bluuebunny/crossref_metadata_2025 huggingface dataset:
mTORC Inhibitors as Broad-Spectrum Therapeutics for Age-Related Diseases
Authors: Walters Hannah E. , Cox Lynne S.
Published: June 2018

Chronological age represents the greatest risk factor for many life-threatening diseases including neurodegeneration, cancer and cardiovascular disease; ageing also increases susceptibility to infectious disease. Current therapies that effectively tackle individual diseases may have little impact on the overall healthspan of older individuals, who would still be vulnerable to other age-related pathologies. However, recent progress in ageing research has highlighted the accumulation of senescent cells with chronological age as a probable underlying cause of pathological ageing. Cellular senescence is an essentially irreversible proliferation arrest mechanism that has important roles in development, wound healing and preventing cancer, but it may limit tissue function and cause widespread inflammation with age. The serine/threonine kinase mTOR is a regulatory nexus heavily implicated in both ageing and senescence. Excitingly, a growing body of research has highlighted rapamycin and other mTOR inhibitors as promising treatments for a broad spectrum of age-related pathologies, including neurodegeneration, cancer, immunosenescence, osteoporosis, rheumatoid arthritis, age-related blindness, diabetic nephropathy, muscular dystrophy, and cardiovascular disease. In this review, we assess the use of mTOR inhibitors to treat age-related pathologies, discuss possible molecular mechanisms of action where evidence is available, and consider strategies to minimize undesirable side effects. We also emphasize the urgent need for reliable, non-invasive biomarkers of senescence and biological ageing to better monitor the efficacy of any healthy ageing therapy.
Slight pH Fluctuations in the Gold Nanoparticle Synthesis Process Influence the Performance of the Citrate Reduction Method
Authors: Contreras-Trigo Braulio , Díaz-García Víctor , Guzmán-Gutierrez Enrique , Sanhueza Ignacio , Coelho Pablo , Godoy Sebastián , Torres Sergio , Oyarzún Patricio
Published: June 2018

Gold nanoparticles (AuNPs) are currently under intense investigation for biomedical and biotechnology applications, thanks to their ease in preparation, stability, biocompatibility, multiple surface functionalities and size-dependent optical properties. The most commonly used method for AuNPs synthesis in aqueous solution is the reduction of tetrachloroauric acid (HAuCl4) with trisodium citrate. We observed variations in the pH and concentration of the gold colloidal suspension synthesized under standard conditions, verifying a reduction in the reaction yield by around 46% from pH 5.3 (2.4 nM) to pH 4.7 (1.29 nM). Citrate-capped AuNPs were characterized by UV-visible spectroscopy, TEM, EDS and zeta-potential measurements, revealing a linear correlation between pH and the concentration of the generated AuNPs. This result can be attributed to the adverse effect of protons both on citrate oxidation and on citrate adsorption onto the gold surface, which is required to form the stabilization layer. Overall, this study provides insight into the effect of the pH over the synthesis performance of the method, which would be of particular interest from the point of view of large-scale manufacturing processes.
N-Benzoyl / (4-nitrobenzoyl)-N'-4-cyanophenyl thioureas
Authors: Aydin Fatma
Published: June 2018

Herein, two title compounds, N-Benzoyl-N’-4-cyanophenyl thiourea (I) and N-(4-nitrobenzoyl)-N’-4-cyanophenyl thiourea (II) were synthesized in high yield, via aroyl isocyanate and 4-aminobenzonitrile. The structure of the prepared compounds was characterized by elementary analysis and FT-IR, 1H, 13C NMR spectroscopic methods. Cyclic voltammetric (CV) experiments were performed with glassy carbon electrode. The reduction potential values of different functional group such as nitro, cyano in title compounds were investigated using CV curves.
Microstructural Characterization and Mechanical Properties of 5 vol.% (TiBw+TiCp)/Ti Composite Produced by Forging
Authors: Han Jianchao , Lü Z.D. , Zhang Changjiang , Zhang S.Z. , Zhang Hongzhou , Lin Peng , Cao Peng
Published: June 2018

In this study, a 5vol. % (TiBw+TiCp)/Ti composite pancake with a diameter of 260mm was prepared by casting followed by open die forging in (α+β) phase region. The microstructures of the composite pancake are inhomogeneous, in terms of both matrix microstructure and distribution of reinforcements. The matrix microstructures were gradually refined from the periphery to centre of the pancake. The TiBw and TiCp reinforcements tend to be uniformly distributed in the centre region and. It is suggested that the microstructure difference can be mainly ascribed to the temperature variation from the periphery to the centre. Additionally, tensile testing results showed that the centre region of the composite pancake exhibits higher strength than the peripheral region. The strengthening mechanism and the softening behavior of the composite pancake with temperature is discussed.
Computing the Real Impact of Wind Turbine Power Curve Upgrades: A SCADA-Based Multivariate Linear Method and a Vortex Generator Test Case
Authors: Astolfi Davide , Castellani Francesco , Fravolini Mario Luca , Cascianelli Silvia , Terzi Ludovico
Published: June 2018

