bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fast-Marching Methods for Complex Grids and Anisotropic Permeabilities: Application to Unconventional Reservoirs
Authors: Zhang Yanbin , Yang Changdong , King Michael J. , Datta-Gupta Akhil 
Published: February 2013

Abstract
Unconventional reservoirs are characterized by sufficiently low permeabilities so that the pressure depletion from a producing well may not propagate far from the well during the life of a development. This is in contrast to conventional plays where the pressure transients may probe the entire reservoir in weeks to months. The concept of depth of investigation and its application to unconventional reservoirs provide the understanding necessary to describe and optimize the interaction between complex multi-stage fractured wells, reservoir heterogeneity, drainage volumes, pressure depletion, well rates, and the estimated ultimate recovery.
Previous studies have performed unconventional reservoir analysis using more conventional reservoir simulation techniques. High resolution local PEBI grids and global corner point grids have been used to represent complex fracture geometry and conductivity and estimate subsequent well performance. However, these techniques do not provide the more geometric understanding provided by the depth of investigation and drainage volumes.
The application of the depth of investigation to heterogeneous reservoirs can be obtained from an asymptotic expansion of the diffusivity equation leading to the Eikonal equation which describes the propagation of the pressure front. This equation is solved using a Fast Marching Method to calculate a diffusive time of flight at every location within the domain. The diffusive time of flight is directly related to pressure front propagation. Unlike in a reservoir simulator, this frontal propagation is determined in a single non-iterative calculation, which is extremely fast. Once the pressure fronts are determined spatially, we may apply a pseudo-steady state pressure approximation within the moving front to determine pressure depletion and well rates.
In the current study, we extend the Fast Marching Method for solution of the Eikonal equation to complex simulation grids including corner point and unstructured grids. This allows the rapid approximation of reservoir simulation results without the need for flow simulation, and also provides the time-evolution of the well drainage volume for visualization. Understanding the drainage volume alone is useful for well spacing and multi-stage fracture spacing optimization. Additional potential applications include well trajectory and hydraulic fracture location optimization, reservoir model screening and ranking, matrix/fracture parameter estimation, uncertainty analysis and production data integration.
Representing Hydraulic Fractures Using a Multilateral, Multisegment Well in Simulation Models
Authors: Edwards D. A. , Cheng N. , Dombrowsky T. P. , Bowen G. , Nasvik H. 
Published: February 2013

Abstract
Hydraulic fracturing is a stimulation treatment routinely performed on oil and gas wells in low-permeability reservoirs. However, simulating fractured wells is still challenging and impractical using local grid refinement in full-field models with a large number of wells each with multiple fractures.
This paper describes a novel modeling technique by which hydraulic fractures are represented as part of the well model, rather than any form of refinement in the simulation grid. In this approach a planar fracture is modeled by the mesh formed from the interconnected branches of a multilateral, multisegment well. The main advantages are: 1) the fracture mesh is made independent of the simulation grid and thus model building is simpler; 2) fractures can be added and altered at any simulation time; 3) fractures can intersect the reservoir grid lines at any angle; 4) fracture geometry and properties can be fully honored. This technique is designed to model long-term pseudo-steady state fracture flows and uses Darcy flow equations in the lateral well branches that represent the fracture.
The accuracy, stability, and practicality of this new technique have been investigated using a suite of simulation models ranging from a single well in a homogeneous reservoir to a real field sector model with numerous wells, each with multiple fractures. Where possible, the behavior of a reference model—built using traditional grid-refinement techniques—is compared against the multilateral, multisegment well model equivalent. The results of these experiments presented in this paper show a close agreement between the reference gridded fractures and the well model fractures when the system reaches a pseudo-steady state. They also show that the new approach suffers from a lesser degree of numerical instability when modeling extremely thin and highly conductive fractures. Finally, the results confirm the practicality and flexibility of this approach.
Multiscale method for simulating two and three-phase flow in porous media
Authors: Pal Mayur , Lamine Sadok , Lie Knut-Andreas , Krogstad Stein 
Published: February 2013

