bluuebunny/crossref_metadata_2025 huggingface dataset:
Impaired Homocysteine Metabolism Associated with High Plasma Interleukin- 17A Levels, a Pro-Atherogenic Marker, in an Endogamous Population of North India
Authors: Kaur Lovejeet , Garg Priyanka Rani , Ghosh Pradeep Kumar , Saraswathy Kallur Nava
Published: October 2018

Background: Impaired homocysteine me­tabolism (IHM; hyperhomocysteinemia) has been linked with many complex disorders like cardiovascular diseases and immu­nological disturbances. However, studies understanding IHM in light of pro- and anti-atherogeneic markers like Interleukin-17A & -10 (IL-17A & IL-10) and Forkhead box p3 (Foxp3, a master transcription factor) are scarce.Aim: In our present study, we aimed to understand the relation of IHM with plasma IL-17A and IL-10 levels and Foxp3 mRNA expression in peripheral blood mononuclear cells (PBMCs) from an endogamous popula­tion (Jats of Haryana, North India) with high prevalence of IHM without the concur­rence of significant adverse cardiovascular outcomes.Methods: Forty (40) clinically healthy individuals, unrelated up to first cousins, were recruited and were subjected to demographic, physiological and anthropometric profiling, followed by intravenous blood sample collection (fasting) and lipid profiling. Plasma homocysteine levels were estimated and individuals with homocysteine levels ≥ 15umol/L and <15umol/L were categorized as the impaired homocysteine metabolism group (IHM, n=30) and normal homocysteine metabolism group (NHM, n=10) respectively. Plasma folate and vitamin B12 and MTHFR C677T (methylenetetrahydrofolate reductase) polymorphism were detected. Relative mRNA expression of Foxp3 in PBMCs (normalized to 18S) was quantitated using SyBR green technology. Plasma IL-10 & 17 levels were estimated by ELISA assays.Results and Conclusion: None of the physiological, anthropometric and lipid variables were different between the two groups. Foxp3 mRNA expression levels were relatively lower, and plasma IL-10 levels were found to be comparable among IHM and NHM group. However, significantly higher IL-17A levels and relatively high LDL cholesterol levels were present in the IHM group as compared with NHM. Our findings suggest that the Jats of Haryana, North India, exhibiting high levels of homocysteine, might also carry the high IL-17A -pro-atherogenic marker, suggest­ing an increasing burden of pre-morbid condition. This apparently does not reach to significant mortality/morbidity attributed to the counter action or balancing act of IL-10 (an anti-atherogenic marker). This further suggests environment-influenced epigenetic control mechanisms of the tar­geted genes in the present population.Ethn Dis. 2018;28(4):525-530; doi:10.18865/ ed.28.4.525
MOGUĆNOSTI UNAPREĐENJA PEDAGOŠKOG SAVETOVANJA U OKVIRU CENTRA ZA PODRŠKU STUDENTIMA FILOZOFSKOG FAKULTETA
Authors: Gašpar Marta , Zuković Slađana
Published: October 2018

Centar za podršku studentima na Filozofskom fakultetu u Novom Sadu, koji je nedavno aktiviran, usmeren je na realizaciju različitih programa pedagoške i psihološke podrške, usmerenih na očuvanje i unapređivanje mentalnog zdravlja studenata, kao i na postizanje akademskih rezultata. U tom okviru, u radu su prikazani rezultati istraživanja čiji je cilj usmeren na ispitivanje mišljenja studenata o radu i aktivnostima Centra za podršku studentima, sa posebnim osvrtom na aktivnosti iz domena pedagoškog savetovanja. U istraživanju je učestvovao 101 student Filozofskog fakulteta, a korišćeni instrument kreiran je za potrebe ovog istraživanja. Dobijeni rezultati pokazali su da studenti uočavaju značaj delovanja Centra za podršku studentima, kao i lične benefite koje mogu dobiti kroz ovakvu vrstu podrške. Ipak, rezultati sugerišu potrebu intenzivnijeg rada na promociji Centra, kao i na motivisanju studenata za uključivanjem u aktivnosti koje mogu da im pruže dodatne informacije i korisno iskustvo. U skladu sa tim, u završnom delu rada date su implikacije koje upućuju na mogućnosti daljeg unapređenja kvaliteta rada Centra za podršku studentima, a samim tim i na mogućnosti unapređenja pedagoško-savetodavnog rada kao značajnog polja delovanja.
O planejamento educacional frente às fragilidades do processo democrático brasileiro
Authors: Scaff Elisangela Alves da Silva , Oliveira Marli dos Santos de , Lima Simone Estigarribia de
Published: October 2018

