bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Polymer Flooding Technology for Improving Heavy Oil Reservoir Recovery-from Lab Study to Field Application- Case Study of High Temperature Heavy Oil Field Z70
Authors: Wu Xingcai , Song Shemin , Xiong Chunming , Guo Zhiqiang , Xu Hanbing , Jiang Peijun , Zhang Jian , Zhang Yong , Chen JingJing , Tian Xiaoyan , Shao Liming 
Published: May 2015

Abstract
The heavy oil block field Z70 has oil viscosity of 165mPa.s and high temperature of 93°C, and is highly heterogeneous. After water injection, the water cut rose quickly and achieved 83% when oil recovery was only 7.6%. In order to control the quick rising of water to oil rate ratio, from 2001 to 2003, crosslinked polymer gel was injected as field test, but the effect was limited. Besides, the highly viscose polymer damaged the low permeability layers or zones, leading to hard water injection on some injectors. Since 2010, A new type of polymer flooding (NPF) technology has been applied and greatly improved oil recovery.
The new polymer is particle-type polymer with various particle sizes. When working, it is dispersed in injected water, and has low apparent viscosity, 1–4 mPa.s, so it is easy to be injected into formation. While the polymer particle moves into formation, the size may increase by water absorbing, and it may temporarily plug the prevailing filtration throats, making the carrying water be diverted into the relatively small pores/throats and displace the remaining oil there. The polymer particle has high deformation capacity, so it can deform and pass through the throat under the follow-up pressure, and then it will go to plug another throat. The process will be repeated again and again, so the technology can inhibit water production and enhance oil production.
The particle size and slug sequence were designed for Z70 field by physical simulation on physical models. Sub-millimeter grade of particle was suitable for some wells, and micrometer grade of particle was suitable for some other wells, while some wells need both of them. Totally 0.086PV of the dispersion fluid was injected in the whole field with the concentration of 3000mg/L. After one month injection, the water cut started decreasing quickly and the oil rate started increasing quickly. During the new polymer injection, the water cut decreased to 74.8% from 81.1%, and the oil rate doubled. During the follow-up water injection period, the water cut continued decreasing to 75%. Until now, the water cut has returned to more than 77%, but the NPF keeps taking effect, and the oil recovery is increased by 5.8%.
Summing up the lab studies and field application, NPF works through decreasing water effective permeability and overcoming the unfavorable mobility ratio. It is different from the conventional polymer flooding, which works through increasing the viscosity of the displacing phase. The new technology is more efficient, and the mechanism deserves further studying.
Integration of PC-SAFT Equation of State into Heat Assisted Solvent Recovery Simulation
Authors: Ma Mingxu , Chen Shengnan , Abedi Jalal 
Published: May 2015

Abstract
The accuracy of Equation of State (EoS) in phase behaviour modeling plays an important role in compositional and thermal reservoir simulations. PC-SAFT (Perturbed-Chain Statistical Associating Fluid Theory) EoS can predict solubility and density of bitumen/solvent systems more accurately than Peng-Robinson and Soave-Redlich-Kwong EoS. In this work, a simplified version of PC-SAFT EoS was integrated into a thermal reservoir simulation to model heat assisted solvent recovery process.
Bitumen was characterized into two scenarios for the simplified PC-SAFT modeling: eight pseudo-components (8-PCs) and three pseudo-components (3-PCs) using a well-developed bitumen characterization method. The solubility and density modeling ability of 3-PCs was evaluated and verified with that of the 8-PCs system. The simplified PC-SAFT with 3-PCs bitumen characterization method was then applied to generate data of K-Value, density, compressibility, and thermal expansion coefficient of each pseudo-component. The generated fluid properties were integrated with reservoir simulation to model a warm C3H8 VAPEX experiments at 40, 50 and 60 °C.
In the 8-PCs characterization, the overall Average Absolute Relative Deviations (AARDs) for the solubility and density of CH4, C2H6, C3H8 and CO2-saturated bitumen were within 6.6 % and 2.3 % respectively, and the predicted AARDs for the density of n-C5H12, n-C10H22, n-C14H30, toluene and xylene-diluted bitumen were as low as 0.9 %. Results of the 3-PCs characterization were found to be as accurate as those of 8-PCs in modeling bitumen/gas solvent systems. In addition, the results of the fluid properties were successfully integrated into commercial reservoir simulator. Relative permeability was history matched with the measured data at 40 °C, and then tested against the measured data at 50 and 60 °C. The reservoir simulation results indicated good agreement with the measured data. The numerical results showed that although bitumen viscosity decreased due to high temperature solvent, solubility was reduced at the same time, compensating the viscosity reduction effects by solvent diluting.
Mathermatical Modeling of Dynamic Mass Transfer in Cyclic Solvent Injection
Authors: Jia Xinfeng , Li Jianli , Chen Zhangxin 
Published: May 2015

