bluuebunny/crossref_metadata_2025_split huggingface dataset:
LMRP Disconnect in Deepwater, Harsh Environment Conditions
Authors: Dupal K. , Curtiss J. P. , van Noort R. H. , Mack C. , Greer S. 
Published: February 2018

Abstract
Operations were being conducted with a drill ship in deepwater, harsh environment conditions offshore Nova Scotia. After securing the well, the rig disconnected the Lower Marine Riser Package (LMRP) from the lower Blow Out Preventer (BOP). After disconnecting, dynamic loads caused an uplift of the marine riser, ultimately resulting in a failure of the tensioner ring support and loss of the riser/LMRP to the seabed. No personnel were injured in this incident and no spilling of synthetic base mud to the environment occurred. This paper provides a summary of the root causes and contributing factors for the incident.
The Tripod beta method was used to conduct the review of the incident. The scope of the review included the following: Measured data (rig heave, tensioner stroke, tensioner pressures)Moonpool video camera recording of riser and tensioners during and after disconnectAnalytical models for vessel & marine riser dynamics, including the riser tensioner anti-recoil systemRig/moonpool geometry, riser tensioner ring design, and space-outWeather forecastingOperating procedures
Based on initial findings, further studies and analyses were conducted to better understand the dynamic behavior during the transition phase from initial disconnect to the hang-off position.
Forecasted Metocean conditions from a late winter storm indicated the potential to exceed the threshold for rig heave, with the marine riser connected to the well.
In preparation for disconnecting the LMRP, the well was secured with two barriers, a storm packer and closed blind shear rams. Once the rig heave limit was reached, the LMRP was disconnected from the lower BOP stack. Seven minutes after unlatching the LMRP, the riser tensioner profile on the slip joint outer barrel lifted off the riser tensioner ring and landed back onto the tensioner ring off-center. This uneven loading caused the tensioner ring halves to separate, dropping the LMRP and riser to the sea floor.
Analysis showed that one of the most critical phases of disconnecting the LMRP from the BOP occurs immediately after disconnecting and prior to moving the rig a safe distance from well center. The investigation indicated that the root causes of the event included human factors, such as adding additional air to tensioner system and re-setting of the Riser Anti Recoil System (RARS) prior to final hang-off condition. Contributing factors included the dynamic behavior of the riser and a lack of specific procedures for addressing the dynamic system conditions during the critical transition phase.
The paper provides additional information for riser/tensioner configuration and riser dynamics analyses during harsh environment conditions. In particular, additional analyses are presented for the transition phase from disconnect to hang-off position. Initial data is provided for further development of a smart disconnect algorithm, based on machine learning techniques of hind cast data.
An Analytical Model Explanation for Recovering Oil from Organic Nanopores of Shales
Authors: Yang Shu , Xu Yanming 
Published: February 2018

Abstract
Previous oil/water counter-current imbibition experiments on shale and tight rock samples showed that oil can be spontaneously recovered by water. The pore size distribution analysis showed the samples are composed of 2nm to 10nm organic nanopores. The oil recoveries range from 10% to 25%, which cannot be explained by the classical imbibition models. We hypothesize that the recoverable oil are the part of the adsorbed oil in small organic nanopores, the density of which is higher than the bulk oil density. We test this hypothesis by analytical modeling the number density profiles and estimating the free energy of oil and water molelcules in the organic nanopores of the target samples, ranging from 2nm to 10nm. We apply the proposed model on octane and water molecules in carbon nanotubes to investigate the driving force of the oil/water counter-current imbibitions in the organic nanopores of the samples. Results show that the number densities of the octane molecules in the adsorbed region of 2nm to 10nm nanopores are higher than the bulk octane value. As a result, the estimated surface tensions of the adsorbed octane molecules in 2nm to 6nm carbon nanotubes are higher than the surface tension of the bulk water. This reveals the driving force of the adsorbed oil in the small organic nanopores is positive during the oil/water counter-current imbibition experiments on shales. In addition, we compare the surface tension of the octane and water molecules in the carbon nanotubes. This result presents the driving force of the adsorbed octane is higher than that of the adsorbed water. These results indicate the part of the adsorbed oil in small organic nanopores can be spontaneously displaced by the water. Particularly, the estimated oil recoveries in the carbon nanotubes increase as the pore size increasese to 3nm, and then decrease as the pore size increase to 6nm. Based on the pore size distribution of the samples, the calculated oil recoveries of 3 samples show a good agreement with the previous oil/water counter-current imbibition experimental results. These results suggest that most of the recoverable oil of shales and tight rocks during the imbibieion experiments are produced from small organic nanopores.
Machine Learning Applied to Optimize Duvernay Well Performance
Authors: Bowie Braden 
Published: February 2018

