bluuebunny/crossref_metadata_2025 huggingface dataset:
The laws of distribution of some parameters when organizing the movement of trains
Authors:   Krasnoyarsk Institute of Railway Transport – a branch of the Irkutsk State University of Railway Transport, Fufacheva M. V.
Published: November 2021

The article discusses the key factors for the organization of train traffic. The analysis of statistical parameters of the intervals of departure of freight trains from railway stations and the length of the freight train flow is carried out. Based on these train schedules, graphical dependences of the intervals of departure of trains from separate points on the volume of train traffic and the distribution of train lengths in even and odd directions are constructed. Polynomial dependencies with coefficients of variation are derived. The curve of the second-order Erlang distribution function for the departure intervals is constructed. It is determined that the average departure intensity in one hour is equal to three trains, and the average departure interval lies between the 25th and 35th minutes with a probability of 0.793. There is a correlation between the coefficient of variation (mean square deviation) of the departure interval and its average daily deviation. The power function of the analytical ratio of the coefficient of variation from the average interval of departure of freight trains from the technical stations of the Krasnoyarsk railway during the day is determined using the least squares method. The degrees of correspondence of theoretical and statistical distributions of the number of cars in trains are studied using the Kolmogorov criterion with the calculation of the probability value and confirmation that the distribution of the number of cars in trains obeys the binomial law. Using the Pearson agreement criterion, it is proved that the frequency of departure of freight trains from railway stations obeys the exponential distribution law.
Gazâlî'nin Kimliği Üzerine Klasik ve Modern Tartışmalar
Authors: GÜNDÜZ Ramazan
Published: November 2021

Bu çalışmada İslam düşüncesinin klasik çağının en etkili âlimlerinden biri olan, sonraki çağlarda da fikirleri üzerinde çok fazla tartışmanın yapıldığı Huccetü’l-İslam Ebû Hâmid el-Gazâlî’nin kimliği üzerine ortaya konulan klasik ve modern tartışmalar konu edilmiştir. Gazali’nin fikirleri üzerinde bitmek tükenmek bilmeyen tartışmalar onun kimliğini tespit etmede de devam etmiştir. Klasik ve modern Gazâlî biyografileri onun doğum tarihinden doğum yerine, isminin etimolojisinden kimliğine, kullandığı künyeden ailesi hakkındaki bilgilere varıncaya kadar birçok husus üzerine tartışma yapmıştır. Klasik kaynakların aktardığı bilgiler, birbiri ile çelişkili olmakla beraber her bir aktarımın diğerinin bilgi değerini yok sayacak düzeyde kuvvetli hüccetlerinin bulunmaması Gazâlî’nin kimliğini açıklığa kavuşturmayı zorlaştırmaktadır. Modern kaynaklarda ise klasik kaynakların ortaya koyduğu Gazâlî biyografisini değiştirecek yine klasik bilgilerle güçlendirilmiş iddialar bulunmaktadır. Diğer yandan bazı modern kaynakların klasik kaynaklarda bulunmayan, yeni bir Gazâlî kimliği inşa etmeye yönelik bilgiler vermeleri, meseleyi daha da karmaşık hale getirmektedir. Bu makalede, Gazali’nin kimliği üzerine bilgiler veren, etkili klasik ve modern kaynaklar taranmış ve mesele kısmen açıklığa kavuşturulmaya çalışılmıştır.,
Editorial: Resultados de pesquisas sobre os (as) Egressos (as) das Licenciaturas em Educação do Campo no Brasil
Authors: Castagna Molina Mônica
Published: November 2021

Apresentamos aos leitores da RBEC o Dossiê “Resultados de pesquisas sobre os (as) Egressos (as) das Licenciaturas em Educação do Campo no Brasil”, trazendo um precioso panorama sobre parte dos resultados alcançados pelos processos de institucionalização dessa política de formação docente.
Quantum Cognitive Triad: Semantic Geometry of Context Representation
Authors: Surov Ilya A.
Published: November 2021

The paper describes an algorithm for semantic representation of behavioral contexts relative to a dichotomic decision alternative. The contexts are represented as quantum qubit states in two-dimensional Hilbert space visualized as points on the Bloch sphere. The azimuthal coordinate of this sphere functions as a one-dimensional semantic space in which the contexts are accommodated according to their subjective relevance to the considered uncertainty. The contexts are processed in triples defined by knowledge of a subject about a binary situational factor. The obtained triads of context representations function as stable cognitive structure at the same time allowing a subject to model probabilistically-variative behavior. The developed algorithm illustrates an approach for quantitative subjectively-semantic modeling of behavior based on conceptual and mathematical apparatus of quantum theory.
Functional Characterization of Transporters for L-Aspartate in Bacillus licheniformis
Authors: Wang Hanrong , Li Youran , Xiao Fengxu , Zhang Yupeng , Shi Guiyang , Zhang Liang , Xu Sha , Ding Zhongyang , Gu Zhenghua
Published: November 2021

