bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of Human Amniotic Membrane Mesenchymal Stem Cells Using Gelatin and Alginate as Nontoxic Scaffolds
Authors: Hendrijantini Nike , Hartono Poedjo , Susilowati Helen , Hartono Cindy K. , Daniati Reni P. , Brahmana Febrian ,   Department of Prosthodontic, Faculty of Dental Medicine, Airlangga University, Surabaya, Indonesia.,   Department of Obstetrics and Gynaecology, Faculty of Medicine, Dr. Soetomo General Hospital, Airlangga University, Surabaya, Indonesia.,   Stem Cell Research and Development Center, Airlangga University, Surabaya, Indonesia.,   Resident Department of Prosthodontic, Faculty of Dental Medicine, Airlangga University, Surabaya, Indonesia.,   Resident Department of Prosthodontic, Faculty of Dental Medicine, Airlangga University, Surabaya, Indonesia.,   Department of Orthopaedics and Traumatology, Dr. Mohammad Soewandhie General Hospital, Surabaya, Indonesia.
Published: September 2019

Perinatal mesenchymal stem cells (MSCs), for example, from amniotic membrane, have advantages over adult sources, such as bone marrow, in terms of ease of availability, cell naivety, tissue stem cell abundance, high capacity of proliferation, and less donor site morbidity, because it does not require invasive procedures. Natural polymer scaffolds, such as gelatin and alginate, are biocompatible. Combination of stem cells from amniotic membrane (hAMSCs) and gelatin or alginate as scaffold can be promising. However, cytotoxicity comparison of gelatin and alginate to hAMSCs has not been widely studied. This study was aimed to compare cytotoxicity of gelatin and alginate on hAMSCs in vitro. Isolation and culture were performed on hAMSCs of the healthy full-term pregnancy. In passage 4, Flow Cytometry CD90, CD105, and CD73 phenotype characterization was done. Colorimetric assay of 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) was performed to measure the cytotoxicity. There were three sample groups: (control group) hAMSCs with alpha-minimum essential medium (α-MEM) solution as control; (gelatin group) hAMSCs with gelatin; (alginate group) hAMSCs with alginate. Each group consisted of 12 samples. Flow cytometry of hAMSCs expressed 28.78% CD90, 36.95% CD105, and 44.41% CD73 surface markers. No sample depicted toxicity in either gelatin or alginate group, and this is indicated by the average percentage of living cells in gelatin 97.26% and in alginate 98.43%. No statistically significant difference (ρ=0.057) of cytotoxicity was found between gelatin and alginate to hAMSCs. Gelatin and alginate were nontoxic to hAMSCs in vitro.
The New Urbanism Principle of Quality Architecture and Urban Design Versus Place Identity. A Case Study of Val D’Europe and the Manufaktura Complex
Authors: Cysek-Pawlak Monika Maria , Krzysztofik Sylwia
Published: September 2019

This article contributes to the New Urbanism debate by considering the relationship between the identity of a place and quality in architecture and urban design. It combines a general theoretical discussion and an operational analysis with a comparative study of two commercial centres: Manufaktura in Łódź (Poland) and Val d’Europe in Marne-la-Vallée (France). It concludes that while the guidelines of New Urbanism can help both private investors and public stakeholders make better strategic decisions, according to the concept of quality architecture and urban design, its framework should be applied with care for community needs and the historical character of the city.
Innovations in Local Public Transport – Significance for the Local Community
Authors: Trippner-Hrabi Justyna , Podgórniak-Krzykacz Aldona
Published: September 2019

The article deals with the issues of the innovations implemented in public transport. Their theoretical background was defined in the form of the latest concepts of territorial development: the theory of sustainable development, circular economy, and smart city. The examples of innovations quoted above have been analysed in terms of their impact on: the local community, the environment, health, safety, and economic and social aspects. The main conclusion drawn from the analysis is that technical innovations in public transport contribute to improving mobility, the comfort and safety of commute, and, at the same time, have a positive impact on the environment.
Educação dos cegos fluminenses: Campos em conexão com Niterói (1950-1970)
Authors: Cardoso Fernanda Luí­sa De Miranda , Martínez Silvia Alicia
Published: September 2019

Este artigo visa compreender o processo de consolidação da educação dos cegos no interior fluminense, com ênfase em Campos, a partir de ações articuladas entre instituições deste município, e de Niterói, durante os anos 1950 a 1970. As instituições que protagonizaram esse processo foram, em Campos, o Educandário para Cegos São José Operário e, em Niterói, a Escola de Serviço Social e a Cruzada de Recuperação e Assistência ao Cego Fluminense. Os apontamentos de Magalhães (1998) a respeito das instituições educativas trouxeram contribuições para os aspectos teórico-metodológicos da pesquisa. Aplicou-se a técnica da triangulação das fontes priorizando os jornais de grande circulação da época; entrevistas orais e os documentos oficiais do acervo do Educandário.
GEOMORFOLOGIA FLUVIAL DO BAIXO RIBEIRA DE IGUAPE, SÃO PAULO, BRASIL
Authors: Veneziani Yuri , Rodrigues Cleide , Mantovani Juliana da Costa
Published: September 2019