Wind turbine upgrades have been spreading in the recent years in the wind energy industry, with the aim of optimizing the efficiency of wind kinetic energy conversion. This kind of interventions has material and labor costs and it is therefore fundamental to estimate realistically the production improvement. Further, the retrofitting of wind turbines sited in harsh environments might exacerbate the stressing conditions to which wind turbines are subjected and consequently might affect the residue lifetime. This work deals with a case of retrofitting: the testing ground is a multi-megawatt wind turbine from a wind farm sited in a very complex terrain. The blades have been optimized by installing vortex generators and passive flow control devices. The complexity of this test case, dictated by the environment and by the features of the data set at disposal, inspires the formulation of a general method for estimating production upgrades, based on multivariate linear modeling of the power output of the upgraded wind turbine. The method is a distinctive part of the outcome of this work because it is generalizable to the study of whatever wind turbine upgrade and it is adaptable to the features of the data sets at disposal. In particular, applying this model to the test case of interest, it arises that the upgrade increases the annual energy production of the wind turbine of an amount of the order of the 2%. This quantity is of the same order of magnitude, albeit non-negligibly lower, than the estimate based on the assumption of ideal wind conditions. Therefore, it arises that complex wind conditions might affect the efficiency of wind turbine upgrades and it is therefore important to estimate their impact using data from wind turbines operating in the real environment of interest.
Effects of Stimulus Processing on Event-Related Brain Potentials of Close Others
Authors: Haffar Maud , Pantecouteau Hugo , Bouten Sheila , Debruille Jacques Bruno
Published: June 2018

We take what we see, hear, smell and feel for the reality. However, as neuroscientists, we know that this reality, that is, our perceptual world, is in fact made up by the brain from the processing of the nerve impulses coming from receptors. Ancient Greeks used to think that this perceptual world, sometimes called our 3D movie (Chalmers), is emitted and has its own physical nature. Given how real the 3D movie looks to us, it is still difficult today to consider that all we would be dealing with would be patterns of brain activity The present study thus aimed at testing whether the perceptual world could have some physical existence in addition to that of the neural patterns responsible for it. To achieve that goal, we tried to see whether brains could be sensitive to the 3D movie of others. This, admittedly unusual, operational hypothesis was based on two assumptions. First, brains are sensitive to the 3D movie, as our experience includes reactions to our perceptual world. Second, the physicality at stake does not differ across individuals. We recorded the event-related brain potentials (ERPs) evoked by stimuli of the international affective picture system in pairs of closely-related participants. Most importantly, they could neither see the stimuli simultaneously presented to their partners nor their reactions to them. As in Bouten et al. (2015), around 400 ms after the onset of the stimuli, ERPs started being more positive in inconsistent conditions. Namely, when the two subjects of each pair were presented with the same stimulus whereas they were told it would be a different one and vice-versa (i.e., different-stimuli expected to be same). ERPs were less positive when the two subjects of a pair were presented with the same stimuli and were told they were the same and conversely (i.e., different-stimuli expected to be different). The same experiment was then run in pairs of strangers. No significant effect of consistency on ERPs was observed even though participants could, this time, see, in the very periphery of their visual field, the reactions of their partner to the stimuli. We thus use the results of both studies to support a new version of the emission theory of consciousness and to suggest that the sensitivity to the perceptual world of others may depend on their prior familiarity with it.
Er:YAG Laser Debonding of Porcelain Laminate Veneers
Authors: Zhang Yong , Rocca Jean-Paul , Fornaini Carlo , Zhen Yinghua , Zhao Zengyi , Merigo Elisabetta
Published: June 2018

The purpose of this study consists to verify if Er:YAG laser, at low fluences, is able to debond porcelain veneers, successfully used to improve anterior tooth esthetics, without damaging the tooth structures. A total of twelve freshly extracted teeth were used and samples were decontaminated, stored, prepared to obtain Veneers adhesion. One week after, Er:YAG laser with a non-contact sapphire tip with air-water spray was used for veneer debonding at 100 mJ of power and 30Hz of frequency (Fluence 5.91 J/cm2). Results demonstrated that veneer debonding is possible with an Er:YAG laser and that the total number of pulses does not seem related to its efficiency. SEM observation confirms that residual tooth structure is not altered when using these low fluences. Low fluences with Er:YAG laser are able to debond veneers while preserving the tooth structures. SEM observation confirmed that residual tooth structure is not altered with low fluences.
APRENDIZAJE AUTÓNOMO DE ALUMNOS DE LOS GRADOS DE CIENCIA Y TECNOLOGÍA DE LOS ALIMENTOS Y VETERINARIA MEDIANTE EL EMPLEO DE LAS TICs EN LA PLANTA PILOTO DE LA UNIVERSIDAD DE CÓRDOBA
Authors: Vioque Amor Montserrat , Gómez Díaz Rafael , Moreno Rojas Rafael , Jordano Salinas Rafael , Millán Pérez María del Carmen , Garzón Sigler Ana Isabel , Medina Canalejo Luis , Molina Recio Guillermo , Ferrer Bas Susana , García Valverde Rosa María , Figueroa Sánchez Antonio
Published: June 2018

