de 144 instituições bancárias do país. Os bancos foram agrupados em três categorias: grande, médio e pequeno porte. Foi utilizada a abordagem da matriz BCG para enquadrar os diversos indicadores de eficiência operacional e de rentabilidade. Os resultados sugerem que os bancos de grande porte são os de melhor desempenho e os de pequeno porte os de pior desempenho.
Índice de sharpe e outros indicadores de performance aplicados a fundos de ações brasileiros
Authors: Varga Gyorgy
Published: April 2009

Implementamos e aplicamos diversas medidas estatísticas de avaliação de performance aos dez maiores fundos de ações oferecidos no mercado brasileiro. Mostramos as diferentes classificações dos fundos de acordo com cada um desses indicadores e os defeitos da sua aplicação na avaliação de fundos de investimento. O principal objetivo deste artigo é mostrar as dificuldades da aplicação dos principais indicadores de performance a fundos brasileiros.
Cultura e comprometimento organizacional em empresas hoteleiras
Authors: Naves Évora Mandim Ribeiro , Dela Coleta Marília Ferreira
Published: April 2009

Trata-se de uma pesquisa de campo que analisa a relação dos tipos de cultura organizacional presentes em algumas empresas hoteleiras com a natureza do vínculo estabelecido entre indivíduo e organização. O campo de pesquisa foi um grupo de hotéis convencionais da cidade de Uberlândia. O grupo de variáveis independentes do modelo proposto compreendia variáveis pessoais/profissionais e os tipos de cultura organizacional. A variável dependente era representada pelas três dimensões do comprometimento. Utilizou-se, além da estatística descritiva, análise de correlações e regressão múltipla. Os resultados indicaram a existência de relação dos tipos de cultura com os tipos de comprometimento. A cultura de função é o principal preditor do comprometimento normativo e instrumental e a cultura de tarefa é o principal preditor do comprometimento afetivo.
Impactos da tecnologia na gestão de pessoas: um estudo de caso
Authors: Mascarenhas André Ofenhejm , Vasconcelos Flavio Carvalho de , Vasconcelos Isabella F. G. de
Published: April 2009

Pesquisas sobre gestão de pessoas no Brasil indicam uma fase de transição pela qual a área de RH passa atualmente, de uma atuação predominantemente operacional para modelos mais estratégicos de gestão de pessoas. Neste contexto, a implementação de tecnologias, como a informatização por meio de aplicações de RH auto-atendimento, vem sendo considerada uma maneira de viabilizar novos arranjos organizacionais da gestão de pessoas. Este artigo tem como objetivo discutir os impactos da tecnologia da informação e o seu papel estratégico no contexto de transição da gestão de pessoas. Por meio de um estudo de caso, mostramos que a tecnologia pode ser ferramenta útil na consolidação de novas estratégias de gestão de pessoas na medida em que interaja com outros aspectos organizacionais para a emergência de novo sistema social. Podemos verificar que a informatização viabilizou a emergência do modelo político de gestão de pessoas, que é condição que viabiliza formas orgânicas de organização, nas quais a informação é melhor aproveitada para a aprendizagem organizacional.
The importance of evolutionary history in studies of plant physiological ecology: examples from cerrados and forests of central Brazil
Authors: Hoffmann William A. , Franco Augusto C.
Published: April 2009

Studies that compare physiology, anatomy, and ecology across species have offered some of the best insight into adaptation and evolutionary constraints in plants. As a result, the comparative approach has become increasingly used in studies of plant physiological ecology. The high species diversity of Brazilian biomes provides many excellent opportunities for comparative plant ecophysiology, and could be better exploited for understanding the evolution of plant form and function. In this paper we emphasize the importance of considering phylogenetic information for the design and analysis of comparative studies, relying on examples from comparisons of woody plants from cerrado and gallery (riparian) forests. The use of congeneric species pairs, each containing one cerrado species and one forest species of the same genus, greatly improves statistical power while assuring phylogenetic independence, an essential condition for inference in comparative studies. For example, in a study of seedlings of nine cerrado species and nine forest species, when we ignore phylogenetic relationships, it is not be possible to conclude that cerrado and forest species differ with regard to leaf area ratio (LAR), specific leaf area (SLA), or seedling height. If, however, we use the generic groupings to account for phylogenetic effects, then we find that seedlings of savanna species have lower LAR, SLA, and seedling height. Much of the phylogenetic inertia observed for these traits appears related to the fact that these traits are all strongly correlated with seed mass, which has been previously shown to be strongly conserved phylogenetically. These examples emphasize the importance of phylogenetic information in comparative studies.
Sequelas pós-intubação e traqueostomia cirúrgica aberta: devemos sempre fazer a istmectomia?
Authors: Lima Alexandre Garcia de , Marques Ariovaldo , Toro Ivan Felizardo Contrera
Published: April 2009