Abstract
Multiscale methods developed to solve coupled flow equations for reservoir simulation are based on a hierarchical strategy in which the pressure equation is solved on a coarsened grid and transport equation is solved on the fine grid as a decoupled system. The multiscale mixed finite-element (MsMFE) method attempts to capture sub-grid geological heterogeneity directly into the coarse-scale via mathematical basis functions. These basis functions are able to capture important multiscale information and are coupled through a global formulation to provide good approximation of the subsurface flow solution.
In the literature, the general formulation of the MsMFE method for incompressible two-phase and compressible three-phase flow has mainly addressed problems with idealized flow physics. In this paper, we present a new formulation that accounts for compressibility, gravity, and spatially-dependent capillary and relative-permeability effects.
We evaluate the computational efficiency and accuracy of the method by reporting the result of series of representative benchmark tests that have a high degree of realism with respect to flow physics, heterogeneity in petrophysical model, and geometry/topology of the corner-point grids. In particular, the MsMFE method is validated and compared against Shell’s in-house simulator MoReS. The fine-scale flux, pressure, and saturation fields computed by the multiscale simulation show a noteworthy improvement in resolution and accuracy compared with coarse-scale models.
Rapid Updating of Stochastic Models Using an Ensemble Filter Approach
Authors: Tavakoli Reza , Srinivasan Sanjay , Wheeler Mary F. 
Published: February 2013

Abstract
Ensemble Kalman filtering (EnKF) is an effective method for reservoir history matching. The underlying principle is that an initial ensemble of stochastic models can be progressively updated to reflect the measured values as they become available. However, the ensemble Kalman filter updating scheme restricts the method to multivariate Gaussian random fields. Therefore, it is challenging to implement the filtering scheme for non-Gaussian random fields such as reservoirs where there is a strong contrast in permeability between different geological facies. In this paper, we develop a methodology to combine multidimensional scaling and the ensemble Kalman filter for rapidly updating models for a channelized reservoir. A dissimilarity matrix is computed using the dynamic responses of ensemble members. This dissimilarity matrix is transformed to a lower dimensional space using multidimensional scaling. The responses mapped in the lower dimension space are clustered and based on distances between the models in a cluster and the actual observed response, the closest models to the observed response are retrieved. Updating of models within the closest cluster are performed using EnKF equations. The results of the update are used to re-sample new models for the next step. A two dimensional water flooding example of a channelized reservoir is set up to demonstrate the applicability of the proposed method. The obtained results demonstrate that the proposed algorithm is viable for sequentially updating reservoir models and for preserving the channel features after the data assimilation process.
History-Matching Production and Seismic Data in a Real Field Case Using the Ensemble Smoother With Multiple Data Assimilation
Authors: Emerick Alexandre A. , Reynolds Albert C. 
Published: February 2013

Abstract
In a recent paper, we introduced a data assimilation procedure based on the application of the ensemble smoother (ES) with multiple data assimilation (MDA). The method, which has the acronym ES-MDA, was theoretically motivated by the equivalence between single and multiple data assimilation for the linear-Gaussian case and an approximate relationship between ES and one iteration of the Gauss-Newton method. ES-MDA is easy to combine with any commercial simulator, in fact, much easier than it is to couple the ensemble Kalman filter (EnKF) with a commercial simulator. Here, we apply EnKF and ES-MDA to generate multiple realizations of the porosity, net-to-gross ratio (NTG) and permeability fields by history matching production and seismic impedance data (3D and 4D) in a turbidite reservoir in the Campos Basin. 3D seismic data are integrated first and then 4D and production data are assimilated together, either simultaneously with ES-MDA or sequentially in time with EnKF.
Adverse Health Effects Of Indoor Moulds / Štetni Zdravstveni Učinci Plijesni Unutarnjih Prostora
Authors: Piecková Elena 
Published: February 2013