Con la finalidad de dotar a los estudiantes de los últimos cursos de los grados de Ciencia y Tecnología de los Alimentos y Veterinaria de las herramientas necesarias para fomentar el aprendizaje autónomo en instalaciones como la Planta Piloto de la Universidad de Córdoba (PPTA) se programaron diferentes actividades encaminadas a la recopilación de información sobre las instalaciones y equipos, realización de experimentos y desarrollo de trabajo fin de grado, de forma que se integrara en una web propia, con información suficiente para que los estudiantes puedan formarse autónomamente mediante la consulta y el manejo de documentación generada a partir del uso de diferentes equipos o de las diferentes líneas de procesado, integrando materiales preparados a partir de la experiencia propia en la misma instalación tales como manuales, vídeos, fotografía de maquinaria y protocolos de experimentos.
IMPACTO DEL ESTUDIO DEL DERECHO FINANCIERO Y TRIBUTARIO EN LA FORMACIÓN DE UNA CONCIENCIA FISCAL EN EL CUMPLIMIENTO DE LAS OBLIGACIONES TRIBUTARIAS EN NUESTROS ALUMNOS
Authors: Mories Jiménez Mª Teresa , Bueno Gallardo Esther
Published: June 2018

Con este Proyecto de Innovación Docente se ha pretendido crear en nuestro alumnado una incipiente conciencia fiscal en el cumplimiento de las obligaciones tributarias para con la Hacienda Pública. Consideramos que el estudio del Derecho Financiero y Tributario en 2º de Grado de Derecho (grupos 1, 2 y 3), 4º de Doble Grado de Derecho y ADE (grupos 4 y 5) y del Sistema Tributario de 3º de Grado de ADE (grupos 1 y 2), además de permitir al alumno conocer las instituciones tributarias desde un punto de vista teórico y práctico, les puede reforzar en la percepción de la importancia que tiene el cumplimiento de las obligaciones tributarias de forma voluntaria y el rechazo al fraude fiscal.
TALENTOEDU: FORMACIÓN DE DOCENTES PARA LA ATENCIÓN EDUCATIVA A LA ALTA CAPACIDAD INTELECTUAL
Authors: Trillo Luque Mª del Carmen , Jimena Pérez Ana , Vilches Vilela Mª Josefa , Aguilar Peñas Enrique , Castro López Rosario , Murillo Paños María Elena , Urquizu Serrano Ana Mª , Blancas Cabello Elena Mª , Poyato Varo Jesús , García del Junco Francisco , Alberca de Castro José F. , Gutiérrez Rubio Matilde , Llamas Castaño Helena , Caballero Cabrera Mª José , Romero Gil Rafael
Published: June 2018

Se presenta TalentoEDU, Proyecto de Innovación que surge ante las necesidades formativas de los futuros docentes respecto al alumnado con Alta Capacidad Intelectual. Este proyecto que se ha insertado en algunas de las asignaturas que conforman el Plan de Estudios de los Títulos de Grado que se imparten en el Centro de Magisterio “Sagrado Corazón”, adscrito a la Universidad de Córdoba. Pretende promover competencias para la atención a la diversidad en este ámbito. Los resultados de la experiencia indican que TalentoEDU ha contribuido a dicha formación, dada la satisfacción mostrada por los universitarios.
RECURSOS TICS ORIENTADOS A MEJORAR LA CAPACIDAD DE RAZONAMIENTO CIENTÍFICO COMO ESTRATEGIA DE RESOLUCIÓN DE PROBLEMAS DE INGENIERÍA
Authors: Varo Martínez Marta , López-Quintero José Luis , Pontes Pedrajas Alfonso , Pérez Martín Pedro , Varo Elena , Jiménez Valle Adrián , Muñoz Peinado Juan
Published: June 2018

En este proyecto se ha diseñado una nueva metodología docente de resolución de problemas en asignaturas científico-técnicas, basada en el uso de recursos TIC, con el objetivo de fomentar la adquisición de la competencia de razonamiento científico. Concretamente, por un lado, en las sesiones presenciales, se han utilizado los sistemas de respuesta interactiva cuyo éxito en el aula ya ha sido comprobado por los autores. Por otro lado, para el trabajo del alumnado fuera del aula, se ha integrado el uso de la herramienta interactiva online (web 2.0) elearningphysics, desarrollada por los autores que, mediante flujos de preguntas concatenadas, guía al estudiante durante la resolución de problemas ayudándole a razonar el porqué de los conceptos y leyes aplicados. Se ha comprobado que ambos recursos TICs contribuyen a que el alumnado adquiera la competencia de razonamiento científico aplicada a la resolución de problemas en asignaturas científico-técnicas, ya que le ayudan a relacionar los conceptos teóricos y prácticos a la vez que aumentan su nivel de motivación y participación en las actividades de resolución de problemas.
LA APLICACIÓN DE LOS MUNDOS INMERSIVOS PARA LA RESOLUCIÓN DE PROBLEMAS ASOCIADOS A CASOS REALES EN EL MUNDO DE LA INGENIERÍA AGRONÓMICA, DE MONTES Y DE LA ENOLOGÍA
Authors: Taguas E. V. , Fernández-Ahumada E. , Ortiz-Medina L. , Sánchez Zamora P. , De Haro-Giménez T. , Andicoberry S. , Lara Vélez P. , Montes Tubío F. , Mérida F. , Moya I. , Gallardo Cobos R.
Published: June 2018