Abstract
In a cyclic solvent injection (CSI) process, a solvent gas is cyclically injected, soaked, and released to produce heavy oil. Through this process the operating pressure is decreased and increased cyclically. This causes a dynamically changing pressure gradient across the solvent–oil mixing zone, leading to a convective mixing of solvent and oil in addition to molecular diffusion. This study aims at modeling the effect of pressure gradient-induced convection on the solvent–oil mixing process in the transition zone. A diffusion–convection model is developed to simulate the dynamic solvent–oil mass transfer in the transition zone during the CSI process. This model consists of two sub-models: a pressure model and a solvent concentration model. The pressure model considers the effect of a practical viscosity profile and the concentration model considers the effect of a dynamic convective mass transfer velocity. These two models are coupled through the convection velocity and oil viscosity across the transition zone. The entire model is semi-analytically solved, in which a piecewise linear approximation scheme is applied for the variable convection velocity and viscosity in the transition zone. Results show that during the solvent injection period, convection can significantly enhance the mixing of solvent and heavy oil. Larger solvent injection rates can be more efficient for heavy oil–solvent mass transfer. In addition, it is found that considerable solvent remains in the oil zone at the end of the production period, and this part of solvent is difficult to retrieve within a short time period.
Restoring Casing Integrity Using an Expandable Steel Patch Prior to Drilling Ahead With Minimal Reduction of Next Hole Size
Authors: Saltel Benjamin , Gonzalez Luis , McIntosh Trevor , Weems Matt 
Published: May 2015

Abstract
The purpose of this paper is to provide field experience feedback on achieving surface casing integrity with the use of an expandable steel patch. Casing integrity may be jeopardized during cement remediation or due to mechanical failure. If cement remediation requires casing perforations, then an expandable steel patch can be used to provide pressure integrity across the perforations. If casing pressure test cannot be achieved due to mechanical failures such as leaking DV tool or casing collar leak, a similar approach can be used to achieve pressure integrity. This paper will describe how to restore casing integrity allowing maximum pass-through diameter to continue drilling operations and maintain planned casing sizes when presented with these challenges.
Well Testing by Sinusoidal Stimulation
Authors: Zenith Federico , Foss Bjarne , Tjønnås Johannes , Hasan Agus 
Published: May 2015

Summary
A new approach to testing of oil and gas wells by means of sinusoidal oscillations in flow and pressure instead of the traditional buildup test is proposed in this article. This approach allows faster testing and simultaneous testing of several wells, with no need for a dedicated test header; it can also be adjusted to strike an appropriate compromise between measurement precision and production loss. This study details various operating issues such as generation of input signals, choice of test frequencies, applicability, and interpretation of results. To demonstrate the method, both a synthetic test and several field tests are presented.
Impact of Fat, Protein, and Glycemic Index on Postprandial Glucose Control in Type 1 Diabetes: Implications for Intensive Diabetes Management in the Continuous Glucose Monitoring Era
Authors: Bell Kirstine J. , Smart Carmel E. , Steil Garry M. , Brand-Miller Jennie C. , King Bruce , Wolpert Howard A. 
Published: May 2015

BACKGROUND
Continuous glucose monitoring highlights the complexity of postprandial glucose patterns present in type 1 diabetes and points to the limitations of current approaches to mealtime insulin dosing based primarily on carbohydrate counting.