O objetivo do presente texto é examinar o Planejamento educacional brasileiro no que se refere às limitações que se apresentam à sua concretização, notadamente o Plano Nacional de Educação (2014-2024) face à recente aprovação da Emenda Constitucional nº 95 de 2016. . A metodologia adotada foi a pesquisa documental, por meio de levantamento de documentos oriundos do governo federal, analisados à luz da literatura atinente a temática. Nota-se que, historicamente, o planejamento educacional brasileiro é marcado por intermitências de ordem político-econômica. A aprovação da Emenda Constitucional nº 95 de 2016 sinaliza percalços no alcance das metas e estratégias dos planos decenais de educação, haja vista reduzir os investimentos públicos, de modo geral, nos direitos sociais e, em particular, na educação.
A escrita de surdos em ambiente internacional de aprendizagem mediado pela LIBRAS
Authors: Almeida Djair Lázaro de , Lacerda Cristina Broglia Feitosa de
Published: October 2018

O presente artigo pretende refletir sobre as práticas discursivas que incidiram no processo de escrita em Língua Portuguesa como segunda língua, empreendido por sujeitos surdos, em contextos interacionais de oficinas. Para tanto, realizou-se um trabalho de reescrita coletiva de uma história de aventura, a partir de interações interdiscursivas entre língua de sinais e o português escrito. Investigando a interação entre participantes surdos e educadores ouvintes como elemento que caracterizou o processo de escrita, analisamos os modos pelos quais as diferentes práticas discursivas se constituíram em ambiente de aprendizagem. No início das oficinas, o educador ouvinte organiza e dirige as interações promovendo o desenvolvimento das competências expressivas dos participantes surdos, provocando um ambiente propício à aprendizagem. Enquanto mediadores na construção do conhecimento, os educadores ouvintes assumem menos responsabilidades em relação à escrita, estimulando os sujeitos surdos a ocuparem cada vez mais o espaço discursivo. O caráter dessas interações gera situações favoráveis à autonomia dos participantes surdos. O que se observou nos movimentos registrados foram os deslocamentos instaurados: do educador como suporte total, à confiança depositada nos pares surdos que se apoiam rumo ao protagonismo na produção de linguagem escrita. Ressalta-se que as práticas e as formações discursivas nas oficinas, voltadas ao desenvolvimento dos mecanismos de produção e compreensão dos discursos, concretizaram-se por meio da língua de sinais como a base para o registro escrito.
Pedagoselfies: os significados do corpo e da imagem na produção de autorretratos entre jovens meninas
Authors: Zago Luiz Felipe , Guizzo Bianca Salazar , Pereira Evelyn Santos
Published: October 2018

O artigo realiza uma investigação teórica sobre as condições culturais da visibilidade dos corpos por meio da prática de produção e publicação de autorretrados – as chamadas selfies – feitos por jovens meninas. O objetivo é analisar, a partir de uma perspectiva culturalista, os modos como meninas estudantes do 1º ano do Ensino Médio de uma Escola pública do Rio Grande do Sul utilizam-se de telefones celulares e redes sociais para produzir e compartilhar suas selfies. A metodologia consistiu na realização de três grupos de discussão com as estudantes da Escola que se voluntariassem a falar sobre corpo, imagem e tecnologia, sob a coordenação de uma pesquisadora. Cria-se o neologismo pedagoselfie para designar, com base nas análises das falas das participantes, a operação de determinada pedagogia no processo de ensinagem-aprendizagem de significados e práticas de produção de selfies, significados esses para os quais convergem pedagogia, corpo, imagem e tecnologia. Conclui-se que a produção e publicação de selfies pode estar articulada à circunscrição de um regime de visibilidade singular do tempo presente, na medida em que a exposição da imagem de si ao outro depende de um escrutínio visual que regula a produção, edição e publicação de selfies em redes sociais on-line.
A docência em filosofia no contexto da profissão docente no país: aspectos conjunturais e reflexão filosófica
Authors: Nascimento Christian Lindberg Lopes do
Published: October 2018

O presente artigo tem como objetivo expor um diagnóstico do docente de Filosofia, não descartando o uso de algumas informações gerais no que se refere à profissão de professor. A investigação, que surgiu da necessidade de suprir uma lacuna existente nos estudos sobre o ensino de Filosofia, partiu da seguinte questão: Qual é o perfil do docente de Filosofia? Alguns dados qualitativos e quantitativos foram considerados, como também a reflexão que Adorno fez em torno da docência. Do ponto de vista metodológico, o texto contempla a preocupação exposta pela Teoria crítica quando anuncia que o diagnóstico de situação é fundamental para identificar o potencial emancipatório existente na sociedade.
A influência da concepção de educação grega na constituição histórica da paideia cristã
Authors: Freitas Charles Lamartine de Sousa
Published: October 2018

Neste artigo, pretendemos abordar os elementos educacionais da Grécia antiga, fundamentais tanto para a formação e o desenvolvimento da cultura ocidental como para a constituição da paideia cristã da antiguidade. Destacamos como a idealização do épos deu lugar à formação do cidadão a partir do ideal de uma areté política que, no período helenístico, tendo seu apogeu na pólis grega, vai ser alternado por outros valores mais ligados à individualidade. Nesse sentido, consideramos que a paideia grega, em seus diferentes momentos, vai ser elemento chave para a construção de uma paideia cristã. Esta, por sua vez além de sintetizar elementos universalistas do pensamento grego, se nutre de um tempo oportuno, de um kairós para expandir a mensagem cristã oriunda das promessas da religião judaica de um messiah para a universalidade dos homens, cuja expressão vai ser fundamental para a construção dos valores da sociedade ocidental.
Organização social de educação e seu financiamento: a nova panaceia para educação de Goiás?
Authors: Souza Fábio Araujo de , Flores Maria Marta Lopes
Published: October 2018

