bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neutron Detection Signatures at Zero Bias in Novel Semiconducting Boron Carbide/Pyridine Polymers
Authors: Echeverría Elena , James Robinson , Pasquale Frank L. , Colón Santana Juan A. , Driver M. Sky , Enders A. , Kelber Jeffry A. , Dowben P.A. 
Published: April 2015

ABSTRACTNovel and more conventional boron carbides were combined with n-type silicon to make heterojunction diodes, with neutron capture signal at zero applied bias. The boron carbides were based on the cross linking of closo-1,2-dicarbadodecaborane (ortho-carborane; 1,2-B10C2H12), and cross linking based on the combination of closo-1,2-dicarbadodecaborane (ortho-carborane; 1,2- B10C2H12) and pyridine. In the latter devices, pyridine concentration was varied; samples with a closo-1,2-dicarbadodecaborane (ortho-carborane; 1,2- B10C2H12) to pyridine ratio of 1:1 (BC:Py1) and 1:3 (BC:Py3). The result is a nonvolatile robust p-type semiconductor of boron carbide (B10C2Hx):(C5NHx)y. The I(V) curves for the resulting heterojunction diodes exhibit strong rectification where the normalized reverse bias leakage currents are largely unperturbed with increasing pyridine inclusion. The devices are largely gamma insensitive and yet neutron voltaic properties of these boron carbides is demonstrated. The neutron capture generated pulses from these heterojunction diodes were obtained at zero bias voltage although without the characteristic signatures of complete charge collection from boron neutron capture generated electron-hole pair production. These results, nonetheless, suggest that modifications to boron carbide may result in better neutron voltaic materials with linking groups chosen from family of aromatic compounds that stretch between borazine (B3N3H6) and benzene that point the way to a whole family of future studies that may ultimately lead to boron carbides better suited to low power and low flux neutron detection.
O livro didático e a circulação do conhecimento: uma análise da questão ambiental na geografia escolar
Authors: Carvalho Márcia Eliane Silva , Cunha Jussara Nascimento , Dias Liliane de Jesus , Lima Lucas , Andrade Vanilza da Costa 
Published: April 2015

A circulação do conhecimento tem como um dos espaços formais de ocorrência a instituição escolar. Nestes espaços, o livro didático tem sido tomado como um grande aliado dos docentes e discentes, pois nele estão sistematizados os saberes historicamente acumulados pela ciência. Nessa perspectiva, o presente artigo tem por objetivo analisar como circula o conhecimento acerca da temática ambiental em livros didáticos de geografia do ensino fundamental, antigas 5ª a 8ª séries. Para atingir os objetivos propostos esta pesquisa foi baseada na abordagem qualitativa, sendo dividida em dois momentos: levantamentos bibliográficos e analisadas de duas coleções didáticas. Na coleção Geografia, Homem e Espaço as questões ambientais predominam nos de textos complementares. Na coleção Geografia, Sociedade e Cotidiano a questão ambiental é tratada em capítulos específicos, ou seja, os autores discutem e sugerem medidas para preservação/conservação dos recursos naturais. De modo geral, a questão ambiental nos livros analisados, instiga os professores e alunos para discussão dos problemas locais, através de textos e atividades complementares. Mas recai sobre o docente permitir esta leitura. Sendo assim, as duas coleções analisadas apresentam a temática de forma a possibilitar a circulação do conhecimento sobre a temática ambiental, mas para isso é necessário o engajamento e comprometimento do professor para desenvolver discussões e projetos que retratem os problemas ambientais da atualidade.
Unusual High-Pressure Tolerance of Polyboronic Crosslinked Gel Under High-Temperature Rheology Condition
Authors: Legemah Magnus , Qu Qi , Sun Hong , Vo Minh , Li Leiming , Carman Paul 
Published: April 2015