Abstract
This paper presents the use of machine learning via a multiple linear regression and a neural network to solve the complex problem of optimizing completions and well designs in the Duvernay shale. Solutions were revealed that could save over a million dollars per well, along with the potential for more than 50% improvement in well performance. This was accomplished through a workflow that rigorously analyzed the relationships between a multitude of well completion variables, generated predictions of future results, and performed optimizations for ideal outcomes. Most importantly, this workflow is not Duvernay specific, and can easily be applied to other basins and formations.
This is a fundamental problem in many industries, in that a responding variable is controlled not just by one predictor variable, but by a number of predictor variables. Inferring the relationship between the responding variable and the predictor variables is then of key importance. Interactions between predictor variables, as well as noise in the data, complicate matters further. This problem can be solved with a multiple linear regression or a neural network, both of which utilizes all predictor variables together. However, care must be taken to obtain a model that is truly predictive and not a result of overfitting the data.
The workflow was applied to 262 Duvernay wells, ranging from dry gas to volatile oil. No wells were excluded for operational or geological reasons, a strength of this methodology. By not excluding any wells, the model could maximize learnings and establish statistical reasons for the variances in well performance observed. The final model achieved very high predictive power, correctly predicting 78% of the variance in well performance on 52 wells the model hadn't been trained on. Conclusions were quite significant, including: Indicating virtually no benefit from more expensive fracturing procedures, such as using ceramic or resin coasted proppant, or having hybrid fluid systems, offering savings of over a million dollars per well in the Duvernay.No benefit from placing wells on an azimuth (parallel to the minimum horizontal stress) vs. a North-South orientation (~45° off azimuth). This allows potentially large savings on a land ownership system not aligned to this direction, by allowing simpler pad design in achieving the same aerial coverage of reservoir depletion.Confirming total fracture tonnage as a key driver of well performance.Suggesting fracture pump rate is associated with better well performance and should be investigated further.
These conclusions would have been very difficult to derive without expensive strategic testing on numerous wells with rigorous control of the completions and geological inputs. When compared to recent well performance of six operators, the neural network predicted substantial ability to improve well performance by varying parameters under operator control. Potential improvement ranged from 19% to 97%, showing large potential improvement for all operators.
Engineered Diversion: Using Well Heterogeneity as an Advantage to Designing Stage Specific Diverter Strategies
Authors: Wutherich K. , Srinivasan S. , Ramsey L. , Katon W. M. , Downie R. 
Published: February 2018

Abstract
When hydraulically fracturing a horizontal wellbore with multiple perforation clusters, the fluid being pumped into the reservoir will preferentially take the path of least resistance. Perforations that are located in the lowest stressed rocks will take a larger amount of fluid, and those perforations located in highest stressed rocks will receive less, or in some cases none. One of the ways that engineers are trying to overcome these differences is the use of diverters. A fluid diverter is typically inserted at some point within a hydraulic fracturing pump schedule to seal off dominant fractures, allowing fluid to flow into under-stimulated fractures.
The problem with this methodology is that without reservoir knowledge, operators rely on rules of thumb developed through trial and error to determine when and how much diverter to use. Data has shown how this methodology can be ineffective, leaving some clusters over stimulated and others under-stimulated. Anecdotal evidence also supports these concerns because equally sized diverter slugs do not always have equal pressure response. This paper will present a methodology currently in use that examines well heterogeneity, and designs the diversion strategy based on actual reservoir properties. Estimations of minimum insitu stress at each cluster are combined with estimates of stress shadow effect both from previous stages and between treatment clusters to determine at which pressure each cluster will accept fluid. This data is then used to bin clusters into primary clusters which will be treated first, followed by a diverter slug, then secondary and possibly tertiary clusters. The volume of diverter slug used will be proportional to the number of clusters within the previous bin.
In addition to this, an engineered diversion strategy will look at the perforation design, fracture treatment design and pump rate. The result of this workflow is a tool that will maximize the effectiveness of diverters that will ultimately result in better producing wells at lower completions cost.
Enhancing Oil Recovery by Adding Surfactants in Fracturing Water: A Montney Case Study
Authors: Yarveicy Hamidreza , Habibi Ali , Pegov Serge , Zolfaghari Ashkan , Dehghanpour Hassan 
Published: February 2018