El Plan de Innovación Docente 2016-2017 de la Universidad de Córdoba planteaba en sus líneas prioritarias de proyectos el trabajo por competencias, las actividades académicamente dirigidas y la transferencia del conocimiento teórico a la práctica. En este contexto, se planteó desarrollar una serie de casos prácticos en un espacio virtual adaptado a las características de los mismos donde, a través de juegos de rol (en los que participaran no sólo los estudiantes sino profesionales del sector) los estudiantes organizados en grupos tendrían que resolver problemas y/o plantear y analizar sus posibles soluciones. Se presenta en el siguiente trabajo un proyecto colectivo donde diferentes escenarios prácticos y agentes involucrados en los temarios de asignaturas como Proyectos y Comercialización y Regulación de Mercados Agrarios comunes al Grado de Ingeniería Agroalimentaria y del Medio Rural, Ingeniería. Forestal y Enología fueron representados. En el primer caso, se propuso la elaboración y presentación de una licitación pública y en el segundo caso, la simulación de los actores de una subasta pública en una lonja. Entre los resultados del proyecto, se destacan los vídeos protagonizados por los alumnos reproduciendo las entrevistas reales y negociaciones de los agentes de la lonja o en el caso de la licitación, la preparación de los pliegos de una licitación por parte de los técnicos de un ayuntamiento, la elaboración de las plicas por parte de empresas licitadoras y la evaluación de las mismas por parte de la mesa de contratación. Además, los resultados de las encuestas a los estudiantes pusieron de manifiesto la importancia de este tipo de proyectos para mejorar la adquisición de conocimiento práctico de las asignaturas así como competencias de comportamiento y particularmente de tipo creativo.
DISEÑO, INSTALACIÓN Y APLICACIÓN DE LA HERRAMIENTA MARTELOSCOPIO PARA EL ENTRENAMIENTO PRÁCTICO Y LA INCORPORACIÓN EFECTIVA DE VALORES ECONÓMICOS, ECOLÓGICOS Y SOCIOLÓGICOS A LOS TRATAMIENTOS SELVÍCOLAS EN MONTE
Authors: Abellanas Oar Begoña , Cuadros Tavira Simón , Pérez Moreno Pedro J. , Sellez Ruiz Álvaro
Published: June 2018

Un Marteloscopio es una herramienta didáctica para el entrenamiento selvícola (ejercicios virtuales de selección de árboles). La disponibilidad de los datos del rodal forestal en un dispositivo móvil (tablet) en combinación con un software adecuado permite obtener una retroalimentación directa entre las decisiones selvícolas ensayadas y sus efectos en términos económicos y ecológicos. A través de este Proyecto de Innovación Docente hemos diseñado, implementado y realizado pruebas preliminares de un Marteloscopio en la Sierra de Cazorla (Jaén). Como resultado, hemos establecido una parcela permanente de 1 ha en el bosque en la cual se han geolocalizado, medido, marcado y evaluado su valor en microhábitats de todos los árboles existentes en la misma. Hemos desarrollado el correspondiente software para pc o tablet para simular en tiempo real los efectos de los ejercicios selvícolas en monte, produciendo salidas instantáneas de los efectos de las claras simuladas sobre la distribución espacial de los árboles y el valor económico y ecológico, tanto de los árboles extraídos como de los que quedan en pie. Hemos realizado un ensayo preliminar del Marteloscopio en un Curso Propio de la UCO denominado "Praxis en el Medio Forestal" que ha tenido lugar en el mes de abril de 2017.
Lessons Learned From Electrical Submersible Pumps Installed in High-Salinity and Corrosive Reservoir, TAGI Formation
Authors: Brahmi Hichem
Published: June 2018

An experience of electrical-submersible-pump (ESP) -issues troubleshooting to overcome the high-corrosion media of GSA wells is presented. Additionally, actions taken to extend the run life of pumps are explained. GSA is the company in Algeria that adopted the ESP system including all services; therefore, there was no chance to share experience with other entities in the country. Thus, it became necessary to try all available approaches during a period of 10 years to mitigate ESP failures and, eventually, production downtime.

To overcome the high salinity of >320 g/L, several actions were introduced by either of two ways—ESP equipment or well completion. Simple motors and protectors were changed to tandem to prevent water penetration inside the motor. Power cable was changed from galvanized to Monel armor for high resistance to corrosion. For well completion, single or double ½-in. water-dilution lines were adopted and were run along tubing and connected to tail pipe, which runs to perforations. Modification in completion metallurgy also took place, when carbon steel was replaced by Super 13Cr. Supplementary actions were taken at the surface; the pressure switch was connected with a variable-speed drive (VSD) to smoothly shut down the ESP for unforeseen surface-controlled subsurface-safety-valve (SCSSV) closures.

