bluuebunny/crossref_metadata_2025 huggingface dataset:
End-Stage Kidney Disease After Pediatric Nonrenal Solid Organ Transplantation
Authors: Ruebner Rebecca L. , Reese Peter P. , Denburg Michelle R. , Abt Peter L. , Furth Susan L.
Published: October 2013

OBJECTIVES:

Adult solid organ transplant (SOT) recipients commonly develop advanced kidney disease; however, the burden of end-stage kidney disease (ESKD) in children after SOT is not well-described. The objectives of this study were to determine the incidence of ESKD after pediatric SOT and the relative risk by SOT type.

METHODS:

Retrospective multicenter cohort study of children, ages ≤18 years, who received SOTs from 1990 through 2010 using Scientific Registry of Transplant Recipients data linked to the US Renal Data System. We performed a competing risks analysis to determine cumulative incidence of ESKD (chronic dialysis or kidney transplant), treating death as a competing risk, and fit a multivariable Cox regression model to assess hazard of ESKD by organ type.

RESULTS:

The cohort included 16 604 pediatric SOT recipients (54% liver, 34% heart, 6% lung, 6% intestine, and 1% heart–lung). During a median follow-up of 6.2 years (interquartile range 2.2–12.1), 426 (3%) children developed ESKD. Compared with liver transplant recipients, in whom the incidence of ESKD was 2.1 cases per 1000 person-years, in adjusted analyses the highest risk of ESKD was among intestinal (hazard ratio [HR] 7.37, P < .001), followed by lung (HR 5.79, P < .001) and heart transplant recipients (HR 1.79, P < .001).

CONCLUSIONS:

In a 20-year national cohort of pediatric SOT recipients, the risk of ESKD was highest among intestinal and lung transplant recipients. The burden of earlier stages of chronic kidney disease is probably much higher; modifiable risk factors should be targeted to prevent progressive kidney damage in this high-risk population.
Gunshot Injuries in Children Served by Emergency Services
Authors: Newgard Craig D. , Kuppermann Nathan , Holmes James F. , Haukoos Jason S. , Wetzel Brian , Hsia Renee Y. , Wang N. Ewen , Bulger Eileen M. , Staudenmayer Kristan , Mann N. Clay , Barton Erik D. , Wintemute Garen
Published: October 2013

OBJECTIVE:

To describe the incidence, injury severity, resource use, mortality, and costs for children with gunshot injuries, compared with other injury mechanisms.

METHODS:

This was a population-based, retrospective cohort study (January 1, 2006–December 31, 2008) including all injured children age ≤19 years with a 9-1-1 response from 47 emergency medical services agencies transporting to 93 hospitals in 5 regions of the western United States. Outcomes included population-adjusted incidence, injury severity score ≥16, major surgery, blood transfusion, mortality, and average per-patient acute care costs.

RESULTS:

A total of 49 983 injured children had a 9-1-1 emergency medical services response, including 505 (1.0%) with gunshot injuries (83.2% age 15–19 years, 84.5% male). The population-adjusted annual incidence of gunshot injuries was 7.5 cases/100 000 children, which varied 16-fold between regions. Compared with children who had other mechanisms of injury, those injured by gunshot had the highest proportion of serious injuries (23%, 95% confidence interval [CI] 17.6–28.4), major surgery (32%, 95% CI 26.1–38.5), in-hospital mortality (8.0%, 95% CI 4.7–11.4), and costs ($28 510 per patient, 95% CI 22 193–34 827).

CONCLUSIONS:

Despite being less common than other injury mechanisms, gunshot injuries cause a disproportionate burden of adverse outcomes in children, particularly among older adolescent males. Public health, injury prevention, and health policy solutions are needed to reduce gunshot injuries in children.
The Red Book Through the Ages
Authors: Pickering Larry K. , Peter Georges , Shulman Stanford T.
Published: October 2013

The first edition of the Red Book was published in 1938. Since then, there have been numerous advances in the fields of infectious diseases and public health that have decreased morbidity and mortality of infants, children, and adolescents. Over the years, emerging pathogens and disease complexes have been described, sophisticated diagnostic techniques developed, advances in antimicrobial therapy have occurred, and immunizations have been implemented to prevent previously deadly diseases. Of the 18 diseases or organisms in the 1938 edition, 13 are now vaccine-preventable. Since inception of the Red Book, the aims of the editors have been to keep pace with these innovations and to continue to inform the medical community. These goals have made the Red Book a fundamental resource for pediatricians and other health care professionals in terms of guiding diagnosis, therapy, and prevention of infectious diseases. The list of 18 diseases or organisms originally described in the 1938 Red Book has expanded to include over 160 diseases or organisms in the 2012 edition. The pace of biomedical discovery, as well as the amount of information available and the number of methods for its delivery, will continue to accelerate in the future. Integration of information into future editions of the Red Book will ensure that practitioners continue to rely on the Red Book in its various electronic formats for clinical guidance and support.
Características clínicas e ecocardiográficas associadas à evolução do canal arterial em recém-nascidos com peso de nascimento inferior a 1.500g
Authors: Visconti Luiza Fortunato , Morhy Samira Saady , Deutsch Alice D'Agostini , Tavares Gláucia Maria Penha , Wilberg Tatiana Jardim Mussi , Rossi Felipe de Souza
Published: October 2013