As inundações são um dos mais graves riscos sociais da atualidade em todo Mundo. No Estado de São Paulo, uma das áreas mais vulneráveis é o médio e baixo terços do Vale do Ribeira, onde recorrentes inundações têm levado a graves crises sociais e econômicas. A abordagem geomorfológica, por meio da cartografia geomorfológica, permite indicar fatores do sistema físico que influenciam na suscetibilidade dos ambientes, pertinentes às escalas espaciais e temporais do fenômeno, avançando na identificação de processos hidrodinâmicos e realização de interpretações morfogenéticas. Este estudo objetivou a compreensão da geomorfologia fluvial da planície meândrica do baixo Ribeira de Iguape, interpretando tendências hidromorfodinâmicas relativas aos processos inundação e apontando aspectos da morfogênese regional. A investigação procedeu com elaboração de mapeamento geomorfológico em 1:50.000, envolvendo etapa de gabinete, com fotointerpretação analógica a partir de estereoscópicos e restituição digital em SIG; e campo, com campanhas para validação de limites espaciais e levantamento de materiais amostrais. Os resultados indicaram ampla variedade de formas e materiais correlativos de canal, planície e terraço no sistema meândrico do baixo Ribeira de Iguape e de paleoambientes fluviais, permitindo a divisão do trecho estudado em duas metades com características geomorfológicas distintas. Quanto à morfogênese, a distribuição das formas e seus arranjos demonstraram o controle estrutural da evolução do Graben de Sete Barras na definição de distintos índices de sinuosidade entre as metades de montante e jusante, acompanhadas da alteração do padrão de forma das seções transversais, concentração de barras arenosas e ilhas. Há interferências de tal controle na formação e resiliência das superfícies de terraços altos no trecho. Quanto à morfodinâmica, a variabilidade de formas mapeadas implica distintas tendências de processos hidrodinâmicos. A montante, além de terraços (que denunciam a incisão fluvial), prevalece níveis de planície e backswamps sugerindo a predominância de mecanismos de inundação na elaboração da planície; enquanto à jusante, a presença de meandros abandonado, cordões arqueados e amplas barras arenosas laterais permite afirmar que são dominantes os processos de migração lateral. O mapeamento geomorfológico viabilizou apontamento de tendências espaciais e temporais relativas às inundações nos distintos compartimentos, para os quais graus de suscetibilidades podem ser atribuídos. Por outro lado, a variabilidade de formas revelou que as relações hidráulicas são descontínuas espacial e temporalmente, impossibilitando o estabelecimento de valores únicos de cota-vazão para extremos fluviais. A compreensão da vulnerabilidade à inundação e sua contribuição à gestão de risco devem passar por aspectos relativos à conectividade dos fluxos na planície fluvial.
MORFOLOGIAS FLUVIAIS EM AMBIENTE SEMIÁRIDO: QUESTÕES TEÓRICAS APLICADAS A UM ESTUDO DE CASO
Authors: Lima Kleber Carvalho , Lupinacci Cenira Maria
Published: September 2019

Morfologias fluviais associadas a drenagens efêmeras são pouco conhecidas na literatura geomorfológica nacional, onde pesquisas sobre o tema abordaram diferentes aspectos da dinâmica fluvial. No estudo de caso do riacho da Cruz, semiárido da Bahia, discutiram-se definições e avaliou-se a empregabilidade de termos geomorfológicos utilizados na bibliografia nacional e internacional relativos ao cenário local, no sentido de produzir conhecimento sobre aspectos ainda não explorados na literatura brasileira para o semiárido. Foram discutidas expressões relacionadas a formas identificadas na área em estudo, como canal de drenagem, cabeceiras de drenagem, discontinuity channel, sheetflood zone, headcut, floodout, terminal fan e channel fan. A partir de trabalhos de campo, de dados granulométricos e das discussões teóricas, parte dos vocábulos foram adaptados ou adotados integralmente, assim como foram elaboradas expressões próprias. Avaliou-se, dessa maneira, que o emprego de terminologias deve ser realizado com precaução, no sentido de adapta-las aos contextos pesquisados, além disso, deve aproximar-se da produção geomorfológica de caráter internacional.
PAISAGENS POLARES NÃO GLACIAIS (PROGLACIAL, PARAGLACIAL E PERIGLACIAL): REVISÃO DE CONCEITOS E CONSTRIBUIÇÕES DA PESQUISA PEDOGEOMORFOLÓGICA BRASILEIRA
Authors: Machado Mariana de Resende , Oliveira Fabio Soares de , Schaefer Carlos Ernesto G. R. , Francelino Marcio Rocha , Michel Roberto Ferreira Machado
Published: September 2019