O artigo apresenta os resultados da pesquisa que analisou o processo de implantação da gestão compartilhada, em Goiás, entre a Secretaria de Estado de Educação, Cultura e Esporte (Seduce) e a Organização Social de Educação (OSE) selecionada pela secretaria. O objeto desta pesquisa se refere aos aspectos relacionados à transferência, acompanhamento e controle social dos recursos da manutenção e desenvolvimento do ensino e da educação para a OSE. Esta pesquisa é qualitativa e quantitativa, de natureza exploratória para a investigação do tema e com isso compreende o problema e os fatores subjacentes ao objeto pesquisado. Para analisar a transferência dos recursos da educação para a OSE que venha a gerenciar as unidades escolares de Goiás, foi realizado um levantamento no orçamento do estado para 2016 e 2017, nas legislações, nos Chamamentos Públicos e nos demais documentos que envolvem o processo de implantação da gestão compartilhada. Foi realizado, também, um levantamento bibliográfico sobre Organizações Sociais (OSs) em notícias de sites oficiais do governo e de entidades que discutem o tema, bem como, em artigos científicos e demais fontes pertinentes, a fim de se analisar, sob a perspectiva crítica, o processo de implantação das OSE na rede estadual. Como resultado foi possível constatar que há muitas incertezas e incoerências no processo de implantação da gestão compartilhada através da OSE na educação básica, especificamente, no que se refere ao seu financiamento.
Uma missão de estudos ao Uruguai: o debate estabelecido nos jornais Correio do Povo e A Federação
Authors: Michel Caroline Braga , Arriada Eduardo
Published: October 2018

O objetivo deste artigo é investigar a Missão de Estudos enviada ao Uruguai no ano de 1913, sob a perspectiva dos discursos produzidos nos jornais A Federação, órgão oficial do governo e favorável a missão, e o Correio do Povo, periódico independente e contrário a esse ato das autoridades. Os dois periódicos estabeleceram um intenso debate em suas páginas sobre as vantagens ou não do envio de um grupo de professores ao Uruguai. Para tanto, foram realizadas pesquisas nas edições do ano de 1913 de ambos os jornais. Ao todo foram localizadas 43 reportagens, sendo 29 em A Federação e 14 no Correio do Povo. As análises permitiram evidenciar um conjunto de oito elementos que justificaram a escolha: (i) o grau de adiantamento da instrução pública do Rio Grande do Sul; (ii) a distinção do Uruguai, (iii) o caráter internacional, (iv) a localização geográfica do Uruguai, (v) a língua utilizada, (vi) o baixo custo financeiro da missão, (vii) as relações culturais, políticas e econômicas estabelecidas entre o Rio Grande do Sul e o Uruguai e (viii) a vigência de um modelo político partidário, tanto no Rio Grande do Sul como no Uruguai, estruturado no positivismo.
Ácidos graxos polinsaturados no sangue de gestantes suplementadas com ômega-3 e óleo de linhaça dourada.
Authors: Foerster Merey Leila Simone , Palhares Durval Batista , Porto Karla Rejane de Andrade , Candido Muller Karla de Toledo
Published: October 2018

O objetivo deste estudo foi avaliar os níveis séricos de docosahexaenóico (DHA) e eicosapentaenoico (EPA) no sangue de gestantes que receberam suplementação de ômega 3 através da ingestão de cápsulas ou óleo de linhaça. Comparando os grupos, houve maior nível para o óleo de linhaça para os conteúdos de AA e DHA, indicando que a suplementação favoreceu a rota metabólica da formação e dos intermediários eicosanoides.
Uma avaliação do Programa Bolsa Família
Authors: Dantas Sara Verônica de Avelar Dias , Miranda Maria Geralda de , Dusek Patricia Maria , Avelar Kátia Eliane Santos
Published: October 2018

A ONU estipulou objetivos e metas de desenvolvimento para os seus estados membros. O Brasil se comprometeu com essas metas, entre elas o combate à pobreza e a fome. Em 2004 o país criou o Programa Bolsa Família (PBF), um programa de transferência de renda direta aos beneficiários. Este artigo avalia o PBF através do índice Gini, índice Theil e do IDH dos estados brasileiros, retratando o sucesso do PBF, que possibilitou, de 1990 a 2013, mais de 20 milhões de pessoas saírem da situação de pobreza no Brasil.
Ways to create, use and control legally information relations at the innovative sphere
Authors: Markeev A. I. , Tsukerblat D. M.
Published: October 2018

