bluuebunny/crossref_metadata_2025 huggingface dataset:
Recuperando a ênfase na dimensão pública dos estudos organizacionais
Authors: Thoenig Jean-Claude
Published: December 2007

A dimensão pública ainda é tema merecedor de pesquisa? A sociologia organizacional clássica (ou teoria-padrão) abriu o caminho para a compreensão da administração e da gerência públicas, mas não explorou todas as possibilidades colocadas. A dimensão pública caracteriza-se, do ponto de vista analítico, por duas funções de produção: eficiência (produtos) e efetividade (resultados societais). Muito embora possa haver semelhanças entre instituições públicas e não-públicas no tocante a alguns aspectos de seus modelos organizacionais, a função de efetividade à qual cada uma delas responde é bastante específica. Tal concepção sugere que os pesquisadores de administração e organização públicas explorem novas perspectivas, tais como organizantes e as organizadas (ou, noutros termos, coloquem uma agenda teórica ampliada).
Trajetória recente da gestão pública brasileira: um balanço crítico e a renovação da agenda de reformas
Authors: Abrucio Fernando Luiz
Published: December 2007

Este artigo reconstitui, em linhas gerais, a trajetória da administração pública brasileira nos últimos 20 anos, analisando tanto os principais avanços e novidades, quanto os erros de condução das reformas e os problemas de gestão que ainda persistem. Após fazer um balanço que percorre a Nova República, a era Collor, o projeto Bresser e o governo Lula, o texto apresenta uma proposta de quatro eixos estratégicos para a modernização do Estado diante dos desafios do século XXI.
Desafio estratégico da política pública: o ensino superior brasileiro
Authors: Nunes Edson
Published: December 2007

Poucas pessoas no Brasil são, em comparação com países desenvolvidos, portadoras de diploma de ensino superior. Admitindo-se que a qualificação da população do país, a este nível, constitua interesse estratégico nacional, este artigo examina as características do caso brasileiro e discute as opções pregressas que o país fez, bem como observa as opções futuras, que estariam abertas ao país. O Brasil deliberou, ainda que não tenha manifestado claramente tal deliberação, por expandir seu ensino terciário por meio do setor privado. Desde o final do século XX esta expansão vem adquirindo uma faceta mercantil. Ao Estado brasileiro, contudo, apetece a estratégia da "não-decisão". Escolhe o setor privado para expandir a oferta de educação superior. E escolhe a via comercial, a partir de 1997, para fazê-lo. Mas não revela tal escolha. Deixa-a ao sabor, senão olhar, do analista das políticas públicas. Resta analisar as conseqüências desta "não-decisão" brasileira. Este artigo oferece números, argumentos e sugestões sobre o tema.
O ensino dos métodos de investigação científica numa universidade particular
Authors: Avelar Maria do Carmo Querido , Silva Arlete , Teixeira Marina Borges , Sabatés Ana Llonch
Published: December 2007

Este estudo descritivo e exploratório teve como objetivo analisar as facilidades e dificuldades referidas por quinze alunos de cursos de especialização em enfermagem, em relação ao processo de ensino da disciplina Métodos de Investigação Cientifica, focalizado no referencial do paradigma do agir comunicativo. As categorias expressas, como facilidades e dificuldades, em relação ao conteúdo da disciplina, elaboração do projeto de pesquisa e seu desenvolvimento, foram analisadas segundo os tipos padronizados de ação comunicativa. Após a análise, pode-se perceber a emersão de elementos em diferentes níveis de desenvolvimento e interpretados numa seqüência de formas de comunicação, destacando-se por não permitir vislumbrar um compromisso com a inovação ou mudança do processo de ensino, demonstrando as perturbações do consenso neste processo.
Variabilidade circadiana da temperatura oral, timpânica e axilar em adultos hospitalizados
Authors: Simões Ana Leda Bertoncini , Martino Milva Maria Figueiredo De
Published: December 2007

Este estudo teve como objetivo verificar a variabilidade circadiana da temperatura timpânica, oral e axilar, considerando o ângulo de medida. Realizou-se em um hospital de ensino HC-Unicamp, na cidade de Campinas-SP. Os dados foram coletados a cada duas horas, por dois dias consecutivos, a partir do horário de vigília até as 22 horas, nas enfermarias de Cardiologia, Geral de Adultos e Gastroclínica. Os resultados mostraram que as medidas dos períodos matutino e vespertino, comparadas com as do período noturno, pela análise de variância, houve diferença significativa com p-value = 0,0001. O teste de Tukey confirmou a diferença no que se refere ao nível de significância µ =0,05. Identificou-se que as medidas do termômetro timpânico mostraram temperaturas mais elevadas em relação aos outros termômetros, confirmando os dados das literaturas internacionais e também demonstrando que a curva de ritmicidade circadiana foi similar à obtida pelas medidas do termômetro oral durante o período de vigília.
Co-infection by porcine circovirus type 2 and porcine parvovirus in aborted fetuses and stillborn piglets in southern Brazil
Authors: Pescador Caroline A. , Bandarra Paulo M. , Castro Luiza A. , Antoniassi Nadia A.B. , Ravazzolo Ana Paula , Sonne Luciana , Cruz Cláudio E.F. , Driemeier David
Published: December 2007