O trabalho teve como objetivo discutir com base na literatura a origem e evolução dos conceitos proglacial, paraglacial e periglacial, elucidando as formas e processos atuantes e as questões e críticas inerentes a cada um deles. Ao longo dos anos os três termos foram empregados de forma redundante e sobreposta, mesmo refletindo conjunturas ambientais distintas, com critérios diagnósticos diferentes. Ademais, mesmo com a participação crescente de pesquisadores brasileiros em trabalhos na Antártica, as discussões epistemológicas acerca desses ambientes ainda constituem lacuna nas publicações nacionais. A paisagem proglacial corresponde à área pioneira em receber os produtos da glaciação e este se revela um ambiente prioritariamente deposicional. É um ambiente complexo totalmente ajustado aos processos fluviais, lacustres e marinhos que ocorrem imediatamente adjacente ao glaciar e consequentemente o domínio proglacial acompanha a movimentação da margem do gelo. A paisagem paraglacial não é definida nem por processos nem pela localização, mas sim pela trajetória de reajustes da paisagem, adotando o critério tempo. Dessa forma, a paisagem paraglacial está em processo de transição, recuperando-se dos distúrbios da glaciação. Por fim, a paisagem periglacial é aquela com atuação de ciclos de congelamento e descongelamento (frost action) e congelamento sazonal do terreno, podendo possuir ou não permafrost.
On The Extension of Compton's Experiment: A Theoretical Investigation
Authors: Pushp Fras Amal
Published: September 2019

With new discoveries and insights in atomic and optical physics, the field of spectroscopy is advancing to a new level with applications ranging from material science to astronomy. We here propose a theoretical description of a potential new phenomenon resulting from the extension of Compton's experiment on the scattering of high energy photons through atomic electrons. How the proposed phenomenon can be tested experimentally is discussed in the paper as well.
Transforming Growth Factor-β3 Chitosan Sponge (TGF-β3/CS) Facilitates Osteogenic Differentiation of Human Periodontal Ligament Stem Cells
Authors: YangFan Li , Qiao zhifen , Yu Fenglin , Hu Huiting , Huang Yadong , Xiang Qi , Zhang Qihao , Yang Yan , Zhao Yueping
Published: September 2019

Abstract: Periodontal disease is the main reason for tooth loss in adults. Tissue engineering and regenerative medicine are the advanced technologies used to manage soft and hard tissue defects caused by periodontal disease. We developed a transforming growth factor-β3 chitosan sponge (TGF-β3/CS) to repair periodontal soft and hard tissue defects. We investigated the proliferation and osteogenic differentiation behaviors of primary human periodontal ligament stem cells (hPDLSCs) to discuss the bioactivity and application of TGF-β3 in periodontal disease. We separately used Calcein-AM/PI double-labeling or CM-Dil-labeling coupled with fluorescence microscopy to trace the survival and function of the cells after implantation in vitro or in vivo. The mineralization of osteogenic differentiated hPDLSCs was confirmed by measuring ALP activity and calcium content. The levels of COL I, ALPL, TGF-βRI, TGF-βRII, and Pp38/t-p38 were tested using Western blot to explore the mechanism of bone repair prompted by TGF-β3. When hPDLSCs were inoculated with different concentrations of TGF-β3/CS (62.5–500 ng/mL), ALP activity was the highest in TGF-β3 (250 ng/mL) group after seven days (P < 0.05 vs. control); the calcium content in each group increased significantly after 21 and 28 days (P < 0.001 vs. control). The best result was achieved in the TGF-β3 (500 ng/mL) group. All results showed that TGF-β3/CS can promote osteogenic differentiation of hPDLSC and may be involved in the p38 MAPK signaling pathway. TGF-β3/CS has the potential for application in the repair of incomplete alveolar bone defects.
Methods for Studying Endoplasmic Reticulum Stress
Authors: Correia da Silva Daniela , Valentao Patricia , Andrade Paula , Pereira David
Published: September 2019

The endoplasmic reticulum (ER) comprises a network of tubules and vesicles that constitutes the largest organelle of the eukaryotic cell. Being the location where most proteins are synthesized and folded, it is crucial for the upkeep of cellular homeostasis. In addition, it is the largest ionic calcium reservoir in cells, tightly regulating the levels of this second messenger according to cellular necessities. Disturbed ER homeostasis triggers the activation of an intricate and conserved molecular machinery, termed the unfolded protein response (UPR). Given the impact of this signaling network upon an extensive list of cellular processes, ER stress is involved in the onset and progression of multiple diseases, including cancer and neurodegenerative disorders. There is, for this reason, an increasing number of publications focused on characterizing and/or modulating ER stress, which have resulted in a wide array of techniques employed to study ER-related molecular events. This review aims to sum up the tools available design a study of this nature.
Predicting Disaggregated Tourist Arrivals in Sierra Leone using ARIMA Model
Authors: Jackson Emerson Abraham , Tamuke Edmund
Published: September 2019

This study have uniquely mad use of Box-Jenkins ARIMA models to address the core of the threes objectives set out in view of the focus to add meaningful value to knowledge exploration. The outcome of the research have testify the achievements of this through successful nine months out-of-sample forecasts produced from the program codes, with indicating best model choices from the empirical estimation. In addition, the results also provide description of risks produced from the uncertainty Fan Chart, which clearly outlined possible downside and upside risks to tourist visitations in the country. In the conclusion, it was suggested that downside risks to the low level tourist arrival can be managed through collaboration between authorities concerned with the management of tourist arrivals in the country.
Compatibility and Stability of Daptomycin Lock Solutions in Combination with Gentamicin, Azithromycin, Heparin and Trisodium Citrate
Authors: Bookstaver P. Brandon , Premnath Padmavathy , Wright Kayisa , McInnes Campbell
Published: September 2019