OBJETIVO: Avaliar a influência da equipe cirúrgica (cirurgia geral ou cirurgia torácica) e da técnica operatória utilizada (com ou sem istmectomia) sobre a incidência de injúrias pós-intubação nas vias aéreas em pacientes traqueostomizados. MÉTODOS: Foram prospectivamente incluídos neste estudo 164 pacientes admitidos na unidade de terapia intensiva para adultos do Hospital Estadual Sumaré e que ficaram sob intubação traqueal por mais de 24 h, no período entre 1º de janeiro e 31 de agosto de 2007. Quando foi necessária a realização de traqueostomia, os pacientes foram aleatorizados para as equipes de cirurgia geral e torácica. Todos os pacientes foram submetidos à traqueoscopia flexível para a decanulação e/ou a avaliação tardia da via aérea. RESULTADOS: Dos 164 pacientes no estudo, 90 (54,88%) faleceram (sem relação com o procedimento), 67 (40,85%) completaram o seguimento e 7 (4,27%) tiveram seguimento parcial. Dos 67 pacientes com seguimento completo, 32 foram traqueostomizados (21 pela equipe de cirurgia geral e 11 pela equipe de cirurgia torácica). A istmectomia foi realizada em 22 pacientes (11 pela equipe de cirurgia geral e 11 pela equipe de cirurgia torácica). Não houve diferença entre o índice de complicações estomais quando se comparou as equipes, mas sim quando se comparou as técnicas (com e sem istmectomia). CONCLUSÕES: A não realização da istmectomia paralelamente à traqueostomia faz com que o cirurgião realize o óstio traqueal mais distalmente do que supõe. Nestes casos, houve um maior índice de complicações do estoma traqueal.
Carcinoma mucoepidermoide da traqueia mimetizando asma brônquica
Authors: Mussi Ricardo Kalaf , Toro Ivan Felizardo Contrera , Pereira Mônica Corso
Published: April 2009

Em casos de asma de início recente em que o controle clínico com tratamento habitual (corticosteroide e broncodilatador) é insatisfatório, é importante considerar outros diagnósticos, tais como insuficiência cardíaca congestiva, refluxo gastroesofágico ou outras formas de obstrução das vias aéreas. Relatamos o caso de uma paciente do sexo feminino com carcinoma mucoepidermoide da traqueia mimetizando um quadro de asma brônquica. A paciente apresentava tosse e sibilância, bem como espirometria anormal com padrão obstrutivo responsivo a broncodilatador. Após um ano, apresentou deterioração clínica e espirométrica. Nenhuma anormalidade foi encontrada no radiograma de tórax. A TC revelou lesão vegetativa, a 1 cm da carina, reduzindo a luz traqueal. A fibrobroncoscopia mostrou imagem semelhante a tumor carcinoide brônquico. O diagnóstico anatomopatológico após a ressecção cirúrgica foi carcinoma mucoepidermoide de baixo grau, sem envolvimento linfonodal. Embora a curva fluxovolume não fosse sugestiva de obstrução de vias aéreas superiores, a espirometria realizada após a cirurgia mostrou redução significativa do grau de obstrução e maior reversibilidade com broncodilatador. Não houve evidência de recidiva da doença ou retorno dos sintomas após dois anos de seguimento.
Avaliação das alterações de elementos meteorológicos em Recife-PE no período de 1961 a 2000
Authors: Dantas Renilson Targino , Oliveira Francisca Magnólia de , Lira Vanda Maria de , Souza Werônica Meira de
Published: April 2009