Porcine circovirus types 1 and 2 (PCV1, PCV2) and porcine parvovirus (PPV) are widespread in pig populations around the world. Nevertheless, only PCV2 has been associated with different clinical syndromes, thus representing a major problem to the pig industry. The association of cases of swine abortions and stillborns with PCV1 and PCV2 and PPV was studied retrospectively (2005-2007). Additional pathogens were also investigated in lesioned fetuses. The studied litters included stillborn piglets and several mummified fetuses of varied sizes. Ventricular dilatation, myocardial pale areas, and mesocolic edema were the gross lesions. Escherichia coli was detected as co-infecting with PCV2 the cases in which mesocolic edema was seen. Microscopic lesions included non-suppurative myocarditis, myocardial necrosis and fibrosis, mineralization foci and intranuclear inclusion bodies in cardiomyocytes, and interstitial mononuclear pneumonia. Samples from 7 (5.78 per cent) of 121 aborted fetuses and stillborn piglets had lesions consistent with a viral cause and showed both positive anti-PCV2 immunostaining as well as PCV2-PCR. In samples from 3 (2.47 per cent) of these 7 fetuses, co-infection with PPV was confirmed by Nested-PCR. Both viruses were detected in fetuses at different stages of gestation. Viral antigens of PCV2 were detected by immunohistochemistry mainly in macrophages and myocytes. PCV1 individually was not detected in any of these affected fetuses, but it was associated with PCV2 and/or PPV in some of them. These findings indicate that PCV2 alone or in association with PPV should be kept in mind when investigating causes of infectious abortion in pigs in Brazil.
Estudo retrospectivo do resultado anatomopatológico de 100 polipectomias colonoscópicas realizadas na FMB-UNESP
Authors: Hossne Rogério Saad , Maranhão Mara Fernandes , Carvalho Flávio Augusto de , Mendes Fabiana Guandalini
Published: December 2007

OBJETIVO: Analisar retrospectivamente o resultado do estudo anatomopatológico de polipectomias colonoscópicas realizadas no Setor de Endoscopia da Faculdade de Medicina de Botucatu - UNESP durante os anos de 2002 e 2003. Material e Métodos: Estudamos retrospectivamente, a partir de procedimentos colonoscópicos realizados em nosso serviço, as características dos pólipos retirados: tamanho, localização e distribuição, bem como o motivo da indicação do mesmo e o resultado do estudo anatomopatológico. RESULTADOS: Num total de 100 polipectomias colonoscópicas realizadas em 75 pacientes, observamos que 63% dos pólipos localizava-se em reto e sigmóide e 15,8% no cólon descendente; o estudo anátomopatologico evidenciou que a grande maioria tinha características adenomatosas (54%). A idade dos pacientes variou entre 6 e 92 anos, não havendo predominância quanto ao sexo; a principal indicação para a realização de colonoscopia foi sangramento. CONCLUSÃO: Constatamos o importante papel diagnóstico e terapêutico das colonoscopias no que diz respeito ao câncer colorretal; os achados demonstram que, em nossa casuística, a maioria os pólipos colônicos são adenomatosos, pequenos e de localização distal.
Melanoma anorretal: relato de 2 casos e revisão da literatura
Authors: Hossne Rogério Saad , Prado Renê Gamberini , Bakonyi Neto Alexandre , Denardi Junior Euclides , Ferrari André
Published: December 2007

Os tumores malignos do canal anal e do anus são muito raros, não ultrapassam 2% de todos os tumores do colo, reto e anus; segundo os principais levantamentos os melanomas não ultrapassam a incidência de 0,1 a 1,2% dos tumores malignos. Os autores descrevem 2 casos de melanoma, discutindo os principais dados da literatura, enfocando os aspectos diagnósticos, tratamento, evolução e prognostico. Os indicies de cura s são baixos e com elevados índices de mortalidade a curto prazo.
Carcinoma basocelular perianal: relato de caso e revisão da literatura
Authors: Damin Daniel C. , Burttet Renata M. , Rosito Mario A. , Tarta Cláudio , Contu Paulo C. , Santos Frederico S. , Kliemann Lúcia , Prolla João Carlos
Published: December 2007

O Carcinoma basocelular (CBC) é a mais freqüente das neoplasias epiteliais, localizando-se preferencialmente em áreas expostas ao sol. A ocorrência deste tumor na região perianal é extremamente rara. Neste artigo, relatamos um caso de CBC perianal. Apresentamos também uma revisão da literatura médica sobre o tema, salientando as características clínicas e histopatológicas, bem como o tratamento preconizado para esse tipo de tumor.
Catodo para célula a combustível de óxido sólido: síntese e caracterização de manganito de lantânio dopado com estrôncio
Authors: Chiba R. , Vargas R.A. , Andreoli M. , Seo E.S.M.
Published: December 2007