Background: Antibiotic lock therapy is an interventional modality used for treatment and prevention of central-line associated bloodstream infections. Stability and compatibility data for combinations are lacking, limiting clinical use. Objective: Compatibility and stability of daptomycin lock solutions in combination with azithromycin, gentamicin, and heparin or sodium citrate were evaluated up to 96 hours. Methods: Eight candidate lock solutions were prepared for compatibility and stability testing. All solutions were prepared in glass vials, and included daptomycin 1mg/mL in varying combinations with heparin 100 – 1,000 units/mL, trisodium citrate, azithromycin and/or gentamicin. Lactated Ringer’s solution was added as a diluent in a sufficient quantity to bring the total volume up to 5mL. Drug stability in the admixture was determined by the degradation of the components. The quantification of drugs was performed using Waters Alliance HPLC using Phenomenex Luna C8 (2), 150*2.6mm, 5µ column. A gradient run was executed for 20 minutes with 0.45% ammonium dihydrogen phosphate, pH 3.25 as eluent A and acetonitrile as eluent B at a flow rate of 1.0mL/min. Each solution was visually inspected for particulates and color change. Lock solutions were tested in triplicate. Results: Daptomycin degradation was <10% for all solutions at 48 hours, and for 7 of the 8 solutions at 72 hours. Gentamicin degradation was <5% for solutions in combination with daptomycin and trisodium citrate. No physical incompatibilities were detected. Conclusion: Study data support the stability and compatibility of daptomycin with additives in solution, allowing for fewer exchanges and longer dwell times for a lock solution. The addition of azithromycin or gentamicin may offer synergy and/or extended spectrum of activity. Daptomycin bioactivity with trisodium citrate needs confirmation.
Imigração internacional: uma alternativa para os impactos das mudanças demográficas no Brasil?
Authors: De Oliveira Helena Nobre , Da Silva César Augusto Marques , De Oliveira Antonio Tadeu Ribeiro
Published: September 2019

A transição demográfica traz consigo inúmeras transformações na estrutura etária, sendo uma delas o envelhecimento populacional. No Brasil, estima-se que 22,6% da população terá 65 anos ou mais em 2050, cenário semelhante ao vivido atualmente pelos países desenvolvidos. Diante dessas mudanças, debatem-se os limites e potencialidades da migração como uma possível forma de amenização dessa situação. De um lado, os imigrantes podem integrar a população em idade ativa, constituindo uma parcela importante da mão-de-obra brasileira futura. Por outro lado, emerge a preocupação que o país seja capaz de absorver esses estrangeiros e que, mais tarde, esses também envelhecerão, aumentando o peso das idades mais envelhecidas. Nesse contexto, surge o termo “migração de reposição” que se refere ao processo migratório com intuito demográfico relativo à estrutura etária ou tamanho populacional. Dessa forma, para analisar o possível impacto da componente migratória sobre a estrutura etária brasileira até o ano de 2050, elaborou-se projeções demográficas a partir de distintos cenários com base no Método das Componentes Demográficas. Os cenários que objetivaram a atenuação da razão de dependência ou basearam-se em taxas líquidas de migração de países receptores de migrantes, como a Alemanha, foram os que resultaram em saldos migratórios mais razoáveis.
Inclusive Public Health Preparedness Program to Promote Resilience in Rural Appalachia (2016–2018)
Authors: Schroeder Jennifer , Bouldin Erin D.
Published: September 2019

Emergencies range from unexpected injuries to natural disasters. Populations with access and functional needs are more likely than other populations to experience adverse health outcomes during an emergency. The three-county Appalachian District Health Department engaged a collaborative array of community partners to build an all-inclusive, all-hazards emergency plan. Tabletop and full-scale exercises demonstrated the plan’s ability to meet the needs of community members with access and functional needs.
Community Assessments for Public Health Emergency Response (CASPERs)—US Virgin Islands, 2017–2018
Authors: Schnall Amy Helene , Wolkin Amy Funk , Roth Joseph (Jay) , Ellis Esther M.
Published: September 2019

Objectives. To assess preparedness levels of communities to help public health and others plan for disasters or emergencies and tailor messaging to increase community preparedness.

Methods. US Virgin Islands Department of Health conducted a Community Assessment for Public Health Emergency Response (CASPER) in June 2017, 2 hurricane response CASPERs in November 2017, and a recovery CASPER in February 2018. CASPER is a 2-stage cluster sampling method designed to provide household-based information about a community’s needs in a timely, inexpensive, and representative manner.

Results. Roughly the same amount of households reported having a 3-day supply of food and water before and 3 months after the hurricanes. During the response, approximately a third of households resupplied between 3 and 6 days and an additional approximately 40% between days 7 and 14.

Conclusions. On the basis of the CASPERs, we were able to track whether households had an emergency preparedness kit, whether they used it during the storms (and what was missing), and if they resupplied their kit in recovery.