METHODS
A systematic review of all relevant biomedical databases, including MEDLINE, Embase, CINAHL, and the Cochrane Central Register of Controlled Trials, was conducted to identify research on the effects of dietary fat, protein, and glycemic index (GI) on acute postprandial glucose control in type 1 diabetes and prandial insulin dosing strategies for these dietary factors.

RESULTS
All studies examining the effect of fat (n = 7), protein (n = 7), and GI (n = 7) indicated that these dietary factors modify postprandial glycemia. Late postprandial hyperglycemia was the predominant effect of dietary fat; however, in some studies, glucose concentrations were reduced in the first 2–3 h, possibly due to delayed gastric emptying. Ten studies examining insulin bolus dose and delivery patterns required for high-fat and/or high-protein meals were identified. Because of methodological differences and limitations in experimental design, study findings were inconsistent regarding optimal bolus delivery pattern; however, the studies indicated that high-fat/protein meals require more insulin than lower-fat/protein meals with identical carbohydrate content.

CONCLUSIONS
These studies have important implications for clinical practice and patient education and point to the need for research focused on the development of new insulin dosing algorithms based on meal composition rather than on carbohydrate content alone.
Vegetation change in variable rangeland environments: the relative contribution of drought and soil type in arid rangelands
Authors: Gamoun Mouldi 
Published: May 2015

AbstractThe response of a plant community to protection from grazing, as a function of year and soil type, was studied in the arid rangelands of southern Tunisia between 2007 and 2009. The vegetation of rangelands is often altered under grazing pressure, but unfortunately, removing the grazing pressure often does not reverse the changes in the way the succession model predicts. Rainfall variability is a key driver of ecosystem structure and function in arid rangelands, and this arid area of North Africa is characterized by low and erratic rainfall and is prone to drought conditions which normally occur every two to three years.Steppes are likely to exhibit strong and rapid structural and functional responses to these altered rainfall patterns. Although drought affects vegetation cover more in loamy soil than in all other soils, it affects diversity on all soils; particularly limestone and loam soils
Identification of season-dependent relationships between spectral vegetation indices and aboveground phytomass in alpine grassland by using field spectroscopy
Authors: Halabuk Andrej , Gerhatova Katarina , Kohut Frantisek , Ponecova Zuzana , Mojses Matej 
Published: May 2015

AbstractHalabuk A., Gerhatova K., Kohut F., Ponecova Z., Mojses M.: Identification of season-dependent relationships between spectral vegetation indices and aboveground phytomass in alpine grassland by using field spectroscopy. Ekologia (Bratislava), Vol. 32, No. 2, p. 186-196, 2013.Spectral characteristics of alpine grasslands across the vegetation season (from May to September) are presented. The results are based on three year field spectroscopy monitoring of acid, nutrient poor grasslands at Kraľova hoľa research site, Low Tatras, Slovakia. Relationships between commonly used spectral vegetation indices (VIs) and field-based estimation of aboveground green phytomass (AG B) were analysed. Finally, season-dependent regression models were created in order to allow spatially extensive non-destructive monitoring of AG B. Spatial-temporal dynamics of background and standing litter markedly affect seasonal variations of relationships between VIs and AG B and predictability of the regression models. Because of a high proportion of litter during the whole season, this was a plant water-sensitive normalized difference water index (NDWI), which dominates as the predictive variable in the regression models across the whole season; except June, where chlorophyll absorption sensitive in normalized difference vegetation index (NDVI) performed the best (R2 = 0.57; rel. RMSE = 34%). However, the accuracy of the models was quite low (May: R2 = 0.45; rel. RMSE = 49%; July: R2 = 0.47; rel. RMSE = 26%; August: R2 = 0.13; rel. RMSE = 31%; September: R2 = 0.53; rel. RMSE = 40%).
Methods of Historical Landscape Structures Identification and Implementation into Landscape Studies
Authors: Slámová Martina , Jančura Peter , Daniš Dušan 
Published: May 2015