Amino acid efflux and influx transport systems play vital roles in industrial microorganisms’ cell growth and metabolism. However, although biochemically characterized, most amino acid transporters remain unknown at the molecular level in Bacillus licheniformis. This study focuses on the molecular and functional characterizations of three transporters, YdgF, YvbW, and YveA, mainly when catalyzing the cross-membrane flux of L-Aspartate. When growing in the minimal medium with L-Asp as the only carbon and nitrogen source, the growth of strains lacking proteins YdgF, YvbW, and YveA was significantly inhibited compared with wild-type strains, while supplementing the expression of the corresponding proteins in the single-gene knockout strains can alleviate the inhibition to some extent. Upon overexpression, the recombinant proteins mediate the accumulation of L-aspartate to varying degrees. Compared with wild-type strains, the single knockout strains of the three protein genes exhibited reduced absorption of L-aspartate. In addition, this paper focuses on the effects of these three proteins on the absorption of β-alanine, L-glutamate, D-serine, D-alanine, and glycine.
Advantages and Challenges of Cooperative Learning in Two Different Cultures
Authors: Keramati Mohammad Reza , Gillies Robyn M
Published: November 2021

Cooperative learning (CL) is a teaching and learning pedagogy that has been used widely in school but there is limited information on instructors’ perceptions of CL nor observations of how CL is implemented in higher education settings. In this study, we investigated the ad-vantages and challenges of embedding CL into instructors’ teaching in Iran and Australia. Data were collected through interview and observation. Results showed that despite challenges such as the lack of familiarity of CL and how it can be implemented in university curricula, issues associated with assessment, and time constraints, CL created an interactive, pleasant and safe environment for deep learning in both countries. The findings showed that there were challenges in Iran such as a tendency to use traditional approaches to teaching, insufficient understanding of how to establish teamwork, and a lack of up-to-date teaching resources. In Australia, changing courses, working with external students, catering for individual differences, and building positive relationships were some of the challenges of implementing CL. We believe that these challenges can be overcome if university instructors are prepared to address them.
Transcriptional Analysis-Based Alterations Affecting Neuritogenesis of the Peripheral Nervous System in Psoriasis
Authors: Romhányi Dóra , Szabó Kornélia , Kemény Lajos , Sebestyén Endre , Groma Gergely
Published: November 2021

An increasing amount of evidence indicates the critical role of the cutaneous nervous system in the initiation and maintenance of psoriatic skin lesions by neurogenic inflammation. However, molecular mechanisms affecting cutaneous neurons are largely uncharacterized. Therefore, we reanalyzed a psoriatic RNA sequencing dataset from published transcriptome experiments of nearly 300 individuals. Using the Ingenuity Pathway Analysis software, we associated several hundreds of differentially expressed transcripts (DETs) to nervous system development and functions. Since neuronal projections were previously reported to be affected in psoriasis, we performed an in-depth analysis of neurite formation-related processed. Our in silico analysis suggests that SEMA-PLXN and ROBO-DCC-UNC5 regulating axonal growth and repulsion are differentially affected in non-lesional and lesional skin samples. We identified opposing expressional alterations in secreted ligands for axonal guidance signaling (RTN4/NOGOA, NTNs, SEMAs, SLITs) and non-conventional axon guidance regulating ligands, including WNT5A and their receptors, modulating axon formation. These differences in neuritogenesis may explain the abnormal cutaneous nerve filament formation described in psoriatic skin. The processes also influence T cell activation and infiltration, thus highlighting an additional angle of the crosstalk between the cutaneous nervous system and the immune responses in psoriasis pathogenesis, in addition to the known neurogenic pro-inflammatory mediators.
College Students’ Knowledge and Perspective of Towards Biodiversity and its Conservation and Protection
Authors: Coracero Ericson Esquibel
Published: November 2021

Rich biodiversity is one of the Philippines’ greatest assets. Unfortunately, there is a continuous decline in the diversity of flora and fauna across the world. This calls for the need to educate people, especially younger generations, to value and protect biodiversity and natural resources. The study aimed to assess the students’ extent of knowledge and identify their perspectives towards biodiversity and its protection and conservation. A total of 268 randomly selected students at Aurora State College of Technology Zabali Campus were involved in the study. Survey questionnaires were used to obtain data and information which were subjected to statistical tests. The students had a moderate knowledge level on biodiversity with a mean score of 6.65 out of 10 items (SD = 1.50). Their perspective on biodiversity was leaning toward its protection and conservation, with a mean score of 7.2 out of 10 items (SD = 1.29). Factors affecting the students’ knowledge were gender (p = .003) and academic department (p = 0.003). Females and those associated with the Department of Forestry and Environmental Sciences and Department of Industrial technology were found to have more knowledge than the others. Males, on the other hand, were found to have a more positive perspective towards biodiversity. Knowledge and perspective had a weak correlation with r = 0.39. Students were not well-aware, but were in support of the Philippines’ biodiversity-related laws, which could help shape their mindset and actions towards biodiversity conservation and protection. As an implication, the college administration must revisit the curricula of all degree programs and ensure that students from each degree program are environmentally educated, emphasizing biodiversity conservation.
Asian Hornet, Vespa velutina Lepeletier 1836 (Hym.: Vespidae), Venom Obtention Based on an Electric Stimulation Protocol
Authors: Feás Xesús , Vidal Carmen , Vázquez-Tato M. Pilar , Seijas Julio A.
Published: November 2021

