bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of Recovery Mechanism of Steam Injection in Heavy Oil Carbonate Reservoir and Mineral Dissolution
Authors: Tang Guo-Qing , Inouye Art , Lee Vincent , Lowry Dustin , Wei Wei 
Published: March 2012

Abstract
Steam injection in carbonate heavy oil reservoirs is a complex process. The main challenge is that the injected steam breaks through from a fracture network resulting in poor sweep efficiency. A large amount of oil remains behind the steam front. In addition, severe mineral dissolution (or precipitation) due to steam/brine/rock interaction occurred at high temperature has a significant impact on steam injectivity and recovery mechanism.
This paper presents an extensive lab study focused on understanding the recovery mechanism and relevant mineral dissolution. Around 10 reservoir cores and crude oil sample with an API gravity of 14 were used for this study. Imbibition, steam flooding, and pressure blow-down tests were conducted. The results show that the recovery mechanism of steam injection in the target carbonate reservoir is composed of imbibition, viscosity reduction, in-situ steam generation induced by pressure blow-down, and oil expansion mechanisms with different contributions. As the rock is heated to near 400°F, imbibition becomes the dominant recovery mechanism. The increased imbibition recovery is strongly dependent on mineral dissolution at a high temperature, which results in wettability alteration towards strong water-wetness. Due to the presence of micro-fractures, steam drive is less efficient compared to imbibition. In-situ steam generation can still increase oil recovery by an additional 17-32% (OOIP) following steamflood displacement at residual oil saturation.
Significant mineral dissolution is observed with high resolution CT scanning and effluent geochemical analysis. CT-image analysis shows the size of vugs is increased 2-5 times due to mineral dissolution. ICP (Inductivity Coupled Plasma) and IC (Ion Chromatogragh) analysis shows that carbonate is the main dissolved mineral. Mineral dissolution does not increase the effective permeability because these vugs are mainly connected by micro fractures where mineral dissolution effects are negligible. In fact, permeability is reduced due to fines migration resulted by mineral dissolution.
Optimization of Core-Log Derived Permeability Using Pressure Transient Analysis in Low-Permeability Waterflood: Ventura Avenue Field Case Study
Authors: Albornoz Fernando , Williams Steve O. 
Published: March 2012

Abstract
A key to effective reservoir characterization lies primarily in obtaining good estimates of permeability. Permeability estimation through the integration of core, wireline and well test data has gained significant attention in recent years. However, these efforts are masked by vague implementation processes arising from calibration and scaling issues. This paper presents a systematic and unique approach for estimating permeability from the integration of core, wireline and pressure transient analysis data and prudently demonstrates the optimization and implementation techniques necessary for scaling the core-log derived (small scale) absolute permeability to the effective permeability data derived from pressure transient analysis (large scale).
This unique approach was accomplished by first integrating reservoir conditioned core data with wireline logs for zonation of reservoirs into flow units. Core derived Flow Zone Indicator (FZI), which is a function of the reservoir quality index (RQI) and normalized porosity (PHIZ), was used as a predictor variable in modeling the selected wireline log responses using an adaptive neuro-fuzzy logic inference system (ANFIS).
Predicted FZI and resultant core-log derived permeability were then calibrated using a water-oil relative permeability model derived from a suite of special cores from the same flow zones. Core-log derived permeability was then fine-tuned with the pressure transient analysis in the same reservoirs of interest.
The results of this study have provided valuable answers to water injectivity predictions in the thick and thinly bedded sand/shale sequence of the Ventura Avenue Field. Water injection profiles in these reservoirs are now better understood and, consequently, the reservoirs are better characterized for waterflood recovery optimization.
Uncertainty Analysis of a CO2 Sequestration Project Using Surrogate Reservoir Modeling Technique
Authors: Amini Shohreh , Mohaghegh Shahab , Gaskari Razi , Bromhal Grant 
Published: March 2012

