bluuebunny/crossref_metadata_2025 huggingface dataset:
Tendencias del uso de drogas en la Ciudad de México: Encuesta de estudiantes, octubre 2012
Authors: Villatoro Velázquez Jorge Ameth , Mendoza Meléndez Miguel Angel , Midiam Moreno López Midiam , Oliva Robles Natania , Fregoso Ito Diana , Bustos Gamiño Marycarmen , Fleiz Bautista Clara , Mujica Salazar Roxana , López Brambila Miguel Angel , Edina-Mora Icaza María Elena
Published: July 2016

Introducción. Los estudios epidemiológicos en nuestro país muestran un incremento en el consumo de drogas ilegales y de alcohol. La edad de inicio también ha disminuido, especialmente en el consumo de alcohol. Por su parte, el consumo de inhalables se ha incrementado en forma importante, especialmente entre las mujeres jóvenes. Son diversos los factores asociados al consumo de drogas, pero de manera importante destacan el desarrollo de estrategias de resistencia, junto con sus habilidades sociales subyacentes, así como los estilos parentales de crianza. Método. La presente es una encuesta probabilística en población escolar de secundarias y bachilleratos de la Ciudad de México que se levantó en noviembre del 2012, con representación a nivel de cada Delegación. La muestra fue de 26 503 alumnos. La información se obtuvo mediante un cuestionario estandarizado y validado en encuestas anteriores. Resultados. El consumo de tabaco disminuyó significativamente (de 44.3% a 41.0%), el 32.9% de los adolescentes comenzó a utilizar tabaco antes de los 13 años. El 68.2% consumió alcohol alguna vez; en tanto que la edad de inicio promedio de consumo de esta sustancia se mantuvo en los 12.6 años. La prevalencia de consumo de drogas alguna vez aumentó de 21.5% a 24.4%. La mariguana es la droga de preferencia en la población estudiantil (15.9%). También se encontraron incrementos en la presencia de abuso sexual, mientras que el intento suicida disminuyó. Discusión. Los resultados muestran el continuo crecimiento que tiene esta problemática, aunque los inhalables se mantuvieron constantes y el tabaco disminuyó de manera importante. Dado estos resultados, es una tarea preponderante dedicar más esfuerzos a la prevención con estudios e intervenciones evaluadas para preescolar y primaria, así como para los padres de familia y los maestros.
The role of diagnostic imaging in evaluation of nasal and paranasal sinus pathologies
Authors: Verma Jagram , Rathaur Shiv Kumar , Mishra Sanjeev , Mishra A.K.
Published: July 2016

Background: The objective of the study was to evaluate the role of radiological imaging in correlation with clinical finding in assessing the severity of nasal and paranasal diseases and in differentiating benign pathologies from malignant sinonasal masses.

Methods: In this study 50 patients with complaints of nasal obstruction , nasal discharge, epistaxis were subjected to detailed clinical examination and evaluated radio logically with X ray PNS, CT and MRI of PNS and biopsy taken from nasal and paranasal masses for histopathological confirmation.

Results: The main presenting complaints were nasal obstruction (82%) followed by nasal discharge (66%), headache and allergic symptoms (52%). The most common type of disease involving nose and paranasal sinuses was inflammatory disease (86%), followed by benign disease (10%) and malignant disease were found in (4%) of cases. The most common benign disease involving nose and paranasal sinuses were inverted papilloma (80%), followed by hemangioma of nasal septum (20%). The most common radiological pattern of sinus involvement is osteomeatal type seen in 38% of cases, followed by unclassified pattern in 23.8%.Maxillary sinuses were most commonly involved in the study 82% cases.

Conclusions: CT is the modality of choice in imaging the paranasal sinuses for evaluating the chronic diseases and associated complication and provides a reliable pre-operative road map. MR imaging plays a critical role in evaluation of sino nasal tumors.
USO DO PROCEDIMENTO DE MÁSCARA PARA VERIFICAR RELAÇÕES DE CONTROLE DE ESTÍMULOS EM MACACOS-PREGO
Authors: Cruz Ilara Reis Nogueira da , Picanço Carlos Rafael Fernandes , Barros Romariz Da Silva
Published: July 2016

Diferenças sutis entre as relações de controle planejadas pelo experimentador e aquelas efetivamente estabelecidas nos treinos discriminativos são frequentemente encontradas em estudos com participantes humanos com desenvolvimento severamente atrasado ou com sujeitos não humanos. Grande parte das vezes, essas diferenças só são identificadas por meio de testes. O presente estudo avaliou a viabilidade do uso do procedimento de máscara para verificar relações de controle em discriminação condicional (emparelhamento ao modelo por identidade) com macacos. Foram utilizados dois macacos da espécie Cebus cf. apella como sujeitos. O procedimento consistiu no treino de emparelhamento ao modelo por identidade e testes de relações de controle, nos quais ora o S+, ora o S– era substituído por uma janela vazia (máscara). Com a remoção desses estímulos em tentativas de sonda, avaliou-se sua participação na determinação de diferentes tipos de relações de controle do comportamento de escolha: Controle pelo S– ou Controle por Rejeição; Controle pelo S+ ou Controle por Seleção; ou ambos, ou seja, Controle Misto. Os dados obtidos mostram que (1) as discriminações estabelecidas não deterioraram com a aplicação dos testes e (2) as escolhas nas tentativas de sonda permitiram inferir com sucesso as relações de controle vigentes. O sujeito M09 apresentou Controle por Rejeição inicialmente em uma das relações condicionais e Controle Misto nas outras relações testadas. O sujeito M16 apresentou Controle Misto em todas as relações testadas. Com esses achados, o procedimento de máscara pode ser considerado adequado para verificação de relações de controle em discriminações condicionais com macacos como sujeitos. Encoraja-se o uso desse procedimento em estudos futuros sobre classes de equivalência com não humanos para verificar se de fato foram estabelecidas relações condicionais arbitrárias modelo-S+ (i.e., Controle por Seleção ou Misto). Palavras-chave: procedimento de máscara, emparelhamento ao modelo por identidade, Cebus cf. apella.
CHRONIC MILD STRESS: UM ESTUDO SOBRE A INTERAÇÃO ENTRE SUBMISSÃO AO PROTOCOLO DE ESTRESSORES, COMPORTAMENTO OPERANTE E PRIVAÇÃO
Authors: Pereira Clarissa Moreira , Sério (in memoriam) Tereza Maria De Azevedo Pires
Published: July 2016