The yellow-legged Asian hornet (Vespa velutina Lepeletier 1836 (Hymenoptera: Vespidae)) is naturally distributed in China, Southeast Asia and India; however it has since detected outside of its native area, confirmed as being established in South Korea, Europe and Japan. Health risks and deaths caused by the invasive Vespa velutina stings have become a public health concern, being the most common cause of anaphylaxis due to hymenopterans in some European regions. This in turn has led to increased demand from medical practitioners and researchers for Vespa velutina venom for diagnostic and therapeutic purposes. In this study, a straightforward, quick and inexpensive method for obtaining Vespa velutina venom by electric stimulation is described. The venom extracts were analyzed by nuclear magnetic resonance spectroscopy (1H-NMR), confirming the composition of the obtained material. The availability of Vespa velutina venom will lead to improved diagnostic and therapeutic methods, mainly by venom immunotherapy (VIT), in patients allergic to this invasive species.
The Genetics and Epigenetics of Satellite Centromeres
Authors: Talbert Paul , Henikoff Steven
Published: November 2021

Centromeres, the chromosomal loci where spindle fibers attach during cell division to segregate chromosomes, are typically found within satellite arrays in plants and animals. Satellite arrays have been difficult to analyze because they comprise megabases of tandem head-to-tail highly repeated DNA sequences. Much evidence suggests that centromeres are epigenetically defined by the location of nucleosomes containing the centromere-specific histone H3 variant cenH3, independently of the DNA sequences where they are located; however, the reason that cenH3 nucleosomes are generally found on rapidly evolving satellite arrays has remained unclear. Recently, long read sequencing technology has clarified the structures of satellite arrays and sparked rethinking of how they evolve, while new experiments and analyses have helped bring both understanding and further speculation about the role these highly repeated sequences play in centromere identification.
КАЧЕСТВЕННАЯ И КОЛИЧЕСТВЕННАЯ ХАРАКТЕРИСТИКА ОДЫШКИ У БОЛЬНЫХ ПРОГРЕССИРУЮЩИМ ФИБРОТИЧЕСКИМ ФЕНОТИПОМ ИНТЕРСТИЦИАЛЬНЫХ БОЛЕЗНЕЙ ЛЕГКИХ, АССОЦИИРОВАННЫХ С СЕРДЕЧНО-СОСУДИСТЫМИ ЗАБОЛЕВАНИЯМИ
Authors:   Central Tuberculosis Research Institute, Russia, MEDVEDEV ALEXANDER V. , ABUBIKIROV ANVER F. ,   Central Tuberculosis Research Institute, Russia, ZAITSEVA ANNA S. ,   Central Tuberculosis Research Institute, Russia, MAZAEVA LARISA A. ,   Central Tuberculosis Research Institute, Russia, MAKARYANTS NATALIA N. ,   Central Tuberculosis Research Institute, Russia, SHMELEV EVGENY I. ,   Central Tuberculosis Research Institute, Russia,   Central Tuberculosis Research Institute, Russia
Published: November 2021

Aim. Analysis of quantitative and qualitative parameters of dyspnea in patients with the fibrotic phenotype of interstitial lung disease associated with coronary artery disease. Material and methods. We examined 49 patients. Among those were 9 patients with idiopathic pulmonary fibrosis, 25 patients with chronic variant of hypersensitive pneumonitis, and 14 patients with nonspecific interstitial pneumonia. The main group consisted of 25 patients with interstitial lung diseases and coronary heart disease; comparison group consisted of 24 patients without ischemic heart disease. Clinical symptoms, questionnaire results, and instrumental study data were analyzed. Results and discussion. Patients with coronary heart disease experienced increased dyspnea earlier (after 3,21 days) than patients without it (after 7,18 days; p<0,05). On functional examination, a significant decrease in pulmonary diffusion capacity was recorded in cardiac patients, p<0,05. Presence of coronary heart disease was accompanied by intensification of dyspnea according to Borg scale, decrease of distance walked in 6 min, significant decrease in pulse oximetry indices (by 7,94% in the main group and by 3,26% in the comparison group). On computed tomography, the severity of «frosted glass» was statistically higher in patients with coronary heart disease, p<0,05. Pulmonary hypertension, changes of right heart sections were observed in both groups of patients, left ventricular hypertrophy was observed only in patients of the main group. Patients with «isolated» phenotype of interstitial lung disease complained of heaviness, shortness of breath, patients with coronary heart disease complained of compression, tightness in chest, patients with pulmonary heart disease and heart failure had combination of these sensations. Conclusion. In patients with interstitial lung diseases, associated with coronary heart disease, dyspnea intensification reflects progression of lung disease, development of heart failure, and chronic pulmonary heart disease. Study of quantitative and qualitative characteristics of dyspnea is a way to specify the origin of dyspnea at the stage preceding specialized instrumental diagnostic methods.
SCREENING FOR COLORECTAL CANCER IN THE EMPLOYEES OF THE MINISTRY OF INTERNAL AFFAIRS OF RUSSIA IN THE REPUBLIC OF TATARSTAN. FIRST RESULTS AND PROSPECTS FOR DEVELOPMENT
Authors:   Clinical Hospital of the Medical Care  unit of the Ministry of Internal Affairs of Russian in the Republic of Tatarstan, Russia, SAKHIBULLIN RAMIL F. , AMIROV NAIL B. ,   Kazan State Medical University, FATYKHOV RENAT G. ,   Clinical Hospital of the Medical Care  unit of the Ministry of Internal Affairs of Russian in the Republic of Tatarstan, Russia, FADEEV GRIGORIY A. ,   Clinical Hospital of the Medical Care  unit of the Ministry of Internal Affairs of Russian in the Republic of Tatarstan, Russia
Published: November 2021