AbstractBuilding associated illnesses - sick building syndrome (SBS) as a common example - are associated with staying in buildings with poor indoor air quality. The importance of indoor fungal growth in this phenomenon continues to be evident, even though no causative relation has been established so far. Indoor humidity is strongly associated with the symptoms of SBS. Fungal metabolites that may induce ill health in susceptible occupants comprise beta-D-glucan, mycotoxins, and volatile organic compounds as known irritants and/or immunomodulators. Indoor toxic fungal metabolites might be located in micromycetal propagules (endometabolites), in (bio-)aerosol, detritus, and house dust (exometabolites) as their particular carriers. It is highly probable that hyphal fragments, dust, and particles able to reach the alveoli have the strongest depository and toxic potential. Most fungal spores are entrapped by the upper respiratory tract and do not reach further than the bronchi because of their size, morphology, and the mode of propagation (such as slime heads and aggreggation). This is why studies of the toxic effects of fungal spores prefer directly applying metabolite mixtures over mimicking real exposure. Chronic low-level exposure to a mixture of fungal toxicants and other indoor stressors may have synergistic effects and lead to severe neuroendocrineimmune changes.
Grapevine Trunk Diseases Associated with Fungi from the Diaporthaceae Family in Croatian Vineyards / Identifikacija Vrsta Roda Fusarium Izoliranih S Plodova Jabuke Nakon Skladištenja
Authors: Kaliterna Joško , Miličević Tihomir , Cvjetković Bogdan 
Published: February 2013

AbstractGrapevine trunk diseases (GTD) have a variety of symptoms and causes. The latter include fungal species from the family Diaporthaceae. The aim of our study was to determine Diaporthaceae species present in the woody parts of grapevines sampled from 12 vine-growing coastal and continental areas of Croatia. The fungi were isolated from diseased wood, and cultures analysed for phenotype (morphology and pathogenicity) and DNA sequence (ITS1, 5.8S, ITS2). Most isolates were identified as Phomopsis viticola, followed by Diaporthe neotheicola and Diaporthe eres. This is the first report of Diaporthe eres as a pathogen on grapevine in the world, while for Diaporthe neotheicola this is the first report in Croatia. Pathogenicity trials confirmed Phomopsis viticola as a strong and Diaporthe neotheicola as a weak pathogen. Diaporthe eres turned out to be a moderate pathogen, which implies that the species could have a more important role in the aetiology of GTD.
Paleoenvironments during the Rhaetian transgression and the colonization history of marine biota in the Fatric Unit (Western Carpathians)
Authors: Michalík Jozef , Lintnerová Otília , Wójcik-Tabol Patrycja , Gaździcki Andrzej , Grabowski Jacek , Golej Marián , Šimo Vladimír , Zahradníková Barbara 
Published: February 2013

Abstract
Terminal Triassic environmental changes are characterized by an integrated study of lithology, litho- and cyclostratigraphy, paleontology, mineralogy, geochemistry and rock magnetism in the Tatra Mts. The Carpathian Keuper sequence was deposited in an arid environment with only seasonal rivers, temporal lakes and swamps with scarce vegetation. Combination of a wide range of δ18O values (-0.7 to + 2.7) with negative δ13C values documents dolomite precipitation either from brackish or hypersaline lake water, or its derivation from pore water comparably to the Recent Coorong B-dolostone. Negative δ13C values indicate microbial C productivity. Rhaetian transgressive deposits with restricted Rhaetavicula fauna accumulated in nearshore swamps and lagoons. Associations of foraminifers, bivalves and sharks in the Zliechov Basin were controlled by physical factors. Bivalve mollusc biostromes were repetitively destroyed by storms, and temporary firm bottoms were colonized by oysters and burrowers. Subsequent black shale deposition recorded input of eolian dust. Bottom colonization by pachyodont bivalves, brachiopod and corals started much later, during highstand conditions. Facies evolution also revealed by geochemical data, C and O isotope curves reflect eustatic and climatic changes and help reconstruct the evolution of Rhaetian marine carbonate ramp. The Fatra Formation consists of 100 kyr eccentricity and 40 kyr obliquity cycles; much finer rhythmicity may record monsoonlike climatic fluctuations. Fluvial and eolian events were indicated by analysis of grain size and content of clastic quartz, concentrations of foraminiferal (Agathammina) tests in thin laminae indicates marine ingression events. Magnetic susceptibility (MS) variations reflect the distribution of authigenic and detrital constituents in the sequence. Increasing trend of MS correlates with the regressive Carpathian Keuper sequence and culminates within the bottom part of the Fatra Formation. Decreasing trend of MS is observed upwards the transgressive deposits of the Fatra Formation.
Foraminiferal assemblage in the coral-bearing limestones of the Vršatec area (Pieniny Klippen Belt, Western Carpathians, Slovakia)
Authors: Morycowa Elżbieta , Olszewska Barbara 
Published: February 2013