Abstract
In this paper, we experimentally investigate the possibility of formation damage reduction during leak-off and flowback processes by adding surfactants to the fracturing fluid. The experiments consist of three phases: In phase I, we conduct compatibility tests on surfactant solutions to select the compatible surfactant solutions with saline reservoir brine. In phase II, we measure interfacial tension between the stable surfactant solutions and the Montney reservoir oil. In phase III, we conduct a series of core flooding tests on the Montney tight core plug to experimentally investigate the leak-off and flowback processes. To evaluate the effects of surfactant solutions on the formation damage reduction we 1) measure the pressure drop across the core plug during both leak-off and flowback processes, and 2) evaluate the oil recovery factor during the leak-off process.
The results of the compatibility tests show that the anionic soloterra surfactant solutions with hydrophile-lipophile balance (HLB) numbers higher than 10 are compatible with the saline/reservoir brine. Among all stable soloterra surfactant solutions, the soloterra 983 solution shows the lowest interfacial tension (IFT) values. The results of core flooding experiments indicate that the addition of soloterra 983 surfactant into the saline reservoir brine can reduce the pressure drop during leak-off and flowback processes, and therefore, it decreases the possibility of aqueous phase trapping and formation damage in the Montney tight core plugs.
A High-fat and High-Cholesterol Diet Potentiates Oxidative Damage in Hippocampus of Mice Lacking Apolipoprotein E
Authors: Guaraldi Mary , Shea Thomas B. 
Published: February 2018

Objective:
We examined genetic and dietary challenge on hippocampal oxidative damage. Mice expressing (ApoE+/+) or lacking apolipoprotein E (ApoE-/-) were maintained on a standard diet or a high fat /high cholesterol (challenge) diet for 11-31 weeks. Similar levels of oxidative species were observed for ApoE+/+ and -/- mice maintained on the basal diet.

Method:
However, treatment of ApoE-/- homogenates with hydrogen peroxide and iron increased oxidative species by >100%, indicating an equivalent amount of potential oxidative species in latent form. We observed a time- and region-specific induction of oxidative damage in the hippocampi of ApoE-/- but not +/+ mice while maintained on the challenge diet. Notably, however, additional significant latent oxidative products were detected during this time. After 31 weeks of dietary challenge, by which time hippocampal oxidative species had doubled, there was an additional 50% in the latent form.

Conclusion:
This highlights the degree to which ApoE deficiency places hippocampal tissue at risk for oxidative damage. Even a modest dietary deficiency may be sufficient to provoke oxidative damage to hippocampal tissue. These results highlight the combinatorial impact of genetic and dietary deficiencies on oxidative damage to hippocampal tissue.
Relative Gratification and Outgroup Prejudice: Further Tests On A New Dimension of Comparison
Authors: Gatto Juliette , Guimond Serge , Dambrun Michaël 
Published: February 2018

Background:Recent studies have shown that the opposite of Relative Deprivation, Relative Gratification (RG), also leads to negative intergroup attitudes. In previous investigations, RG was manipulated in terms of positive economic expectations.Aims:The aim of the present research was to examine whether the effect of RG is limited to an economic dimension or if it reflects a more general process that is observable in different domains of comparison. In the first experiment, we choose to gratify – or not – psychology students on a new dimension with an important social value: their intellectual abilities.Conclusion:As expected, participants of the RG condition expressed a significantly higher level of prejudice towards low status outgroups than participants of the control group. In the second study, we found support for a model in which ethnic identification and group-based dominance mediated the relationship between intelligence based RG and prejudice toward low status ethnic outgroups.
Estudo de tradução, adaptação e validação do ASSIST numa amostra de estudantes universitários portugueses
Authors: Valadas Sandra T. , Gonçalves Fernando R. , Faísca Luís 
Published: February 2018