Background. Colorectal cancer is one of the most common cancers. The medical society continues to search for evidence-based colorectal cancer screening methods. Aim. The aim of the study was to evaluate the effectiveness of colorectal cancer screening in MIA employees using a preliminary questionnaire. The role of questionnaires in informing patients about modifiable risk factors for colorectal cancer was assessed. Material and methods. Thirty- seven employees of the Ministry of Internal Affairs, undergoing inpatient treatment, aged 40 to 51 years, participated in the study. Study protocol: on admission, patients were asked to fill out a questionnaire to identify risk and exclusion factors. Depending on the results of the questionnaire, each patient was assigned a method of primary colorectal cancer screening – fecal occult blood test or colonoscopy. If small epithelial masses were detected on colonoscopy, a one-stage polypectomy was performed. Results and discussion. Screening examinations allow the detection of precancerous diseases of the colon and, if certain conditions are met and equipment is available, the removal of masses at the initial colonoscopy. Performing a pre-screening survey allows you to identify risk factors for colorectal cancer and to select the right method of screening, as well as to inform patients about opportunities to reduce their likelihood of getting colorectal cancer. Thirty-seven patients were selected for screening. After analysis of the questionnaires, one patient was referred for colonoscopy and 36 patients underwent fecal occult blood tests; 15 of them were found to be positive. As a result, screening colonoscopy was performed in 13 patients, 9 of whom had epithelial masses with different histological structures detected and removed. Conclusion. The first results of screening for colorectal cancer in the Ministry of Internal Affairs allow us to conclude that it is effective for the diagnosis and treatment of precancerous diseases of the colon. The introduction of systematic screening is possible only if certain conditions are met.
Re-imagining freedom as elderly female porters: A study of buruh gendong at Beringharjo traditional market of Yogyakarta
Authors: Mahadika Gilang , Setiadi Setiadi
Published: November 2021

This paper expects to reveal the struggle of elderly female porters or buruh gendong who mostly had a historical background of working in industrial production (factory) but ended up being self-employed at Beringharjo traditional market of Yogyakarta. They used to work as factory workers. However, most factories collapsed in the aftermath of the 1997 economic crisis, especially in Southeast Asia. These older people from peri-urban (and rural) areas with lower-class status ended up in urban areas to be self-employed and became precarious workers. Therefore, the research questions are how they cope with the income uncertainties only to meet their daily needs and still desire their children to have a better living condition. Observations and interviews were done with 25 elderly female traditional porters as the research methods from 2020. They are primarily in the age range of late 50-80 years old. The results show that income uncertainties and social insecurity bring about precariousness. Buruh gendong have to work every day only to make ends meet. However, these conditions could also open up alternative perspectives that they often found themselves liberated from the control of industrial production. They do not work for capital owners or bosses; they work for themselves (self-employed). They are free or more flexible on working hours, but, at the same time, they have to accept their insecure employment. Buruh gendong also have desires for their children to be able to achieve a higher education level. Eventually, the desires are mostly unfulfilled; their children get unfortunate work and still live barely.
The Covid-19 cascade of care in Mexico: symptoms, positivity, and health care seeking decisions amid the pandemic
Authors: Colchero M. Arantxa , Moreno-Aguilar Luis Alberto , Bautista-Arredondo Sergio A
Published: November 2021

Objective. The study describes health care services utilization contextualized by the needs of the Mexican population during the Covid-19 pandemic. Materials and methods. We used data from the National Health and Nutrition Survey, Covid-19. Among the population with symptoms compatible with Covid-19, we describe the proportion who sought care, received care, were tested, were diagnosed positive, and survived, and whether they received care in public or private services. We estimated factors associated with the probability of seeking and receiving care. Results. Out of 7.1% of the population with symptoms compatible with Covid-19, 64.4% received care, and 15.4% tested positive; 74.5% received care in the private sector, even among the population with social security. Those with social security, in contact with a suspected or confirmed Covid-19 case, and with at least one comorbidity had a higher probability of seeking and receiving care. Conclusions. The most relevant finding of our study is the large proportion of the population with Covid-19 symptoms who sought and received care in private facilities an essential aspect for decision-makers to consider as the current health reform moves forward in Mexico.
Trends in the prevalence of metabolic syndrome and its components in Mexican adults, 2006-2018
Authors: Rojas-Martínez Rosalba , Aguilar-Salinas Carlos A , Romero-Martínez Martín , Castro-Porras Lilia , Gómez-Velasco Donaji , Mehta Roopa
Published: November 2021