Public Health Implications. CASPER is a promising tool to measure community preparedness to help state, local, tribal, and territorial jurisdictions plan for disasters or emergencies.
Impactos del cambio climático sobre la flora acuática de las Lagunas Verdes, volcán Chiles, Ecuador
Authors: Jácome Esteban Terneus , Vallejo Berenice , Gómez de la Torre Mateo
Published: September 2019

Evaluamos los impactos del cambio climático sobre la estructura y composición florística de las plantas acuáticas en cinco lagunas altoandinas (3900 m s. n. m.), al pie del volcán Chiles. Utilizamos transectos y cuadrantes de profundidad para evaluar riqueza y patrones de cobertura vegetal, y evaluamos la físicoquímica de agua con equipos electrónicos de medición in situ.  Esta información fue comparada con la generada hace 17 años. Registramos 15 especies de plantas acuáticas, de las cuales se evidenció reducción en las poblaciones de Isoetes sp., Crassula venezuelensis y Elatine ecuadoriensis. Al parecer, Lilaeopsis schaffneriana y Juncus stipulatus son remplazadas por Lachemilla nivalis, y una Poaceae del género Agrostis como colonizadora. Las características abióticas de las lagunas evidencian cambios en el pH y la conductividad de sus aguas, generando condiciones particulares para un posible establecimiento de especies distintas a los registros históricos. Evidenciamos perjuicios sobre la naturaleza del ecosistema acuático, por la pérdida o reemplazo de especies hidrófitas por helófitas, como indicadoras de un potencial proceso de transformación de ambientes naturales, y un inminente riesgo de la permanencia y la funcionalidad ecológica de los ecosistemas acuáticos del lugar.
Medium and large mammals of the mid Planas River basin, Colombia
Authors: Aya-Cuero Carlos A. , Mosquera-Guerra Federico , Esquivel Diego A. , Brooks Daniel , Trujillo Fernando
Published: September 2019

Estudiamos la diversidad de mamíferos medianos y grandes en un área no protegida de la Orinoquia Colombiana durante tres años, empleando cámaras trampa en 72 estaciones de muestreo y haciendo recorridos por bosques y sabanas. Con un esfuerzo de 1789 días-cámara y 469.5 km recorridos se documentaron 31 especies de mamíferos (9 órdenes, 19 familias). Se registraron especies amenazadas como ocarro (Priodontes maximus), danta (Tapirus terrestris), pecarí de labio blanco (Tayassu pecari) y hormiguero gigante (Myrmecophaga tridactyla). Se registraron especies raras, como el perro vinagre (Speothos venaticus) y semiendémicas como el cachicamo sabanero (Dasypus sabanicola). Las especies mejor representadas a través del índice de abundancia relativa fueron el pecarí de collar (Pecari tajacu) y la zarigüeya (Didelphis marsupialis). Las especies registradas se enfrentan a diversas presiones, como cacería para subsistencia, especies invasoras y ganadería. Por lo tanto, los resultados sugieren que las áreas no protegidas son importantes para la conservación de los mamíferos en los Llanos Orientales de Colombia.
Deep Recurrent Neural Network DRNN Model for Real-Time Step-Down Analysis
Authors: Madasu Srinath , Rangarajan Keshava Prasad
Published: September 2019

A new real-time machine learning model has been developed based on the deep recurrent neural network (DRNN) model for performing step-down analysis during the hydraulic fracturing process. During a stage of the stimulation process, fluids are inserted at the top of the wellhead, while the flow is primarily driven by the difference between the bottomhole pressure (BHP) and reservoir pressure. The major physics and engineering aspects involved are complex and, quite often, there is a high level of uncertainty related to the accuracy of the measured data, as well as intrinsic noise. Consequently, using a machine learning-based method that can resolve both the temporal and spatial non-linear variations has advantages over a pure engineering model.

The approach followed provides a long short-term memory (LSTM) network-based methodology to predict BHP and temperature in a fracturing job, considering all commonly known surface variables. The surface pumping data consists of real-time data captured within each stage, such as surface treating pressure, fluid pumping rate, and proppant rate. The accurate prediction of a response variable, such as BHP, is important because it provides the basis for decisions made in several well treatment applications, such as hydraulic fracturing and matrix acidizing, to ensure success.

Limitations of the currently available modeling methods include low resolution BHP predictions and an inability to properly capture non-linear effects in the BHP/temperature time series relationship with other variables, including surface pressure, flow rate, and proppant rate. In addition, current methods are further limited by lack of accuracy in the models for fluid properties; the response of the important sub-surface variables strongly depends on the modeled fluid properties.

The novel model presented in this paper uses a deep learning neural network model to predict the BHP and temperature, based on surface pressure, flow rate, and proppant rate. This is the first attempt to predict response variables, such as BHP and temperature, in real time during a pumping stage, using a memory-preserving recurrent neural network (RNN) variant, such as LSTM. The results show that the LSTM can successfully model the BHP and temperature in a hydraulic fracturing process. The BHP and temperature predictions obtained were within 5% relative error. The current effort to model BHP can be used for step-down analysis in real time, thereby providing an accurate representation of the subsurface conditions in the wellbore and in the reservoir. The new method described in this paper avoids the need to manage the complex physics of the present methods; it provides a robust, stable, and accurate numerical solution throughout the pumping stages. The method described in this paper is extended to manage step-down analysis using surface-measured variables to predict perforation and tortuosity friction.
Innovative Water Salinity Management Through Integrated Asset Model Applied to Mexico Area-1
Authors: Maiorano Stefano , Selvaggio Pietro , Distaso Ripalta Eleonora , Rossi Roberto , Stano Elena
Published: September 2019

The objective of this work is the prediction of water salinity evolution trend for Mexico Area-1 development that foresees the injection of a mixture of seawater and produced water from the six different reservoirs connected to the same FPSO.