The adopted actions yielded considerable positive results. ESP failures that originated from the motor were reduced from four per year during 2012 to only one failure in 2016. However, salt-deposition blocs were almost prevented, and resulted in decrement in bullheading and coiled-tubing interventions by 85%, except for some wells when salt-bloc buildup was occasionally quicker and more important than water-dilution rate. Running a ½-in. injection line along with the tail pipe lowered ESP-shutdown frequency. Also, changing the power-cable type gave roughly good results. After running Monel armor, the number of related power-cable failures decreased, contributing to the reduction of whole failures, because related power-cable failure represented 70% of ESP failures in 2015. Considering Super 13Cr instead of carbon-steel tubing gave positive indications, and reduced sharply related tubing-integrity failure. The problem still exists, however, with very low frequency. For surface equipment, all unforeseen SCSSV closures actuated from the control panel are always accompanied by a gradual decrement of frequency and, consequently, smoother ESP shutdown.

Because our organization is the company that uses ESP with a proper sense in Algeria, this paper presents some best practices to be considered for other companies and ESP contractors that are based in the country or abroad that intend to install an ESP system in very high-salinity and corrosive fields and to adopt a lease model for downhole equipment.
Rate-Transient Analysis in Multifractured Horizontal Wells of Tight Oil Reservoir
Authors: Haitao Li , Hongwen Luo , Jianfeng Zhang , Junchao Wang
Published: June 2018

Multifractured horizontal wells (MFHWs) have become the most commonly used technology for developing unconventional oil and gas reservoirs. Because unconventional reservoirs are currently the focus of exploration and exploitation around the world, a growing number of researchers and scholars are concentrating on production-performance evaluation of unconventional MFHWs to obtain the stimulated reservoir volume (SRV) or hydraulic-fracture properties, which are usually obtained from expensive reservoir tests or production logs. Rate-transient-analysis (RTA) techniques that use continuous-production and flowing-pressure data have proved to be convenient and applicable approaches to estimate the reservoir parameters and hydraulic-fracture properties. Although many cases or work flows of RTA have been previously studied, most of those works were performed for shale-gas or conventional reservoirs. Few studies on RTA have been conducted for MFHWs completed in tight oil reservoirs, particularly for actual field cases in which the usually scattered production data significantly increase the difficulty in analyzing the production performance.

In this research, the authors focus on using convenient and economical methods (RTA techniques) to obtain the SRV parameters and hydraulic-fracture properties that characterize the fracturing-treatment effectiveness of an actual MFHW in a tight oil reservoir, which many engineers and technical personnel expect to achieve. A comprehensive work flow [including production-data filtering, flow-regime diagnosis, straight-line analysis, type-curve matching (TCM), analytical-model analysis (AMA), numerical-model analysis (NMA), and uncertainty and nonuniqueness analysis] has been developed to perform a production-performance analysis of an MFHW completed in a tight oil reservoir. In particular, two approaches for calculating the permeability of SRV (kSRV) and effective half-length of hydraulic fracture (Xf) have been introduced. Moreover, the dual permeability parameters, the storativity ratio, and the interporosity coefficient (ω and λ, respectively), have been derived to enter into the AMA model to improve the accuracy of history matching. With the combination of AMA and NMA, the estimated ultimate recovery (EUR) of an actual MFHW completed in a tight oil reservoir can be predicted. Considering the uncertainty and nonuniqueness of the original reservoir parameters or nature of the adopted methods, a probabilistic analysis using Monte Carlo simulation has been performed to address the uncertainty of the analysis results. In addition, a simplified application of the developed method has been introduced. To demonstrate the feasibility and practicability of the developed work flow, two field cases from an actual tight oil reservoir have been analyzed. The consistent analysis results for field cases validate the developed work flow and proposed methods.
Phosphonate Speciation - Challenges and Solutions
Authors: Ewing Sarah J. , Hunter Nicole , MacKinnon Kirsty , Whittingham Kelly , Graham Gordon M. , Heath Stephen
Published: June 2018

Reliable and accurate analysis of inhibitors is vital for decisions on efficiency and cost-effectiveness of scale inhibitor squeeze treatments. Recent developments have resolved issues for residual sulphonated polymer chemistries which were previously difficult to isolate. Attention now is directed to challenges associated with phosphonate based inhibitors, particularly when assay is required from a multi-component produced water sample containing other P based inhibitor species which currently poses a significant challenge.

This paper describes the advantages and limitations of techniques used for phosphorus assay including inductively coupled plasma spectroscopy, ion chromatography and wet chemical methods (e.g. Phospho-molybdenum blue, PMB) approaches. Field examples are discussed to emphasize the analytical challenge with cases whereby speciation is readily achieved and others where this is not the case.

To overcome the limitations of these methods, novel approaches for analysis of P – containing inhibitors (in the presence of other –containing additives) include time resolved fluorescence spectroscopy (TRF) and mass spectrometry (MS) detection (which also require development) are considered with potential benefits and limitations / interferences highlighted. These are discussed with highlights of TRF development presented. This technique shows significant scope and potential with promising results showing speciation and discrimination of both polymeric and phosphonate based scale inhibitors as well as a phosphate ester based corrosion inhibitor.