O chronic mild stress (CMS) é um modelo experimental para estudo dos efeitos da exposição a esses estressores no comportamento dos sujeitos. No presente estudo, pretendeu-se verificar se o protocolo completo, e não apenas alguns estressores apresentados isola¬damente (privação de água e privação de alimento), seria responsável pelos efeitos comumente descritos na literatura (diminuição na ingestão e preferência por substância doce pela submissão ao protocolo). Foi verificada, também, a interferência de sessões operantes em esquema concorrente (água-sacarose) nos efeitos considerados. Os resultados encontrados foram analisados com relação à ingestão de líquidos nos testes da gaiola viveiro. Tanto a privação, isoladamente, quanto o protocolo incompleto (sem privação) produziram efeitos na ingestão e preferência de líquidos. Além disso, foi encontrada diferença nos valores de ingestão entre os sujeitos que passaram por sessões operantes e os sujeitos que não passaram (valores maiores para os primeiros). Com relação aos resultados, duas sugestões são colocadas: (a) a manipulação neonatal pode ser uma variável responsável pela não produção de todos os efeitos do protocolo no comportamento dos sujeitos; e (b) a exposição prolongada à sacarose pode ter efeitos similares à analgesia nos sujeitos, fazendo com que os possíveis efeitos do protocolo de estressores não sejam produzidos. Palavras-chave: protocolo de estressores, privação, comportamento operante, manipulação neonatal, exposição à sacarose.
EFEITOS DE INSTRUÇÕES PRELIMINARES, ESPECÍFICAS E MÍNIMA SOBRE UMA TAREFA EXPERIMENTAL E SEGUIMENTO DE INSTRUÇÕES
Authors: Teixeira Júnior Ronaldo Rodrigues , Paracampo Carla Cristina Paiva
Published: July 2016

Estudos sobre regras têm mostrado que alterações em trechos de diferentes tipos de instruções podem interferir no desempenho de participantes de pesquisa. O presente trabalho teve como objetivo avaliar os efeitos da apresentação de instruções preliminares, específicas e mínima sobre a realização de uma tarefa experimental e seguimento de instruções. Seis estudantes universitários foram expostos a um procedimento de escolha de acordo com o modelo, fazendo-se uso de um delineamento de sujeito como seu próprio controle. Os participantes foram divididos em duas condições que diferiam quanto ao tipo de instrução específica apresentada (correspondente ou discrepante). Nas Fases 1 e 2, os participantes não recebiam nenhuma instrução preliminar e eram expostos a instruções mínimas e específicas, de acordo com sua condição. Nas Fases 3 e 4, os mesmos participantes eram expostos a fases idênticas às anteriores, mas após terem recebido instruções preliminares, que incluíam descrições da tarefa, materiais e consequências. Os resultados mostraram que o fornecimento de instruções preliminares favoreceu a realização da tarefa e o seguimento de instruções, principalmente entre participantes que receberam instruções correspondentes. Esses dados sugerem que novos trechos de instruções preliminares precisam ser investigados para conhecer seus efeitos. Palavras-chave: instruções preliminares, instruções específicas, instrução mínima, escolha de acordo com o modelo, estudantes universitários.
Reflexiones sobre el campo de las relaciones internacionales en Latinoamérica. Una mirada a partir de las publicaciones
Authors: Abadía Adolfo A. , Milanese Juan Pablo , Fernández Juan José
Published: July 2016

Este trabajo presenta una reflexión sobre el desarrollo más reciente del campo de las relaciones internacionales en América Latina. Se apoya principalmente en un análisis bibliométrico de las principales revistas latinoamericanas que publican estudios afines, y en un análisis cualitativo de publicaciones destacadas provenientes de algunos de los departamentos de Ciencia Política y Relaciones Internacionales de la región. Sin pretender ser un estudio exhaustivo del estado del campo en la región, el ejercicio recoge información novedosa y de utilidad para construir una reflexión sobre debilidades, fortalezas y cuentas pendientes del área de estudios en Latinoamérica. El trabajo se cierra con una serie de reflexiones y sugerencias que buscan resaltar la importancia de un mayor debate teórico y, particularmente, metodológico para el fortalecimiento del estudio de la política internacional en –y desde– América Latina.
Nada nuevo qué contar: la irrelevancia de los aportes a la teoría de las relaciones internacionales en América Latina
Authors: Garay Javier , Martínez Miguel
Published: July 2016