Abstract
Borate-crosslinked gels are preferred for hydraulic fracturing treatment of wells over metal-crosslinked gel because of their ability to reheal after shear and their reduced proppant pack damage. Conventional monoborate-crosslinked fluid is mostly limited to wells with low to medium bottomhole temperatures (120 to 200°F), while polyborate-crosslinked fluid is applicable at moderate to high temperatures (250 to 350°F). Recent work has found that the viscosity of conventional borate-crosslinked fluid underwent sequential viscosity loss at room temperature with stepwise pressure increases from 500 to 10,000 psi. This compromise in viscosity at high pressure can undermine fracture geometry as well as proppant transport and distribution in created hydraulic fractures. Also, it will be interesting to carry out this type of study under high-temperature conditions.
We reported in SPE 140817, 164118, and 168186 a high-temperature-tolerant polyamino-boronate crosslinker (PAB) containing multiple boron sites capable of interacting with multiple polysaccharide strands to form more complex crosslinking networks at lower polymer loadings than conventional fluids. Two crosslinkers constituted with different polyamine backbones (tetraethylenepentamine and tris-(2-aminoethyl)amine) were synthesized and crosslinked with hydrated guar. The optimized rheology was investigated at 250°F under a pressure ramp of 500 to 10,000 psi. The results indicate that viscosity of a 30 pound per thousand gallon (ppt) PAB-crosslinked guar is sustained up to 7000 psi at 250°F, whereas viscosity of conventional 30 ppt guar crosslinked by conventional borate crosslinkers fluid declines on ramping pressure from 500 to below 5000 psi.
The detailed results of the rheology tests at high temperature and pressure, 11B NMR of synthesized PAB crosslinkers and intermediates, as well as fluid chemistry will be discussed in this paper.
Development of a Numerical Scheme for Simulation of Asphaltene Dependent Phenomena in Porous Media
Authors: Hematfar V. , Chen Z. , Maini B. B. 
Published: April 2015

Abstract
Asphaltene is the highest molecular weight fraction of crude oil that under some conditions can undergo deposition and adsorption and affect the properties of porous media. This work presents a mathematical model for fractionation of asphaltene content of crude oil into different parts that evolve as a result of mechanisms like precipitation, flocculation, adsorption and entrapment during pressure depletion and solvent injection tests in core samples.
A fully coupled numerical scheme that bundles all nonlinear partial differential equations (PDEs) and pertinent relations is developed to compute the distribution of these fractions and other properties with respect to time and space. Flow of suspended asphaltene particles in the oil phase is modeled and phase behavior properties are predicted by the Peng-Robinson equation of state. A thermodynamic equation is derived to calculate the solubility parameter as an indication of asphaltene stability in the flowing system. The pressure distribution along the core is determined by combining the mass balance equations for oil, gas and asphaltene components into one PDE. In addition, a convection-dispersion PDE is developed to calculate the distribution of asphaltene concentration and include the effect of dispersion of asphaltene particles in the model. A reduction in transmissibility and large additional pressure drop due to asphaltene precipitation are used to infer the extent of damage to porous medium. Furthermore, an artificial neural network is trained using asphaltene deposition data and is then applied to calculate permeability evolution based on porosity. Finally, the modeling results are validated by experimental data.
Interpretation of the obtained results and tracking of distribution for various fractions of asphaltene are useful to detect and evaluate the asphaltene dependent phenomena, their real cause and relative importance, and the locations where they may occur.
Asphaltene is shown to affect the oil production rate and recovery efficiency. An enhanced knowledge of all relevant mechanisms and considering them in simulation and decision making will lead to the development of improved production schemes.
Alkalinity in The 21st Century: An Improved Methodology for Carbonate Determination in Oilfield Brines
Authors: Fisher Russell A. , Palkowetz Joseph M. , Combes Christopher J. 
Published: April 2015