OBJETIVO: Identificar parâmetros clínicos e ecocardiográficos associados à evolução do canal arterial em recém-nascidos com peso de nascimento <1.500g. MÉTODOS: Estudo retrospectivo de 119 recém-nascidos, no qual foram analisados parâmetros clínicos (pré-natais: idade materna, risco infeccioso e corioamnionite, uso de corticoide, tipo de parto e idade gestacional; perinatais: peso, Apgar, gênero e classificação peso/idade gestacional; pós-natais: surfactante, sepse, oferta hídrica, sopro cardíaco, frequência cardíaca, movimento precordial e pulsos, diurético, índice de oxigenação, queda de saturação/apneia, suporte ventilatório, intolerância alimentar, radiografia de tórax, função renal, instabilidade hemodinâmica e alterações metabólicas); parâmetros ecocardiográficos (diâmetro do canal arterial, relação canal arterial/peso, relação átrio esquerdo/ aorta, diâmetro diastólico ventrículo esquerdo, direção, padrão e velocidade de fluxo pelo canal arterial). Os parâmetros clínicos e ecocardiográficos analisados foram considerados estatisticamente significantes quando p<0,05. RESULTADOS: Nos 119 recém-nascidos, a incidência de canal arterial foi de 61,3%, 56 receberam tratamento (46 medicamentoso e 10 cirúrgico), 11 tiveram fechamento espontâneo, 4 foram a óbito e 2 receberam alta com persistência do canal arterial. Houve maior incidência de corioamnionite, uso de surfactante, menor peso e idade gestacional, sepse, sopro cardíaco, ventilação e piores índices de oxigenação nos recém-nascidos tratados. O grupo com fechamento espontâneo apresentou menor diâmetro do canal arterial, menor relação canal arterial/peso e maior velocidade do fluxo pelo canal arterial. CONCLUSÃO: Com base em parâmetros clínicos e ecocardiográficos, foi possível diferenciar os recém-nascidos com fechamento espontâneo do canal arterial daqueles com necessidade de tratamento.
Efeitos de curto prazo de um programa de atividade física moderada em pacientes com síndrome metabólica
Authors: Colombo Caroline Macoris , Macedo Rafael Michel de , Fernandes-Silva Miguel Morita , Caporal Alexandra Moro , Stinghen Andréa Emilia , Costantini Costantino Roberto , Baena Cristina Pellegrino , Guarita-Souza Luiz Cesar , Faria-Neto José Rocha
Published: October 2013

OBJETIVO: Avaliar se um programa de exercícios de intensidade moderada por um pequeno período pode alterar os parâmetros inflamatórios e melhorar os diferentes componentes da síndrome metabólica em pacientes sedentários. MÉTODOS: Dezesseis pacientes completaram 12 semanas de exercício supervisionado, que consistiu em caminhar 40 a 50 minutos 3 vezes por semana, atingindo 50 a 60% da frequência cardíaca de reserva. Os parâmetros avaliados pré e pós-intervenção foram circunferência de cintura, pressão arterial sistólica e diastólica, triglicérides, LDL-colesterol, HDL-colesterol, colesterol total, proteína C-reativa e interleucina 8. RESULTADOS: Houve redução significativa na circunferência da cintura (102,1±7,5cm versus 100,8±7,4cm; p=0,03) e índice de massa corporal (29,7±3,2kg/m² versus 29,3±3,5kg/m²; p=0,03). A pressão arterial sistólica diminuiu de 141±18 para 129±13mmHg e a diastólica de 79±12 para 71±10mmHg (p<0,05 para ambos). Não foram observadas alterações no colesterol total, LDL-colesterol e triglicérides, mas houve melhora significativa nos níveis de HDL-colesterol, - 45,5±6,0 versus 49,5±9,8mg/dL (p=0,02). Houve uma tendência na redução de proteína C-reativa (8,3%; p=0,07) e interleucina 8 (17,4%; p=0,058). A melhora na capacidade cardiovascular foi demonstrada por um aumento de 13% no volume de oxigênio estimado (p<0,001). CONCLUSÃO: Os benefícios do exercício aeróbico com intensidade moderada puderam ser observados em apenas 12 semanas de treinamento em pacientes sedentários com síndrome metabólica. Considerando a facilidade de autoaplicabilidade e os efeitos metabólicos comprovados, tal programa pode ser uma primeira abordagem para pacientes sedentários com síndrome metabólica.
Evolução clínica de pacientes com mediastinite pós-cirurgia de revascularização miocárdica submetidos à oxigenoterapia hiperbárica como terapia adjuvante
Authors: Egito Julyana Galvão Tabosa do , Abboud Cely Saad , Oliveira Aline Pâmela Vieira de , Máximo Carlos Alberto Gonçalves , Montenegro Carolina Moreira , Amato Vivian Lerner , Bammann Roberto , Farsky Pedro Silvio
Published: October 2013