Después de participar en muchos congresos de Relaciones Internacionales en los últimos diez años en América Latina, es recurrente el tema de si existe o debe existir un punto de vista latinoamericano de las relaciones internacionales. En este artículo se muestra que esta insistencia en los congresos no es algo que se refleje en la creación de conocimiento sobre la disciplina, puesto que la producción científica no muestra dicha tendencia. Por otro lado, se demuestra que esa insistencia, que resulta casi una obsesión y, por tanto, una necesidad, no es tal, puesto que el área geográfica no debe ser el factor fundamental que determine la creación de conocimiento.
Structural Change and Income Inequality – Agricultural Development and Inter-sectoral Dualism in the Developing World, 1960-2010
Authors: Andersson Martin P. , Palacio Chaverra Andrés F.
Published: July 2016

Structural change consists of the long-term changes in the sectoral composition of output and employment. We introduce a structural change perspective to the study of income inequality in 27 countries of the developing world for the period 1960-2010. The service sector has become the main employer, but the agricultural sector is central to the income distribution because poverty is mostly rural, and the labor surplus is high. We decompose the sectoral composition of aggregate labor productivity at the country level, divide the countries into agrarian, dual (beginner, intermediate and advanced), and mature economies and use the inter-sectoral productivity gap to test the effect of structural change on income inequality. We confirm increases in agricultural productivity everywhere and find that the inter-sectoral gap is positively associated with income inequality. The effect is negligible in agrarian and advanced economies but powerful in dual beginner economies: an increase of 1% in the inter-sectoral gap increases income inequality by 0.5%. The effect peters out in dual intermediate economies and disappears completely in dual advanced economies. Finally, redistribution has been the key to compensating the losers in the income changes, particularly for those entering the non-agricultural economy.
El nexo migración-desarrollo y la economía política de la vivienda en América Latina
Authors: Zapata Gisela P.
Published: July 2016

En los últimos años, varios gobiernos de América Latina han promovido la noción de que los migrantes pueden actuar como agentes de desarrollo, principalmente mediante la canalización de remesas hacia sectores específicos como los de vivienda y financiero. Los estudios desarrollados hasta el momento aún no han expuesto cómo estos hechos están reconfigurando la economía política de la vivienda en la región. Con base en datos empíricos recogidos en ambas puntas de la cadena migratoria Colombia-Reino Unido, este artículo sostiene que estos esfuerzos tienen como objetivo institucionalizar los flujos de remesas y las actividades socioeconómicas transnacionales que de ellas se derivan. Estos esfuerzos están fundamentados en el reposicionamiento de la vivienda como un bien de consumo a un bien de inversión y motor del crecimiento económico, al igual que del sector financiero como el principal medio de los hogares para acceder a vivienda pública y privada, y a otros servicios básicos. Estas acciones han tenido lugar en el contexto de un proceso más amplio de financialización de la agenda global de pobreza durante las últimas tres décadas.
Estrutura populacional de Macrobrachium amazonicum em dois lagos de várzea da Amazônia
Authors: COSTA Tiago Viana da , MATTOS Luciana Antunes de , MACHADO Noedson de Jesus Beltrão
Published: July 2016

Macrobrachium amazonicum é uma espécie de camarão amplamente consumida pelas comunidades tradicionais da Bacia Amazônica, sendo capturada de forma artesanal ao longo de todo ano e especialmente no perí­­odo de seca amazônica, quando se concentra no interior dos lagos de várzea. O objetivo deste trabalho foi avaliar a estrutura populacional deste crustáceo nos lagos do Macurany e do Catispera, ambos situados no municí­­pio de Parintins/Amazonas, a partir dos seguintes aspectos: comprimento total, razão sexual, distribuição temporal, fecundidade e perí­­odo reprodutivo. Espécimes de M. amazonicum foram coletados mensalmente, de setembro de 2009 a abril de 2010, utilizando-se artes de pesca regionais (camaroeiras). Considerando os dois lagos, os tamanhos médios de machos e de fêmeas e a fecundidade total foram significativamente maiores no lago do Catispera. A maior fêmea oví­­gera foi registrada no lago do Catispera (56,2 mm de CT) e a menor, no lago do Macurany (18,3 mm de CT). Indiví­­duos sexualmente indiferenciados foram capturados ao longo de todo o perí­­odo de coletas nos dois lagos. Na população estudada, verificou-se maior proporção de fêmeas, sendo o maior desvio registrado no lago do Macurany (1:2,6). O perí­­odo de enchente-cheia (dezembro-abril) foi identificado como o de ocorrência do pico reprodutivo desta espécie na região. Possivelmente, o momento de maior vazão do rio e transbordamento da água dos lagos favorece a dispersão das larvas.
Avaliação de uma rede-de-arrasto camaroeira estruturalmente modificada
Authors: DOMINGOS Marcelo Manoel , RODRIGUES-FILHO Jorge Luiz , FARIAS Eduardo Guilherme Gentil de
Published: July 2016