Abstract
Long-standing techniques for alkalinity determination in oilfield brines were derived from analysis of potable water as given in standard methods guidebooks (APHA, 1985). Such traditional potable water methods are unable discriminate the contribution from the naturally occurring organic anions. This lack of sensitivity has led to higher scale-inhibitor costs than would be indicated using the technique presented here. Other industry-accepted methods have demonstrated the ability to parse the organic and inorganic alkalinity components but are time consuming and unsuited for the brisk pace of a production lab environment.
A rapid and robust method employing classical acid-base titration techniques has been developed to meet the requirements of advanced scale-prediction models. This method involves two separate titrations; one using 0.10 N hydrochloric acid followed by a back-titration using 0.10 N sodium hydroxide.
Standard solutions of bicarbonate and acetate blended at set proportions were employed to determine total alkalinity and organic acid content using this manual technique. The bicarbonate ion is estimated by subtracting organic acids from titrated total alkalinity.
The validation of the automated implementation of this method shows strong reproducibility and accuracy that is achieved in less than fifteen minutes. The new alkalinity method provides quality data for scale modeling.
More than one hundred runs of the newly developed method have shown excellent reproducibility from field locations in Texas, Louisiana, Utah, Colorado and Oklahoma. The laboratory adaptation using an auto-titrator has shown good correlation with the manual field method, and it can be automated for a high-throughput commercial laboratory. Concentrations of iron above 30 mg/l can interfere with the method if oxidation is allowed.
Carbonate Scale Control under High Level of Dissolved Iron and Calcium in the Bakken Formation
Authors: Peng Yang , Yue Zhiwei , Ozuruigbo Chioma , Fan Chunfang 
Published: April 2015

Abstract
The Bakken formation has emerged as one of the major oil and gas sources in the United States primarily because of technological advancements in hydraulic fracturing and horizontal drilling. Because of the high level of dissolved iron and calcium, water in the Bakken formation can be challenging in terms of scale control compared to other types of formation water with low levels of dissolved iron and calcium. Generally, for controlling carbonate scale, the high level of dissolved iron present in water significantly reduces the performance of commonly used scale inhibitors, such as polycarboxylic acids and amino tri(methylene phosphonic) acids etc. Most studies attribute such adverse impacts to the additional consumption of scale inhibitors by iron carbonate. However, evidence has shown the mechanism can be more complicated because of potential crystal distortion and scale seed effects during the coexistence of the two scale forms (Smith et al. 2008). In addition, compatibility issues caused by high concentrations of calcium in water can also help vitiate the performance of scale inhibitors.
This paper presents a series of field and laboratory studies conducted to better understand and address such problems. A discussion of acquired results and their implications is presented. Using Bakken formation water with more than 200 mg/L offerrous ions and 18,000 mg/L calcium ions, the inhibition performance of some conventional scale inhibitors and a few innovative solutions under anaerobic static and dynamic test conditions are evaluated and compared. Modeling analyses of Bakken water helped identify calcium carbonates and iron carbonates as primary potential scales. The compatibility of scale inhibitors in Bakken water with and without crosslinked gel fracturing fluid was also investigated. The results revealed two new chemicals are compatible with the fracturing fluid, both exhibiting high iron and calcium tolerance. These new solutions enabled effective control of calcium carbonate and iron carbonate scales in Bakken formation water.
Development and Application of a State of the Art Fully Synthetic Single Filtration Control Additive Providing Optimum Rheology in WBM: An Innovation for the Medium Temperature Drilling Market
Authors: Kayser Christoph , Botthof Gernold , Wylde Jonathan 
Published: April 2015