Objective. To examine trends in the prevalence of metabolic syndrome (MS) and its components. Materials and methods. Data from 27 800 Mexican adults who participated in Ensanut 2006, 2012, 2016 and 2018 were analyzed. Linear regression was used across each Ensanut period to assess temporal linear trends in the prevalence of MS. Logistic regression models were obtained to calculate the percentage change, p-value for the trend and the association between the presence of MS and the risk of developing type 2 diabetes mellitus (T2DM) over 10 years using the Finnish Diabetes Risk Score (FINDRISC) and cardiovascular disease (CVD) using Globorisk. Results. The prevalence of MS in Mexican adults according to the harmonized definition was: 40.2, 57.3, 59.99 and 56.31%, in 2006, 2012, 2016 and 2018 respectively (p for trend <0.0001). In 2018, 7.62% of metabolic syndrome cases had a significant risk for incident DM2 and 11.6% for CVD. Conclusion. It is estimated that there are 36.5 million Mexican adults living with metabolic syndrome, of which 2 million and 2.5 million have a high risk of developing T2DM or cardiovascular disease respectively, over the next 10 years.
Health care utilization during the Covid-19 pandemic in Mexico: the cascade of care
Authors: Colchero M. Arantxa , Gómez Rouselinne , Pineda-Antúnez Carlos J , Bautista-Arredondo Sergio A
Published: November 2021

Objective. The objective of the study is to describe trends in selected services offered at public health facilities and utilization patterns during the Covid-19 epidemic in Mexico. Materials and methods. We used administrative data and the National Health and Nutrition Survey Covid-19, 2020. Results. We found a reduction in the rates of diabetes and detection screening during 2020 compared to 2014-2019. From the demand side, we found that 18.6% of the population reported health needs, and only 34% of them received care in public health facilities. The use of private health services was extensive even among the population with social security. The uninsured and the population with high and medium socioeconomic status had a lower probability of receiving care in public health facilities. Conclusion. We document trends in selected services, as well as the cascade of care during the Covid-19 epidemic in Mexico and its potential impact on displaced health care.
Family and household characteristics associated with seropositive cases to SARS-CoV-2 across Mexican households
Authors: López-Olmedo Nancy , Stern Dalia , Canto-Osorio Francisco , Barrientos-Gutiérrez Tonatiuh , Alpuche-Aranda Celia
Published: November 2021

Objective. To assess the association of family and housing characteristics with the number of seropositive cases to SARS-CoV-2 in households. Materials and methods. We analyzed 874 households from Encuesta Nacional de Salud y Nutrición (Ensanut) 2020 Covid-19 using Poisson regression models. Results. The number of seropositive family members was higher among families composed of children/adolescents, adults and older adults, households with more than two members per bedroom, and among households with closed windows. No association was found for bathroom availability and piped water. Conclusions. Family composition and housing characteristics can impose significant structural barriers to safe home confinement.
Seroprevalencia de SARS-CoV-2 en adultos y adultos mayores en México y su asociación con enfermedades crónicas. Ensanut 2020 Covid-19
Authors: Sánchez-Pájaro Andrés , Pérez Ferrer Carolina , Basto-Abreu Ana , Rivera-Dommarco Juan , Barquera Simón , Denova-Gutiérrez Edgar , Barrientos-Gutiérrez Tonatiuh
Published: November 2021

Objetivo. Analizar la asociación entre seropositividad a SARS-CoV-2 y enfermedades crónicas en adultos y adultos mayores mexicanos. Material y métodos. Se utilizó la Encuesta Nacional de Salud y Nutrición 2020 sobre Covid-19 (Ensanut 2020 Covid-19) para evaluar la asociación de seropositividad a SARS-CoV-2 con hipertensión arterial sistémica, diabetes tipo 2, índice de masa corporal, LDL-c elevado, HDL-c bajo, colesterol total elevado e hipertrigliceridemia. Resultados. Se observó una mayor seropositividad en personas con mayor índice de masa corporal. La seroprevalencia fue 25% mayor entre los adultos que presentaban obesidad en comparación con aquellos de peso normal en modelos ajustados (RP: 1.25 IC95%: 1.08,1.46). No se observó asociación entre seropositividad y otras enfermedades crónicas en adultos o adultos mayores. Conclusiones. Las personas con obesidad podrían tener una mayor susceptibilidad a la infección por SARS-CoV-2. Este hallazgo debe ser confirmado con estudios longitudinales. No se encontró evidencia de asociación para otras enfermedades.
Joint Optimization of Well Completions and Controls for CO2 Enhanced Oil Recovery and Storage
Authors: Chen Bailian , Pawar Rajesh
Published: November 2021

Carbon dioxide (CO2) enhanced oil recovery (EOR) is considered one of the technologies to help promote larger scale deployment of geologic CO2 storage because of associated economic benefits through CO2 storage, associated benefits of oil recovery, and the 45Q tax credit (a tax incentive that would reduce CO2 emission in the United States) as well as potential for utilization of existing infrastructure. The objective of this study is to demonstrate how optimal operation strategies (including well completions and controls) can be used to optimize both CO2 storage and oil recovery. The optimization problem was focused on joint estimation of well completions (i.e., fraction of injection/production well perforations in each reservoir layer) and CO2 injection/oil production controls [i.e., rates or bottomhole pressures (BHPs)] that maximize the net present value (NPV) in a combined CO2-EOR and CO2 storage operation. We used the newly developed stochastic simplex approximate gradient (StoSAG), one of the most efficient optimization algorithms in the reservoir optimization community, to solve the optimization problem. The performance of the joint optimization approach was compared with the performance of the well-control-only optimization approach. The superiority of joint optimization was demonstrated with two examples. In addition, the performance of co-optimization of CO2 storage and oil recovery approach was compared with the performances of maximization of only CO2 storage and maximization of only oil recovery approaches.
Strategies to Enhance the Performance of Gaussian Mixture Model Fitting for Uncertainty Quantification
Authors: Gao Guohua , Vink Jeroen , Saaf Fredrik , Wells Terence
Published: November 2021