OBJETIVO: Avaliação da utilização de oxigenoterapia hiperbárica, como tratamento adjuvante, em casos de mediastinite, em pós-operatório de cirurgia de revascularização miocárdica. MÉTODOS: Estudo descritivo retrospectivo, no período entre outubro de 2010 e fevereiro de 2012. A oxigenoterapia hiperbárica foi indicada nos casos de difícil manejo clínico a despeito da antibioticoterapia. RESULTADOS: Identificaram-se 18 pacientes com mediastinite, nos quais 33 microrganismos foram isolados, estando a infecção polimicrobiana presente em 11 casos. Enterobactérias foram os germes mais prevalentes e seis agentes multirresistentes. Ocorreu 1 óbito, na evolução, 7 meses após o término da oxigenoterapia, por septicemia, não relacionado à terapêutica. O tratamento foi bem tolerado. CONCLUSÃO: Os resultados clínicos iniciais foram favoráveis.
Calcificação vascular: fisiopatologia e implicações clínicas
Authors: Liberman Marcel , Pesaro Antonio Eduardo Pereira , Carmo Luciana Simão , Serrano Jr Carlos Vicente
Published: October 2013

A calcificação vascular na doença arterial coronária está ganhando importância, tanto em pesquisas científicas como em aplicações clínicas e de imagem. A placa calcificada é considerada a forma mais relevante de aterosclerose dentro da árvore arterial coronária e frequentemente apresenta um desafio para a intervenção percutânea. Estudos recentes têm demonstrado que a calcificação da placa é dinâmica e está estreitamente ligada ao grau de inflamação vascular. Vários fatores inflamatórios, produzidos durante as diferentes fases da aterosclerose, induzem a expressão e ativação de células osteoblásticas localizadas na parede arterial, que, por sua vez, promovem a deposição de cálcio. As células do músculo liso vascular possuem uma capacidade extraordinária de sofrer diferenciação fenotípica osteoblástica. Não há dúvida de que o papel desses fatores, bem como os elementos de genômica e proteômica, poderia ser um ponto estratégico fundamental na prevenção e no tratamento. Neste contexto, realizamos uma atualização sobre a calcificação coronária, com foco em fisiopatologia, modelos experimentais e implicações clínicas da calcificação vascular.
Influência do transtorno fonológico sobre os transtornos de leitura e da escrita
Authors: Silva Monique Cantelli da , Ávila Clara Regina Brandão de
Published: October 2013

OBJETIVO: Investigar a influência do transtorno fonológico sobre o desempenho em tarefas de leitura e de escrita e as relações entre essas variáveis. MÉTODOS: Foram avaliados 28 escolares matriculados no 4° e 5° anos do Ensino Fundamental, divididos em Grupo Pesquisa 1, Grupo Pesquisa 2 e Grupo Controle. Foram avaliadas as seguintes competências: leitura, escrita, processamento fonológico e auditivo. Os dados foram analisados estatisticamente. RESULTADOS: O Grupo Controle mostrou melhores resultados em leitura, escrita e processamentos. Os Grupos Pesquisa mostraram-se semelhantes quanto à consciência fonológica e memória fonológica de curto prazo. O Grupo Pesquisa 1 mostrou valores médios de desempenho mais baixos na maioria das tarefas, quando comparado ao Grupo Pesquisa 2, embora sem diferença estatística. O processamento auditivo mostrou-se semelhante entre os três grupos, com exceção da prova de Memória Sequencial Verbal. Os três grupos apresentaram diferentes padrões de correlações entre as variáveis. CONCLUSÃO: O transtorno fonológico mostrou-se associado aos piores desempenhos em leitura, escrita e processamento fonológico. Os grupos apresentaram padrões diferentes de correlação entre as variáveis de leitura, escrita, auditiva, processamento auditivo e fonológico, o que confirmou os resultados das comparações.
Aplicação de medidas de gravidade e de inconsistência de fala em crianças com transtorno fonológico
Authors: Wertzner Haydée Fiszbein , Pereira Karina , Silva Thaís Zemlickas , Pagan-Neves Luciana de Oliveira
Published: October 2013

OBJETIVO: Descrever os índices PCC-R, IRS, IRO e IRD, PDI e IIF em crianças com transtorno fonológico, com e sem os processos fonológicos de ensurdecimento, e verificar a eficiência desses índices na identificação de diferenças entre as crianças. MÉTODOS: Trata-se de pesquisa retrospectiva e transversal com 20 crianças com transtorno fonológico e idade entre 5 e 8 anos. Foram realizados dois agrupamentos, de acordo com a presença dos processos fonológicos de ensurdecimento de plosivas e de fricativas. Todos foram submetidos ao teste de fonologia ABFW, no qual foi verificada a produtividade dos processos fonológicos, o número de diferentes tipos de processos fonológicos e os índices PDI, PCC-R, IRS, IRO e IRD. A prova de inconsistência de fala foi aplicada para calcular o índice de inconsistência de fala. Os dados foram submetidos à análise estatística inferencial. RESULTADOS: O estudo indicou que crianças com transtorno fonológico e presença de ensurdecimento de fricativas e/ou plosivas têm maior comprometimento de fala e apresentam valores mais altos do índice de inconsistência de fala, PDI, IRS, IRO e IRD. O erro articulatório mais ocorrente em ambos os grupos foi a substituição, sendo que a distorção ocorreu mais no grupo sem os processos fonológicos de ensurdecimento. CONCLUSÃO: Os índices aplicados foram eficientes para diferenciar crianças com e sem a presença dos processos fonológicos de ensurdecimento. Há evidências de que as crianças que apresentam os processos fonológicos de ensurdecimento têm dificuldade na representação fonológica.
Procurement clinics in public procurement and urban development
Authors: Kuronen Matti , Vaara Pekka
Published: October 2013