Impactos decorrentes da captura de camarões com redes de arrasto têm gerado discussões ao longo das últimas décadas. Buscando colaborar nos esforços para reduzir os descartes da modalidade, este trabalho propõe restringir a abertura vertical das redes de arrasto, evitando a captura de indiví­­duos que se encontrem na coluna d'água. Adicionalmente, testou-se um dispositivo de redução dirigido í­Â  exclusão de juvenis de peixes teleósteos. Ciente das implicações do consumo de combustí­­vel, também se avaliou a resistência de arrasto dos petrechos como indicativo de consumo de combustí­­vel. Para avaliar o proposto foram realizados 18 arrastos entre dezembro de 2014 e fevereiro de 2015, divididos em três campanhas de pesca experimental na enseada da praia da Pinheira (SC), alternando entre as redes modificadas (CT e ST) e a utilizada pelos pescadores locais (RN). A rede RN apresentou as maiores capturas de camarão (CA) e ictiofauna acompanhante (FA). Em contraponto, com as redes modificadas, obtiveram-se as maiores proporções de CA em relação í­Â  RN, assim como diminuição de FA entre 50% e 80%. As resistências das redes indicaram que os petrechos modificados proporcionam redução do consumo de combustí­­vel. Os resultados demonstram que as modificações nas redes contribuem para a redução dos descartes, comuns nos arrastos.
Rehabilitación de la alimentación por vía oral en niños con enfermedades respiratorias crónicas y nutrición enteral prolongada
Authors: Barja Salesa
Published: July 2016

Introducción: la rehabilitación de la alimentación por vía oral (RVO) es compleja en pacientes que han recibido nutrición enteral (NE) prolongada.Objetivo: describir este proceso en niños con enfermedades respiratorias crónicas y sonda nasoenteral (SNE) o gastrostomía (GT).Pacientes y métodos: Estudio retrospectivo con revisión de registros clínicos de niños con NE mayor a dos meses, ingresados entre 2005 y 2014 al Hospital Josefina Martínez. Resultados: Se incluyeron 116 pacientes, con mediana de edad 10 meses (Rango: 3 a 101), 56% hombres. Diagnóstico: 34,5% Daño pulmonar crónico postinfeccioso (DPC), 29,3% Insuficiencia respiratoria por enfermedad neuromuscular, 19% Displasia broncopulmonar y 17,2% Enfermedad de la vía aérea. Con traqueostomía: 82,8%. Eran usuarios de GT 89,7% y de SNG 10,3%, instaladas con mediana de edad 6 meses (0 a 74), por ingesta insuficiente (6,6%) o trastorno de deglución (92,4%). Del grupo total, 36,2% (42/116) tenía indicación de RVO, los cuales habían recibido NE durante 12,2 meses (2 a 41); de estos 50% (21/42) logró alimentarse exclusivamente por vía oral (91% SNG y 35,4% GT, Chi2 p= 0,023), 14% parcialmente y 36% no lo logró. El tiempo para lograr la vía oral exclusiva fue de 9,75 meses (0,5 a 47), sin diferencia por edad, sexo, vía de acceso, duración NE ni presencia de enfermedad neurológica.Conclusión: en pacientes con enfermedades respiratorias crónicas graves y NE prolongada, la RVO es un proceso lento pero posible: 64% lo logra de modo completo o parcial.
Machining of a Rock Surface Shaver with a Piezoelectric Actuator forIn situAnalysis in Lunar and Planetary Exploration
Authors: Furutani Katsushi ,   Toyota Technological Institute, Kagami Eiji ,   ,
Published: July 2016

Future lunar, planetary, and asteroid exploration will strongly demandin situanalysis of rock samples to obtain data related to various aspects. For precise composition analysis, a sample surface should be smoothed. In this paper, a surface shaver with a piezoelectric actuator is proposed and its machining performance in air is investigated. Shaving teeth are mounted at the ends of a pair of lever mechanisms. The device is pressed through four springs onto the workpiece with a linear actuator. When a sinusoidal voltage of 50 Vp-pand an offset voltage of 25 V were applied, the resonance frequency was 556 Hz and the unloaded amplitude of the shaving teeth was 0.77 mmp-p. Basalt workpieces were machined for 10 min in air. Increasing the thrust force reduced the surface roughness, although the amount removed diminished with a further increase in the thrust force. The surface roughness varied widely not only due to the amount removed but also due to containing the pores.
Study of Rotary-Linear Ultrasonic Motor Output Shafts
Authors: Kanada Ayato ,   Toyohashi University of Technology, Mashimo Tomoaki , Terashima Kazuhiko ,   ,
Published: July 2016

We propose output shafts with a preload generation mechanism to improve the output torque and thrust force of the rotary-linear ultrasonic motor. The stator is comprised of a single metallic cube with a through-hole, and the output shafts are inserted into the hole to generate motion in both its circumferential and axial directions arbitrarily. In this paper, two design concepts for optimizing the preload using the output shafts are examined. The first involves a cylinder shaft with micron-order accuracy diameter realization. The cylinder shaft makes contact with the entire inner surface of the stator and generates a preload between the stator and shaft. The second concept employs a spring shaft having a slightly larger diameter than the stator hole, which expands in the radial direction and generates the preload. Experiments show that these design concepts improve the output torque and thrust force.
A Spherical Motor Driven by Electro-Magnets Based on Polyhedrons
Authors: Gofuku Akio ,   Graduate School of Natural Science and Technology, Okayama University, Adachi Kazuki , Okido Yuta , Yano Tomoaki ,   ,,   Research Institute of Fundamental Technology for Next Generation, Kinki University
Published: July 2016