Neste estudo são analisadas as abordagens ao estudo, concepções de aprendizagem e preferências por diferentes estilos de ensino características de estudantes universitários. Foi nossa intenção construir uma versão portuguesa do Approaches and Study Skills Inventory for Students — short version (Tait, Entwistle & McCune, 1998), aferindo a sua validade e fidelidade numa amostra de estudantes universitários portugueses. Os resultados na validade de constructo e os indicadores de fidelidade do instrumento parecem demonstrar que, no global, o ASSIST avalia os constructos teóricos subjacentes e os estudantes que integraram este estudo parecem, de facto, revelar determinadas formas de abordar as tarefas de estudo e de aprendizagem. São, contudo, de destacar algumas limitações, não só características de instrumentos desta natureza, mas também resultantes dos próprios procedimentos e de alguns resultados menos satisfatórios em algumas das subescalas do inventário. Palavras-chave: Abordagens ao estudo; Concepções de aprendizagem; Estudantes universitários; ASSIST
Pesquisa e produção intelectual na área de didática: resultados de um estudo múltiplo de casos
Authors: Pimenta Letícia Brito Mendes , Aquino Orlando Fernández 
Published: February 2018

Este trabalho buscou analisar o estado da pesquisa e produção didática, no período de 2004 a 2010, em três Programas de Pós-Graduação em Educação pertencentes à região Sul do Brasil, tomados como estudos de caso. Surgiu da análise de importantes estudos precedentes que mostraram um esvaziamento do campo teórico-científico da ciência didática. Com as informações levantadas, concluímos que os estudos sobre didática não são referência dentro das linhas da própria área. Pesquisa-se e se produz muito no campo investigativo e na dimensão dos fundamentos, mas as questões sobre ensino de didática enquanto disciplina acadêmica, bem como as formas e maneiras de se efetivar, do ponto de vista metodológico, o processo de ensino-aprendizagem, não estão sendo objeto de interesse. Palavras-chaveDidática; Pesquisa e produção intelectual; Programas de Pós-Graduação em Educação
Factores de deserción estudiantil en la Universidad Surcolombiana
Authors: Sánchez Amaya Guillermo , Navarro Salcedo Wisberto , García Valencia Alejandro David 
Published: February 2018

En la universidad Surcolombiana en sus 35 años de existencia, el retiro de estudiantes no se ha auscultado ni teórica ni prácticamente y es verdaderamente preocupante que de 100 jóvenes que logran acceder a ésta, cerca de 40 la abandonen, sin culminar su respectivo ciclo académico. Ante tal situación esta investigación se planteó como objetivo central la identificación, análisis, determinación y clasificación de los factores de deserción que presenta la USCO en el periodo 2002-2005.Metodológicamente es una investigación expostfacto, con un análisis cuantitativo y cualitativo, que aborda el fenómeno de la Deserción Universitaria en la Universidad Surcolombiana, desde una doble perspectiva: la primera de carácter externo; referida al orden socioeconómico; y la segunda de carácter interno; que considera factores académicos.
Análisis crítico del discurso ¿Por qué y para qué? Bolívar Adriana (Compiladora). 2007 caracas, universidad central de venezuela
Authors: Suárez Licet Katerine 
Published: February 2018

Para hacer la presentación del texto que vamos a reseñar, llevaremos a cabo la enumeración de algunas reflexiones teóricas sobre las posibilidades de ese objeto llamado 'discurso' y alrededor del cual se ha tratado de tejer una gran cantidad de representaciones bajo la forma de teorías. No siempre ha habido claridad en los textos que se ocupan del discurso; quedan lagunas y dudas que son importantes confrontar. Esta suerte de introducción nos ayudará a entender el valor y la pertinencia del libro arriba mencionado.El profesor Patrick Charaudeau en un artículo programático, plantea de manera interesante la problemática epistemológica de ese campo llamado 'análisis del discurso', ya que no siempre es fácil determinar variables propiamente discursivas tanto en la constitución como en la selección de su objeto de estudio. Podemos preguntarnos por el tipo de ejercicio epistemológico que la mayoría de analistas del discurso ha intentado llevar a cabo y sin ir muy lejos, la respuesta aún está en camino de configuración.
Caracterización y evolución postoperatoria en cirugía bariátrica en una clínica privada. Neiva, año 2010 al 2014
Authors: Rojas Molina Sandra Milena , Leiva Panqueba Lina María 
Published: February 2018