The aim of this paper is to present the concept of ‘procurement clinics’, which have been used in complex property and urban development-related procurement processes in Finland, and to evaluate the benefits of the aforementioned concept. Procurement clinics are a systematised form of market dialogue under the Act of Public Procurement, which derives from the EU procurement directive. As a major finding, the paper presents a successful way to improve property and urban development-related procurement processes, especially when using competitive dialogue. As a by-product, the paper also presents methods of implementing a procurement clinic. The study was conducted in Finland only, which poses some limitations when applying the findings elsewhere. However, in EU countries the public procurement processes follow the aforementioned directive and should be rather similar. Practical implications of the study consist of improving procurement and urban development processes. These improvements are better private sector participation in procurement, shorter procurement processes and changes in the formatting of procurement.
Combinatorial approaches for efficient screening of multicomponent photocatalysts and fuel cell catalysts
Authors: Shi Wenwu , Chopra Nitin
Published: October 2013

Environmental issues and fossil fuel demands have propelled renewable energy research and development. Photocatalytic systems are inspired by artificial photosynthesis, which is capable of converting solar energy into chemical energy. Fuel cells, on the other hand, hold great potential for direct conversion of chemical energy into electricity. A rational combination of photocatalytic systems and fuel cells can effectively convert, store and utilize solar energy as compared with hybrid solar cell–battery systems. The critical issues for both the systems are to discover suitable and low-cost catalysts for chemical conversion with high efficiency. In general, catalysts involved with several synergistic components and an optimal recipe for each constituent should be derived. Traditional methods were based on pure empirical and trial-error testing, which are time consuming and labor intensive. Alternative method that can screen catalysts rapidly could be of great importance. In this mini review, preparation of sample arrays with various compositions and libraries suitable for combinatorial characterization is discussed. Next, the focus is on discussing several methods including scanning mass spectrometry, pH imaging and scanning electrochemical microscopy for efficient screening in serial. Successful implementation of these approaches has a potential to open up opportunities for identification and commercialization of efficient solar energy–harvesting catalysts.
Pushing the limit: experimental evidence of climate effects on plant range distributions
Authors: Pfeifer-Meister Laurel , Bridgham Scott D. , Little Chelsea J. , Reynolds Lorien L. , Goklany Maya E. , Johnson Bart R.
Published: October 2013

Whether species will be extirpated in their current geographic ranges due to rapidly changing climate, and if so, whether they can avoid extinction by shifting their distributions are pressing questions for biodiversity conservation. However, forecasts of climate change impacts on species' geographic distributions rarely incorporate a demographic understanding of species' responses to climate. Because many biotic and abiotic factors at multiple scales control species' range limits, experimentation is essential to establish underlying mechanisms. We used a manipulative climate change experiment embedded within a natural climate gradient to examine demographic responses of 12 prairie species with northern range limits within the Pacific Northwest, USA. During the first year, warming decreased recruitment of species even at the coolest edge of their current ranges, but this effect disappeared when they were moved poleward beyond their current ranges. This response was largely driven by differences in germination rates. Other vital rates responded in unique and sometimes opposing ways (survivorship vs. fitness) to species' current ranges and climate change, and were mediated by indirect effects of climate on competition and nutrient availability. Our results demonstrate the importance of using regional‐scale climate manipulations and the need for longer‐term experiments on the demographic responses that control species' distributions.
Capital and income breeding: the role of food supply
Authors: Stephens Philip A. , Houston Alasdair I. , Harding Karin C. , Boyd Ian L. , McNamara John M.
Published: October 2013

An aspect of life history that has seen increasing attention in recent years is that of strategies for financing the costs of offspring production. These strategies are often described by a continuum ranging from capital breeding, in which costs are met purely from endogenous reserves, to income breeding, in which costs are met purely from concurrent intake. A variety of factors that might drive strategies toward a given point on the capital–income continuum has been reviewed, and assessed using analytical models. However, aspects of food supply, including seasonality and unpredictability, have often been cited as important drivers of capital and income breeding, but are difficult to assess using analytical models. Consequently, we used dynamic programming to assess the role of the food supply in shaping offspring provisioning strategies. Our model is parameterized for a pinniped (one taxon remarkable for the range of offspring‐provisioning strategies that it illustrates). We show that increased food availability, increased seasonality, and, to a lesser extent, increased unpredictability can all favor the emergence of capital breeding. In terms of the conversion of energy into offspring growth, the shorter periods of care associated with capital breeding are considerably more energetically efficient than income breeding, because shorter periods of care are associated with a higher ratio of energy put into offspring growth to energy spent on parent and offspring maintenance metabolism. Moreover, no clear costs are currently associated with capital accumulation in pinnipeds. This contrasts with general assumptions about endotherms, which suggest that income breeding will usually be preferred. Our model emphasizes the role of seasonally high abundances of food in enabling mothers to pursue an energetically efficient capital‐breeding strategy. We discuss the importance of offspring development for dictating strategies for financing offspring production.
Experimental Investigation and Correlation of Treatment in Weak and High-Permeability Formations by Use of Gel Particles
Authors: Al-Ibadi Adnan , Civan Faruk
Published: October 2013