This paper describes the development of a spherical motor, hereinafter called “14-12 spherical motor.” This spherical motor utilizes two polyhedrons – a truncated regular octahedron and a regular dodecahedron – for the arrangement of permanent magnets on the rotor and electro-magnets on the stator. The 14-12 spherical motor has two types of rotation axes and six rotation axes in all. Five-phase alternating current was applied to the electro-magnets to rotate the rotor. This study also developed a simulation model for the 14-12 spherical motor to numerically simulate the dynamic behavior of the motor. Basic performance was measured and simulated to evaluate (1) the relation between rotation speed and maximum output rotation torque and (2) cogging torque. Waveforms of the five-phase alternating current were improved using the simulation model in order to increase output rotation torque for the rotation axis with the smaller torque.
Age of Compensation – Challenge and Chance for Machine Tool Industry
Authors: Wegener Konrad ,   Institute of Machine Tools and Manufacturing, ETH Zürich, Weikert Sascha , Mayr Josef ,   ,,   Inspire, Transfer Institute for Mechatronic Systems and Manufacturing Technology, Zürich, Switzerland
Published: July 2016

This paper firstly gives an introduction to the development of machining accuracy, and the contemporarily feasible compensations in the field of machine tools. The metrological means used for primarily static and kinematic compensations are discussed. Furthermore the focus is laid on the kinematic, dynamic and thermal compensation approaches, using various examples for these fields. The different phenomena to be compensated and the associated models are discussed in detail. As conclusions to be drawn, the repeatability of the systems, the ability of the models used in the CNC to represent the systematic behavior and the capabilities of the CNC can be seen as significant prerequisite for a successful application of compensation means.
Ultraprecision Cutting of Nickel Plated Mold for X-Ray Mirror
Authors: Suzuki Hirofumi ,   Chubu University, Okada Mutsumi , Masuda Yuki , Namba Yoshiharu , Miura Katsuhiro , Morita Shinya , Yamagata Yutaka ,   ,,   MITAKA KOHKI Co. Ltd, Tokyo, Japan,   Tokyo Denki University, Tokyo, Japan,   RIKEN, Saitama, Japan
Published: July 2016

To improve the machining preciseness of X-ray telescope mirrors for astronomical use, the molds of electroless nickel and electro nickel are diamond-turned, and the tool wear and machining accuracy are then quantitatively evaluated. The machined surface roughness is measured and discussed in terms of the effects of cutting conditions on the resulting quality. Finally, the actual nickel-plated molds of X-ray mirrors are test cut, and their form accuracy and surface roughness are measured and evaluated. These experiments reveal that a surface roughness of 0.5 nm Ra and a form accuracy of 0.1 μm P-V can be obtained under the optimized cutting conditions.
Harnessing the Power of Type-2 Fuzzy Logic System to Achieve Improved Permeability Prediction Accuracy in a Hybrid Setting
Authors: Olatunji S. O. , Selamat Ali , Azeez Abdur Raheem
Published: July 2016

The unique power of type-2 fuzzy logic system is demonstrated in this work by using it to improve the prediction accuracy of permeability in a hybrid intelligent model system. A hybrid intelligent model through the hybridization of type-2 FLS (T2) and extreme learning machines (ELM) is presented and have been shown to considerably achieved improved performance over the constituent models. It is generally believed that a hybrid scheme performed better than any of its constituent model and this work has fully corroborated this established slogan in the field of machine learning and data mining. ELM, as a learning tool, have gained popularity due to its unique characteristics and performance. However, the generalization capability of ELM and other neural network based solutions often depend, to a large extent on the characteristics of the dataset, particularly on whether uncertainty is present in the dataset or not. This work proposes a hybrid system through the combination of type-2 fuzzy logic systems (type-2 FLS) and ELM, and then use it to predict permeability of carbonate reservoir. Type-2 FLS has been chosen to be a precursor to ELM in order to better handle uncertainties existing in datasets. The dataset first pass through the type-2 FLS for possible uncertainty handling and prediction and then the output from the type-2 FLS is then passed to the ELM for its training and then final prediction is done using the unseen testing dataset. Simulations have been carried out, using the built hybrid model, on different industrial permeability datasets obtained from middle Easter oil fields. Results from empirical studies show that the proposed hybrid system performed better than each of the constituent parts, though the improvement made over that of ELM performance is higher compared to that of type-2 FLS, possibly because type-2 FLS is originally adept at modeling uncertainties. Overall, the proposed scheme achieved improved permeability prediction accuracy thereby setting another unique area to be looked into in the quest to achieving better accurate predictions of other petro physical properties in the oil and gas field.
First Worldwide Successful Implementation of Coiled Tubing Compatible Novel Fiber Laden Diverter for Matrix Stimulation Using New Generation High Rate Fiber Optic Real Time Telemetry System
Authors: Malik Ataur R. , Yaseen Ali H. , Ogundare Tolulope M , Asiri Mohammed A. , Younis Abdulmohsin A. , Ahmed Danish , Omar Yosr
Published: July 2016

The objective of this paper is to highlight first worldwide implementation of coiled tubing (CT) compatible self-degradable fiber laden diverter for matrix stimulation treatment using enhanced high rate fiber optic real time telemetry system.