The article considers the information relations at the innovation sphere with the point of creation, use and legal regulation approaches. The authors analyze actions of various subjects entering information relations in the field of innovation, starting with the state ending with individuals. The researchers conclude that the improvement of information relations in the field of innovation should occur by strengthening the administration, rather than civil law regulation.
Centralized Unmanned Aerial Vehicle (UAV) Mesh Networks Placement Scheme: A Multi-Objective Evolutionary Algorithm Approach
Authors: Sabino Sérgio , Grilo António
Published: October 2018

In the past, Unmanned Aerial Vehicles (UAVs) were mostly used in the military operations to prevent pilot losses. Nowadays, the fast technological evolution enables the production of a class of cost-effective UAVs which can service a plethora of public and civilian applications, specially when configured to work cooperatively to accomplish a task. However, designing a communication network among the UAVs is challenging task. In this article, we propose a centralized UAV placement strategy, where UAVs are used as flying access points forming a mesh network, providing connectivity to ground nodes deployed in a target area. The geographical placement of UAVs is optimized based on a Multi-Objective Evolutionary Algorithm (MOEA). The goal of the proposed scheme is to cover all ground nodes using a minimum number of UAVs, while maximizing the fulfillment of their data rate requirements. The UAVs can employ different data rates depending on the channel conditions, which are expressed by the Signal-to-Noise-Ratio (SNR). In this work, elitist Non-Dominated Sorting Genetic Algorithm II (NSGA-II) is used to find a set of optimal positions to place UAVs, given the positions of the ground nodes. We evaluate the trade-off between the number of UAVs used to cover the target area and the data rate requirement of the ground nodes. Simulation results show that the proposed algorithm can optimize the UAV placement given the requirement and the positions of the ground nodes in the geographical area.
Transformative Sustainable Business Models in the Light of the Digital Imperative—A Global Business Economics Perspective
Authors: Brenner Barbara
Published: October 2018

We examine how external triggers, including the digital imperative and the need for more sustainable resource and stakeholder employment, spark the development of transformative sustainable business models. Drawing on the resource-based view and the shared value approach we conceptualize a multifaceted framework that helps to identify key determinants and coherent layers of transformative sustainable businesses models. Our theoretical arguments integrate recent research findings on external dynamics, such as digital technological advances and rising global competitive dynamics, with internal capabilities on both the organizational and the individual level, allowing for a more complete understanding of transformative potentials on the firm level. We propose that key determinants of sustainable transformative business models adhere to both, innovative value-creating reconstructionist and sustainable shared-value logic, and include elements such as co-creation with customers, usage-based pricing, agile and adaptive behavior, closed-loop resource employment, asset-sharing, and collaborative business ecosystems. At the same time, organizational, economic, and environmental layers encompassing sustainable business models need to be both horizontally and vertically coherent to unfold their full potential.
Simulation and Optimization of CO2 Huff-n-Puff Processes in Tight Oil Reservoir: A Case Study of Chang-7 Tight Oil Reservoirs in Ordos Basin
Authors: Lei Zhengdong , Wu Shuhong , Yu Tao , Ping Yi , Qin He , Yuan Jiangru , Zhu Zhouyuan , Su Hao
Published: October 2018

Advancements in horizontal drilling with hydraulic fracturing have enabled commercial oil production from tight oil reservoirs. However, the primary recovery factor remains very low, usually less than 15%. It is a big challenge to supply formation drive energy to sustain production. After hydraulic fracturing, there is often pre-mature water breakthrough or gas channeling when we inject water or gas. Therefore, CO2 huff-n-puff becomes an attractive option to improve oil recovery in tight oil reservoirs.

Based on typical reservoir and fracture properties in Ordos Long-7 tight oil reservoir, a compositional reservoir simulation model with hydraulic fracture network was established to evaluate the performance of CO2 huff-n-puff enhanced oil recovery (EOR) method. Through numerical simulation, we perform sensitivity study to explore the impacts of operation parameters such as CO2 injection rate, injection time, soaking time, number of huff-n-puff cycles on EOR performance. Some of these parameters have rarely been investigated for recovery in tight reservoirs, such as in-situ fluid composition, fracture pore volume and hydraulic fracture characterization. Furthermore, correlation analysis is used to evaluate the performance of CO2 huff-n-puff process.

In this study, we find that hydraulic fracture morphology and fracture conductivity can have a large impact on the performance of CO2 huff-n-puff. Due to the existence of natural fractures in tight reservoirs and the stimulated reservoir volume, CO2 huff-n-puff can not only mobilize the crude oil near the well, but also have certain recovery effects on the remaining oil between the adjacent wells. Simulation results show that the most important parameter is number of cycles, followed by CO2 injection rate and soaking time. It is found that the optimum injection pressure of CO2 huff-n-puff process can be set around the minimum miscibility pressure (MMP) for CO2 and the crude. We set the soaking time period to be 30 days, injection rate to be 150 ton/day, number of cycles to be 4 for optimized oil recovery. The incremental oil recovery factor after one cycle is 1.59%, and the output-to-input ratio is 1:1.75.