Near-wellbore formation treatment by injection of suspensions of deformable gel particles is explored as a method of prevention of lost circulation of drilling fluids, handling of reservoir permeability heterogeneity, and controlling water production in mature waterflooded oil fields containing highly permeable and weak zones. Conditioning and plugging of such formations and the resulting permeability impairment occurring during injection of suspensions of deformable gel particles are investigated experimentally. The effect of concentration, flow rate, and gel-particle sizes of suspensions on the prevailing pore-plugging processes is inferred by flow tests conducted with 3,800-md 16- to 20-mesh sandpacks. Prevailing particle-entrapment and -permeability-impairment mechanisms are identified under various conditions by means of specially formulated diagnostic equations. Appropriate dimensionless groups are used to develop several empirical correlations of the experimental data, which can assist in choosing suitable gel-particle suspensions and proper application conditions required for effective near-wellbore-formation treatment. This reveals valuable insights and information about the functional trends of sandpack plugging by gel-particle suspensions, which can help in successful design and mitigation of formation-plugging treatments in the field.
The Impact of Non-technical Risks on Oil and Gas Activities in Alaska's Arctic
Authors: Southam Anne L.
Published: October 2013

This paper presents Alaska as a case study for evaluating the impact of non-technical risk on oil and gas exploration and development in the Arctic. Stakeholder relationships, regulatory uncertainty, government funding, listing species under the Endangered Species Act, cumulative impacts, and litigation are all non-technical risks that can delay oil and gas projects. Since 2005, there have been over a dozen legal challenges to oil and gas activities due to non-technical risks. The magnitude of costs associated with project delays due to non-technical risks in Alaska’s Arctic is on the order of billions. The February 2008 Chukchi Sea Lease Sale 193 attracted 667 bids totaling almost $3.4 billion, the most for any offshore lease sale in Alaska’s history. In 2012, according to a United States Department of Interior report, approximately three-quarters of Alaska’s offshore leases (3.7 million acres) were subject to litigation. As a result of legal challenges, agency staff must respond to court orders rather than process permits and authorizations required for exploration and development. With permit applications sitting idle, company profit margins are diminished and public trust deteriorates. In recent years, three major oil companies have reported spending over $75 million over five years to collect environmental data, yet data gaps are still perceived to exist. In particular, the absence of a regional assessment of cumulative impacts of development activities is leaving companies and authorizing agencies vulnerable to stakeholder scrutiny and litigation. Despite these issues, sustainable project exploration and development is possible. Understanding what non-technical risks exist, and then integrating methods to minimize them at the strategic leadership level during the pre-feasibility stage can minimize delays and lay the foundation for sustainable oil and gas projects.
Experience of Application of Extended Logging Suite and Formation Testers for characterization of Jurassic Age Deposits of the Em-Egovsky Field
Authors: Martinov M E , Kozlov A V , Platunov A A , Filimonov A Y , Ezersky D M , Egorov S S , Charupa M V , Tsiklakov A M , Mikhalteva I V , Weinheber P
Published: October 2013

In a recent Em-Egovskoe well an extended logging suite was performed with the aim to evaluate the petrophysical properties of Jurassic and Paleozoic formations as well as to improve the structural geological model of this part of the oilfield and to do detailed characterization of the dynamic model by desired properties of formations and fluids. Apart from a standard "triple combo" logging suite the following advanced technologies were applied in the well: neutron-gamma spectroscopy, nuclear magnetic resonance, formation micro imager, formation testers in different modes of reservoir and fluid properties evaluation. Noteworthy, the zone of interest was considered to contain only oil-saturated reservoirs – no gas cap was expected. Indeed on the initial triple combo log data there were no routine gas attributes were observed. Gas-saturated reservoirs were only observed based on integrated analysis of standard and advanced log data, particularly, nuclear magnetic resonance and cross-dipole sonic measurements. Gas-saturated intervals were fully proven by formation tester using downhole fluid analysis (DFA) As a result, one of the Jurassic layers was acknowledged as gas/gas-condensate saturated down to the bottom and the rest of Jurassic intervals were found to be oil saturated.

The Abalak formation was also encountered in this well and evaluated. Thin carbonate streaks were identified with the micro-imager and were tested with the dual-packer module of the wireline formation tester. The result was the first ever Abalak oil sample in this field. Furthermore, based on pressure transient analysis of the build-up from the pressure test it was suggested that these tight streaks are laterally discontinuous.