Prediction of salinity trend evolution is crucial for forecasting possible biogenic hydrogen sulphide (H2S) formation and foreseeing the relating impacts over completion and facility material selection and on health, safety and environment (HSE) management.

Traditional numerical simulations through stand-alone models do not consider the effects of the reciprocal interaction among the fields on production profiles and are not able to simulate salinity evolution of produced and injected water mixture, variable over time. To overcome this limit, a new tool was developed. It consists in a python script that, introduced into the Area-1 Integrated Asset Model, allowed to generate forecasts of the water salinity along the project lifetime. These simulations were essential for souring risk assessment, providing the following results: water salinity trend evolution at each injector well;water salinity trend evolution at each producer well;injection water breakthrough timing at the producer wells.

Moreover, it gave the opportunity to assess the injection strategy efficiency and to quantify the impact of changing salinity on water viscosity and on the field recovery.

In conclusion, the innovative methodology applied in the Area-1 IAM (Integrated Asset Model) permits to predict the salinity of injected water and to foresee salinity evolution of produced water generating several valuable information, providing a flexible tool that allows to investigate simultaneously several uncertainties related to the project and to evaluate promptly solutions and mitigation.

Moreover, when the reservoirs will be on production, the numerical models integrated with the developed script will reproduce the historical salinity data allowing to identify preferential flow path established by fluids virtually acting as a reservoir tracer technology.
Recovery Estimates from Micromodel Experiments: Processing, Uncertainty, and Rate-dependence
Authors: Kaidar Ziyad , AlSofi Abdulkareem , Al-Anazi Amer
Published: September 2019

Micromodels are commonly utilized to investigate the fundamentals of multiphase displacements and oil mobilization. Definitely, the utility of micromodels has been well demonstrated in the literature. Yet, while the generic workflows are mutual, there is no standard protocol. Therefore, the primary objective of this work was to develop reliable protocols for micromodel experimentations. These protocols are developed within the context of investigating flow-rate effects on oil trapping and recovery, which represents a supplementary objective.

The presented experimental work utilized a high pressure and high temperature setup. A metalloid pattern with a pore-volume of 0.08 mL constitutes the porous-media micromodel. The model is positioned vertically, which permits investigation of gravity effects. Displacement experiments were performed to establish the image processing workflow. Those experiments were performed at different injection rates for fixed volumes starting from 10 mL up to 50 mL. All experiments were replicated to assess the associated uncertainties. Initial conditions were established via drainage of connate brine by dead crude oil followed by imbibition of injection brine.

The performed experiments established a preferred workflow for image processing that includes in order: thresholding, despeckling, and binary conversion. Thresholding limits were found to be dependent on the camera including its position and focal length. The final binary images can be used for oil recovery estimation based on areal analyses. High rate experiments demonstrated better repeatability. Prolonged injection helped reduce variations in recovery estimates between replicates. At the investigated macroscopic scale and in light of associated uncertainties, recovery was found to be negligibly dependent on injection rate up to a critical flow-rate of around 1 mL/min above which recovery increases with higher injection rates. A trend that is consistent with capillary desaturation.

This paper demonstrates the procedure to establish a micromodel image processing protocol. It also illustrates the possible uncertainties associated with recovery estimates obtained from such images. Finally, key observations and recommendations with respect to the significance of high throughput and replications were uncovered.
Numerical Simulation of Gas Tracers for Reservoir Characterization, a Case Study
Authors: Del Moral Jaime , Abad Beatriz , Panadero Asier , Sendín Rubén
Published: September 2019

In this paper we describe how incorporating inter-well flow of gas tracers into a numerical simulation model of an oil producing field allowed us to improve the reservoir characterization. Gas tracers evidenced the lateral and vertical reservoir connectivity, identified preferential flow paths and eventually provided an additional tool for the dynamic history match.

The field produces light oil with the support of miscible gas injection, from a reservoir composed of two stacked fluvial sandstones units. To improve the reservoir characterization four inter-well gas tracer campaigns involving a total of 13 injector wells have been successfully completed. All these tracer injections have then been modeled at our full field numerical simulation model with the purpose of challenging the reservoir description in it. Input from this exercise have been later-on used during the construction of geomodels, benefiting from our improved reservoir knowledge.

The reservoir is composed of two units, Middle (M) and Upper (U), both deposited as laterally amalgamated fluvial channels. Both units appear as vertically separated by an impervious shale interval, only absent in 2 wells out of 30.

The shale interval was originally considered as a possible flow barrier by the earliest geological models. However, numerical simulation models were only able to replicate observed tracers arrivals when specific vertical connections existed between both units, indicating the shale interval was no as laterally continuous as formerly suspected.

History matching the tracers arrivals in the western field area was also helpful to reveal a fast gas breakthrough between wells which were aligned perpendicularly to the main channel orientation (NW-SE). This finding confirmed that this prevailing channel orientation was not the only responsible for a good reservoir communication, but also the lateral amalgamation (SW-NE) of channels was exerting a significant control in low sinuosity fluvial systems, as well as secondary flow directions in high sinuosity systems.