Abstract
Synthetic polymers are mainly used at HTHP conditions (&gt;400°F), but there is also an application for them at medium temperatures (250 to 350°F) where generally modified natural polymers, synthetic polymers or combinations can be used. These products support fluid loss control and rheology; however, combinations of different products add cost and complexity to the mud system. These are becoming less robust and often there is a trade-off between good fluid loss control and creation of a negative influence on mud rheology.
This paper details the development of three new fully synthetic, single additive polymers for the medium temperature range. The simplified formulation contributes to a robust drilling fluid combining excellent fluid loss control and low rheology profile. These new co-polymeric materials were designed for the most common WBM drilling applications and can be used in fresh water, in saturated NaCl and different mixed salt brines mainly for filtration control performance and rheological properties. Comprehensive data has been provided on mixed salt brines containing NaCl up to saturation and seawater together with 3% mg/L Mg++, 5% mg/L Ca++ and 6% KCl.
Physicochemical Interactions of Source Rocks with Injected Water-Based Fluids
Authors: Abdulsattar Z.R. , Agim K. , Lane R.H. , Hascakir B. 
Published: April 2015

Abstract
Water-based fracturing fluids contain polymers to function either as fluid viscosifiers or friction-reduction agents. Whereas much work has been done on optimizing these functions, little or no published work focuses on their chemical interactions with the rock they are targeting. Guar gum or one of its derivatives is used as a base for linear or cross-linked gels, while co-polymers of polyacrylamide are used in slick-water fracturing. This paper reports studies on the adsorption behavior of some, primarily, guar-based polymers onto the surface of source rock outcrop samples in order to provide a better picture of the interactions of polymers with these rocks. Outcrop samples from the Barnett, Eagle Ford, and Marcellus were collected, analyzed for mineralogy and total organic carbon, then exposed to different polymer solutions under elevated temperature and moderately elevated pressure. Viscosities of these polymer solutions were measured before and after exposing them to the rock in order to establish a correlation between polymer adsorption and the rock mineralogy and organic content. Results indicate that there is a significant correlation between the adsorption behavior of the polymer and the rock mineralogy and its organic carbon. Cationic polymers are more prone to be adsorbed on the surface of the rock than non-ionic polymers. The importance of polymer adsorption has not yet been determined. We speculate that adsorption could be useful in aiding wellbore cleanup after the fracturing stimulation is complete, but it might also have detrimental impacts on hydrocarbon production. We also conclude that oxidizing breakers might be spent on removing the organic content of the rock rather than being spent on breaking cross-linked gels, especially in rocks with high organic content. The results from this work point out that fluid-rock interactions are significant, and that further research regarding shale polymer interactions and its effects on hydrocarbon production is needed.
Iron Sulfide Inhibition: Field Application of an Innovative Polymeric Chemical
Authors: Wylde Jonathan J. , Okocha Cyril , Bluth Matthew , Savin Adam , Adamson Ben 
Published: April 2015

Abstract
Iron sulfide scale is prevalent in the industry and its chemical prevention is an area of recent focus by several research groups. There are very few examples where true inhibitor chemistry has been effective at controlling the scale, rather stoichiometric amounts of chelating agents are required. Partial inhibition has been achieved using classic scale inhibitor species such as phosphonates or maleic acid or sulfonated copolymers. Efficacy of these classic inhibitors against sulfide scale is poor and often uneconomically high concentrations are required.
This paper summarizes the work performed to deliver to the industry a true, high-performance sulfide scale inhibitor. This chemistry offers a true step-change in performance from existing technologies. An industry best-in-class rapid screening technique was used to systematically evaluate all current technologies in the market place and from this develop a detailed understanding on the structure-performance relationships of functional groups. By ranking the correlations, a range of novel polymeric chemistries were synthesized which provided significantly superior inhibition. Test methods are presented that mimic formation of these scales in the field and order of magnitude increases in performance over standard species are reported, thus representing a true step-change in the efficacy of sulfide scale inhibition.
The paper is largely dedicated to a field trial of this novel chemistry in USA. A severe iron sulfide fouling issue was being experienced in the water handling system. Intense sampling was performed when trialing classic chemistries such as THPS and phosphonate scale inhibitors as well as the novel polymeric product. The results speak for themselves and show that threshold concentrations of the new chemistry controlled sulfide deposition whereas order of magnitude more of standard chemistries are required to achieve the same efficacy.
Method for Rapid Assessment of Additives to Prevent Asphaltene Precipitation at Reservoir Conditions
Authors: Ovalles Cesar , Rogel Estrella , Morazan Harris , Moir Michael E. 
Published: April 2015