Finally, we created a stress profile in the Jurassic and Paleozoic layers. Based on formation micro-imager and acoustic scanning measurements the maximum horizontal stress directions and magnitudes were estimated. Then dual-packer formation tester micro-stress measurements were made to acquire direct measurements of fracture closure pressure. These measurements were used to calibrate our stress model.
Geosciences and Reservoir Integration – Key to Better Predict Behavior Of Complex Fractured And Karstified Kharyaga Field
Authors: Shchukina Natalia , Neumann Catherine , Nely Georges , Spina Vincenzo , Debroux Jean-Luc
Published: October 2013

This paper presents an integrated Geosciences and Reservoir work approach used for complex fractured and karstified carbonate Kharyaga field. Synthesis is fulfilled for all available data, such as seismic interpretation, static well data, well tests etc. It has been launched on Kharyaga field mid 2012. Kharyaga field is a NW-SE elongated anticline lying 60km north of the Artic polar Circle, in Nenets Autonomous Territory on Kolva regional swell. Total E&P Russie (TEPR) is operating Object 2 and 3 of this field. The Object 2 accumulation, subject of this study, is characterised by oil bearing Devonian carbonate reservoir with a gross thickness of 160–250m with high vertical and lateral heteregenity. Current production from Object 2 is around 23 kbopd.

The purpose of the synthesis is to create new and more reliable geological and dynamic models in order to better optimize next development phase and fine tune production profiles estimation. Geosciences and Reservoir synthesis imply the following: gathering all available information starting from newly reprocessed seismic data, various static well data and ending by well tests and production history over the whole life of the field,depth analysis and putting in coherence of all information in order to better address the various heterogeneity scales and reservoir characterization.

There are two main challenges related to characterization of existing heterogeneities: defining the fault pattern including sub seismic faults, understanding karst and fractures distribution,defining vertical and lateral sedimentary heterogeneity as well as reservoir extension.

Many experts and specialists are involved in this synthesis. The joint approach between geologist and geophysicist, based on tectno-stratigraphic timing and stress field combined with seismic attributes and thickness map, allowed to proposed a new fault pattern which honors FMI data and dynamic interference tests recorded during the 14 years of field production. Interpretation of newly reprocessed seismic data helped the sedimentologists in inter-well correlation. Looking just at seismic amplitudes cubes, it was possible to propose a new sedimentary model and change inter-well correlation accordingly. This led to the updated vision of the reservoir.
Geospline: Mathematical Model of 3D Complex Geological Medium
Authors: Maximov G.A. , Larichev V.A. , Lesonen D.N. , Derov A.V.
Published: October 2013

Abstract

The original approach and releasing software GEOSpline for modeling of complex 3D geological structures are developed. The joint use of parametric b-splines for approximation of arbitrary distributed in space data, to build separate geophysical surface, and volume splines for approximation of continuous volume properties together with special tree-hierarchial structure for ordering of separate surfaces in the model and cutting of their intersecting parts are the original approaches of the development. The developed mathematical model for construction of 3D geological structures with faults allows to create complex geological structures by real data with their 3d visualization, to build adaptive grids for finite-difference and finite element modeling, as well as to make calculations of seismic and other fields in real geological structures.

Introduction

When the current structure of oil reserves is regressing (number of big reservoirs with high capacity collectors is decreasing, their geographical location is worsening) the requirements to detail and accuracy of the geological medium description increase. These requirements are determined by necessity of searching and determinating of thin and structurally complex oil and gas collectors. All of this causes necessity of creation of more accurate and detail models of the geological medium for solving of direct and invers geological and geophysical problems.

The modern level of detail and accuracy of the geological medium description, what is necessary for searching and selection of prospective oil and gas horizons, requires the using of three-dimensional models of geological structures to solve both direct and inverse problems of seismic profiling. Thus, the three-dimensional geological modeling of complex structures with internal boundaries of real arbitrary distributed data for further three-dimensional visualization and calculation of geophysical fields in such structures is an actual problem.
The Principles of Selection and Optimization of Drilling Fluid for Drilling Operations in the Vankor Field in Eastern Siberia
Authors: Kharitonov A.. , Burdukovsky R.. , Pogorelova S.. , Sidubaev S..
Published: October 2013

Vankor is the flagship mine of the Rosneft Oil Company in Eastern Siberia. Developmental drilling began there in mid-2006. The pace of the construction of wells and surface facilities has been among the fastest in Russia, with a 15 to 20% acceleration in annual drilling activities.

The Vankor field is located in the northwest of the Krasnoyarsk Territory in the Turuhansk area, near the Arctic Circle, and it is quite removed from population centers (the closest populated area being the town of Igarka at a distance of 142 km away). Motorized transportation is used on winter roads from December to May only. Because of these conditions, strict criteria must be applied in the planning and selection of drilling fluid for the drilling of wells. These criteria include environmental, technical, technological, geological, logistical, and economic aspects that are not satisfied when using classical potassium chloride (KCl) inhibited solutions.

This paper discusses the selection process for the drilling fluid used in the Vankor field, the evolution of its formulations, and laboratory studies of various geological samples. It also discusses the application expertise required, as well as the technical and economic benefits and advantages of using a highly effective, inhibited, non-dispersed drilling fluid system based on a fresh water solution at the Vankor field.
Hybrid Drill Bit For Horizontal Drilling In Highly Interbedded Formations Of Timano-Pechora Arctic Fields
Authors: Kamatov K..
Published: October 2013

Timano-Pechora is one of the fast growing hydrocarbon-containing areas of Russian Federation, possessing reserves of already discovered and being developed fields, as well as high offshore potential. Operators’ goals on intensive area development and increased well production rates were followed by a splash of lateral and sidetrack drilling in recent years. Doubtless, the upcoming huge regional projects would require a multiple increase of horizontal drilling work scope at an early date.