Abstract
The paper deals with benthic foraminifera occurring with the scleractinian corals in the Jurassic biohermal and peribiohermal coral-bearing limestones of the Vršatec area (Czorsztyn Succession, Slovak Pieniny Klippen Belt). The coral community is dominated by branching forms of the genus Thecosmilia. Co-occurring abundant benthic foraminifera belong to the species Rumanolina seiboldi, R. elevata, Paalzowella turbinella and Troglotella incrustans. The coral-bearing limestones were initially assigned to the Oxfordian on the basis of the microfacies analyses and bivalve and scleractinian faunas. In recent papers they are assigned to the Bajocian on the basis of ammonites found in the neptunic dykes and stratigraphic superimposition criteria. However, the stratigraphic distribution of the majority of the identified foraminifera indicates that like most scleractinian coral taxa they are not known earlier than in the Late Jurassic. The Late Jurassic age of these coral-bearing limestones is also suggested by an encrusting microproblematic organism Iberopora bodeuri.
Oribatid mites (Acari, Oribatida) of open and forested habitats of Korčula Island (Croatia)
Authors: Seniczak Stanisław , Kaczmarek Sławomir , Seniczak Anna , Rraczyk Radomir 
Published: February 2013

Abstract
Oribatid mites were investigated on Korčula Island (Croatia) in various microhabitats in an open habitat (moss on rock, moss on soil) and in stone pine forest floor (moss, litter, rotting wood) in late August 2004. Special attention was paid to the age structure of species. These mites were rather abundant but their species diversity was low. The highest density was observed in patches of moss in the forest floor, and the lowest density was in rotting wood. Among the oribatid mites, only several species were abundant (Achipteria nitens, Zygoribatula propinqua, Pilogalumna crassiclava, Scheloribates initialis, S. laevigatus, and Tectocepheus velatus). Some species were rich in juveniles, while in others the adults dominated.
Operating characteristics of transcritical CO2 heat pump for simultaneous water cooling and heating
Authors: Sarkar Jahar , Bhattacharyya Souvik 
Published: February 2013

Abstract
The effects of water-side operating conditions (mass flow rates and inlet temperatures) of both evaporator and gas cooler on the experimental as well as simulated performances (cooling and heating capacities, system coefficient of performance (COP) and water outlet temperatures) of the transcritical CO2 heat pump for simultaneous water cooling and heating the are studied and revised. Study shows that both the water mass flow rate and inlet temperature have significant effect on the system performances. Test results show that the effect of evaporator water mass flow rate on the system performances and water outlet temperatures is more pronounced (COP increases by 0.6 for 1 kg/min) compared to that of gas cooler water mass flow rate (COP increases by 0.4 for 1 kg/min) and the effect of gas cooler water inlet temperature is more significant (COP decreases by 0.48 for given range) compared to that of evaporator water inlet temperature (COP increases by 0.43 for given range). Comparisons of experimental values with simulated results show the maximum deviation of 5% for cooling capacity, 10% for heating capacity and 16% for system COP.
Thermodynamic analysis of biofuels as fuels for high temperature fuel cells
Authors: Milewski Jarosław , Bujalski Wojciech , Lewandowski Janusz 
Published: February 2013

Abstract
Based on mathematical modeling and numerical simulations, applicativity of various biofuels on high temperature fuel cell performance are presented. Governing equations of high temperature fuel cell modeling are given. Adequate simulators of both solid oxide fuel cell (SOFC) and molten carbonate fuel cell (MCFC) have been done and described. Performance of these fuel cells with different biofuels is shown. Some characteristics are given and described. Advantages and disadvantages of various biofuels from the system performance point of view are pointed out. An analysis of various biofuels as potential fuels for SOFC and MCFC is presented. The results are compared with both methane and hydrogen as the reference fuels. The biofuels are characterized by both lower efficiency and lower fuel utilization factors compared with methane. The presented results are based on a 0D mathematical model in the design point calculation. The governing equations of the model are also presented. Technical and financial analysis of high temperature fuel cells (SOFC and MCFC) are shown. High temperature fuel cells can be fed by biofuels like: biogas, bioethanol, and biomethanol. Operational costs and possible incomes of those installation types were estimated and analyzed. A comparison against classic power generation units is shown. A basic indicator net present value (NPV) for projects was estimated and commented.
Basal Cell Carcinoma Aggressiveness, Molecular Factors And Therapy: A Clinician Perspective
Authors: Dorobanţu D. , Opriş Mihaela , Cif Georgeta Liliana , Trâmbiţaş C. , Seres Sturm L. , Petcu E. B. 
Published: February 2013