The findings in this work have the potential to advance our understandings of the role of CO2 EOR in developing unconventional oil reservoirs, which will benefit both the energy industry and the environment with the potential benefit of CO2 geological sequestration.
Foam Cementing in Australian Coal Seam Gas Operations
Authors: Saunders Troy , Shaban Alex , Zaman Mohammad
Published: October 2018

The Australian coal seam gas (CSG)/coal bed methane (CBM) fields present multiple challenges (i.e., losses, naturally fractured formations, and highly depleted zones) typically addressed using various well design and cementing techniques (i.e., additional casing strings, stage cementers/tools, lost-circulation materials, lightweight designs, and additional cement volume) to manage the potential risk of losses.

Foamed cement is a viable option to address these challenges; however, despite the documented benefits, its application within Australia has been minimal at best. The lack of application can be primarily attributed to misconceptions concerning cost, potential risk, excessive equipment footprint, and a limited proven track record, which increases the potential risk of execution.

A recent 10-well campaign conducted within the Bowen Basin, Queensland, Australia, demonstrated that foamed cement can be used as an alternative to traditional lightweight and/or elastomeric cement slurries. Further, the benefits of foamed cement make it an economically and technically advantageous solution compared to conventional cementing techniques used to overcome CSG challenges.

This case study details the campaign challenges, cement design, and detailed results of the 10 wells with the intention of providing other engineers a road map to better understand foamed cementing with a specific Australian context and how it could be applied to their projects.
The Permian Deep Coal Play, Cooper Basin, Australia. Unlocking the Next Gas Giant
Authors: Cooper Gareth , Lockhart Duncan , Walsh Ainslie
Published: October 2018

Unconventional gas exploration in the Cooper Basin, Australia, has historically concentrated on fracture stimulation of tight gas sandstones within mapped structural closures. In drilling these sandstones, and other clastic reservoir targets, it has been recognised for many years that the Permian coal measures of the Toolachee, Epsilon and Patchawarra Formations record high levels of gas, often in excess of 4000 units, encountered at depths between 2500 and 3500m. Unlike shallower Coal-Seam-Gas reservoirs, which rely on de-pressuristion through de-watering to liberate adsorbed gas from the kerogen surface, deep coals are a "dry" system in which the free gas component is produced via kerogen and fracture permeability.

However maintaining a consistent and commercial flow rate from deep coals alone remained enigmatic until the first dedicated fracture stimulation program of deep Permian coals was commenced in the Moomba Field in 2007. Understandings of Permian source-rock reservoirs, the roles of the coal type and rank on sorption capacity and porosity, the influence of effective pressure and depth on coal permeability and the interrelation of coal fracture permeability with in-situ stress and mechanical stratigraphy has now advanced.

The deep Permian coal fairway in the Patchawarra and Nappamerri Trough of the Cooper Basin has been defined and mapped using a generative potential approach within a comprehensive 3D basin model. Net coal thicknesses from log electro-facies for 879 wells has been combined with available well maturity, TOC, HI and kerogen kinetic data, and calibrated against corrected temperatures in a basin-wide Trinity retention model which incorporates 14 mapped regional horizons. Play fairways have been overlain with observations of in-situ stress direction and fracture orientations from 3D seismic curvature volumes, FMI data and stress states from Mechanical Earth Models (MEM).

Within the basin, this approach has defined a P50 in-place resource of 14.6 TCF of gas and a P10 of 20.7 TCF of gas within the deep coals of the Permian Toolachee, Epsilon and Patchawarra Formations in Senex permits, of which 8-11 TCF is within the North Patchawarra Trough. MEM's have also demonstrated that deep coal seams are consistently in a normal stress state and therefore provide excellent scope for both propagating and constraining vertical fracture growth. Work is now underway to define further those areas, within the mapped resource parameters, which provide the best opportunity to site pilot lateral wells for multi-stage fracture stimulation within deep coals.
Re-defining the Potential-Determining-Ions PDIs for Low Salinity Effect LSE based on Oil/Brine/Solid Interfacial Behaviors and Oil Water Relative Permeability
Authors: Wei Bing , Zhang Xiang , Lu Laiming , Xu Xingguang , Yang Yang , Chen Bin
Published: October 2018

Although the low salinity effect (LSE) in enhanced oil recovery (EOR) is widely accepted, its underlying mechanisms have not conclusively determined largely due to the complex interactions at oil/brine/rock interfaces and their relation with the dynamic flow behaviors in porous media. Given the vast diversity of brine composition in different reservoirs, the current studies are not yet sufficient to map the complicate interfacial behaviors. Therefore, the attention of this work was placed on the events that occurred on oil/brine/rock interfaces through direct measurements of oil water IFTs, interfacial dilational rheology, zeta potential and oil water relative permeability in sandstone porous media. The effect of brine composition including ion types, salinity and valency on LSWF was examined for the intent of re-defining the potential-determining-ions (PDIs) for LSE. The results showed that the oil water interfacial behaviors closely depended on the brine composition. The wettability alteration of the sandstone surface was found to be associated with the divalent ions and the double layer expansion (DLE) failed to interpreted the observed wettability in our work. The injection of MgSO4 brine produced the highest oil recovery factor compared to other three brine. On the basis of the previous observations, we concluded that the LSE was strongly dependent on the events occurred on the oil-brine-solid interfaces. The most significant LSE was observed at a salinity of 2000ppm in our work and the ions of Mg2+ and SO42− appeared to be critical for LSWF.
A Particulate Gel Based System for Water Shut-Off Applications
Authors: Lafitte Valerie , Panga Mohan Kanaka , Vaidya Nirupama , Nikolaev Max , Enkababian Philippe , Teng Ling Kong , Zhao Haiyan
Published: October 2018