As células a combustível (CaC) destacam-se como geradoras de energia distribuída, nas quais são dispositivos eletroquímicos de baixo impacto ambiental, que são basicamente alimentadas pelo combustível hidrogênio e pelo oxidante oxigênio, tendo como principais produtos, a eletricidade e a água. Estes dispositivos vêm sendo considerados como uma opção real para a geração de energia elétrica distribuída de maioria dos países, devido à possibilidade de construção modular, baixo nível de ruídos, produção simultânea de energia elétrica e térmica, baixa restrição quanto à localização e elevada eficiência de conversão, dependendo do tipo de CaC. As aplicações da CaC em demonstrações significativas têm atestado a viabilidade em unidades estacionárias, móveis e portáteis. Neste contexto, o manganito de lantânio dopado com estrôncio (La1-xSr xMnO3), é um material cerâmico de grande importância, devido principalmente ao seu uso como catodo em células a combustível de óxido sólido (Solid Oxide Fuel Cells - SOFCs). Nos últimos anos, o grande interesse dos pesquisadores em relação a este material se deve principalmente às suas características tais como: boa estabilidade química e térmica, alta atividade catalítica na redução do oxigênio, coeficiente de expansão térmica razoavelmente similar ao eletrólito sólido (zircônia estabilizada com ítria) e alta condutividade elétrica. No presente trabalho apresenta-se uma contribuição ao estudo das composições químicas e estruturais de La1-xSr xMnO3 com concentrações de estrôncio (15 e 50 % em mol) pela técnica dos citratos. As resinas foram caracterizadas por análise termogravimétrica (ATG) e análise térmica diferencial (ATD); e os pós sintetizados foram caracterizados por absorção gasosa (LECO), espectrometria de fluorescência de raios X (FRX), granulometria por espalhamento de feixe de laser (CILAS), adsorção gasosa (BET), picnometria por gás hélio, difratometria de raios X (DRX) e microscopia eletrônica de varredura (MEV). As características dos pós de La1-X SrX MnO3 foram avaliadas visando a utilização na preparação de suspensões catódicas de filmes finos das SOFCs.
Análise por difração de raio-x de uma hidroxiapatita carbonatada usando o método de Rietveld
Authors: Moreira E.L. , Araujo J.C. , Moraes V.C.A. , Moreira A.P.D.
Published: December 2007

A estrutura cristalina da hidroxiapatita (HAP) é conhecida por permitir substituições aniônicas e catiônicas. Dentre essas substituições, a inserção do íon CO32- se destaca por sua importância. Nesse trabalho uma amostra sintética de hidroxiapatita carbonatada nanoestruturada (CHA) foi submetida a um tratamento térmico a 500 ºC por seis horas. Posteriormente, aspectos estruturais, microestruturais e tamanho de cristalitos da amostra foram analisados por difração de Raio-X, com o Método de Rietveld (programa FULLPROF). O refinamento dos parâmetros estruturais, em particular os fatores ocupacionais atômicos, indicou uma distribuição de íons CO32- entre os sítios do PO43- e da OH‑, ocorrendo uma maior inserção no sítio do fosfato. Os parâmetros da célula unitária quando comparados a uma HAP de referência padrão (ICSD 26 -204), mostraram uma contração nos eixos a e b e expansão no eixo c. Os tamanhos de cristalitos estimados nas direções dos eixos cristalográficos sugerem que a amostra tem morfologia equiaxial. O valor obtido para o teor em peso do íon carbonato na amostra pelo refinamento dos fatores ocupacionais foi de 10,7%, estando em boa concordância com o valor de 12,8% obtido pela técnica de dessorção termo programado (DTP).
Resultados preliminares de um estudo qualitativo sobre a interação entre mãe e criança desnutrida grave, no contexto da hospitalização
Authors: Sampaio Marisa Amorim , Falbo Ana Rodrigues , Camarotti Maria do Carmo , Vasconcelos Maria Gorete Lucena de
Published: December 2007

OBJETIVOS: analisar elementos da psicodinâmica interativa entre mães e crianças desnutridas graves hospitalizadas. MÉTODOS: método qualitativo baseado no referencial psicanalítico, com entrevistas semi-estruturadas, observações e filmagens. Empregou-se a análise de conteúdo, elegendo-se temas representativos. RESULTADOS: foram acompanhadas oito díades de crianças entre seis e 18 meses de idade e a mãe biológica, internadas no Instituto Materno Infantil Prof. Fernando Figueira-IMIP, em Recife, Pernambuco. Identificaram-se três temas, os quais ilustram o processo de parentalidade, sua importância na psicodinâmica interativa da díade, fatores que podem ter interferido na construção/ruptura do vínculo, sua contribuição para a situação de desnutrição e expressão na hospitalização. CONCLUSÕES: a partir da análise preliminar, reforça-se a influência mútua de mãe e filho na construção da interação e a complexidade dos distúrbios funcionais, sugerindo que estados extremos de desnutrição podem estar associados a faltas e/ou falhas nutricionais, bem como a vivências de privação ou excesso psicoafetivo. A observação da interação mãe-criança em momentos críticos, como desnutrição e hospitalização, pode auxiliar a família e a equipe de saúde na compreensão do processo de adoecimento e da necessidade do atendimento integral.
A changing climate for claims?
Authors: Hamer A. , Peters C.
Published: December 2007