On this background, it’s necessary to distinguish a range of oilfields with highly interbedded terrigenous and carbonate rocks in their structure. Just 5 years ago drilling companies ran only insert cone bits of high IADC code with enhanced gauge protection due to hardness and abrasivity of rocks. Such a conservative method led to low ROP and high NPT for additional round-trips. Modern generations of PDC drill bits allow successful passing of homogeneous carbonate interval with a displacement motor (PDM) in few runs. However, deeper lying frequent interbeds of shale, siltstone, limestone and dolomite cause unpredictable torque on PDC bit, severe bottomhole vibrations and loss of BHA steerability. Therefore, drilling and service companies are forced to run roller cone bits to ensure planned build-up rates and hole quality. The conducted analysis of field data outputs that no type of drill bit (i.e. roller cone or PDC) can be effective enough under described conditions.

This paper depicts alternative combinations of BHAs and drill bits to provide higher technical and economical drilling indicators. It mainly focuses on the pair of conventional PDM with hybrid drill bit utilizing combined PDC and roller cone bits elements. Recommendations on drill bit selection are given based on case studies in similar conditions from two wells of Canadian Arctic oilfield.
"Secure Drilling" Services for Safe and Effective Drilling
Authors: Kulikov Stanislav , Veliev Gurban , Bakhtin Andrey , Zakomoldin Vitaliy
Published: October 2013

In the past few decades, well depths and conditions have grown significantly, and the regulatory environment has become more comprehensive. High temperatures and pressures, and narrow-to-nonexistent drilling windows have hindered the development of assets and substantially increased risks and the cost of hazard mitigation generated by high drilling costs and time spent on well control incidents.

From land rigs to semisubmersibles, closing the loop opens the door to a flexible set of drilling capabilities that improve safety of personnel, environment, and equipment while optimizing economics. In each drilling operation the key to success is the use of versatile closed-loop drilling methodologies to meet varied operational and economic objectives.

In Arctic conditions, the challenges are to overpass potential risk of environmental spills and optimize AFEs through mitigation of NPTs. Rotating control devices (RCD), which has secured a strong position in the industry, will be a considerable source to hit above targets. RCDs—whether as a top on the BOP stack or as an integral part of a riser system — is a safe and easy way to monitor pressure within the closed loop and divert the drilling fluids safely from the rig floor.

Integration of RCD in conjunction with early kick/loss detection and control systems through manipulation of surface backpressure, allows access to more accurate real-time downhole data, resulting in the ability to better manage downhole pressures. Changing choke settings results in a rapid modification of bottomhole pressure throughout the wellbore without the cost and effort of changing mud weight.

The closed loop method cuts across operational and economic applications to enable, for instance, the drilling of previously undrillable.
Development of Solutions for Arctic Offshore Drilling
Authors: Wassink Alain , van der List Remco
Published: October 2013

The paper discusses the origins and development of a portfolio of Arctic mobile offshore drilling unit designs, comprising both jack-up type and drillship type solutions. These designs are developed to address the specific challenges of exploratory and development drilling in the Arctic, and are developed to cover the full extent of the Arctic, from the very shallow to the deep water. The paper describes both challenges and proposed solutions, as well as providing an outline of the designs.

Drilling offshore in the Arctic poses many challenges to the field operators and drilling contractors alike. More capable and bespoke solutions than available today are required to enable commercially feasible exploration and field development in the Arctic. The key factor to the drilling part is total well cost, which requires an integral solution for the drilling system to be deployed, as opposed to the traditional day rate model of the industry. The design of the drilling rig plays a central role in this, and new designs for Arctic MODUs will be required to achieve this goal.

One of the dominant factors in total well cost in the Arctic is the length of the drilling season and subsequently the ability to drill one or more wells in a season. Lowering well cost by extending the season or even enabling year round drilling is a key factor. Efficient MODU designs, allowing maximum use of the available drilling season can further enhance economics.

The paper discusses the main challenges, such as harsh environmental conditions, ice loads, shallow water challenges and logistics, and their influence on the design of Arctic MODUs. It also discusses the main principles applied in development of these designs, related to subjects such as technology qualification, safety and environmental concerns. Finally, it provides an overview and outline of the proposed design solutions.
Optimized Particles Size Distribution Lightweight Cement at Low Temperatures: Case Study from Eastern Siberia, Russia
Authors: Malyshev Alexander , Doronina Tatiana , Popov Mikhail , Ryabchikov Alexander , Shulga Vladimir
Published: October 2013

Verkhnechonskoe oil field is situated in Eastern Siberia, Russia. This field is quite unique due to low formation temperatures –the bottom hole static temperature does not exceed 13 degC. This low temperature environment together with low formation fracture gradient present unique challenges for cementing operation. Conventional lightweight system extended by sodium silicate does not meet client well acceptance criteria – no sustained casing pressure (SCP) and successful annular space pressure test due to delayed compressive strength development and relatively high permeability of set cement stone. Failure to meet those criteria’s result in remedial cementing operations and delay of putting wells in production. To overcome this challenge new lightweight cement system based on optimized particles size distribution is successfully introduced for primary cementing of production casing on Verkhnechonskoe field. Implementation of the novel lightweight cement system with high solid volume fraction has allowed client to overcome highlighted issues. Rapid compressive strength development also helped in reduction of well construction time due to shorter wait-on-cement period.