Water production is a major concern for oil companies because it involves not only a high cost for handling the water on surface, but also issues related to scale and corrosion in tubulars, and an overall decrease of hydrocarbon production. Finding the right solutions for each case is a challenge because there is no one solution that fits all. Chemical treatments for water shutoff are cheaper than mechanical treatments and can offer more targeted and customized design, but they often come with higher operational risks.

A new water control system based on a single particulate additive was extensively evaluated under laboratory conditions and then successfully implemented in the field. The fluid is easy to prepare using traditional field mixers and does not need curing after it is pumped into the formation, thus saving time and cost compared to most conventional water shutoff systems. The fluid was evaluated in the laboratory with a wide range of formation permeabilities and injection conditions using the fluid loss apparatus, permeameter, and formation response tester. The viscosity and stability of the fluid in different water salinity and concentrations were also investigated.

Overall, it was found that the new fluid system was very efficient in shutting-off formations greater than 50 md up to a few darcies. Those results were consistent with the nature of the plugging mechanism, which relies on physical pore plugging alone. The system could be further tuned depending on the formation permeability. In the presence of oil saturation, the penetration of the particulate system was found limited as compared to a single-phase, water-saturated core.
Efficient Integration Method of Large-Scale Reservoir Compaction and Small-Scale Casing Stability Models for Oilfield Casing Failure Analysis
Authors: Yamada Kenta , Furui Kenji
Published: October 2018

Many casing failure incidents have been reported in oil and gas fields around the world. These casing failure events can occur not only within reservoirs but also in surrounding formations. Engineers must evaluate risks of casing failure when drilling and completing wells especially in highly compacting reservoirs. However, one of the challenges encountered during the evaluation of casing failure risks is that field-scale stress changes and displacements as a result of drilling wells and producing hydrocarbon from reservoirs must be properly taken into account for casing stability analysis. The objective of this study is to develop an efficient integration method for large-scale reservoir compaction and small-scale casing stability analyses for the evaluation of casing deformation and failure.

The numerical model developed in this work is based on 3D elasto-plastic finite element method (FEM). Reservoir compaction and subsidence are analyzed using a large-scale FEM model considering details of geological settings while casing stability is analyzed separately by a small-scale FEM model. The two FEM models are integrated by interpolating displacements calculated by the large-scale model and assigning resultant displacements for boundaries of the small-scale casing stability analysis model. The validation of the proposed integration method is also presented in the paper.

Our study results indicate that the integration method presented in this paper significantly improves computational efficiencies on an order of 5 times faster than the conventional simulation method that requires a large number of finite elements for reservoir, surrounding formations, cement, and casing. Also it is demonstrated that the integrated model can be applied to inclined wells completed in highly heterogeneous formations at sufficient accuracy. The field case study also indicates that the risk of casing deformation highly depends on its inclination and the position relative to the compacting formation.

The small and large scale coupling method developed in this work helps engineers evaluate casing deformation and failure in various locations in reservoir and surrounding formations in an efficient manner and also develop safe and efficient drilling and completion programs to reduce risk of casing mechanical problems.
Relative Permeability Curve Shapes in Coalbed Methane Reservoirs
Authors: Salmachi Alireza , Clarkson Christopher , Zhu Suyang , Barkla James Ashton
Published: October 2018

Relative permeability curves in coalbed methane reservoirs (CBM), acquired by analysis of production data, can differ from laboratory-measured curves due to complications such as stress-desorption dependent permeability and cross-formational flow. This paper aims to derive relative permeability curves for coalbed methane reservoirs using production data analysis, as well as discuss curve characteristics and shapes. Field examples from the San Juan Basin in the US and the Qinshui and Ordos Basins in China are presented to provide a worldwide view of relative permeability curve shapes. These field examples are analysed using a tank type model, a common production data analysis tool, and the influential factors on curve shapes are discussed. The results and analysis indicate that permeability enhancement during the life of the well, and cross-formational flow between the coal seam and adjacent formations, can strongly control curve shapes. These effects, when not detected, can result in irregular relative permeability curve shapes obtained by analysis of production data. Direct measurement of permeability enhancement requires time-lapse production tests while investigation of cross-formational flow of water into coal seams requires hydraulic connectivity assessment, which are time consuming and expensive to conduct. The signatures of relative permeability curves presented in this study allow indirect determination of permeability enhancement and cross-formational flow in coal seam gas reservoirs.
A Novel Nanosilica-Based Solution for Enhancing Mechanical and Rheological Properties of Oil Well Cement
Authors: Qalandari R. , Aghajanpour A. , Khatibi S.
Published: October 2018