AbstractSlamova M., Jančura P., Daniš D.: Methods of historical landscape structures identification and implementation into landscape studies. Ekologia (Bratislava), Vol. 32, No. 3, p. , 267-276, 2013. Valuable historical rural landscapes are found in the sub-mountainous and mountainous regions of the Carpathian Mountains in Slovakia. Authors contributed to the research about historical landscape structures (HLS) by several methods. Method of ‘identification and assessment of characteristic landscape’ was developed in order to provide maintenance to about HLS and improve application of responsibilities resulting from the European Landscape Convention (Florence, 2000) into practice of landscape planning. We bring a new perspective on landscape’s value identification in the field of landscape ecology. The main aim of the paper is identification of HLS as components of land cover structures in the cadastral area of Budina (agrarian terraces) and as micro-relief forms in Nižna Boca (mines). Studied areas represent two different rural landscape types which contain different values related to HLS and they are not especially protected by laws. We evaluate attributes of relief, visual-optometric parameters of landscape, landscape types, land cover structures and types of HLS. Maintenance about HLS in landscape is important for the preservation of unique types of cultural landscapes. Finally, we compare realisations of the visions, suggested in previous landscape studies, which concentrated on development of tourism in the studied areas.
The importance of rural parks for the occurrence of the Rook Corvus frugilegus in the eastern part of the Lublin region (E Poland) – ecological and social factors
Authors: Kitowski Ignacy 
Published: May 2015

AbstractKitowski I.: The importance of rural parks for the occurrence of the Rook Corvus frugilegus in the eastern part of the Lublin region (E Poland) - ecological and social factors. Ekologia (Bratislava), Vol. 32, No. 3, p. 283-298, 2013. This study deals with the population size and the distribution of breeding colonies of the rook in rural parks in the eastern part of the Lublin region (Eastern Poland). Large parks with a large number of tree species were appropriate sites for larger rookeries. Small, degraded parks, with few species of trees, were used by smaller rookeries, which showed tendencies to disappear more quickly. Small colonies were irrevocably abandoned if disturbed by man, whereas large ones had a very high reoccupation potential, even after a few years. Unfortunately, ownership changes concerning rural parks in Eastern Poland may endanger the rookeries located there.
Urban Ecosystem services on the local level: Urban green spaces as providers
Authors: Breuste Jürgen , Schnellinger Johanna , Qureshi Salman , Faggi Anna 
Published: May 2015

AbstractBreuste J., Schnellinger J., Qureshi S., Faggi A.: Urban ecosystem services on the local level: Urban green spaces as providers. Ekologia (Bratislava), Vol. 32, No. 3, p. 209-304, 2013. Ecosystem services are provided at different spatial and service/functional scales. The local level is the basic unit for ecosystem services, especially when it comes to the human dimension of urban landscapes. These services are provided by green elements (patches) or basic complex ecosystems (green areas) which differ from their neighbourhoods through their structures and functions. This study reviews the generally available knowledge on urban green functions and services at the site level and explains them by using own studies in five different cities in three different continents related to distinct ecosystem services. This allows the development of a methodology to evaluate and compare ecosystem services at the site level. The methodology is based at two levels, patch and green space, and includes the relationship with the surrounding green and built-up space. Different urban green space types are characterized by their internal structures of vegetation, size, shape and location in relation to at least a semi-quantitative scaling of their urban ecosystem services. The evaluated urban green spaces are public urban green spaces. The urban ecosystem services assessed include climate regulation, biodiversity, nature experience, recreation and health. The actual urban challenges, such as land use change, adaptation to climate change, demographic change and urban cultural diversity, demand a systematic and very concrete monitoring of urban ecosystem services at the site level.
Transfer of landscape ecological knowledge from theory to practice as a multistage process (Selected theoretical and meta-scientific aspects)
Authors: Žigrai Florin 
Published: May 2015