As the effects of climate change are already beginning to be felt, the impact it will have on structures could expose the civil engineer to claims of liability for failure to consider the changing climate in the design process. A project on the drawing board now might not suit the climate of the future. The civil engineering fraternity must be aware of the legal consequences of designing for the future and ensure their insurance can cover any claims that subsequently arise.
Dispute avoidance—looking after the pennies
Authors: Bewsey G.
Published: December 2007

Good quality project records, prepared for the purpose of managing a project well, are the records most likely to bring clarity to difficult situations which might otherwise descend to dispute. The author describes the use of an integrated record system for monitoring a subcontractor's progress and productivity which helped to keep costs under control during the works period and provided the key information which led to rapid resolution of an otherwise difficult claim.
Using Neural Networks for Candidate Selection and Well Performance Prediction in Water-Shutoff Treatments Using Polymer Gels—A Field-Case Study
Authors: Saeedi A. , Camarda K. V. , Liang J. T.
Published: December 2007

Using actual field cases, a neural network model was developed to identify candidate wells and predict well performance for water shutoff treatments using polymer gels. A feed forward back propagation algorithm was used to develop the neural networks. The before and after treatment data for 22 wells treated with polymer gels in the Arbuckle formation in central Kansas were used to train and verify the neural networks.

Polymers and gels have been used extensively in field applications to suppress excess water production and improve oil productivity. Field experience has demonstrated that candidate-well selection is critical to the success of gel-polymer treatments. To date, most candidate-well selections are on the basis of anecdotal screening guidelines, which often results in inconsistent treatment outcomes. With only pretreatment well data as input parameters, the neural networks developed in this work can accurately predict the post-treatment cumulative oil production of the well one month after treatment with an average error of 16%, and the post-treatment cumulative oil production three months after treatment with an average error of 10%. This is a dramatic improvement over the current method of using anecdotal screening guidelines for candidate-well selections.

This method represents a major breakthrough where the candidate selection can now be on the basis of the accurate predictions of treatment outcomes without having to use complicated reservoir models to simulate the well performance after treatment.
Capillary Equilibrium in Porous Materials
Authors: Morrow Norman R. , Harris Colin C.
Published: December 2007

The experimental points which describe capillary pressure curves are determined at apparent equilibria which are observed after hydrodynamic flow has ceased. For most systems, the time required to obtain equalization of pressure throughout the discontinuous part of a phase is prohibitive. To permit experimental points to be described as equilibria, a model of capillary behavior is proposed where mass transfer is restricted to bulk fluid flow. Model capillary pressure curves follow if the path described by such points is independent of the rate at which the saturation was changed to attain a capillary pressure point. A modified suction potential technique is used to study cyclic relationships between capillary pressure and moisture content for a porous mass. The time taken to complete an experiment was greatly reduced by using small samples.

Introduction

Capillary retention of liquid by porous materials has been investigated in the fields of hydrology, soil science, oil reservoir engineering, chemical engineering, soil mechanics, textiles, paper making and building materials. In studies of the immiscible displacement of one fluid by another within a porous bed, drainage columns and suction potential techniques have been used to obtain relationships between pressure deficiency and saturation (Fig. 1). Except where there is no hysteresis of contact angle and the solid is of simple geometry, such as a tube of uniform cross section, there is hysteresis in the relationship between capillary pressure and saturation. The relationship which has received most attention is displacement of fluid from an initially saturated bed (Fig. 1, Curve Ro), the final condition being an irreducible minimum fluid saturation Swr. Imbibition (Fig. 1, Curve A), further desaturation (Fig. 1, Curve R), and intermediate scanning curves have been studied to a lesser but increasing extent. This paper first considers the nature of the experimental points tracing the capillary pressure curves with respect to the modes and rates of mass transfer which are operative during the course of measurement. There are clear indications that the experimental points which describe these curves are obtained at apparent equilibria which are observed when viscous fluid flow has ceased; and any further changes in the fluid distribution are the result of much slower mass transfer processes, such as diffusion. Unless stated otherwise, this discussion applies to a stable packing of equal, smooth, hydrophilic spheres supported by a suction plate with water as the wetting phase and air as the nonwetting phase.

SPEJ

P. 15ˆ
A Computer Simulation of Gas Flow in Long Pipelines
Authors: Taylor T.D. , Wood N.E. , Powers J.E.
Published: December 2007

A computer program has been developed to simulate a gas transmission line operating under transient conditions. The program was developed by application of the basic mass and momentum balance equations. The nonlinear equations thus obtained were transformed by the method of characteristics and finite-difference techniques to make them suitable for machine computation. Three tests of the computer program were made. In each of these, the initial condition was assumed to be steady-state flow, the inlet density was held constant at the initial condition, and the outlet mass flow rate was varied with time. One test was theoretical in nature, but the others were made for direct comparison with actual field data. Results of the tests are presented in graphical form.