The improved reservoir characterization have been reflected in subsequent reservoir geological models and numerical simulators, avoiding misleading history matching solutions. Also, it is worth to note that this have had a direct impact on the gas injection strategy followed in the field.

Quite commonly interwell tracer flow is not fully incorporated into numerical simulators. This is a time consuming process, which, in addition to the conventional model uncertainties, requires sensitivities to the associated tracer parameters. This paper demonstrate through a real case how valuable this additional effort may result, and how it may improve the geological and dynamic understanding of our field.
Evaluation of Reservoir Dynamic Uncertainties in Digital Concept Based Green Field Before Implementation of Full Field Development Scheme
Authors: Altaf Basit , Allouti AbdelKader
Published: September 2019

Reservoir A is being developed in early and interim phases in order to gather static & dynamic data to minimize the risk associated to subsurface uncertainties. In early and interim phases, only production is taking places. During full field, water injection scheme will be implemented using mainly 5-spot pattern. It is very crucial to measure the subsurface uncertainties and their impact on the reservoir development. For this purpose, the uncertainty parameters are identified and their ranges are selected based on the current well performances during probabilistic History matching (PHM) phase. In full field runs, the uncertain subsurface parameters are quantified to prioritize the future reservoir monitoring and data gathering plans. Note that wells are equipped with the permanent downhole pressure gauges.

Reservoir A is one of the major reservoirs of a green-field located offshore Abu Dhabi and is being developed with a 5-spot water injection pattern. The producers and water injectors are horizontal wells which are drilled across different flow unit within the reservoir. The reservoir properties are variable across all the flow units, which may results in a non-uniform water front. Being a green field, there are more uncertainties as compared to the brown field. More than three years production & pressure data is available which is used in this uncertainty study. This production data is mainly used to achieve the probabilistic History match on well-wise basis. In this uncertainty study, previous HM parameters are removed. However, based on previous history matching learnings, the subsurface uncertain parameters ranges are selected for this probabilistic History match phase. The criteria for filtering the valid runs during this phase are set to be ±150 Psi compared to the actual downhole pressure readings. In case of decreasing this filtering range to 75 Psi, results in reduction in the reserve range in P90 to P10. Based on ±150 Psi principle, the subsurface parameter ranges are furthered reformed for full field uncertainty study/run. The industry standard workflow is followed to quantify the subsurface parameters during this phase. In this study, we used the Permeability modifiers based on RRT, Faults transmisibilities, Relative Perm curves (based on SCAL data), Kv/Kh ratio (from PTA), etc. as uncertain parameters. The impact of each parameter is measured and quantified with respect to plateau and total reserves.
Dynamic Multilevel Multiscale Simulation of Naturally Fractured Reservoirs with Generic Fracture-Matrix Conductivity Contrasts
Authors: HosseiniMehr Mousa , Al Kobaisi Mohammed , Vuik Cornelis , Hajibeygi Hadi
Published: September 2019

An algebraic dynamic multilevel (ADM) method for multiphase flow in heterogeneous fractured porous media using the projection-based embedded discrete fracture model (pEDFM) is presented. The fine-scale discrete system is obtained independently for matrix and each lower-dimensional fracture. On the fine-scale high resolution computational grids, an independent dynamic multilevel gird (i.e., ADM grid) is imposed. The fully implicit discrete system is mapped completely algebraically to this ADM grid resolution using sequences of restriction and prolongation operators. Multilevel multiscale basis functions are locally computed and employed to honor the heterogeneity contrasts of the fractured domain by interpolating the solution accurately. These basis functions are computed only at the beginning of the simulation to increase the computational efficiency. Once the ADM system is solved for all unknowns (i.e., pressure and saturation), the solution at ADM resolution is prolonged back to fine-scale resolution in order to obtain an approximated fine-scale solution. This dynamic multilevel system employs the fine-scale grid cells only at the sharp gradient of the solution (e.g., at the moving front). With two fractured test-cases (homogeneous and heterogeneous), the performance of ADM is assessed by comparing it to fine-scale results as reference solution. It will be shown that ADM is able to reduce the computational costs and provide efficiency while maintaining the desired accuracy.
Thief Zone Characterization and its Impact on Well Performance Based on Surveillance Data, Experimental Data and Theoretical Analysis for a Carbonate Reservoir
Authors: Wei Chenji , Zheng Jie , Ouyang Xiaohu , Ding Yutao , Ding Mingming , Lin Shiyao , Song Hongqing
Published: September 2019

Understanding the heterogeneity is critical for a successful water injection in a carbonate reservoir. Thief zone is one of the most obvious forms of heterogeneity, which indicates the thin layer with higher permeability compared to the average reservoir permeability. The existence of thief zone results in earlier water breakthrough and faster water cut increase, which then lead to lower sweep efficiency and smaller recovery factor. Therefore, determining the distribution of thief zone and its impact towards production, and proposing a corresponding development plan are very important.