Neste trabalho foram utilizados dados de precipitação, temperatura e umidade relativa do ar correspondente a um período de 40 anos, compreendido entre 1961 e 2000 no município de Recife-PE, com o objetivo de avaliar as alterações ocorridas nos referidos elementos meteorológicos ao longo desse período. Inicialmente, o período de 40 anos foi distribuído em séries de 10 anos, e, analisados o comportamento dos parâmetros climáticos. Em seguida, foi utilizado o desvio normalizado e o método dos mínimos quadrados para todo o período, e, constatou-se que houve diminuição da precipitação, principalmente na última década (1991-2000) em 247,0 mm, fato que está associado a dois episódios intensos de El Niño ocorrido em 1993 e 1997/1998. Com relação à temperatura do ar, verificou-se um aumento global, em torno de 0,2ºC nos últimos 40 anos e uma diminuição média mensal da umidade relativa do ar, principalmente na última década.
Redefinição da centralidade urbana em cidades médias
Authors: Oliveira Júnior Gilberto Alves de
Published: April 2009

O texto ora apresentado realiza um esforço reflexivo cujo objetivo principal é analisar os processos de descentralização e recentralização em cidades médias que, conjugados, resultam em novas centralidades e na redefinição da centralidade nessas cidades. As novas centralidades expressam a saturação dos centros tradicionais para as necessidades impelidas pelas novas formas contemporâneas de reprodução e acumulação do capital, além da imposição de (novos) tempos hegemônicos. Assim, são criados e inseridos novos artefatos que favorecem e aperfeiçoam a reprodução capitalista do espaço: o espaço como produto social constrangido pela acumulação do capital. Dessa forma, depreende-se que as alterações na dinâmica econômica determinam que a cidade possua novas centralidades porque as tradicionais não são mais funcionais à reprodução e acumulação do capital, bem como ao acolhimento de novos capitais que se descentralizam para os espaços que economicamente apresentam-se como mais propícios e rentáveis.
Poder local: conceito e exemplos de estudos no Brasil
Authors: Silva Márcia da
Published: April 2009

O estudo das diversas formas de poder (e suas teorias), dentre elas a do Estado são relacionadas, neste texto, às abordagens e às singularidades expressas no poder local. Este é compreendido não como um recorte territorial localizado e localizável, mas como um espaço com história e memória próprias, com identidades e práticas políticas determinadas, ou seja, socialmente construído. O que se pode considerar, tendo em vista a investigação realizada é que, como nas demais instâncias sócio-territoriais, também no poder local (e talvez até muito mais nele), é ímpar uma pluralidade de poderes que se digladiam ou se associam (depende do objetivo e do momento) como os do Estado, das elites, dos micro-poderes, do poder simbólico, do poder de influência etc. Nesse sentido, revela-se a atuação dos mesmos em decisões reais, impostas ou ofertadas por alguns atores e atendidas ou não por outros e, então, as alianças e os conflitos.
Sandstone Cores as Reaction Vessels: Synthesis of Calcium Carbonate Particles for Artificial Formation Damage in the Qualification of Matrix Acidizing Solutions
Authors: Fuller Michael J.
Published: April 2009

Generally, matrix acidizing fluids for sandstone are executed in the field only after core tests qualify their ability to remove damage. However, most cores that are used come from sandstone quarries and the cores are largely clean and undamaged (and not representative of the sandstone conditions in actual producing wells). This study proposes novel applications of straightforward chemistry to synthesize calcium carbonate particles that damage the porosity of clean sandstone cores (in core flow tests); the study includes reactions carried out under controlled conditions as well as within the pore space of sandstone cores. In the controlled reactions, solutions of calcium chloride are mixed with solutions containing one of a variety of soluble inorganic or organic carbonates, and the reaction generates calcium carbonate particles. The resulting particles were characterized using both light scattering and scanning electron microscopy (SEM). The reaction rate and size distribution of calcium carbonate particles varies depending on the temperature, stir rate, chemistry of the carbonate species, and the concentrations (and concentration ratio) of calcium brine and carbonate species. This technique is also applied in actual core tests, where a sandstone core saturated in calcium brine is exposed to a solution of the soluble carbonate species and generates calcium carbonate solid (damage) throughout the length of the core from the injection face. The final permeabilities of cores subjected to this treatment exhibit damage compared to before the treatment, which is likely due to the precipitation of calcium carbonate solids. This method for damage generation has ramifications in the screening of a variety of stimulation fluids, including acids and scale inhibitors.
Impact of Successive Squeezes on Treatment Lifetime and Well Productivity: Comparative Assessment of Viscosified and Non-Viscosified Treatments
Authors: Fleming Niall , Ramstad Kari , Kidd Sam , Hoeth Laurien Wichers
Published: April 2009