Introduction

Theoretical investigations of the transient flow of gas in long pipelines have been limited in number. In 1951, Olds and Sage developed a graphical method of solving the nonlinear flow equations describing transient gas flow in a long pipeline. Research in this field at the U. of Oklahoma was initiated by Nelson in 1956. Nelson utilized a computer to solve numerical equations involving a lengthy trial-and-error procedure, and his results have been reported in the literature. It does not seem likely that Nelson's method can be extended to the analysis of transient behavior of pipeline networks; therefore, the investigation to be discussed in this paper was undertaken to improve and extend the previous work. The following discussion presents, briefly:the basic differential equations governing transient flow,transformation of these equations into a form suitable for machine computation,role of boundary conditions in the calculations,a very brief description of the computer program which was developed to simulate the pipeline andresults of tests of the computer program.

DEVELOPMENT OF EQUATIONS

BASIC DIFFERENTIAL EQUATIONS

The isothermal flow of fluids can be adequately described by the mass and momentum balance equations as applied to the system under consideration. Using as a system a section of pipe having a differential length, the continuity equations were developed as follows. Mass balance:

.......................(1)

Momentum balance:

.......................(2)

where p = gas density, G = mass flow rate of gas, x = distance along pipe from system inlet, t = time from start of time interval of interest, gc = gravitational constant, R = gas constant T = gas temperature, absolute, M = gas molecular weight, D = pipe diameter, and f = Moody friction factor.

The following assumptions are involved in the development of Eqs. 1 and 2: constant temperature, rod-like flow, negligible effect of changes in elevation, no chemical or atomic reactions, single-phase fluid, pipe has constant cross-sectional area, and ideal gas.

SPEJ

P. 297^
Produced Water Management Strategy and Water Injection Best Practices: Design, Performance, and Monitoring
Authors: Abou-Sayed Ahmed S. , Zaki Karim S. , Wang Gary , Sarfare Manoj D. , Harris Martin H.
Published: December 2007

Key factors in framing a produced water management (PWM) strategy include a company's internal and external environments, technology, and business drivers. Emerging trends for establishing an environment-friendly PWM position comprise adoption of these policies:

Move toward zero emissions. No discharge to surface or seas. Waste-to-value conversion. Incremental and progressive separation. Proactive efforts to influence partners, regulators, and environmental laws.

This paper covers technical approaches for addressing the production, separation, and disposal/injection segments of water injection and reservoir waterflooding procedures and the basis for selecting strategy components and PWM actions. Best practices result both from comprehensive assessments of current PWM tools and from the insights obtained from a decade-long joint industry project (JIP) on produced water re-injection (PWRI).

PWRI for waterflooding or disposal is an important strategy for deriving value from waste while preserving environmental integrity during exploration and production (E&P) operations. Advances in best practices and lessons learned for injector design, operation, monitoring, assessment, and intervention provide the basis for cost minimization and green operations. Facility and subsurface engineering are linked through PWM quality targets, pumping needs, injector completions, and facility constraints. Field cases and data mining results (Abou-Sayed et al. 2005) show the variation in injector responses and underline the key elements contributing to performance. Field evidence indicates that injec-tivities suffer in matrix injection schemes despite the injection of clean water. Alternatively, injectivity maintenance using untreated produced water is feasible.

The majority of injectors fracture during injection, thereby impacting facilities' statement of requirement (SOR), injector completion, sweep, and vertical conformance. This paper assesses fracture propagation during seawater and produced water injection and its impact on injector performance. Models depicting plugging of formations and fractures, vertical water partitioning, and well testing are discussed. Best practices are highlighted and the impacts on injection strategy outlined. Several field cases, as well as water injection design and analysis tools for quantifying the impact on flood and well performance, are presented.
Analysis of Buildup Tests With Short Producing Time
Authors: Soliman M. Y.
Published: December 2007

Pressure buildup data with short producing time are often difficult to analyze. Although the semilog method, known as the Horner1 method, can be used, the drawdown type curve should not. Thus it is difficult to determine whether the semilog plot actually includes the correct straight line.

In this paper, a new log-log graph specially designed for a pressure buildup test with short producing time is suggested. This graph allows the user to determine easily the type of flow regime (linear, bilinear, or radial). Consequently, it can be used to detect the presence of the correct semilog straight line. The new graph can also be used to calculate the formation permeability or fracture conductivity in a fashion similar to the semilog method. The analytical models used to develop the new technique are presented. The models consider both well-bore storage and skin effect. A field example is presented and discussed. Use of the new technique to analyze a buildup test with short producing time is presented and briefly compared with the existing techniques.
A Method to Account for Afterflow at the Pulsing Well During Pulse Tests
Authors: Winston Hubert
Published: December 2007

The nature of wellbore storage is such that afterflow during a pulse test can affect the reservoir pressure performance and can lead to the calculation of erroneous values for formation transmissibility and storage. This is most likely to occur when the wells of interest are close together or when afterflow persists for a long time relative to the pulse length. This article describes a technique that was developed to account for the effects of afterflow at the pulsing well during pulse testing of a small production pilot. The technique is not general because it requires that a computer-generated simulation of each pulse test be made. An application of the method is given.
Effect of Surfactant Structure on Phase Behavior of Alkylxylenesulfonate/Crude-Oil/Brine Systems
Authors: Bolsman T. A. B. M. , Daane G. J. R.
Published: December 2007

One of the major criteria for designing surfactants for micellar flooding is their effectiveness in stabilizing a middle-phase microemulsion under the conditions of the candidate reservoir. We studied the performance of linear alkyl-o-xylenesulfonates (Enordet™ LXS) with equivalent weights ranging from 345 to 472 with well-defined molecular structures.