When formulating history matching within the Bayesian framework, we may quantify the uncertainty of model parameters and production forecasts using conditional realizations sampled from the posterior probability density function (PDF). It is quite challenging to sample such a posterior PDF. Some methods [e.g., Markov chain Monte Carlo (MCMC)] are very expensive, whereas other methods are cheaper but may generate biased samples. In this paper, we propose an unconstrained Gaussian mixture model (GMM) fitting method to approximate the posterior PDF and investigate new strategies to further enhance its performance.

To reduce the central processing unit (CPU) time of handling bound constraints, we reformulate the GMM fitting formulation such that an unconstrained optimization algorithm can be applied to find the optimal solution of unknown GMM parameters. To obtain a sufficiently accurate GMM approximation with the lowest number of Gaussian components, we generate random initial guesses, remove components with very small or very large mixture weights after each GMM fitting iteration, and prevent their reappearance using a dedicated filter. To prevent overfitting, we add a new Gaussian component only if the quality of the GMM approximation on a (large) set of blind-test data sufficiently improves.

The unconstrained GMM fitting method with the new strategies proposed in this paper is validated using nonlinear toy problems and then applied to a synthetic history-matching example. It can construct a GMM approximation of the posterior PDF that is comparable to the MCMC method, and it is significantly more efficient than the constrained GMM fitting formulation (e.g., reducing the CPU time by a factor of 800 to 7,300 for problems we tested), which makes it quite attractive for large-scale history-matching problems.

NOTE: This paper is also published as part of the 2021 SPE Reservoir Simulation Conference Special Issue.
Integrated Production Model as a Tool for Optimization the Development Strategy of the Sakhalin Oil and Gas Condensate Field
Authors: Doroshenko Oleksandr , Cimic Miljenko , Singh Nicholas , Machuzhak Yevhen
Published: November 2021

A fully integrated production model (IPM) has been implemented in the Sakhalin field to optimize hydrocarbons production and carried out effective field development.

To achieve our goal in optimizing production, a strategy has been accurately executed to align the surface facilities upgrade with the production forecast.

The main challenges to achieving the goal, that we have faced were:

All facilities were designed for early production stage in late 1980's, and as the asset outdated the pipeline sizes, routing and compression strategies needs review. Detecting, predicting and reducing liquid loading is required so that the operator can proactively control the hydrocarbon production process. No integrated asset model exists to date.

The most significant engineering tasks were solved by creating models of reservoirs, wells and surface network facility, and after history matching and connecting all the elements of the model into a single environment, it has been used for the different production forecast scenarios, taking into account the impact of infrastructure bottlenecks on production of each well.

This paper describes in detail methodology applied to calculate optimal well control, wellhead pressure, pressure at the inlet of the booster compressor, as well as for improving surface flowlines capacity.

Using the model, we determined the compressor capacity required for the next more than ten years and assessed the impact of pipeline upgrades on oil gas and condensate production.

Using optimization algorithms, a realistic scenario was set and used as a basis for maximizing hydrocarbon production.

Integrated production model (IPM) and production optimization provided to us several development scenarios to achieve target production at the lowest cost by eliminating infrastructure constraints.
Predicting of the Geometrical Behavior of Formations in Subsurface Based on the Analysis of LWD/MWD Data While Drilling Horizontal Wells
Authors: Tyvonchuk Serhii Petrovych
Published: November 2021

The successful penetration of oil and gas formations by a horizontal well depends on the accuracy of the forecast of the depth and angle of the layers’ dip at the entry point. Methods and mathematical algorithms for predicting the geometric behavior of formations during drilling of a horizontal well at the stage of its approach to the entry point into target productive horizons are developed.

The relationship between the formation dip, their stratigraphic thickness, and apparent vertical thickness in vertical and sub-horizontal wells is considered. It is shown that even small angles of inclination can lead to a significant influence on the prediction of the point of formation opening by a horizontal well. A detailed correlation of the offset well section with a horizontal well one while drilling was used for the analysis. A method for predicting the depth of disclose of the target formation by a horizontal well based on the change in the apparent vertical thickness is shown. A mathematical algorithm for calculating the apparent bedding angle on the basis of initial and while drilling data has been obtained. The calculated bedding angle allows predicting the depth of the target formation penetration with a horizontal well.

The proposed method for predicting the horizontal well landing point depth allows avoiding errors associated with non-horizontal layering. The use of the proposed technique when drilling a number of horizontal wells in the oil fields of the Dnieper-Donets Basin (DDB) and the Pre-Carpathian Foredeep made it possible to determine with high accuracy the apparent bedding angle, even at their small values. The calculations made it possible to predict the depth of entry into the target formation during drilling with high accuracy. This is especially important in the context of small oil deposits, where it is impossible to make significant adjustments to the lateral position of the horizontal part of the wellbore. The predicted depths of the entry points into the formations were confirmed by the drilling results.