Over the lifetime of a well it is possible that several squeeze operations will be performed depending on scaling severity. Downhole squeeze operations have been performed for many years and have on the whole been an effective scale management tool. However, the long term impact that successive squeezing has on treatment lifetime and well productivity has received little attention. SPE 113656 detailed the results of a unique sequence of long term corefloods that were designed to replicate five successive treatments on the kaolinite rich, Middle Tarbert core from Oseberg S⊘r. Relatively few squeeze treatments have been performed on this field, and the coreflood results were up-scaled to provide a potential prediction of the effects of long term squeezing and well productivity on Oseberg S⊘r. Furthermore, the laboratory results were cross-checked by comparing with the Heidrun field that has been squeezed for many years. Heidrun is an analog of Oseberg S⊘r with kaolinite rich producing intervals and similar productivity issues related to kaolinite mobilization.

In recent years viscosified squeeze treatments have become popular for improved inhibitor placement within horizontal wells and have been used on Heidrun and Norne. However, the long term impact that such squeezing has on treatment lifetime and well productivity has not until now been examined. The paper will give details of an identical sequence of long term corefloods as described above but in which the inhibitor was viscosified. All testing parameters have been kept identical between viscosified and non-viscosified treatments including the core material and scale inhibitor. The impact on squeeze lifetimes will be demonstrated along with potential formation damage mechanisms.
Sorel Cement for HPHT Downhole Applications
Authors: Santra Ashok Kumar , Liang Feng , Fitzgerald Rocky
Published: April 2009

Magnesium-based Sorel cement was discovered in 1867 and since then it has been used extensively for industrial flooring, fire protection, grinding wheels, and wall insulation because of its superior mechanical and thermal properties. In general, Sorel cement is extremely fast-setting and reaches very high compressive-strength (close to 10,000 psi) within a few hours. However, in terms of downhole applications, especially higher temperature, made it almost impossible to achieve acceptable placement time. In the last decade or so, advances in a retarder system made them pumpable only up to a bottomhole circulating temperature (BHCT) of 200°F with a relatively short pump time (approximately 2 hrs). Advantages of Sorel cement when applied downhole can include shortened waiting on cement (WOC) time, complete acid solubility, lean rheology to access narrow annulus, and lower thermal conductivity to name a few. The main impetus of this paper is the new retarder system that has been developed to achieve pump time for several hours at BHCT of close to 400°F. This new technology will also potentially make Sorel cement based systems useful for HPHT, SAGD and geothermal wells because these are already proven to be stable at extremely hot conditions.
The Modelling, Application and Monitoring of Scale Squeeze Treatments in Heterogeneous Reservoirs, North Sea
Authors: Jordan M. M.
Published: April 2009

Scale control within produced fluids as water follows the cycle of injection, production, processing and reinjection in oil/gas production facilities is critical to the effective production of hydrocarbons in a safe, economic and environmentally acceptable manner.

This paper will focus on the scale challenges associated with seawater injection into two North Sea reservoirs with a moderate Barium Sulphate scale challenge (80 to 220 ppm Barium, seawater injection) and will describe the impact of scale ion reduction from injection to production wells and the lower minimum inhibitor concentration that results

The paper will outline the selection of the inhibitor chemical for squeeze application, initially via bullhead application of the squeeze treatment without diversion then development of a diversion methodology in conjunction with production logging tool data. The paper outlines the application of the diversion treatment applied via bull heading and the improvement in treatment life as well as treatment economics that resulted in the heterogeneous formation.

The paper will clearly demonstrate using the four squeeze treatments to a single well how squeeze treatments can be enhanced without the need for coil tubing to allow selective placement. The design methods for this diversion technology will presented along with the methods of monitoring such treatment to ensure effective placement was achieved with the use of inert tracer, produced water analysis, evaluation of type/amount of suspended solids and inhibitor residuals.
Development of High-Performance Water-Based Mud Formulation Based on Amine Derivatives
Authors: Gholizadeh-Doonechaly Nima , Tahmasbi Kourosh , Davani Ehsan
Published: April 2009

Many benefits by use of Oil-Based Mud (OBM) in drilling oil and gas wells have been identified in the oil industries worldwide. However the current ever increasing environmental legislations in preventing OBM application in the industries have dictated the use of water-based drilling fluid as the most environmentally acceptable alternative. On the other hand, drilling with water-based systems in shaly formations may cause many problems such as wellbore instability and high torque and drag. Therefore the most optimum alternatives would be different kinds of inhibited water-based systems in which adverse effects of shaly formations can also be controlled. These water-based alternatives are called High-Performance Water-Based Mud (HPWBM). Also the OBM properties is the final goal of the researchers to reach in their investigations to design a suitable HPWBM since OBM is the ideal drilling fluid to drill problematic formations.