This paper highlights the concept that for residual scale inhibitor assay, one analytical approach does not fit all environments and applications. However the availability of a range of techniques, some of which are still in development, allows for effective monitoring in complex, multi-component environments. The paper highlights development opportunities for some of the newer approaches such as TRF and MS as well as discussing their limitations in complex produced fluids.
Sea Water Desulphation – Optimisation of Scale Treatment and Reduction of OPEX & CAPEX
Authors: Baraka-Lokmane S. , Lesage N. , Fayed A. , Jungas M. , Heng S. , Jacob M. , Pedenaud P.
Published: June 2018

One barrel of seawater has to be injected into the reservoir in order to be able to produce the same amount of oil. In order to avoid problems of souring and/or incompatibility with reservoir water, desulphated seawater is injected.

In this paper, we have completely reconsidered the desulphation process with the objective of producing more water while optimising the quantity and type of scale inhibitors, with a priority given to green chemicals. The desulphation process established since 1992 has not been modified since. Our new philosophy adapts to the constraints of the field life. Theoretical and simulations studies have been carried out on risks of scale deposition on the membrane (polarisation layer) taking into account parameters and physical laws based on fluid mechanics, electroneutrality and material transfer. The behavior of membrane and risk of deposition depends on temperature, pressure, flux, tangential flow, potential accumulation of scale on the membrane and spacer; site and laboratory pilots have been used. Tube blocking tests have been carried out in order to select the scale inhibitors. Results showed that it is possible to operate beyond 80% of recovery with the help of a scale inhibitor. 83% recovery appears to be a maximum limit. Without the use of a scale inhibitor it is possible to obtain 75% of recovery under certain circumstances.

These results have enabled us to issue operational recommendations on TOTAL operating fields, on projects under development and on our future projects. The increase of the recovery and / or decrease in the concentration of scale inhibitor will conduct to less chemical discharged to the sea (via the concentrate). In addition, the selection of scale inhibitors has allowed selection of several biodegradable products, with better efficiency than currently used products. Of the 11 products tested, four have been selected. Reduction of OPEX: The consumption of scale inhibitor could be reduced by 2 or 3 and even suppressed for certain operating conditions. Selection tests have allowed us to choose most appropriate chemical from a technical, economic and environmental friendly point of view. Reduction of CAPEX: The increase of recovery has allowed us to reduce the dimensioning of the whole pretreatment of the nanofiltration as the flowrate is the parameter that influences the most the cost of a water treatment plant.
Impact of Gas Hydrate Inhibitors on Halite Scale Precipitation: An Experimental and Morphological Investigation
Authors: Hosseini Seyed Ahmad , Joonaki Edris , Buckman Jim , Ruggeri Bernardo , Tohidi Bahman
Published: June 2018

Inorganic scale deposition is one of the most serious flow assurance problems. One of these exotic scales is halite (NaCl). Injection of hydrate inhibitors (HIs) [methanol, monoethylene glycol (MEG), triethylene glycol (TEG)] to prevent plugging of flow lines and tubing could induce precipitation of halite scales. Thus, utilizing these chemicals might adversely affect salt solubility, causing scaling problems, particularly halite scales, in high total dissolved solid (TDS) brines. In this study, the influence of HIs on scaling of a supersaturated NaCl solution with and without inhibitor was experimentally investigated.

The results of these experiments show that increasing the concentration of HIs results in a higher amount of halite precipitation. Moreover, the effect of methanol on halite precipitation is more severe compared to MEG and TEG. On the other hand, the static efficiency results illustrate that raising the concentration of HI reduces the scale inhibition efficiency in the presence of methanol and TEG to a lower extent, while the inhibitor could have a 100% inhibition efficiency in the MEG solution. Furthermore, in the case of methanol, the optimum inhibition efficiencies at HI concentrations of 10 and 40 wt% were observed at SI concentrations of 500 and 200 ppm, respectively. Alterations in the morphology of halite in the presence of HIs were analyzed using optical microscopy and environmental scanning electron microscopy (ESEM) techniques. In this study, the effect of morphology changes of halite due to the addition of HI is addressed for the first time. These investigations can help provide a better understanding of the mechanism of halite scaling in the presence of HIs.
New Generation Squeezable Sulfide Inhibitor Successfully Averts Challenging Sulfide Scale Deposition in Permian Basin
Authors: Okocha Cyril , Kaiser Anton , Underwood Shane , Samaniego Walter , Wylde Jonathan
Published: June 2018

Sulfide scales (zinc, lead and iron sulfide) are currently causing considerable production challenges as mature fields are kept operational, and as deeper-hotter reservoirs are been developed. An effective way to combat conventional scaling is to inject "squeeze" scale inhibitors into the formation which are then slowly released as production resumes, providing scale protection. This option has not been the case for sulfide scales due to formation kinetics and lack of suitable products.

In this study we present two field cases where new generation squeezable sulfide inhibitors were deployed with clear success in inhibiting sulfide deposition and establishing stable production. Also presented are the development methods and chemical synthesis details for the development of a squeezable product. A novel fast screening technique is detailed as well as a new type of residual monitoring method for the polymeric species that inhibit the sulfide scales.