El tratamiento de pacientes obesos se basa en el manejo médico y cambios del estilo de vida para disminuir comorbilidades y desarrollo o empeoramiento de enfermedades crónicas. Durante los últimos años la cirugía bariátrica ha adquirido un papel relevante en el tratamiento de pacientes con obesidad severa. Objetivo: Determinar las características y la evolución postoperatoria de los pacientes sometidos a cirugía bariátrica tipo manga gástrica y bypass gástrico en Y de Roux. Métodos: Estudio retrospectivo, observacional, descriptivo corte transversal en una Clínica Privada, desde el 1 de junio de 2010 al 30 de junio de 2014. Resultados: En el periodo descrito se realizaron 74 cirugías, la frecuencia de edad fue 34 años 8,1%, sexo femenino 66,2%, procedentes de Neiva en un 71,6%, peso más frecuente 110 kg, valor medio índice de masa corporal (IMC) 41,236, ocupación más común hogar 39,2%. El principal diagnostico encontrado fue la hipertensión arterial en el 21,6%, obesidad clase III predomino en el 63,5%, cirugíamás frecuente Sleeve gástrico en un 83,8%, promedio tiempo quirúrgico 125,35 minutos, tolerancia vía oral promedio de 60,03 horas, movilización 34,22 horas, hospitalización valor medio 3,41 días. Principales complicaciones en el periodo postoperatorio: sangrado 6,8%, lesión esplénica + sangrado 5,4%, fuga 1,4%, se corrigieron en el periodo postoperatorio 10,8%, requirieron reintervención quirúrgica 2,7%, correlación entre tiempo quirúrgico e IMC con p=0,0001, tolerancia a vía oral y días de hospitalización con un nivel de significancia 0,00, asociación significativa entre sexo femenino y obesidad clase III (p=0,019).
Explorando tecnologias de IoT no contexto de Health Smart Home: uma abordagem para detecção de quedas em pessoas idosas
Authors: Mano Leandro Yukio , Funes Marcio Maestralo , Volpato Tiago , Neto José Rodrigues Torres 
Published: February 2018

Atualmente, é crescente o número de pacientes que são tratados em casa, principalmente em países como o Japão, Estados Unidos e da Europa. Além disso, o número de idosos tem aumentado significativamente nos últimos quinze anos, e essas pessoas, muitas vezes, preferem receber tratamento médico em suas residências. No entanto, podem acontecer situações críticas durante esse período de recuperação, como por exemplo, o paciente idoso sofrer uma queda e agravar o seu quadro clínico. Neste cenário, avanços em Computação Ubíqua e Internet das Coisas (IoT) têm contribuído para evitar essas situações. Em particular, dispositivos embarcados, juntamente com a captura de movimentos por meio de sensores, podem ser aplicados para desenvolver soluções que ofereçam mais segurança para essas pessoas. Todavia, observa-se uma dificuldade de classificar os movimentos de um indivíduo e identificar, de fato, um movimento considerado anormal. Assim, o principal objetivo deste trabalho é a detecção e classificação dos movimentos utilizando dados conjuntos de sensores distintos e dispositivo embarcado. Paradigmas de Inteligência Artificial (AI) foram aplicados para a classificação dos movimentos e os testes realizados na arquitetura SAHHc. Os resultados apontaram uma precisão de 96.62\% na identificação das atividades executadas por um paciente/idoso.
Inter-Professional Collaboration as the Main Cooperation Trend in the International Forensic Community
Authors: Usov A. I. 
Published: February 2018

The paper reflects on the outcomes of the most recent conference of the International Association of Forensic Sciences (IAFS) held in Toronto, Canada. The meeting of delegates from all continents was organized around the theme «Inter-Professional Collaboration in Forensic Science», with the aim of exploring forensic scientists' responses to the challenges of the modern world. The meeting outcomes are analyzed in terms of valuable insights for the development of forensic practicesin Russia through the strengthening of multidisciplinary methodological approaches