AbstractŽigrai F.: Transfer of landscape ecological knowledge from theory to practice as a multistage process. (Selected theoretical and meta-scientific aspects). Ekologia (Bratislava), Vol. 32, No. 3, p. 305-319, 2013. Successful and efficient transfer of landscape ecological knowledge from theory to practice is a complex scientific and social topic, the solution of which requires elaboration of suitable theoretical, meta-scientific and empirical-applied research approaches. In this context, the burning question is, to what extent is landscape ecology as a science with its theoretical basis, methodological infrastructure and quantitative-qualitative nature of empirical knowledge prepared to solve this fundamental problem effectively. The transfer of landscape ecological knowledge from theory to practice should be understood as a multistage process bound to bridge and reduce the distances between the theoretical and practical landscape ecological knowledge on the empirical, methodical, theoretical, meta-scientific, didactic and applied level and simultaneously as a great challenge for landscape ecology.
Abandonment of agricultural land in central Poland and its ecological role
Authors: Majchrowska Anna 
Published: May 2015

AbstractMajchrowska A.: Abandonment of agricultural land in central Poland and its ecological role. Ekologia (Bratislava), Vol. 32, No. 3, p. 320-327, 2013. The intent of this paper is to give an overview of the ongoing study of farmland abandonment in central Poland. The goal of this project, initiated in 2011, is to provide field-verified information: 1. What is the spatial distribution of abandoned agricultural land in central Poland? How is it related to biophysical features of the study area? 2. What are botanical characteristics of spontaneous vegetation succession in the abandoned agricultural lands? What are their environmental determinants? 3. How do the abandoned lands correspond to existing protected areas? How could they be used to strengthen the ecological landscape structure of central Poland? The paper summarises the general study approach, discusses some methodological difficulties, presents preliminary findings and formulates the expected results.
Landscape Ecology and Rural Roads: Traffic Calming for improving both landscape and wildlife?
Authors: Jaarsma Catharinus F. , Langevelde Frank van , Beunen Raoul 
Published: May 2015

AbstractJaarsma C.F., van Langevelde F., Beunen R.: Landscape ecology and rural roads: Traffic calming for improving both landscape and wildlife? Ekologia (Bratislava), Vol. 32, No. 4, p. 352-360, 2013.The concept of traffic calming has successfully improved road safety. This concept applied in rural areas has provided new insights in the mitigation of negative effects of roads and traffic. Earlier studies have shown that the concept, distinguishing between local access roads and rural arterial highways, can also improve landscape connectivity for wildlife. Physical speed-reducing devices are frequently used in the context of traffic calming, but applying these devices may negatively impact the coherence and identity of the landscape. Therefore an alternative approach for speed reduction has been proposed, namely applying local landscape elements (such as hedgerows), plantings and objects of cultural heritage (such as railings of small bridges over local water courses) as speed-reducing devices. We explain this ‘green approach’ with examples from Dutch practice. We conclude that a combination of disciplines is needed to realize this new approach, which may be more cost-effective than the traditional approach and additionally improve the landscape quality. The new insights are at least equally effective from a landscape ecological viewpoint.
The disappearance of Barn Owl Tyto alba and Little Owl Athene noctua occurrence sites in farmland in East Poland
Authors: Kitowski Ignacy , Stasiak Krzysztof 
Published: May 2015

AbstractKitowski I., Stasiak K. The disappearance of barn owl Tyto alba and little owl Athene noctua occurrence sites in farmland in East Poland. Ekologia (Bratislava), Vol. 32, No. 4, p. 361-368, 2013.Complexes of buildings belonging to vast farms, distributed in the form of islands over a landscape of monoculture farming constituted important occurrence sites of the barn owl and the little owl. During 1999-2012, the fate of 59 farms inhabited by the studied species was observed. Both species of owls preferred using three categories of buildings: cowsheds, warehouses and blocks of flats. Cases have been reported of the same building being simultaneously occupied by two species of owls. The study showed that the disappearance of sites of the studied owls is caused by factors connected with the decreasing intensity of farming. The most common of these factors turned out to be demolitions of buildings occupied by owls and the abandonment of animal production. Cases of predation by carnivore mammals were also reported. The process of disappearance of owl sites appears to manifest itself more intensely on those farms where residential and industrial infrastructure occupies a smaller area.