In the Permian Basin, newly completed long horizontal wells in the Sprayberry Formation were on a constant rotation of work overs (every 3 to 5 days) due to severe zinc and iron sulfide deposition. Early squeezes performed with known phosphonate/ester scale inhibitors, and end-capped polymer were unsuccessful. A new generation of squeezable sulfide inhibitor was deployed and stabilized production as well as the scaling ion data. A unique and fast residual analysis methodology (using a specialized HPLC column) was developed as part of the squeezable sulfide inhibitor development project capable of providing a unique selectivity in a high TDS brine without interferences increasing residual monitoring and squeeze confidence.

In the Williston basin many fields are known for their troubled history with iron sulfide. To date, the preferred option has been continuous well cleanout that impacts production, next generation squeezable sulfide inhibitor was deployed and it successfully increased productivity and eliminated well clean outs for the trialed wells. This technology summarized in the paper offers a substantial step change in the ability to protect against sulfide scale via squeeze application.

These field treatments show that next generation squeezable inhibitors were successful in inhibiting sulfide scales with no observed formation damage, upset to process facilities during flow back, or decline in productivity.
Evaluating Evaporative Processes - Gas Lift Chemical Applications, Halites and Gunking
Authors: Goodwin Neil , Graham Gordon
Published: June 2018

This paper describes a number of different evaporative processes which can cause flow assurance issues within oilfield production systems including chemical application via gas lift systems, halite deposition and gunking in injection lines. Similarities and differences are described and laboratory test methods are presented for each case.

While the challenges all involve evaporative processes, each system is different and requires suitable approaches to evaluate and mitigate the risks. These attempt to mimic the field system in the laboratory and allow observation under controlled conditions. Laboratory test methods vary from basic static bottle tests, through glass capillaries in autoclaves to dynamic tests using brine and a partially saturated gas phase, or neat chemical and dry gas lift media. In particular, the challenges when applying a chemical via a gas lift system will be described including field case studies.

Static tests with unlimited volume to evaporate produce a worst case for any evaporative process. However, it is frequently too severe to produce any useful results. Instead a test regime should be designed to mimic the field conditions. For example, evaporation within a pressure vessel can mimic the self-limiting process within a downhole injection line. Application of a chemical via a gas lift system requires a dynamic test where hot pressurised dry gas and neat chemical are co-injected with continual monitoring of gunking as indicated by flow path restrictions. Halites require a similar dynamic test method but with extensive modelling of the in situ saturation ratio to fully understand the system.

This paper will present case studies, summarise our understanding of the different evaporative processes, and give best practice guidelines for laboratory evaluation of the risks and mitigation strategies.
Management of Scale Control in Produced Water Reinjection - The Near Wellbore Scale Challenge Overcome
Authors: Jordan M. M.
Published: June 2018

Formation of sulphate and carbonate scale is well understood within the hydrocarbon extraction industry with injection of incompatible water such as seawater into reservoir with significant concentration of barium, strontium and calcium. To overcome this challenge chemical inhibition has been utilized for many decades and in the past 15 years elimination/reduction of the sulphate ion source from injection seawater using sulphate reduction membranes has been employed.

This paper present laboratory work to qualify a scale inhibitor and field results of its application to prevent scale formation when an operator had to change from low sulphate seawater (LSSW) mixed with produced water (PW) for their water injection source to a blend of LSSW/PW and full sulphate seawater (SW). The increased level of sulphate presented a significant scale risk within the topside process on fluid mixing but more significantly increased the risk of scale formation within the near wellbore region of the injector wells which were under matrix injection rather than fracture flow regime. The qualification of a suitable inhibitor required assessment of the retention of a potentially suitable vinyl sulphonate co polymer scale inhibitors to ensure it had low adsorption and was able to propagate deep into the formation before being adsorbed from the supersaturated brine.

Coreflood studies using reservoir core were carried out to assess the scale risk of the LSSW/PW/SW brine, propagation and release characteristic of the short-listed scale inhibitors. The recommendation that followed the laboratory studies was to apply a batch treatment of concentrated scale inhibitor to each injector well to provide a high concentration pad of scale inhibitor that would be transported into the reservoir when the scaling LSSW/PW/SW fluid was injected. Protection was provided by continuous application of the same chemical at minimum inhibitor concentration to prevent scale formation within the topside and the desorption of the batched inhibitor within the near wellbore would prevent scale formation within this critical region. Thirteen injection wells were treated with a pad of 10% vinyl sulphonate co polymer scale inhibitor to a radial distance of 3 ft. prior to the start of LSSW/PW/SW injection. Highly scaling brine has been injected now for 16 months into the thirteen wells at an average rate of 25,000 BWPD per well with no decline in injector performance observed.

The lessons learned from this study are that changes in scaling potential within a PWRI system can be controlled by carrying out an assessment of location of scale formation and adoption of more typical production well scale squeezes treatment technology to protect the critical near wellbore region around PWRI injection wells.
Simulation Study for Scale Management During Shale Gas Production
Authors: Wang Xu , Mackay Eric J.
Published: June 2018

Hydraulic fracturing for shale gas production involves pumping large volumes of water; as a consequence of this, produced water management is an important topic to address in order to sustainably produce shale gas. It has been well documented that only approximately 10-40% of the pumped fluids will be produced back to the surface, and that there will be increased concentrations of various ions in the flowback water during this process. This flowback water, with high total dissolved solids and high concentrations of certain ions, presents a significant risk of mineral scaling (Blauch, 2009).