The use of the proposed method makes it possible to perform high-quality geosteering while drilling horizontal wells at the stage of approaching the target formation entry point using the minimum data set.

The simplicity of the method allows you to quickly analyze the geological section penetrated by a horizontal well and determine its geometric behavior. This approach makes it possible to successfully open pay formations with horizontal wells even without using a pilot well.
A Case Study of High-Rate Multistage Hydraulic Fracturing in Petrikov Horizon of the Pripyat Trough
Authors: Mironenko Kirill Victorovich , Voytekhin Oleg Leonidovich , Marchenko Vladimir Vladimirovich
Published: November 2021

Currently, the vast majority of the oil fields of the Republic of Belarus are at the final stage of development. In this connection, in order to expand the resource base, Belarusian oil companies are assigned with the task of searching, exploring and developing hard-to-recover reserves. In recent years, a number of geological works have been carried out to search and study the sedimentary cover rocks of the Belarusian part of the Pripyat Trough, the results of these works were the discovery of promising deposits of the Petrikov Horizon of the Upper Devonian.

These deposits are represented by dense fractured carbonate rocks with ultra-low permeability (less than 0.01 mD) and low effective porosity (up to 10%). The most promising technology for the development of such reservoirs is the drilling of horizontal wells and the subsequent implementation of Multistage hydraulic fracturing.

This article presents the experience of developing ultra-low-permeability reservoirs in the Republic of Belarus in the period 2014-2021, briefly describes the main technologies used, the evolution of technological solutions for effective involvement in the active development of hard-to-recover reserves.
The SMART SRP Well – Application of Edge Analytics for Automated Well Performance Control and Condition Monitoring in a Mature Brownfield Environment – A Case Study from Austria
Authors: Windisch Christian
Published: November 2021

This paper presents a holistic approach to modern oilfield and well surveillance through the inclusion of state-of-the-art edge computing applications in combination with a novel type of data transmission technology and algorithms developed in-house for automatic condition monitoring of SRP systems. The objective is to enable the responsible specialist staff to focus on the most important decisions regarding oilfield management, rather than wasting time with data collection and preparation.

An own operated data communication system, based on LPWAN-technology transfers the dyno-cards, generated by an electric load cell, into the in-house developed production assistance software platform. Suitable programmed AI-algorithms enable automatic condition detection of the incoming dyno cards, including conversion and analysis of the corresponding subsurface dynamograms. A smart alarming system informs about occurring failure conditions and specifies whether an incident of rod rupture, pump-off condition, gas lock or paraffin precipitation occurred in the well. A surface mounted measuring device delivers liquid level and bottomhole pressure information automatically into the software. Based on these diverse data, the operations team plans the subsequent activities.

The holistic application approach is illustrated using the case study of an SPR-operated well in an Austrian brownfield.
Influence of Abandonment Pressure on Recoverable Reserves, Special Application to the Depleted Dnipro-Donetsk Basin Reservoirs
Authors: Cimic Miljenko , Sadivnyk Michael , Doroshenko Oleksandr , Kovalchuk Stepan
Published: November 2021

Volumetric gas reservoirs are driven by the compressibility of gas and a formation rock, and the ultimate recovery factor is independent of the production rate but depends on the reservoir pressure. The gas saturation in the volumetric reservoir is constant, and the gas volume is reduced causing pressure drop in the reservoir. Due to this reason, it is crucial to minimize the abandonment pressure to the lowest possible level. Concerning Dnipro-Donetsk Basin (DDB) gas reservoirs, it is widespread to recover sometimes more than 90% of the OGIP. Often, OGIP was estimated not considering lower permeability gas layers due to inaccurate logging equipment used in the past, causing that such layers were not included in the total netpay. This is one of the reasons for OGIP overestimation and higher recovery factors. On many P/Z graphs, we observe that at certain drawdown, lower permeability reservoirs kick in lifting up P/Z plot curve.

Abandonment pressure is a major factor in determining recovery efficiency. Permeability and skin are usually the most critical factors in determining the magnitude of the abandonment pressure. Reservoirs with low permeability will have higher abandonment pressures than reservoirs with high permeability. A specific minimum flow rate must be sustained to keep the well unloading process, and a higher permeability will permit this minimum flow rate at lower reservoir pressure.

Abandonment pressure will depend on wellhead pressure, friction and hydrostatic pressures in the system, pressure drop in reservoir, and pressure drop due to skin. This last factor is often neglected, which sometimes leads to a significant reduction of the recovery factor. It is common practice that skin factor and pressure drop due to the skin are solved with well stimulation. Also, well stimulation has its limits concerning the level of reservoir pressure. It is very common that the stimulation effect of low reservoir pressure well is negligible or even negative. This is caused by the minimum required drawdown to flow back a stimulating aqueous fluid out of the reservoir. The required minimum drawdown is caused by the Phase Trapping Coefficient (PTC), which drives reservoir stimulation fluid cleaning behavior.