We used information about a previously described quantitative relationship between the mole fractions of the individual surfactant components and their effect on the optimal salinity in surfactant/crude-oil/brine systems. This relationship makes it possible to calculate blend compositions that have near-optimal properties with respect to the required salinity at which the three phases—i.e., oil, microemulsion, and brine—occur. In this work, however, we have further refined the correlation between surfactant structure parameters and performance by including the effect of factors such as the mole-fraction distribution, the aromatic substitution pattern of the alkylxylenesulfonates, and the presence of the cosurfactant Enordet 3ES.

We studied the performance aspects of optimal salinity, the solubilization of crude oil and brine at the optimal salinity, and the sensitivity to divalent ions expressed as the "effectiveness ratio."

The data generated in this study make it possible to adjust the properties of a surfactant blend in relation to the characteristics of a crude-oil reservoir, thus minimizing the need for trial-and-error experiments.
Numerical Simulation of the Transient Behavior of Coal-Seam Degasification Wells
Authors: King Gregory R. , Ertekin Turgay , Schwerer Fred C.
Published: December 2007

This paper describes the mathematical and numerical developments for a series of fmite-difference models that simulate the simultaneous flow of water and gas through dual-porosity coal seams during the degasification process. Models for unstimulated and hydraulically stimulated degasification wells are included in this series. The hydraulically stimulated wells are assumed to be intercepted by a single infinite- or finite-conductivity vertical fracture.
Practical Control of Timestep Selection in Thermal Simulation
Authors: Sammon P. H. , Rubin B.
Published: December 2007

We present a new technique for estimating accumulating time truncation error in thermal reservoir simulation. The calculation uses only current reservoir information, thereby avoiding difficulties encountered by some past formulations, and is integrated easily into fully implicit reservoir simulators. We describe an error-controlled timestep selector based on this estimate as well as provisions for limiting the calculated timestep based on the imminent appearance or disappearance of a gas phase. We also provide a new technique for estimating the solution of certain Newtonian iterations. The algorithm is capable of calculating timesteps at the beginning of a simulation and when major well rate changes are specified.

The resulting timestep selector enhances simulator accuracy without increasing computational work and affords greater reliability through the reduction of failed timesteps.
A Laboratory Study of Chemical Reactions With Reservoir Sand in the Recovery of Petroleum by Alkaline Flooding
Authors: Lieu Van T. , Miller Samuel G. , Miller Steve
Published: December 2007

This paper presents the results of a laboratory study of the chemical reactions between alkaline chemical solutions and petroleum reservoir sand material. Long-term studies were made of alkaline solution flow through reservoir sandpacks. Analyses were conducted to determine the chemical compositions of the effluents.

The results obtained are related to the mineral content of the reservoir sand material. Individual chemical reactions of various minerals are discussed. It appears that mere is an important initial combination of rapid reversible adsorption and chemical reactions followed by slower nonreversible chemical reactions that later can assume great importance because of the long contact time that may prevail in flooding a petroleum reservoir.

This long-term alkali consumption is critical, because successful alkaline flooding must provide sufficient alkalinity to survive the time it takes to traverse the reservoir from injection well to production well.
Field Tests of the Stem-Induced Explosive Fracturing Technique
Authors: Young Chapman , Barker D. B. , Clark H. C.
Published: December 2007

The explosive stem-induced fracturing technique has been field tested in over 20 producing oil wells in western Pennsylvania. The technique basically involves the placement of a primary explosive charge in an expendable rathole below the pay zone(s) to be fractured and of a solid gravel stem near the top of the pay zone to cause local fracturing through the dynamic reflection of the explosive gases. In the best cases, production increases realized with the technique are comparable to those obtained with conventional hydraulic fracturing in the area. A 35-mm downhole camera was developed and used to obtain photographs that show the absence of any vertical fracturing before the explosive treatments and well-developed vertical fractures in all zones designed to be fractured. This vertical fracturing is developed despite the fact that the in-situ stresses favor horizontal fracturing. The photographs also show that multiple radial fracturing, which might be expected with the high rates of the explosive loading, does not usually occur and that wellbore damage is less than predicted.
Semisubmersible Drilling Tender Unit
Authors: Chitwood James E. , McClure Alan C.
Published: December 2007

The offshore industry has shown significant interest in deepwater production in the Gulf of Mexico, as evidenced by the large number of deepwater leases. This paper addresses an innovative method to control cost of field-development wells on deepwater leases. Drilling tender rigs have been economically attractive in shallow water depths. The limitations experienced by conventional tenders in deep water with regard to mooring and motions in a seaway can be overcome by use of a semisubmersible tender.
A Method for Drilling Moving Salt Formations—Drilling and Underreaming Concurrently
Authors: Holt Charles A. , Johnson Joseph B.
Published: December 2007

Casing deformation opposite the Preuss salt formation in the Anschutz Ranch East (ARE) field of northern Utah has been a constant problem since the field was discovered in 1979. To improve hole geometry in the salt, an oil-based mud was used to drill a flank West Lobe well thought to have a thick, complex salt section.