Abstract
Asphaltenes are blamed for several operational issues throughout the petroleum value chain such as: reducing volumetric production of wells, plugging of valves, pumps, tubing and pipelines during lifting, production, transportation, and storage. During refining operations, asphaltenes can cause heat exchanger and oven fouling and contributing to catalyst poisoning by coke and metal depositions. There are several techniques that can be used to deal with asphaltene precipitation issues: a) control pressure or other operational variables such as oil comingling, b) periodical cleaning (either chemical or mechanical), and c) additive injection to prevent asphaltene precipitation. Specifically, current methods for additive evaluation are time-consuming, rely exclusively on measurements at room temperature and could be very costly if they are carried out at reservoir conditions. Thus, the need for a method for rapid assessment of additives to prevent asphaltene precipitation is necessary to maintain well production and maximize economic benefits.
A new analytical technique was developed for screening and selection of asphaltene dispersants at reservoir conditions (&lt;200°C). It is based on the On-Column Filtration method (Rogel 2009 and Ovalles 2015) and can quantitatively measure asphaltene dispersion activity by determining the percentage of reduction of asphaltene content versus the case without additives. It allows performing mass balances, is fast (&lt;50min), repeatable, has small human intervention and uses a small amount of sample. A nonylphenolformaldehide resin (MW = 1600 g/mol) and three commercial additives were tested using gravimetrically separated asphaltenes and a Mid-continent crude oil. Reductions in the asphaltene contents up to 56% were found for the former and 38% for the latter. The mechanism in which asphaltene inhibitors and dispersants interact with asphaltenes depends on the type of additive and asphaltene composition and concentration. Some mechanistic considerations on the action of additives to prevent asphaltene precipitation are presented.
Microbial and Formation Damage Assessment of Secondary Treated Sewage Effluent for a Low Permeability Carbonate Reservoir Water Injection
Authors: Osode Peter I. , Rizk Tony Y. , Al-Obied Marwa A. , Alutaibi Ahmed S. , Al-Khaldi Mohammed H. 
Published: April 2015

Abstract
Large-scale seawater injection in two high permeability carbonate reservoirs within a remote onshore field commenced with the onset of oil production in early 2000. Following a recent incremental development plan that included an underlying low permeability (2 millidarcies (md)) reservoir with high calcium content (37,000 mg/L) formation water, it became necessary to examine alternative options to the seawater to avoid calcium sulfate scaling and microbial fouling. Secondary treated sewage effluent (TSE) is abundant from nearby urban treatment plants and presents an attractive option for the high-risk divalent ion formation brine environment.
An initial feasibility study focused on geochemical and microbial compatibility to assess the benefits expected from substituting the use of costly desulfated water1. Formation damage risk evaluation was also considered critical in the low permeability reservoir development since a significantly high initial capital expenditure associated with an injection water processing facility would further erode the economic value of the project. Laboratory coreflood experiments and conventional bottle tests were therefore conducted in addition to software simulation to appraise the TSE formation fluid interaction and inorganic scale deposition tendency at in situ conditions. The microbial study looked at the potential impact of both the microbial contamination and the nutritional load of TSE injection on the reservoir.
The study confirmed that sampled TSE had a relatively low content of contaminants such as oxygen demanding substances (ODS), heavy metals and dissolved solids with minimal formation damage risk compared to both seawater and field produced water. It also revealed variations of total organic carbon (TOC) in TSE, which may enhance troublesome microbial activities and impact the various systems' operational stages2.
This paper discusses the laboratory experiments and simulation conducted to assess the impact of injection TSE on microbial growth, in situ scale deposition and the associated formation damage risk. It also provides an insight into the effluent quality threshold required for injection in a reservoir of high divalent-salt connate water.