Abstract
Basal cell carcinoma represents the most common skin and epithelial cancer. Most of the patients are cured by surgery. However, some cases display fullblown aggressiveness which has a dual connotation. The tumour may reach an impressive size being locally destructive while in rare cases, basal cell carcinomas may metastasize. If this agressivetumour is located on the face or neck, the surgeon is confronted with a clinical dilemma since total removal of the lesion with clear margins is impossible. Therefore, nonsurgical approaches need to be adopted in these cases. A better understand of the molecular pathways could theoretically lead to new improved therapeutic treatments. The current paper presents an update on the molecular factors with clinical importance for the treatment of basal cell carcinoma in parallel with presentation of an aggressive case as well as a review of the current therapeutic methods.
Impact of a Childcare Centre Nutrition Program: On Nutrient Intakes in Nunavik Inuit Children
Authors: Gagné Doris , Blanchet Rosanne , Vaissière Émilie , Lauzière Julie , Vézina Carole , Vinet-Lanouette Chantal , O'brien Huguette Turgeon 
Published: February 2013

Purpose: We assessed the impact of a nutrition program implemented in Nunavik childcare centres on Inuit children's food and dietary intakes.Methods: Two hundred and forty-five Inuit children (aged 25.0 ± 9.6 months) were recruited between 2006 and 2010 in Nunavik childcare centres. Dietary intakes were assessed using a single 24-hour dietary recall (n=217). We compared participants’ energy and nutrient intakes, and the proportions who met iron requirements and Canada's Food Guide – First Nations, Inuit and Métis recommendations, depending on whether or not they attended a childcare centre during the 24-hour dietary reference period.Results: Children who attended a childcare centre on the day of the recall had significantly higher intakes of omega-3 fatty acids, calcium, total iron, bioavailable iron, phosphorus, betacarotene, folate, pantothenic acid, riboflavin, and vitamin K, while a higher proportion of them met the recommended intake for total and bioavailable iron. The proportion of children who met the recommended servings for vegetables and fruit, grain products, and milk and alternatives was also significantly higher among participants who attended a childcare centre.Conclusions: The nutrition program was effective at improving these Inuit preschoolers’ diet.
Classe(s) moyenne(s) : une revue de la littérature
Authors: Darbon Dominique 
Published: February 2013

Résumé Par leur hétérogénéité, les divers groupes intermédiaires s’affirment plutôt par défaut, entre « ni vraiment pauvre, ni vraiment riche ». L’abondante littérature consacrée au(x) classe(s) moyenne(s) montre qu’il n’y a aucun effet systématique et automatique à attendre de cette catégorie en Afrique en tant que telle. Il s’agit pourtant d’un objet de recherche fondamental, parce qu’il permet à la fois de dévoiler des dynamiques sociales nouvelles qui agissent aussi bien sur l’économie que sur le politique et qui transforme durablement la manière de penser le développement et l’aide sur le continent.
Les Nana Benz de Lomé
Authors: Toulabor Comi 
Published: February 2013

Résumé À partir du cas des célèbres Nana Benz du Togo, le présent article examine à partir de quand et comment les frustrations sociales prennent une expression politique. Les différentes ressources mobilisées dans l’action collective (mode d’organisation, démocratie interne, rapport des leaders au pouvoir, politisation de la base) permettent de comprendre pourquoi des frustrations réelles peuvent déboucher ou non sur des actions collectives. N’est-il pas de l’intérêt du pouvoir, de tout pouvoir, de favoriser des couches sociales telles que les commerçants qui s’accommodent d’un pouvoir « stable », même s’il est corrompu ?