After field-established salt-drilling techniques failed, a unique method of drilling and underreaming concurrently was employed and perfected. With modifications, the technique can be used to drill any moving formation.
Approximate Flash Calculations for Equation-off-State Compositional Models
Authors: Nghiem Long X. , Li Yau-Kun
Published: December 2007

An approximate flash-calculation (AFC) method with an equation of state (EOS) is presented. The equations for AFC are obtained by linearizing the thermodynamic equilibrium equations at an equilibrium condition called the reference condition. The AFC equations are much simpler than the actual equations for flash calculations and yet give almost the same results. A procedure for generating new reference conditions to keep the AFC results close to the true flash-calculation (TFC) results is described. AFC is compared with TFC in the calculation of standard laboratory tests and in the simulation of gas-injection processes with a compositional model. Excellent results are obtained with AFC in less than half the original execution time.
Guidelines for Converting Steamflood to Waterflood
Authors: Hong K. C.
Published: December 2007

This paper presents a set of guidelines that field engineers can use for the optimum conversion of maturing steamflood projects to waterfloods. The guidelines were developed from a simulation study of Chevron's oldest steamflood-followed-by-waterflood project, the Kern River 10-Pattern project in California. They have been validated against different reservoirs and operating conditions.

The simulation study showed that by judicious conversion of a steamflood to a waterflood as the steamflood matures, the cumulative net salable oil (cumulative oil produced minus oil used as steam generator fuel) can be maximized. The optimum time of conversion has been characterized in terms of eight performance variables that can be monitored in the field. A field engineer can use these characteristics or guidelines to estimate the optimum time of conversion and use this result to maximize the net salable oil production from his project.

The procedures used for developing the guidelines from the Kern River 10-Pattern project performance and for validating them against different reservoirs and operating conditions are presented. The recommended procedure for applying these guidelines to other fields is also discussed.
Bit Sticking Caused by Borehole Deformation
Authors: Dunbar M. E. , Warren T. M. , Kadaster A. G.
Published: December 2007

The stress relaxation associated with drilling a hole in the earth causes the borehole wall to deform toward the center of the hole. Usually this deformation is inconsequential, but sometimes the deformations are sufficient to cause the borehole to be smaller than the bit. The problems associated with this phenomenon are related largely to the magnitude of the lateral earth stresses, formation mechanical properties, and drilling-tool geometry.
Dynamics of Rock-Chip Removal by Turbulent Jetting
Authors: Wells M. R.
Published: December 2007

The efficiency of the drilling process is largely governed by the efficiency with which the available hydraulics removes rock chips created by the mechanical action of the bit. To date, a physical understanding of the process associated with the hydraulic removal of the chips remains unknown. Rock chips mechanically freed from the parent rock by the drilling action of the bit are generally held in place by overbearing pressures. These pressures must be overcome either by hydraulic action or by mechanical regrinding before the chip may be removed. This work presents the experimental results of a study designed to examine the effects of dynamic forces brought about by jet turbulence on the removal of loose rock chips. Synthetic chips of known shape and size, embedded in a simulated hole bottom and held in place by hydrostatic pressure, were removed solely by the jetting action of a vertically impinging jet. The synthetic chips were flush-mounted into the plate, rendering the shear forces on the surface of the chips at least two orders of magnitude less than the hold-down forces. Measurements of the static jet-impingement pressure and the dynamic fluctuating pressure caused by the jet turbulence were related to turbulent time-scale measurements made using a laser Doppler anemometer, producing an analytical tool to predict the necessary conditions for chip removal. Tests were conducted in both water and an optically clear synthetic clay mixture having non-Newtonian viscosity characteristics similar to a bentonitic fluid. The results indicate that chip hold-down forces can be overcome by the turbulent action of the jet nozzle. Correlations are given indicating the conditions necessary (i.e., jet standoff, radial chip location, chip size, and viscosity) to permit chip removal. These results can be used to place and size jets optimally to maximize chip removal and bottomhole cleaning.
The Effect of Freezing of Slightly Consolidated Cores
Authors: Torsaeter Ole , Beldring Baard
Published: December 2007

This paper presents laboratory experimental techniques, procedures, and routine core analysis data of unconsolidated to slightly consolidated core plugs from North Sea reservoirs. The effect of freezing on permeability has been investigated, and results from about 30 core plugs with permeabilities ranging from 0.2 to 12 darcies indicate a considerable change in permeability after freezing. Both increased and decreased permeability were obtained after freezing. For one rock type, the freezing seemed to increase the permeability in cores with initial permeability less than 2 darcies, while decreasing the permeability of core plugs with initial permeability greater than 2 darcies. The observed changes in permeability depend on the amount of kaolinite in the core plugs and the changes in kaolinite morphology during freezing and thawing.
Casing Wear: Laboratory Measurements and Field Predictions
Authors: White Jerry P. , Dawson Rapier
Published: December 2007

Casing wear caused by rotation of nonhardbanded tool joints has been investigated with a full-sized test machine. Three grades of casing were used during this study: K55, N80, and PI 10. Tests were conducted in both water-based and oil-based muds. Contact forces between the tool joint and casing were either 1,000 or 2,000 lbf [4.4 or 8.9 kN]. Both the casing wear and friction forces were measured during the tests.