The main purposes of employing cement in oil wells are to isolate the zones within formations, secure casing from axial loading and corrosion and improve wellbore integrity. There are plenty of nanomaterials represented in the literature which were introduced to cement in order to advance the strength and rheological properties of cement slurry. The objective of this study is to propose a novel nanomaterial which can upgrade the mechanical and rheological properties of cement. The smaller the size of Nano-particles, the higher surface area and hence higher efficiency they possess to advance particular properties of the support material. Bio-templating has been offered as an approach to reduce the size of utilized nanoparticles. In this study, Nanosilica particles were synthesized and functionalized using modified sol-gel method. Bio-templating was then implemented through crosslinking of the procured Nanosilica with soluble egg protein using glutaraldehyde. In order to investigate the effect of bio-templated Nanosilica on cement slurry, synthesized Nanosilica was added to cement and rheological and mechanical experiments were conducted. To validate the performed bio-templating, ATR-FTIR spectrum was acquired which confirmed successful crosslinking between the functionalized Nanosilica and SEP. Furthermore, experimental tests were conducted to evaluate the effect of bio-templated Nanosilica on mechanical and rheological properties of neat cement. The results were then compared to inclusion of commercial Nanosilica in cement. Through the rheological studies, it was found that the modified Nanosilica has acted as dispersant in cementitious system by decreasing the plastic viscosity of cement and maintaining the density. It was also obtained that novel bio-templated Nanosilica has significantly increased uniaxial compressive strength of cementitious system by 16.59% upon addition of only 0.25 wt.%. It was due to its pozzolanic reaction in cement and its pore filling effect where the porosity of cementitious system was decreased. The proposed synthesized Nanosilica demonstrates superior results than commercial Nanosilica which shows its remarkable efficiency in cement strength reinforcement and rheological properties improvement. The research study has successfully proposed a novel method to utilize biomaterial waste in the process of synthesizing Nanosilica particles which is not only environmental friendly but also yields in phenomenal rheological and mechanical properties of Class G cement.
Evaluating Natural Gas-Based Foamed Fracturing Fluid Application in Unconventional Reservoirs
Authors: Pankaj Piyush , Phatak Alhad , Verma Sandeep
Published: October 2018

Foamed fracturing fluids have been used in unconventional reservoirs to reduce the water use and minimize deleterious impact on water-sensitive formations. As part of a Department of Energy (DOE) sponsored program, we previously identified an optimal thermodynamic pathway to transform wellhead natural gas (NG) into pressurized NG suitable for use as the internal phase in a foamed fracturing fluid. This study now aims to extend that work by determining the impact of using NG foam fracturing fluids on hydraulic fracture geometry and on productivity from the unconventional reservoirs.

The current study is focused on investigating the impact of the NG-based foam of various foam qualities in hydraulic fracture geometries and their production through simulation models. Field data and laboratory-based measurements for NG foam fluid properties are incorporated in the study. In addition, the transient response of the fluid flowback from foam-based fluid is studied using numerical simulation. Comparative analysis is done with typical slickwater, linear gel, and crosslinked fluid application for hydraulic fracturing using 3D-complex hydraulic fracture models. 1D and 2D particle transport models have been used to verify the differences in proppant distribution in the hydraulic fractures.

Rapid wellbore clean-up, low formation damage, and effect of the relative permeability improvement are added advantages apart from reducing the water requirements for hydraulic fracturing. In addition to providing the logistical benefit of using wellsite liberated low pressure gas, NG foamed fracturing fluid has a dynamic fluid leak-off behavior and increased effective viscosity over the base fluid that allows pumping and transporting proppant at least 10% farther in the hydraulic fractures than linear gel. Slickwater displays poor proppant transport and hence poses inability to pump higher concentrations of sand. NG foam fracturing fluid on the other hand displays improved proppant transport and has been shown to create more complexity than slickwater in our simulations.

Use of NG foamed fracturing fluid has not been practiced widely yet. Application of NG Foaming field test and reaping the economic benefit from simplified logistics and improved production would enables operators to invest in creating a safer handling environment for wellsite application of NG foam.
An Online Water Cut Measurement System Based on the Conductance Sensor
Authors: Yang Qinghai , Li Ming , Wang Quanbin , Meng Siwei , Ming Eryang
Published: October 2018