In this investigation attempts have been made to develop and formulate a water-based drilling fluid in which a suitable amine derivative has been successfully added to the system as a strong shale inhibitor agent instead of other conventional alternatives. Besides shale inhibition, an important challenge when using amine compounds in HPWBM is to overcome the thermal instability. Such a system must be formulated to achieve the right concentration of each mud additive to satisfy the necessity of a system that provides proper thermal stability during the drilling operation in high temperature sections. The newly HPWBM that was developed in this study comprises a specific concentration of a unique poly-ethoxylated alkyl diamine compound for shale inhibition, an amphoteric/polymeric shale encapsulator, a high-performance lubricant/deflocculating agent and special fluid loss additive to reach thermal stability up to 200°F. The designed system has exhibited optimum rheological properties and shale recovery in laboratory testing that was very close to that of OBM. The designed system has optimally improved the performance of previously formulated HPWBMs.
New Polymer Technology for Sand Control Treatments of Gas Storage Wells
Authors: Zaitoun Alain , Pichery Thierry
Published: April 2009

A new polymer technology has been successfully implemented in two Gaz-de-France Underground Gas Storage (UGS) facilities. The technique uses water-soluble polymers and microgels having a strong tendency to adsorb on the surface of the rock, thus forming a protective film to prevent the erosion process. All products have RPM properties (Relative Permeability Modifiers), i.e. they affect little gas relative permeability while reducing strongly the relative permeability to water. They can thus be injected into the whole open interval (bullhead injection) without specific tools for placement. A long post-flush of gas is injected after the polymer treatment to re-saturate the formation around the wellbore and check gas injectivity. Seven wells have been treated so far with the following results: All treatments were successful in stopping sand productionThe first treatment lasted about four years, after which it had to be renewed. All other treatments show long-term efficiency.Only one well suffered from a loss in Gas Productivity Index (around 20%), for all the others, gas injectivity and productivity remained unaffected by the treatment.The well treated with microgel has been producing much less water than before, in addition to the stopping of sand production
An Experimental Study of the Pore-Blocking Mechanisms of Aphron Drilling Fluids Using Micromodels
Authors: Bjorndalen N. , Alvarez J. M. , Jossy W. E. , Kuru E.
Published: April 2009

Drilling fluid containing colloidal gas aphron (CGA) microbubbles can bridge the pores of the reservoir rock in the near wellbore region and reduce the risks of lost circulation and formation damage. The advantage of using CGA systems is that the CGA's can be easily removed during the initial stages of production thereby reducing the costs associated with stimulation processes such as acidizing.

Although there has been some work done on the flow of the microbubbles through porous media, little is known about the optimal conditions for blocking the pores. Specifically, the effect of the interaction between microbubbles and reservoir fluid on the microbubble stability and pore blocking ability has not been determined.

This study is focused on determining the pressure at which the microbubbles invade the porous medium and the CGA/reservoir fluid interaction for pore blocking. The pore blocking ability of various CGA compositions and flow rates is also discussed.

In order to determine the effect of reservoir fluid interaction, experiments were carried out by injecting the microbubbles into a micromodel cell saturated with various fluids. The effect of water, brine, mineral oil and crude oil on the microbubble stability and pore blocking ability are investigated.
Chemistry and Mechanisms of Completion/Packer Fluids: Annular Environmentally Assisted Cracking (AEAC) of Martensitic Stainless Steel Tubing: Misconceptions Regarding the Chemical Role of Completion/Packer Fluids
Authors: McKennis Jeffrey S. , Bae Nam , Termine Enrico J. , Shimamoto Ken , Kimura Mitsuo
Published: April 2009

The increased use of corrosion resistant alloys (CRAs) in deep HPHT wells has led to production-tubing cracking failures throughout the industry. Many of these failures have occurred from the outside (annulus side) and been attributed to Environmentally Assisted Cracking (EAC) and hence, best described as Annular EAC (AEAC). Examination of these failures points to a serious incompatibility of the production tubing metallurgy with the packer fluid under stress.