In general, it can be very challenging to identify the in situ formation water composition in shale reservoirs since samples of the formation water can be difficult to obtain. They may have been contaminated during the drilling process, reactions may have taken place due to fluid mixing between the injected fluid and the formation water, or simply they may not have been preserved appropriately (Pan, 2017). Some calculations of formation water compositions require to be preceded based on the observed compositional data; thereafter, the predicted formation water compositions are validated by comparison with the observed total dissolved solids (TDS) data. A two-phase 3D numerical flow model has been developed that includes a hydraulic fracture and is populated with shale reservoir properties. (This model assumes the hydraulic fracture is already established – i.e. the calculations include coupled flow and component transport, but the geomechanics are not considered). It is used to simulate fluid transport mechanisms within the shale system and to address the question – what causes the significant retention of fracture fluid in shale reservoirs. A series of simulations was performed to achieve a history match with observed flowback water data in a western Canadian basin (the Horn River Basin).

A further two-phase 3D flow model was developed to examine the scaling tendency due to the evolving produced brine composition over the lifetime of the well. It is based on the previously history matched model and includes the fracture fluid and formation water compositions to predict precipitation of minerals. Finally, scale inhibitor injection was simulated to examine the impact of inhibitor retention on well protection.
Development and Improvement of a Novel IC-MS Technique for Phosphonate Scale Inhibitors
Authors: Cheng Lei , Durnell Christopher , Linares-Samaniego Sandra , Littlehales Ian , Fidoe Julie , Casado-Rivera Emerilis
Published: June 2018

Accurate and precise analysis of scale inhibitor residuals is important to managing oilfield squeeze treatments. Phosphonate scale inhibitors are effective for the prevention and control of scale problems in oilfields. The traditional analytical technique for monitoring phosphonate scale inhibitor residuals is inductively coupled plasma optical emission spectroscopy (ICP-EOS). ICP-OES is simple and has been used for monitoring squeeze treatments for decades. However, it can only measure the total phosphorus in the system and is unable to differentiate the different forms of phosphonates in commingled samples.

This paper presents a novel technique using ion chromatography and mass spectrometry (IC-MS and IC-MS/MS) for monitoring and quantifying different phosphonate scale inhibitors with high sensitivity and specificity. Ion chromatography efficiently separates phosphonate ions from other salt ions, and mass spectrometry speciates and quantitates molecular ions or fragment ions of each phosphonate. Previous work in our group (Zhang, et.al., 2014) had shown that IC-MS could be used to differentiate two phosphonates in a squeeze treatment using the characteristic molecular ions of each phosphonate. As the complexity of the squeeze treatment increases with the addition of other phosophates to the local oilfield, the development of an advanced IC-MS/MS method has been required to differentiate up to four phosphonates in a single commingled sample. This innovative technique has a detection limit of <1 ppm for each phosphonate in the mixture. The technique has been validated using both synthetic brine and field brine. Solid phase extraction cleanup work has also been performed to improve the capability of the technique in high-salinity brines. This novel analytical method will provide a powerful tool in squeeze scale management for subsea and deepwater oilfields.
Rigorous Carbonate and Sulphide Scale Predictions: What Really Matters?
Authors: Ness G. , Sorbie K. S.
Published: June 2018

Predicting the formation of pH- dependent scales such as carbonates and sulphides requires a full calculation of all hydrocarbon and aqueous phases present to determine the distribution and speciation of CO2 and H2S in the system. Several commercially available software packages combine PVT calculations with scale predictions, but such packages are more targeted to aqueous systems and have limited hydrocarbon capabilities. Likewise, PVT modelling software focusing on the hydrocarbon phase does not always fully model the aqueous phase or can only predict a limited number of scales/complexes. Moreover, within each software we can select a large number of different Equations of State (EOS), activity models, equilibrium parameters etc., which may ultimately impact the final carbonate and sulphide scale prediction profile. The questions we try to answer in this work are: How important is the software selection and which parameters really affect the final scale prediction profiles? In what scenarios do these values matter and when are they not important?

In previous publications we laid out a clear rigorous procedure (workflow) for the prediction of carbonate and sulphide scales which can be applied using any commercial PVT and scale prediction software. Here we apply this general workflow using different software and EOS models to evaluate their impact on the final carbonate and sulphide scale prediction profiles for some specific carbonate/sulphide field scaling scenarios. The results show that despite the large number of modelling options available, there are two parameters that play a key role in pH-dependant scale predictions: partition coefficients of CO2 and H2S between gas, oil and water and the relative mole (and volume) distribution between each phase at selected temperature and pressure. The final scale prediction results can be accurate only when these values are accurate, irrespective of how they are obtained. This work shows the impact of choosing different software and equations on carbonate and sulphide scale predictions, not just as a "black box" software comparison exercise but with a clear connection between the aqueous and hydrocarbon phase thermodynamics, the scaling system and the final results.