Abstract
While CO2 Capture and Sequestration (CCS) is considered a part of the solution to overcoming the ever increasing level of CO2 in the atmosphere, one must be sure that significant new hazards are not created by the CO2 injection process. The risks involved in different stages of a CO2 sequestration project are related to geological and operational uncertainties. This paper presents the application of a grid-based Surrogate Reservoir Model (SRM) to a real case CO2 sequestration project in which CO2 were injected into a depleted gas reservoir. An SRM is a customized model that accurately mimics reservoir simulation behavior by using Artificial Intelligence & Data Mining techniques. Initial steps for developing the SRM included constructing a reservoir simulation model with a commercial software, history matching the model with available field data and then running the model under different operational scenarios or/and different geological realizations. The process was followed by extracting some static and dynamic data from a handful of simulation runs to construct a spatio-temporal database that is representative of the process being modeled. Finally, the SRM was trained, calibrated, and validated.
The most widely used Quantitative Risk Analysis (QRA) techniques, such as Monte Carlo simulation, require thousands of simulation runs to effectively perform the uncertainty analysis and subsequently risk assessment of a project. Performing a comprehensive risk analysis that requires several thousands of simulation runs becomes impractical when the time required for a single simulation run (especially in a geologically complex reservoir) exceeds only a few minutes. Making use of surrogate reservoir models (SRMs) can make this process practical since SRM runs can be performed in minutes.
Using this Surrogate Reservoir Model enables us to predict the pressure and CO2 distribution throughout the reservoir with a reasonable accuracy in seconds. Consequently, application of SRM in analyzing the uncertainty associated with reservoir characteristics and operational constraints of the CO2 sequestration project is presented.
Application of Well-Based Surrogate Reservoir Models (SRMs) to Two Offshore Fields in Saudi Arabia, Case Study
Authors: Mohaghegh Shahab D. , Liu Jim , Gaskari Razi , Maysami Mohammad , Olukoko Olugbenga 
Published: March 2012

Abstract
Well-based Surrogate Reservoir Model (SRM) may be classified as a new technology for building proxy models that represent large, complex numerical reservoir simulation models. The well-based SRM has several advantages over traditional proxy models, such as response surfaces or reduced models. These advantages include (1) to develop an SRM one does not need to approximate the existing simulation model, (2) the number of simulation runs required for the development of an SRM is at least an order of magnitude less than traditional proxy models, and (3) above and beyond representing the pressure and production profiles at each well individually, SRM can replicate, with high accuracy, the pressure and saturation changes at each grid block.
Well-based SRM is based on the pattern recognition capabilities of artificial intelligence and data mining (AI&DM) that is also referred to as predictive analytics. During the development process the SRM is trained to learn the principles of fluid flow through porous media as applied to the complexities of the reservoir being modeled. The numerical reservoir simulation model is used for two purposes: (1) to teach the SRM the physics of fluid flow through porous media as applied to the specific reservoir that is being modeled, and (2) to teach the SRM the complexities of the heterogeneous reservoir represented by the geological model and its impact on the fluid production and pressure changes in the reservoir.
Application of well-based SRM to two offshore fields in Saudi Arabia is demonstrated. The simulation model of these fields includes millions of grid blocks and tens of producing and injection wells. There are four producing layers in these assets that are contributing to production. In this paper we provide the details that is involved in development of the SRM and show the result of matching the production from the all the wells. We also present the validation of the SRM through matching the results of blind simulation runs.
The steps in the development of the SRM includes design of the required simulation runs (usually less than 20 simulation runs are sufficient), identifying the key performance indicators that control the pressure and production in the model, identification of input parameters for the SRM, training and calibration of the SRM and finally validation of the SRM using blind simulation runs.
Uncertainty Analysis on In-Situ Combustion Simulations Using Experimental Design
Authors: Ogunbanwo Olufolake , Gerritsen Margot , Kovscek Anthony R 
Published: March 2012

Abstract
Experimental design is a widely used statistical method for understanding the factors that impact an information gathering exercise such as mechanistic simulations. It is used here to gain insight into flow and operating conditions that affect in-situ combustion. Specifically, experimental design was applied to understand in-situ combustion of very heavy oil using a commercial thermal simulator. The design parameters investigated were selected based on combustion laboratory results and literature. These included activation energies of the reaction schemes, oil saturation, air injection rate and pressure control at the producer. A full factorial design was used to create the parametric space considering interactions between the parameters. The degree to which the combustion peak temperature, pressure, combustion front speed, recovery efficiency and coke deposited changed was used to determine the most critical parameters. Results showed the activation energy of the coke deposition reaction had the greatest influence on the combustion process. For the 3-reaction pathway assumed for crude-oil combustion, a slight increase in this activation energy inhibited the combustion reactions. The injection pressure of the system was impacted significantly by the initial oil saturation while the speed at which the front propagated was shown to be primarily a function of the air injection rate. Results also showed that for a given initial oil saturation, a limiting air flux existed below which oil plugging of the linear system occured. Given successful ignition and propagation of the front, optimal recovery was obtained between initial oil saturations of 45-70%. We also observed interaction between the parameters. The effect of the activation energy of the combustion reaction on the recovery was strongly dependent on the amount of oil initially in place. Recovery decreased with increasing activation energy at lower initial saturations, but was independent of activation energy at greater initial saturations. In addition, the velocity profile showed different incremental oil recovery rates with different initial oil saturation.
Production Performance of Multiply Fractured Horizontal Wells
Authors: Belyadi A. , Aminian K. , Ameri S. 
Published: March 2012