A linear wear-efficiency model was used to correlate the data. This model relates casing-metal removal to the amount of energy dissipated as friction in the wear process. The wear-efficiency model fits the data well and is easily used for field wear predictions.

The data from this study indicate that high-strength casing steels wear more rapidly than K55 and that wear in oil muds is possibly more rapid than in water muds. Partial hydrodynamic lubrication occurred during many tests; friction measurements and the wear-efficiency model were used to account for its effects.
Dispersion and Reservoir Heterogeneity
Authors: Arya Atul , Hewett Tom A. , Larson Ronald G. , Lake Larry W.
Published: December 2007

Macroscopic dispersion is the mixing, on the scale of several hundreds of grain diameters, at a point in a permeable medium that is free of boundary effects. Megascopic dispersion is the one-dimensional (1D) dispersion derived by averaging across an entire cross section. This work investigates how both dispersions vary with heterogeneity, aspect ratio, diffusion coefficient, and autocorrelation. The theoretical results are compared to existing field and laboratory data and to existing theories for limiting cases.

The degree of autocorrelation in the medium determines whether or not megascopic dispersivity (dispersion coefficient divided by velocity) is uniquely defined. Large correlation distances (with respect to the medium dimensions) imply a dispersivity that grows with distance traveled. Small correlation distances imply a dispersivity that is eventually stabilized at some constant value. This value is related to the heterogeneity of the medium. On the field scale, diffusion is insignificant, but on a laboratory scale, it can stabilize the dispersivity even if the medium is correlated. Macroscopic dispersivity is sensitive to diffusion in both the laboratory and field scale. It is smaller than or equal to megascopic dispersivity, also in conformance with experimental data, and comparable to laboratory-measured dispersivity.
Radioactive Tracers Monitor Solvent Spreading in Rainbow Vertical Hydrocarbon Miscible Flood
Authors: Mclntyre F. J. , Polkowski G. A. , Bron J. , Pow M. J.
Published: December 2007

This paper describes the design, implementation, and results of a tracer project. Three different radioactive tracers (tritiated methane, ethane, and butane) were used to monitor the initial phase of solvent spreading. As a result, adjustments were made to the distribution of injected solvent, ensuring the placement of a stable solvent bank.
Reservoir Engineering in Coal Seams: Part 2—Observations of Gas Movement in Coal Seams
Authors: Gray Ian
Published: December 2007

This paper, the second of two concerning the movement of gas in coal seams, covers observations of seam fluid pressures and flows in mines in northern and central Queensland, Australia. Techniques based primarily on underground measurement rather than measurements from surface boreholes were used to gain information on the seams. The techniques used for in-seam studies are described because they differ substantially from conventional oil and gas surface borehole techniques. The paper demonstrates the importance of cleats and joints in the control of fluid movement and records flow increases consistent with increasing permeability with production.
Well Singularities in Reservoir Simulation
Authors: Carey G. F. , Chow S. S.
Published: December 2007

In this study, we examine the problem of relating the computed solution at a well in reservoir simulation to the actual bottomhole pressure (BHP) and the related questions concerning determination of an effective radius for the computed pressure. We provide a mathematical analysis of this problem from a slightly different standpoint than that used elsewhere. Our approach provides further insight into the nature of the singularity, the extension to multisingularities, nonuniform grids, and the development of related approximation techniques for radially symmetric nonhomogeneous problems. We present some fundamental new results based on the analysis.
Application of the van Everdingen-Meyer Method for Analyzing Variable-Rate Well Tests
Authors: Whitson C. H. , Søgnesand Sigmund
Published: December 2007

This paper discusses application of superposition to pressure-transient analysis when rate varies significantly before and during pressure measurements. To apply rigorous superposition, use of conventional pressure-transient and rate-time methods is recommended to estimate permeability, skin, and in some cases, drainage area. These properties allow calculation of the dimensionless time constant used in superposition calculations on the basis of rate change and dimensionless pressure. As van Everdingen and Meyer proposed, the time constant is varied until a linear fit of the pressure variable is made vs. superposition time. An important step is to use all available rate data, even though pressures may not be measured during periods of rate change. Our work shows the use of full superposition to check the consistency of standard well-test analysis based on the constant-rate or constant-pressure assumption. Data from two gas wells and results from a gas-well simulator provide the basis for our discussion. Problems covered are choosing the dimensionless pressure solution, estimating initial pressure by extrapolation of the superposition plot, and analyzing rate-dependent effects.