In 2003, combining expertise in fluid chemistry and metallurgy, the authors formed a research alliance to address the AEAC problem by examining the compatibility of a wide spectrum of completion fluids with various martensitic stainless steel (MSS) metallurgies. This unique research collaboration involving extensive stress cracking testing performed with different metallurgies and different fluids under simulated well conditions has resulted in an extensive database (> 4000 test entries for 27 fluids and 6 MSS metallurgies) and new body of knowledge regarding the causes behind AEAC failures.

Conventional wisdom holds that chloride ion and oxygen play major causative roles. The authors' findings, however, identify other contaminants in completion/packer fluids that play the dominant role in the chemical mechanism of the crack failures. Such contaminants include sulfur-containing species, oxidants other than oxygen, and select basic ionic species. This paper addresses the impact of the new information and identifies serious misconceptions regarding the role of completion & packer fluids in the tubular failures.

The authors' comprehensive study has advanced the industry's knowledge of the causes of AEAC by detailing the previously unrecognized importance of various contaminants present in the fluids. As a consequence, the need for quality assurance and best-practice fluid management throughout the life cycle of the fluids is now recognized. Misconceptions with respect to the chemical mechanisms and causative factors of AEAC failures are discussed. Such information should expand the industry's AEAC knowledge base and minimize the risk of tubular failure.
Stability of Partially Hydrolyzed Polyacrylamides at Elevated Temperatures in the Absence of Divalent Cations
Authors: Seright R. S. , Campbell A. R. , Mozley P. S.
Published: April 2009

At elevated temperatures in aqueous solution, partially hydrolyzed polyacrylamides (HPAM) experience hydrolysis of amide side groups. However, in the absence of dissolved oxygen and divalent cations, the polymer backbone can remain stable so that HPAM solutions were projected to maintain at least half their original viscosity for over 7 years at 100°C and about 2 years at 120°C. Within our experimental error, HPAM stability was the same with/without oil (decane). An acrylamide-AMPS copolymer (with 25% AMPS) showed similar stability to that for HPAM. Stability results were similar in brines with 0.3% NaCl, 3% NaCl, or 0.2% NaCl + 0.1% NaHCO3. At temperatures of 160°C and above, the polymers were more stable in brine with 2% NaCl + 1% NaHCO3 than in the other brines. Even though no chemical oxygen scavengers or antioxidants were used in our study, we observed the highest level of thermal stability reported to date for these polymers. Our results provide considerable hope for the use of HPAM polymers in enhanced oil recovery at temperatures up to 120°C if contact with dissolved oxygen and divalent cations can be minimized.

Calculations performed considering oxygen reaction with oil and pyrite revealed that dissolved oxygen will be removed quickly from injected waters and will not propagate very far into porous reservoir rock. These findings have two positive implications with respect to polymer floods in high-temperature reservoirs. First, dissolved oxygen that entered the reservoir prior to polymer injection will have been consumed and will not aggravate polymer degradation. Second, if an oxygen leak (in the surface facilities or piping) develops during the course of polymer injection, that oxygen will not compromise the stability of the polymer that was injected before the leak developed or the polymer that is injected after the leak is fixed. Of course, the polymer that is injected while the leak is active will be susceptible to oxidative degradation. Maintaining dissolved oxygen at undetectable levels is necessary to maximize polymer stability. This can readily be accomplished without the use of chemical oxygen scavengers or antioxidants.
The Corrosiveness of Nitrite in a Produced Water System
Authors: Jenneman Gary , Achour Mohsen , Joosten Mike
Published: April 2009

Increasing concentrations of sodium nitrite were added to synthetic North Sea produced water in the presence of either 1 bar CO2 or N2 to determine its effect on corrosion. These tests were run at 80°C in the presence of sulfide and at a sheer stress up to 25 Pa. The test materials were either A106 carbon steel or duplex stainless steel, representing the range of materials typical of upstream production equipment.

Nitrite is an effective inhibitor of sulfate reducing bacteria activity as well as an enhancing agent for biocides. Because it is a green chemical it is desirable for controlling Microbiologically Influenced Corrosion (MIC) in oilfield brines. Although known to be an effective anodic corrosion inhibitor in fresh water systems its inhibitory effects in oilfield brines are less understood.