Abstract
The objective of this study was to conduct a modeling study to determine the production performance of multiply fractured horizontal well completed in Shale formations and to investigate the impact of hydraulic fractures on the production performance of horizontal wells in ultra-low permeability formations. A commercial reservoir simulator was utilized to model both single and a dual porosity reservoir since both hydraulic fractures and natural fractures play significant roles in well performance of the low permeability reservoirs. The adsorbed gas component was also included in the models. The single and a dual porosity models were utilized to investigate the flow regimes for horizontal wells with multi-stages of hydraulic fracturing stimulation. History matching with actual production from Marcellus Shale wells was utilized to determine the basic model parameters. The results indicated the presence of number of different flow regimes. The hydraulic fractures appear to dominate the early production performance. The impact of reservoir and hydraulic fracture parameters on the flow regimes as well as the production performance and gas desorption were also investigated. The results can be utilized to investigate the feasibility horizontal wells with multiple hydraulic fractures and optimize the production from the shale formations.
Effect of Hydrogen Peroxide at 35% on the Morphology of Enamel and Interference in the De-remineralization Process: An In Situ Study
Authors: de Arruda AM , Santos PH dos , Sundfeld RH , Berger SB , Briso ALF 
Published: March 2012

SUMMARY
This study evaluated the microhardness and histomorphology of bovine enamel when 35% hydrogen peroxide is used. A total of 44 specimens were adapted to removable devices used by 11 individuals subjected to dental caries challenge. A decrease in microhardness was observed for all groups after the cariogenic challenge. Microscopic analysis revealed that fragments subjected to cariogenic challenge associated with bleaching had more intense superficial histologic changes, but the depth of the lesions remained unchanged. It was concluded that 35% hydrogen peroxide enhanced the reduction in hardness and histomorphologic changes in the enamel surface exposed to cariogenic challenge.
The Regulation of Ventilation by Changing the Operation of the Main Fan and its Impact on the Face Worked Under the Main Haulage Level / Regulace Větrání Změnou Provozu Hlavního Ventilátoru A Její Dopad Na Podpatrově Dobývaný Porub
Authors: Zapletal Pavel , Prokop Pavel , Dorazil Václav 
Published: March 2012

Abstract
The regulation of mine ventilation by changing the operation of the main fan (HV) has both positive and negative aspects. One of the positive aspects is that this regulation can be made directly on the mine surface without lowering into the mine, namely by turning the fan blades from the minimum to maximum position. This regulation can be performed either from the control room or directly at the fan.
The utilization of this control method in the mine ventilation (the reducing or increasing of the depression of main fans) brings with also certain disadvantages. By the overall regulation of the depression of main fans we influence the overall mine ventilation network. The HV regulation can without further interventions cause problems in other part of the mine. Therefore, to eliminate the negative effects we have to do partial steps in the regulation of ventilation in the ventilation network to achieve the desired effect in a specific part of the mining field and prevent the unwanted effect in other parts of the ventilation network. In this article we deal with the negative effects on a face worked under the main haulage level
The Future of Blue Economy: Lessons for European Union
Authors: Kaczynski Wlodzimierz 
Published: March 2012

The Future of Blue Economy: Lessons for European UnionAdvancing global economic integration through the oceans, an interplay of economic, social, climatologic and technical forces are bringing the oceans to the forefront of resource development and business activity. With oceans covering over 70 percent of the Earth's surface, the future of the ocean space is increasingly being shaped by the interaction of numerous and powerful forces, most important of them being human activities. Over next 20 years, increasing uncertainty will be generated by the confluence of rapid social, cultural, technological and geopolitical changes. The rapid global increase in the production outputs of industry, agriculture and fisheries, as well as rising levels of consumption of marine products and the demand for coastal space worldwide is exerting increasing environmental pressure on the ocean. There is a need to identify more effective means to reduce the environmental impacts generated by the economic growth and its by-products. Sustainable approaches meet the needs of present without compromising the ability of future generations to satisfy their own needs. The Blue Economy concept is about the commercial development of oceans in a sustainable way. Poland's future economic security is linked with country's presence in the world ocean and successful membership in international bodies such as European Union, NATO and various United Nations maritime organizations. These factors will also determine Poland's place and its role in the global ocean economy.
The Development of Production Management Concepts
Authors: Kosieradzka Anna , Kąkol Urszula , Krupa Anna 
Published: March 2012