The conductance sensor based water cut meter is usually used to measure content of the oil-water two phase mixed fluid for periodical well production logging. In order to solve the real-time monitoring problem of downhole water cut, this paper proposes an online water cut measurement system based on the conductance sensor technology. Through the newly developed system, the continuous and permanent water cut measuring can be realized. The system consists of two conductance sensors, one temperature sensor, sampling mechanism and control & storage unit. Due to different density of oil and water, the two conductors with cylindrical poles, equipped on the upside and downside of the fluid inlet respectively, sense the conductivity of the oil-water mixed fluid and the detached water. With the real-time sampled downhole temperature, the conductivity values are compensated to reflect the real characters of the two kinds of liquid. According to Maxwell's model of oil-water mixed fluid and the correction parameters from offline calibration, the water cut is deduced. Since all units are designed with low-power consumption and high protection level, the system can operate permanently and provide online monitoring values. The water cut measurement system is tested in a physical testing environment with different conditions of the oil-water mixing ratio, the mineralization degree of water, the liquid temperature and the flow rate. Testing results show that the water cut in oil-water mixed fluid and the sampled conductivity follow the Maxwell's model approximately, where the error between testing data and theoretical value is within 3% especially for the high water cut cases. When the temperature changes, the measured water cut value basically does not variate, although sampled conductivity of the two sensors change a lot with temperature. Different mineralization degree of water would affect the measured water cut result slightly, which should be due to the conflicts between the large conductance range and the sampling accuracy. The flow rate is another element to make the measured result fluctuation, but the water cut would be stable when using the average value within a period. In brief, the system provides real-time water cut measurement and the measuring accuracy can satisfy the requirements of petroleum production. The conductance sensor based water cut measurement system realizes real-time measuring of oil-water mixing ratio for oil production and can provide online parameters for optimizing production process rapidly. All electronic units are designed with low-power consumption, which ensure the system to run downhole permanently.
Volume Change of Cement Plugs: Spotlight on the Role of Boundary Conditions Using an Improved Testing Method
Authors: Jandhyala Siva Rama , Pangu Ganesh , Deshpande Abhimanyu , Wolterbeek Tim , Cornelissen Erik , van Eijden Jip
Published: October 2018

Expansion additives have been used in cement plugs to mitigate the potential risk of plug failure resulting from shrinkage. These additives are effective only when their amount is tailored for downhole boundary conditions, and their role should be well understood. This work discusses using an improved testing method that enhances the dependability of the volume change measurement and exhibits the impact of test boundary conditions on the shrinking and expanding behaviors of cement plugs.

Boundary conditions investigated with this method include temperature, pressure, water access to the cement from the formation, and the role of mechanical constraints. Dependability is demonstrated by verifying the repeatability and reproducibility of the method at two different laboratories. Together with the noninvasive continuous volume change, supplementary measurements, such as ultrasonic compressive strength, tensile strength, and chemical composition analysis, have provided inferences about the mechanism of volume change.

The new method embodies all attributes listed in API 10 TR2 (1997), including a constant external stress state in all measurements and a constant pore pressure during total volume change measurement. The results of percentage volume change from this test method present an extremely small variance, highlighting its repeatability; additionally, the measurement was reproducible between laboratories. Expansion value increased with a decrease in confining pressure, and excessive expansion in the absence of an effective confining pressure produced weak samples. The absence of outside water caused cement containing the expansion aid to shrink more than its neat equivalent; such observations highlight the importance of fluid boundary on the action of expansion additives.

These observations were possible because the test method can capture temporal and boundary condition effects more aptly. Thus, the improved method provides a dependable measurement for tailoring plug properties.
Improved Numerical Stability and Upscaling of Low Salinity Water Flooding
Authors: Al-Ibadi Hasan , Stephen Karl , Mackay Eric
Published: October 2018

Numerical stability and precision are required when using simulations to predict Enhanced Oil Recovery processes and these can be difficult to achieve for Low Salinity Water Flooding (LSWF). In this paper we investigate the conditions that lead to numerical instabilities when simulating LSWF. We also examine how to achieve more precise simulation results by upscaling the flow behaviour in an effective manner.

An implicit finite difference numerical solver was used to simulate LSWF. The stability and precision of the numerical solution has been examined as a function of changing the grid size and time step. We used the Peclet number to characterise numerical dispersion with these changes. Time step length was compared with the Courant condition. We also investigated some of the nonlinear elements of the simulation model such as the differences between the concentrations of connate water salinity and the injected brine, effective salinity concentration range and the net mobility change on fluids through changing the salt concentration.

We observe that numerical solution of LSWF tends to be conditionally stable, with problems occurring as a function of the range of effective salinity concentration relative to the initial reservoir water and the injected brine concentrations. We observe that the Courant condition is necessary but not sufficient. By definition, the precision of the numerical solution decreased when increasing numerical dispersion but this also resulted in slowing down the low salinity water and increased the velocity of the formation water further reducing precision. These numerical problems mainly depend on fluid mobility as a function of salt concentration. We conclude that the total range and the mid-concentration of effective salinity affect the stability and precision of the numerical solution, respectively. In this work, we have developed two approaches that can be used to upscale simulations of LSWF and tackle the numerical instability problems. The first method is based on a mathematical form that gives the relationship between the fractional flow, effective salinity concentration and the Peclet number. The second method is that we have established an unconventional proxy method that can be used to imitiate pseudo relative permeabilities.

This work enables us for the first time to simulate LSWF by using a single table of pseudo relative permeability data, instead of two tables as traditionally done in previous studies. This removes the need for relative permeability interpolation during the simulation and will help engineers to more efficiently and accurately assess the potential for improving oil recovery using LSWF and optimise the value of the field development. We also avoid the numerical instabilities inherent in the traditional LSWF model.