Duplex stainless steel did not show any enhanced corrosion in an inert or CO2 environment in presence of nitrite. In the case of carbon steel, nitrite displayed an inhibiting role when exposed to 1 bar CO2 at 80°C. Increases of chlorides or sulfates had only a small effect on increasing corrosion rates in the presence of nitrite and CO2. However, in the presence of an inert gas, increases in nitrite above 2 mM significantly increased corrosion rates of carbon steel. The addition of small amounts of sulfide in the presence of 2 mM nitrite resulted in a small increase in corrosion rates of carbon steel as did the impact of 25 Pa of sheer stress. The presence of 2 mM nitrite interfered with the corrosion inhibiting activity of a commercial inhibitor in the presence of CO2.

This paper presents results of testing performed to determine the corrosiveness of nitrite in synthetic North Sea produced water.
A Study of Proppant Formation Reactions
Authors: Weaver Jim , Rickman Richard , Luo Hongyu , Logrhy Ray
Published: April 2009

Based on long-term API conductivity data, proppants are generally chosen to optimize fracturing cost versus fracture conductivity. This long-term data is acquired by measuring conductivity for two days at simulated conditions of closure stress and reservoir temperature. It is recognized that the majority of the conductivity damage to a proppant pack occurs rapidly during the first day at simulated conditions. It is clear on examination of raw data that conductivity has not reached equilibrium after two days of flow, but rather it is still declining. Investigators who have studied the effect of longer flow-time on fracture conductivity of proppants have all concluded that the decline in conductivity continues for a much longer time.

Much attention has been given to the mechanical properties of proppants to aid in the selection of the best material for a particular fracture treatment. These properties include: size, proppant-size distribution, sphericity, hardness, crush resistance, and acid solubility. Other than acid solubility, little information about the chemical reactivity of the proppants has been noted. Recent work has demonstrated that, at some reservoir conditions, certain proppants become significantly chemically reactive.

This paper presents the proppant as starting material for geochemical reactions with various aqueous fluids saturated in typical formation minerals. Methods have been developed for rapid testing of these interactions, and test results clearly demonstrate how important proppant chemical reactivity is as losses in proppant-pack permeability of 50–90% were obtained, owing to the genesis of cementatious and porosity-filling minerals. In addition, some proppant chemistries were found to be much more susceptible to these types of reactions, losing much of their mechanical strength in a surprisingly short period of time. Results from this study indicate that operators who rely solely on API test methods in evaluating the suitability of proppants for particular downhole conditions might miss significant damage potential from geochemical reactions occurring between the proppant and formation fluids.
Effects of Hydrogen Sulfide on Gel Typed Plugging Agents
Authors: You Qing , Wang Yefei , Zhou Wei , Zhao Fulin , Zhang Jian , Yang Guang
Published: April 2009

In view of the gels applied as plugging agents in drilling plugging and water plugging in oil and gas reservoir containing hydrogen sulfide (H2S), the effects of H2S on widely used gel blocking agents were studied in this article. The gel blocking agents include Na2Cr2O7/Na2SO3/HPAM gel, Na2Cr2O7/(NH2)2CS/HPAM gel, Cr(III)-acetate & Cr(III)-lactate/HPAM gel and phenol formaldehyde resin/HPAM gel. The results show that the effects of H2S on Na2Cr2O7/Na2SO3/HPAM gel and Na2Cr2O7/(NH2)2CS/HPAM gel are significant, while the effects on Cr(III)-acetate & Cr(III)-lactate/HPAM gel and phenol formaldehyde resin/HPAM gel are relatively slight. The mechanisms of H2S affecting the gels were also researched. For Na2Cr2O7/Na2SO3/HPAM gel and Na2Cr2O7/(NH2)2CS/HPAM gel, the H2S as reductant(the reducibility is more than that of Na2SO3 and (NH2)2CS) can reduce Cr(?) into Cr(III) and accelerate crosslinking reaction with HPAM in low concentration of H2S, while it can react with Cr(III) generating Cr2S3 precipitation in high concentration of H2S, for which the bulk gel can not form without Cr(III). For Cr(III)-acetate & Cr(III)-lactate/HPAM gel and phenol formaldehyde resin/HPAM gel, the changes are mainly affected by pH value. Therefore, according to the comprehensive survey of the effects of H2S on gel typed plugging agents, the phenol formaldehyde resin/HPAM gel is recommended as the plugging agents suitable for oil and gas reservoir containing H2S.