The Development of Production Management ConceptsThe aim of this paper is the analysis of contemporary concepts used in production management in relation to the paradigms which accompanied their appearance and development. The first chapter contains a definition of the term 'paradigm', discusses the importance of the paradigms for the development of a scientific approach to management and lists examples of paradigms relevant to production management. In the second chapter such management concepts as LM, Kaizen, TOC, TQM, TPM, Six Sigma and BPR are presented, along with their respective old and new paradigms, main goals, fundamental rules and tools (methods and techniques). Some less popular concepts are also dealt with. The last chapter is devoted to an analysis of interactions between the analyzed concepts, with an emphasis on their mutual compatibility and complementarity, which can be of benefit in the process of their implementation.
Loyalty Programs Effectiveness
Authors: Szczepańska Katarzyna , Gawron Patryk 
Published: March 2012

Loyalty Programs EffectivenessAn increasing number of loyalty programs is one of the most common phenomena observed in the practice of marketing companies on the market today. Objectives and tasks of loyalty programs determine the type of use of marketing instruments affecting the attitudes and behaviours of customers, which is aimed at the program. The diversity of factors influencing the effectiveness of loyalty programs should set the scope and object of empirical research. As the results of studies to evaluate the effectiveness of loyalty programs mainly on the B2C market is diverse in terms of the criteria. This article presents the essence of loyalty programs and the factors influencing their effectiveness.
Capacity Evaluation of Roundabouts in Slovakia
Authors: Gavulová Andrea , Drličiak Marek 
Published: March 2012

Capacity Evaluation of Roundabouts in Slovakia
Two technical regulations for capacity estimation of roundabouts are valid in the Slovak Republic at the present time. Each of these regulations is based on a different theory of capacity estimation which affects the outcome of the capacity of roundabouts and their evaluation. The capacity of various roundabouts was estimated according to both methods in the previous analysis made at our department [3] and in some cases different results of the evaluation were achieved. The question is: which one of the mentioned theories better reflects a real capacity of the roundabout? For this reason some of the existing roundabouts in the town Žilina were selected and they were evaluated according to both methods and a micro simulation using PTV Vissim software. The geometrical parameters of roundabout, real driving behaviour (speed, proportions, acceleration, etc.) and also pedestrian behaviour were taken into account in the microscopic models. The first assumption for capacity evaluation by a microscopic traffic model is a calibration process which is based on traffic surveys results. Thus created models allow several capacity analyses during the peak traffic loading. Then, the results of micro-simulation can be compared with the capacity evaluation according to the technical regulations. The article deals with creation and calibration of microscopic traffic models and with the mentioned comparing of results.
Results of Automatic Identification of Transport Units in Postal Environment
Authors: Vaculík Juraj , Kolarovszki Peter , Tengler Jiří 
Published: March 2012

Results of Automatic Identification of Transport Units in Postal Environment

This article primarily deals with identification of postal items and transport units in the logistic chain of postal operators. Nowadays, the identification is carried through barcodes and optical character recognition. In this article we would like to specify, how the transport units can be identified in the transmission process by RFID technology. In the carriage of postal items it is necessary to decide what type of transport is used for that purpose, what the flows of items are and what their intensity is. The RFID technology is complex, combining a number of different computing and communication technologies to achieve the desired objectives. Each object, which has to be identified, is stuck inside of a small object known as an RFID tag. RFID tag has a unique identifier, through which you can store additional information about the object. Equipments which are known under the name of RFID readers wirelessly, communicate with RFID tags with a view to identify RFID tags attached as well as the possibility to read and update information stored in the RFID label.
The article describes the scheme of the transport process, including planned technology and there is also simulated a real postal process in conditions close to operational.
Reducing co-administration of clopidogrel and proton pump inhibitors in acute coronary syndromes
Authors: Vassiliou V , Silva A , Kavvoura F , Schofield R , Rowlands DB 
Published: March 2012

Background: Recent concerns about clopidogrel and proton pump inhibitor (PPI) co-administration in patients following an acute coronary syndrome (ACS) led us to investigate our practice. Guidance recommends that omeprazole and esomeprazole should not be co-administered with clopidogrel as they can decrease its efficacy. Pantoprazole and lansoprazole are safer for use in these cases. Methods: Patients discharged between August 2008 and July 2009 with a diagnosis of ACS, on both clopidogrel and any PPI, were identified using the pharmacy database. Their notes were retrospectively reviewed, the indication for a PPI was checked and whether an appropriate one had been prescribed was assessed. As a result of our findings a simple algorithm was introduced to set out guidance on appropriate use and junior doctors were informed of the new procedure. We then performed another audit of patients discharged between August 2009 and February 2010 to ensure that the guidelines were being followed. Results: During the first phase of the audit 43 out of 91 patients (47.5%) received a PPI with clopidogrel. Following our intervention, re-auditing confirmed that clopidogrel and PPI co-administration had decreased significantly to 27 out of 101 patients (26.7%) (p = 0.018). Conclusions: Through a simple intervention with an algorithm and education of junior doctors we have shown that significant improvement and adherence to guidance can be achieved.