This paper outlines an approach based on the usage of optimized particles size distribution lightweight cement system in low temperature environment included three steps of cementing operation: design of cement system, implementation and evaluation results.
A Novel Approach to Fluid Selection to Drill Pay Zones in Eastern Siberia: An Engineered Oil-in-Water Emulsion
Authors: Kharitonov Andrey B. , Burdukovsky Ruslan , Pogorelova Svetlana , Rodin S. V. , Kostarev N. A. , Usenko A. Yu. , Khampiev E. D.
Published: October 2013

The majority of promising oil and gas fields in Russia are located far north in remote, sparsely populated areas lacking infrastructure. The Srednebotuobinsky oil and gas field is one such example with stringent well construction, planning, and design requirements, particularly related to the selection of drilling fluids.

Drilling fluid selection is essential to help: achieve successful well construction, ensure wellbore stability, carry out and suspend cuttings, establish hydrodynamic equilibrium in the "wellbore-reservoir" system, prevent the ingress of gas, oil, and water, plug permeable formations, and preserve reservoir properties of the productive formation.

The main criteria for selecting a drilling fluid includes compatibility with the geological section, meeting design parameters, and environmental compliance/personnel safety. Projects in the far north are subject to additional criteria related to logistics, such as the ability to transport necessary materials by truck, the availability of roadways limited to the winter months, and abnormally low ambient temperatures.

This paper presents optimization results for a drilling fluid selected for penetration into a productive formation with an abnormally low reservoir pressure in the Srednebotuobinsky field. Also included are drilling fluid formulations, laboratory testing results, hydraulic calculations, and the technical and economic benefits of using a novel mud, which is a direct emulsion of mineral oil in water with biodegradable polymers.
Complex of New Solutions for Well Cementing in Deep North Conditions
Authors: Korostelev A. S. , Beley I. I. , Gilfanov V. R.
Published: October 2013

The development of Arctic offshore and outer continental shelf outlines for specialists a series of complex technical tasks related, in addition, to well construction (drilling and casing). Poorly developed transport infrastructure, severe climate conditions, permafrost zones and other complications require the application of an integrated approach to well drilling and construction design.

The description of innovation integrated of production solutions and approaches, applied at well cementing in the fields of the Yamal Peninsula, including the solution of a cementing unit with mixing and pumping systems (with an integral dry mixture pneumatic system) integrated into the echelon rig, is presented in the paper. And also the description and analysis of application of the unified compositions of cement slurries and preflushes, specially developed for this "on-the-fly" mixing system, that enable to facilitate materials’ delivery and storage operations at remote locations and encourage simplifying cementing technologies.
New Technologies Application to Solve Practical Challenges in Exploration and Development of HC in the Russian Sector Of Caspian Sea
Authors: Deliya S. V. , Valisevich A. Y. , Abetov A. E. , Bulybenko K. A. , Khusainov R. F.
Published: October 2013

Hydrocarbon deposits in the Russian sector of the Caspian Sea are characterized by a considerable variety of traps in a

wide stratigraphic range, substantial lateral substitution of lithological and reservoir properties, variation of structural and morphological characteristic, fluid saturation and hydrocarbons phase composition. Exploration and development of these fields are complicated by the fact that they are located in challenging ice conditions zone (in wintertime), in the region with the strictest environmental requirements where LLC "LUKOIL" is the pioneer in offshore projects.

To overcome successfully geological, technical and climatic difficulties LLC "LUKOIL – Nizhnevolzhskneft" supported technically by "Schlumberger" applied a number of unique technological solutions concerning drilling muds, stem assemblies, geo-steering and geomechanics, wireline and mud logging, hydraulic fracturing, high-performance drilling bits, as well as intelligent completions, application of up-to-date high-performance tools, advanced software, methods of processing and interpretation of geological and geophysical data. Overview and analyze these solutions is the objective of this article.

Availability of theoretical and practical resources while implementing the project, mutually-beneficial cooperation of all interested parties together with innovative decisions supported by corporate management became a key point of success in fulfillment of capital-intensive projects by LLC "LUKOIL Nizhnevolzhskneft" in the Russian sector of the Caspian Sea.

It is obvious that there are quite serious reasons for further application of new technologies according to proven algorithm: problem statement-finding solutions – planning- implementation- analysis of obtained results, recommendations working-out, and establishment of close partnership relations between Project operator and multifunctional engineering company.

Further improvement of drilling technologies, optimization of hydrocarbon production, provision of the necessary facilities for field development, adaptation of DOF concept, geological monitoring while well drilling, application of new scientifically dereived, technologies and advanced logging tools without chemical sources, drilling mud and bits, using modeling and prediction in real time are considered as prospective conceptual ways.

It can be said with confidence that fulfillment of the above mentioned measures and already implemented solutions at the Northern Caspian region will change dramatically approaches to hydrocarbon deposits development, and will help to explore hydrocarbon potential to the full extent in the Russian sector of the Caspian Sea.