In this paper, a novel method is established to determine the thief zone distribution based on dynamic surveillance data. A new index is proposed as the relative contribution index to characterize the relative contribution of a certain layer, which is fundamental for thief zone determination. In addition, effect on water flooding development of thief zone's location is studied by experimental and theoretical analysis. The changes of water cut and production rate are analyzed under different conditions such as location of the thief zone, injection rate, and variogram. Finally, optimized development strategy is proposed to deal with the existence of thief zone.

Distribution of thief zone is characterized based on the proposed method, which indicates that thief zone development has intimate relationship with depositional facies and diagenesis. Experimental and theoretical analysis results show that the present model considering stratified water-flood is consistent with the experimental results. The water displacement effect is the best when the thief zone is located in the upper reservoir. This paper also points out the optimal adjustment period for water shutoff and profile control of the reservoir with thief zones. In addition, the greater the injection rate, the faster the water cut increase. Furthermore, the smaller the variogram, the slower the water cut increase, and the later the water breakthrough time.

This study provides a method to characterize thief zone, which can be used as a reference for similar oilfield development. In addition, it provides a quick and reasonable guide in the later adjustment of water flooding development of carbonate reservoirs with thief zones.
EOS Workflows Uncertainties and Implications in Reservoir Modeling
Authors: Angulo Yznaga Reinaldo Jose
Published: September 2019

Data from seismic to production is integrated to build models to provide estimations of parameters such as petroleum volumetrics, pressure behavior, and production performance (Fig. 1). The level of confidence of these models depends on the representativeness of the data. The quality of the generated models is based on the data interpreted and integrated aimed to build computational realizations of petroleum reservoirs.

Reservoir dynamic simulation is the most applied process that integrates all reservoir data, where an Equation of State (EOS) is coupled with the objective to estimate the fluid thermodynamic state at each computational step. The simulation consists of iterative mathematical computations in which the reservoir-defined conditions at the previous time step is an input to determine the properties at the next and subsequent time steps. The calculated pressure is a fundamental variable in each time step, which means that a representative and high level of confidence Pressure Volume Temperature (PVT) model is required to avoid scale-up of errors resulting from fluid pressure estimation.

A PVT modeling includes three main stages: Fluid sample and data acquisitionLaboratory analysis and fluid characterizationThe EOS model.

The emphasis in this work is on the EOS model, which is the fluid model used for the simulation process. The objective of this work is to analyze the main uncertainties associated with typical EOS modeling and defining the level of confidence of these EOS approaches. In this work, some of the most-used approaches for EOS modeling are reviewed. An assessment of these methods is also provided based on their application to actual petroleum fluids with the objective of defining their statistical level of confidence.

First, the study analyzes the sources of critical uncertainties in a PVT EOS model. Second, a statistical number of PVT laboratory studies of petroleum fluids is used to determine the level of confidence of four approaches that are based on the two well-known Peng-Robinson and Soave-Redlich-Kwong EOS. Third, statistical analysis is performed to determine the level of confidence of the different methods. Fourth, a correlation to determine the optimal number of pseudo-components is defined. These steps include: Characterization of fluid and heavy componentsTuningLumping.

As a result of this study, one can conclude: The level of confidence of the four analyzed approachesThe significance of the difference between the analyzed methodsA correlation to determine the optimal number of pseudo-components.

In this work, a statistical analysis over some of the most-used EOS modeling approaches and on a set of petroleum fluid PVTs was performed to determine the level of confidence of four EOS modeling methods. In addition, a correlation was introduced for a priori determination of the optimal number of pseudo-components in a PVT fluid.
Pitfalls of 3D Saturation Modelling in the Middle East
Authors: O'Meara Daniel J.
Published: September 2019

This paper shows how greater scientific rigor in discussions of modelling 3D saturations in the Middle East can lead to better understanding of the reservoirs. It demonstrates with examples how vocabulary limits ability to solve problems related to saturations, compartmentalization, and permeability. It raises the bar on technical discussions of saturation.

"Saturation-height modelling", "transition zones", and "Thomeer hyperbolas" are examples of terms that repeatedly confuse discussions of modelling 3D saturations in the Middle East. Vocabulary exposes a lack of scientific rigor, impedes progress, and leads to notable failures. Saturation is not merely a function of height. At the very least, it also depends on porosity, permeability, fluid densities, interfacial tension, and contact angle. Limiting it to height requires adding in all of these other functionalities as afterthoughts rather than incorporating them naturally through dimensional analysis. Most glaringly, it obscures the very useful role that saturations have in constraining permeability modelling and identifying reservoir compartments.

"Transition zones" focus on saturation and take emphasis away from relative permeability and fractional flow. Bimodal pore systems (abundant in the Middle East) can have such low relative permeability to water at high saturations that even 70% water saturation can produce dry oil. In such cases, talk of a transition zone is counterproductive as it implies high water production.

"Thomeer hyperbolas" reveal biases in how to fit capillary pressure curves. Force-fitting all data with a single model is inadequate. It takes emphasis away from understanding pore systems of rocks in favor of promoting a single-minded view. These examples and their implications are discussed in detail.

The existing literature is replete with incomplete explanations and misunderstandings that lead to notable failures in modelling Middle Eastern fields. Understandings predicated on simplified descriptions of homogeneous reservoirs are no longer sustainable. A more scientifically rigorous methodology is presented.