The self-degradable fiber laden diverter has been used in bullheading acid stimulation treatments aimed to maximize reservoir contact and enhance gas production. Recently, the physical properties of fiber has been re-engineered enabling them to be pumped down coiled tubing to enhance diversion and stimulation effectiveness. Coiled tubing with fiber optic real-time telemetry has been utilized for many years in Saudi Arabia for matrix stimulation treatments and well interventions as it provides real-time bottom-hole parameters such as pressure, temperature, casing collar locator, gamma ray, tension and compression as well as distributed temperature sensing (DTS) to optimize fluids placement. The successes achieved with previously used 2 1/8-in. bottom hole assembly (BHA) for coiled tubing with real time telemetry system offered the maximum rate of 2.0 barrel per minute (bpm), whereas this rate became a limitation to achieve the desired fiber concentration for diversion when fiber laden fluids were used. The low rate provision by 2 1/8-in. BHA led to the need of a new generation high rate 3.25-in. BHA to be used for coiled tubing fiber optic real-time telemetry system that can enable higher fiber concentration at higher pumping rates.

For the first time in Saudi Arabian Carbonate reservoir, the novel fiber laden diverter was used during matrix stimulation treatment through 180 ft. perforated interval with new generation 3.25-in. BHA for coiled tubing fiber optic real-time telemetry system. The DTS used with the new generation coiled tubing high rate fiber optic real-time telemetry system helped in preand post-treatment evaluation. After successful high pressure coiled tubing stimulation using self-degradable fiber laden diverter with visco-elastic surfactant based acid system, the well performance exceeded expectation. The encouraging result was achieved by uniform stimulation coverage throughout the long perforation intervals. The operation also proved the feasibility of using the new generation fiber optic real-time telemetry system in challenging environment.
New Method to Estimate IPR for Fishbone Oil Multilateral Wells in Solution Gas Drive Reservoirs
Authors: Abdulazeem A. , Alnuaim S.
Published: July 2016

Multilateral wells were used in the petroleum industry to increase hydrocarbon recovery from oil and gas fields as a cost effective technology. The objective of this study is to develop new empirical inflow performance relationship (IPR) model to estimate the productivity of fishbone multilateral wells producing from homogeneous oil saturated reservoirs.

A simulation model was built including a fishbone well producing from two-phase reservoir with a typical fluids and rock properties. Sensitivity analysis was done to study the effect of initial water saturation, porosity, permeability, oil gravity and bubble point pressure on the productivity of the fishbone well. Moreover, the influence of the well dimensions such as the number and length of the branched holes and distance between them were evaluated by running many scenarios. Then dimensionless IPR curves were generated by plotting bottom-hole flowing pressure versus oil production rate.

The results of the normalized IPR curves showed that the most significant factor influenced the fishbone well productivity is the number of rib holes. New empirical IPR correlation in Vogel's form for fishbone multilateral wells in solution gas drive reservoirs includes the number of rib holes as a variable was developed. The New IPR-fish bone model showed good results compared to generalize Vogel's model.

The obtained IPR model from this work will significantly improve the productivity estimation of complex fishbone multilateral wells producing from solution gas drive reservoirs.
Development and Field Test of ESP Reliable Power Delivery System
Authors: Xiao J. J. , Shepler Randall , Windiarto Yhossie , Parkinson Stuart , Fox Rob
Published: July 2016

In high H2S and high pressure/temperature fields, the average run life of ESPs is still limited to 3 years. Dismantle Inspection Failure Analysis (DIFA) results show that around 50% of ESP failures are directly or indirectly related to electrical delivery problems concentrated in about 200 ft between the packer and the motor. This paper presents a collaborative R&D effort to develop and trial test a Reliable Power Delivery System (RPDS) with the goal of extending the average ESP run life from the current 3 years to 10 years.

The development focuses on improving reliabilities of key power delivery components including packer penetrator, Motor-Lead-Extension (MLE) cable, and cable connection with the motor. The design integrates learnings from advanced completion and subsea technology, and includes new concepts, features and materials. Field pressure-testable connections are implemented to ensure proper field connections makeup. Factory testing incorporated a robust Highly Accelerated Life Test (HALT) methodology to simulate a ten-year service life.

Prototype components were designed, fabricated and tested. These components were integrated and subjected to a rigorous system integration test. After the comprehensive factory tests, a field prototype system was built and installed in an offshore well. The system has been operated and exceeds the trial test successful criteria of minimum 180 days run-life.

For years, engineers and companies have battled with ESP reliability, with electrical problems at the center of many failure causes. This paper shows the development and field trial of a new generation ESP power delivery technology with the potential of extended run life.
Case Study of Intelligent Completion with New Generation Electro-Hydraulic Downhole Control System
Authors: Jacob Suresh , Abdulbaqi Nibras , Verma Chandresh , Younes Rabih
Published: July 2016

Extended reach wells with thousands of feet of open hole reservoir contact and multilateral wells with 8-10 laterals are becoming common practice as the industry develops tight and difficult reservoirs. Over the years, drilling and well construction technologies have made significant advances in the field of geosteering, multilateral junctions, etc. to make these complicated wells a reality and commonplace. The industry has recently introduced several new well completion technologies for the downhole monitoring and control inflow of these extended reach and multilateral wells. Over the last 10 years Saudi Aramco has drilled and completed hundreds of multilateral wells with intelligent completions for real-time downhole monitoring and remote valve operation to control inflow from each laterals. These technologies have improved well performance and reduced well intervention.