For water drive gas reservoirs, Cole (1969) suggests that the recovery is substantially less than recovery from bounded gas reservoirs. As a rule of thumb, recovery from a water-drive reservoir will be approximately 50 to 75% of the initial gas in place. The structural location of producing wells and the degree of water coning are essential considerations in determining ultimate recovery. In the cases studied in this paper, we consider gas and rock expansion reservoir energy, if abandonment pressure needs to be coupled with a water drive, then it is recommended to use a numerical, not analytical approach.
Adoption of Integrated Asset Modeling Approach to Kick-Start the Corporate Digital Transformation Strategy
Authors: Siew Hiang Khor , Volodymyr Petrunyak , Melnyk Yevgen A. , Oleksii Prykhodchenko , Viktor Stefaniv , Andrew Dogar , Michael Ojukwu , Andres Viscaino
Published: November 2021

The adoption of an integrated asset modeling approach was explored to kick-start the corporate digital transformation strategy for its oil and gas section. Besides the integrated asset model, the digital initiatives included predictive maintenance, well performance optimization, and a flow assurance advisor aimed at daily production operations and maintenance, creating a pathway to the digital oilfield (DOF). The integrated asset model would be the main pillar of DOF realization and implementation, its offered technology aimed at short-term, medium-term, and long-term planning.

The adopted well-proven integrated asset modeling methodology enabled a geological complex with a high-fidelity physics reservoir model, multiple interdependent wells, pipeline networks, process facility models to be integrated seamlessly on a single platform for validation of its existing production operation strategy and field development plan. The black-oil reservoir model was history matched, and the production network models had detailed wellbore and pipeline hydraulics calibrated with the latest well-test data. The compositional fluid modeling allowed the capture of any flow assurance issues that arose across the networks, which were mapped to the corresponding process facility models with physical specifications and operational constraints defined.

A fully integrated asset model was developed for the studied asset, where liquid/vapor tables were prepared for black-oil delumping (Ghorayeb and Holmes, 2005) of the reservoir models to surface network models (Mora et al. 2015), while fluid models of both production network and process models were validated before mapping to ensure fluid fidelity. The availability of this integrated asset model with an embedded spreadsheet program incorporating some simple economic calculations allowed the flexibility of short-term production optimization and long-term asset planning, which was focused to provide all the vital valuable inputs to better field management, fast and accurate decision making, and optimum safe operation of process units in meeting the sales contract.

The integrated asset model offered a platform for engineers from different domains to collaborate with aligned common operational and planning objectives. It empowered assessments of production operation strategy and field development scenarios conducted at full field level from pore to process. The customized reporting, the ability to connect to other tools, and to push results to dashboards helped to kick-start the corporate digital transformation strategy.
Physical Testing of a High-Speed Helico-Axial Pump for High-GVF Operation
Authors: Ejim Chidrim Enoch , Xiao Jinjiand , Lee Woon Yung , Zabala Wilson Andres
Published: November 2021

High-speed rotordynamic pump operation for downhole or surface production is required and also beneficial to handle very high gas volume fraction (GVF) flows. Operating speeds of these pumps can be in excess of twice those of conventional pumps. This study presents results showing a high-speed helico-axial pump (HAP) can operate satisfactorily at intake GVFs up to 98%. The findings increase capabilities of field engineers and operators to boost and maximize production from high gas-content wells.

The HAP tested had a housing outer diameter of 4.00-inch and operated at a rotational speed of 6000 revolutions per minutes (RPM). Air and water were the test fluids with the water volume flow rate held constant while the air volume flow rate was varied. The liquid and gas volume flow rates varied from 63 to 143 barrels per day (BPD), and 549 to 3238 BPD, respectively. Intake pressures varied from 14 to 76 psig, with average inlet temperature of 18°C. The corresponding discharge pressures and temperatures were recorded for each test point and observed for stable pump operation.

The results showed that the HAP had stable operation during the tests for intake GVF range from 84% to 98%. Pump discharge pressures for this range of high intake GVF varied from 21 to 89 psig. The corresponding differential pressures across the HAP all had positive magnitudes indicating that at such high-speeds, the HAP was still able to add energy to the fluid even with the high gas content at intake. Analysis at fixed intake pressure with varying GVFs showed that the discharge-to-intake pressure ratio decreased with increasing intake GVF. For instance, at 33psig intake pressure, increasing the intake GVF from 84% to 94% decreased the discharge-to-intake pressure ratio from about 1.27 to 1.20, respectively. It was also observed that tightening the clearance between the impeller and diffuser of the HAP increased the discharge pressure compared to when the clearance was loose. Furthermore, ensuring the upstream flow is properly conditioned also improved the stable operation of the HAP. Overall and in conclusion, running a HAP at high speeds in addition to optimizing certain features of the HAP can result in stable pump operation and enhanced pressure boosting in high-GVF flows.

This study mainly highlights the importance of operating HAPs at high speeds of up to 6000 RPM. Tightening clearances between rotordynamic components as well as tailored inlet flow conditioning are also additional features that enhance pressure boosting. This architecture opens up opportunities for field operators, and engineering personnel to maximize hydrocarbon production from their very high-gas content field assets, thereby increasing the economic bottomline for the stakeholders.