The paper presents the case study for the design, planning, installation, and operation of Saudi Aramco's first intelligent completion that is operated with combined electro-hydraulic control system. New technologies like these are expected to improve the operation and inflow from the new generation multi-compartment wells. Conventional intelligent completion systems uses downhole valves that are operated by hydraulic pressure and the pressure is supplied from surface through dedicated hydraulic lines to each of the downhole valves. The wellhead and operations equipment has a maximum limit of eight downhole lines and this limits the number of downhole valves in a completion to five. The system in this case study uses a electro hydraulic control module at each of the downhole valves and can control of up to 12 intelligent completion tools with the use of only two hydraulic lines and one electrical line from surface. Technologies like these allow inflow control from each of the laterals and enhance the performance of the completion.
Sensitivity of Crude Oil T2 Distribution: Lessons Learned
Authors: Valori Andrea , Ali Farhan , Mohammed Al-Haji Abdulhadi , Abdallah Wael , Badri Mohammed
Published: July 2016

Nuclear magnetic resonance (NMR) is sensitive to fluid properties such as viscosity and also to surface properties interactions as wettability. The challenge while interpreting NMR data is typically separating multiple effects on the overall signal. We investigated the sensitivity of the bulk oil T2 distribution with different fluid sample storage conditions in terms of temperature and seal imperfection.

Aim of the study was to prove the importance of extremely careful sample handling during laboratory studies, especially if the intention is to interpret NMR data in terms of wettability alterations. For example, T2 distributions can be used to extract information on the wettability of the rock surface. A wetting fluid experiences faster relaxation (and therefore shorter T2) compared with the non-wetting situation. However, the same effect can be originated by an increase in fluid viscosity. Generally, to interpret a T2 shift, either viscosity or wettability must be considered constant to address the T2 shift to the other cause.

The results of this study and lessons learned are as follows: Even small evaporation of crude light components causes the NMR signal to shift considerably toward shorter T2 values. This effect, if wrongly assigned to surface interactions, leads to the wrong wettability considerations.Food-grade cling film is permeable to oil vapour and should not be considered a good seal for crude oil storage while aging.There was evidence of water volume reduction, even when the water was topped with crude oil.

Crude oils are complex fluids with thousands of components which include different surface-active species (e.g., polar species). Therefore, minute changes in the conditioning or handling of such fluids may cause considerable changes in rheological properties and therefore NMR properties.
Dynamic Validation of AMAL Phase Behavior for EOR Applications Using CO2 as Solvent Injection
Authors: Khazam M. M. , Abufarwa A. I. , Bizan A. E. , Elneca'a M. M.
Published: July 2016

Injection of CO2 into a reservoir for enhanced oil recovery (EOR) results in complex fluid phase behaviour that they require accurate reservoir fluid characterizations by equations of state (EOS) to capture the phase interactions in miscible CO2 floods.

AMAL is a giant Libyan field classified as low shrinkage type of oil and characterized by relatively law solution gas-oil ratio (GOR) of ~ 400 scf/stb and oil gravity of 35° API. The field was producing since 1960's under active bottom water drive that maintained the current reservoir pressure at levels higher than the bubble point pressure.

The main objective of this paper is to establish an EOS model able to characterize AMAL phase behaviour accurately in immiscible and miscible conditions. A model that statically validated against the conventional PVT data and dynamically validated to match the slim-tube experiments.

Three parameters Peng-Robinson (PR) and Soave-Redlich-Kwong (SRK) equations of state are used to model the Amal phase behaviour. In addition, 1-D slim-tube model is built using commercial compositional simulator to simulate four slim tube experiments.

The main outcome revealed that the match of only the conventional PVT data will not reflect the proper phase behaviour model when it was used to simulate the slim tube experiments. Therefore, further efforts are giving to EOS tuning to match both the conventional and special tests. Also, the lumped compositional model was not so perfect to simulate the hump phenomenon in slim tube experiments like extended model did. Perfect match of all slim tube experiments from immiscible to miscible conditions at pressures of 2000, 3000, 3600 and 4000 psia were achieved indicating the validity and reliability of the realized phase behaviour model. The multiple contact MMP pressure of AMAL field, using CO2 as injection solvent, is around 3140 psia based on measured and predicted results.

The adverse flow effects, such as numerical dispersion and flow effects, are eliminated by the proper selection of the number of grid blocks in the 1-D compositional model and by imposing the concept of interfacial tension (IFT) forces where the base relative perm curves will approach to straight lines as the IFT approaches to zero. The base relative perm curves are back calculated from the immiscible slim tube experiment at 2000 psia (IFT 5.0 dyne/cm2) using graphical techniques (Bardon-Longeron and JonesRoszelle models).[1] [2]
Optimal Parameter Selection in a Polymer Alternating Gas PAG Process
Authors: Jamal Md Sarim , Al-Nuaim Sami , Awotunde Abeeb A. , Khan Rizwan Ahmed
Published: July 2016

As the majority of conventional reservoirs are reaching maturity, the attention is gradually shifting towards unconventional and heavy oil reservoirs. Steam flooding, Miscible/Immiscible CO2 flooding, Polymer flooding and Water Alternating Gas (WAG) are the most common EOR techniques currently being employed in the industry. However, it has been recently proved that Polymer alternating gas (PAG) is a better alternative to the other EOR processes as it provides improved sweep efficiency (Zhang et. al. 2010, Li and Schecter, 2014, Kong et. al., 2015). A PAG process alternately inject miscible CO2 and water mixed with polymer. Different parameters directly affect the performance of this method. Thus, it is important that these parameters are carefully selected to increase the recovery along with the profitability. In this paper, an attempt has been made to optimize a PAG process for five production and five injection wells using two different global optimization algorithms.

One injection cycle of a PAG process constitutes of two stages – (i) Injection of miscible CO2 (ii) Injection of polymer. CO2 dissolves in oil, swelling it and decreasing the viscosity thereby increasing the mobility of oil. The injection of polymer increases the sweep efficiency and reduces viscous fingering. In this paper the operational parameters that have been selected for optimization are well locations, number of injection cycles required, production BHP, CO2 injection rate, CO2 injection time, polymer injection rate and polymer injection time and the concentration of the polymer that needs to be injected. The algorithms used are the Covariance Matrix Adaptation Evolution Strategy (CMA-ES) and the Particle Swarm Optimization (PSO). A synthetic reservoir model was used to study the performance of the method. The Net Present Value (NPV) was used as the objective function to gauge the suitability of the solution and hence optimize the different parameters to obtain the highest NPV. Both used optimization algorithms yielded NPV that were well within the acceptable range. Additionally, sensitivity studies were conducted which showed that PAG gave a higher recovery efficiency when compared to the other EOR processes.

Although some case studies have been performed to show the performance of the PAG process, to the best of our knowledge, no studies have been conducted on the use of global optimization algorithms for the estimation of the operational parameters of the PAG process.
Toward Improving Reservoir Management Practices in Naturally Fractured Carbonate Reservoirs Using Adjustable Inflow Control Devices ICDs
Authors: Al-Anazi Amer , Al-Shammeri Faleh , Widjaja Danang , Faizal Syed Abu , Galimzyanov Artyom , Suherdiana Hedy
Published: July 2016

Field development of a mature, highly fractured carbonate field presents several challenges. Most of the horizontal wells drilled in such fractured reservoirs suffer from early gas or water breakthrough because conductive fractures dominate the influx from the reservoir and cause an unbalanced flux profile along the wellbore. Premature gas or water breakthrough can result in poor sweep efficiency and reduced oil recovery for the well.

To address the aformentioned challenges, passive inflow control devices (ICDs) can be used to equalize influx from the reservoir to the wellbore, thereby delaying gas or water breakthrough. However, during the life of the well, as water or gas breakthrough occurs, a passive ICD can be less effective in preventing water or gas production. This can effect well productivity and reduce the production life of the well, especially for a naturally flowing well.

This paper describes how adjustable ICD technology with a sliding sleeve can be used as an effective reservoir management tool in mitigating challenges faced in a naturally fractured Middle Eastern carbonate field. Various examples from the subject field are presented to describe production challenges faced by barefoot and passive ICD-completed horizontal wells. The field cases suggest the need for adjustable ICD with sliding sleeve technology which provides a zonal shut-off option in case of water or gas breakthrough. A detailed workflow for usage of adjustable ICDs is described, and which includes well candidate selection, well monitoring and pre and post shifting well performance evaluation to determine which ICD unit must be shifted to a closed or open position. A dynamic simulation using a single-well model was also conducted to establish the benefits of a sliding sleeve on well production performance.

An adjustable ICD with a sliding sleeve was chosen as the preferred completion technology over the passive ICD for horizontal wells for the subject field with a naturally fractured carbonate reservoir. A sliding sleeve integrated in an ICD is a simple and cost-effective tool for zonal water or gas shut off compared to conventional intervention technology available for horizontal wells. Sliding sleeves maximize the value of ICD technology by adding an adjustability feature to ICD to overcome the challenges faced by unexpected changes in well behavior and premature water or gas breakthrough. Dynamic simulation results also confirm the sliding sleeves can prolong the life of the well by reducing high water and free gas production, thereby increasing cumulative oil production.
Investigation of Tubing Failure Rates in Standalone Water Injectors with Dual Completions
Authors: Al-Hajri Nasser M. , Al-Ajmi Mohammed D. , Al-Mujaljil Saleh R.
Published: July 2016

This paper investigates the frequent tubing failure tendencies of standalone water injection systems with dual completions. The paper also recommends remedial solutions to mitigate tubing failures based on a rigorous evaluation. Standalone well designs include completing the same well in two water zones; a shallow producing zone and a deep injecting zone. The produced water flows naturally to the surface through the tubing casing annulus (TCA). A surface pump injects the produced water into the deeper formation through the tubing. Standalone dual completions present an attractive and cost-effective option of the Field-A water injector's well design, especially in populated areas inaccessible by pipelines.

The shallow water producing zone is known to be corrosive. The produced water has dissolved carbon dioxide, traces of hydrogen sulfide, and traces of oxygen. The standalone dual completion well design includes the installation of strapped stainless steel hydraulic control lines outside the tubing to allow pumping chemical corrosion inhibition treatment into the shallow producing zone.

The scope of this work assesses known attributes to tubing failures of standalone water wells. These attributes include galvanic corrosion and erosional corrosion due to fluid jetting effect. Methods of evaluation include collective inputs from the following: Chemical inhibition residual concentration analysis.Oxygen, iron, and sulfate reducing bactria (SRB) counts.Corrosion rate of coupons samples.Data from ultrasonic logs.

With availability of the above data, the corrosion attack mechanism was discerned. Also, tubing mean failure times were quantified using recorded leaks in several wells with varying status of operation over an extended period of evaluation. Insightful trends were generated during the monitoring period. The evaluated tubing types are carbon steel, corrosion resistant alloy, and glass reinforced epoxy wrapped tubing.