bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic variants and magnetic resonance imaging measures in multiple sclerosis: a systematic review
Authors: Nowak Jan Krzysztof , Guzikowska-Ruszkowska Izabela , Łopaciuch Jadwiga , Jankowska Wiesława , Piotrowska Ewa , Dziedzic-Szeszuła Ewa , Kapecka Kinga , Walkowiak Jarosław 
Published: April 2017

Introduction. Although environmental factors play the major role in the etiopathogenesis of multiple sclerosis (MS), genetic factors are implicated as well. We aimed to summarize the current knowledge on the relationship between genetic variants and magnetic resonance (MR) imaging measures in MS.Material and Methods. A systematic review. In December 2016, Scopus (since the year 1980; including MEDLINE) was searched for studies meeting predefined criteria designed to identify articles regarding: multiple sclerosis, genetic variants, and MR imaging. These were then analyzed to identify publications linking polymorphisms and MR findings.Results. The search yielded 290 items; 26 were included in the final analysis. Two genome‑wide association studies (GWAS) and two projects employing panels of a few dozen of genes of interest provided most of the data. The other publications concerned no more than 5 genes at a time. Twenty studies reported positive findings. The relationship between HLA‑DRB1*15:01 or BDNF rs6265 (Val66Met) and the radiologic course of MS was not consistent across the studies. An intersection of the results of the two GWAS yielded: OPCML (rs11223055), PTPRD (rs1953594), and WWOX (rs11150140, rs1116525) (brain atrophy) as well as CDH13 (rs692612) and PLCB1 (rs6118257) (lesion load).Conclusions. Genetic variants were shown to correlate with MS‑related brain atrophy and lesion load. Further research in the field is required.
FÉ CRISTÃ E MUNDO MODERNO
Authors: Caliman Cleto 
Published: April 2017

No debate pós-conciliar sobre a relação entre fé cristã e mundo moderno, se constata que o processo de secularização no Ocidente cristão é irreversível. O mundo ocidental tomou consciência de sua autonomia em relação à religião, ao cristianismo, à Igreja. Assume-se a tese de F. Gogarten: a secularização como consequência do impacto da fé bíblica sobre a história. Desta forma, a teologia da seculariza ção abriu o caminho para a reconciliação do cristão com o mundo moderno e suas conquistas. Todavia, o mundo moderno que a fé cristã encontra é o mundo burguês, que relegou a religião ao espaço privado. Por isso, a teologia europeia buscou a sua superação na teologia política de J. B. Metz - a desprivatização da fé cristã pela conquista de um espaço público - e na teologia da esperança de J. Moltmann. Mas a teologia da secularização e as tentativas de sua superação a partir do Primeiro Mundo revelam-se insufiientes para explicar a contradição principal do Terceiro Mundo e da América Latina em situação de dependência: o contraste entre a minoria rica e abastada e a imensa maioria empobrecida. A teologia da libertação encontra o lugar concreto para fazer a leitura da realidade: a prática libertadora dos pobres. Passa-se, assim, da teologia da secularização à teologia política, e desta à teologia da libertação, como horizonte do fazer teológico. Abre-se, assim, o caminho para uma renovada compreensão da Igreja do Concílio Vaticano II.
A CARNE SE FAZENDO VERBO UMA CONTRIBUIÇÃO AO DEBATE TEOLÓGICO NO BRASIL
Authors: Adão Francys Silvestrini 
Published: April 2017

O artigo se propõe, a partir do exame acurado de alguns traços socioculturais da história do Brasil, encontrar perspectivas pouco exploradas, que descortinam o processo pelo qual nossa teologia vai se tornando singular, desejosa de corresponder aos anseios mais lídimos dos homens e das mulheres desta nação. A singularidade de nossa “carne”, vivida na “coragem de se deixar enviar”, na vocação ao serviço dos outros, vai se tornando herança, fazendo palavra de Deus. Esta dinâmica insuflda “da paixão pelo Cristo, da paixão com Cristo, pelo projeto do Pai”, pela reconciliação com a criação, com a humanidade “e, de modo especial, pela vida dos mais vulneráveis” é contribuição para o debate teológico, porque feita a partir de nossa própria experiência.
Coupled Flow and Geomechanical Modeling of Reservoir Seismicity: Effects of Hydraulic Communication and Well Type
Authors: Asaithambi Renuhaa , Jha Birendra 
Published: April 2017

Abstract
Oilfields in California are heavily faulted, stress sensitive and need to be monitored for geomechanical effects such as fracturing, subsidence and seismicity induced by production or injection in the field. The objective of this paper is to investigate well production and injection-induced activation of a fault based on two factors: 1) hydraulic communication between the fault and the well i.e. intersecting vs. non-intersecting reservoir fault, and 2) sign of pressure change in the reservoir i.e. positive during injection vs. negative during production. Using a novel coupled flow and geomechanical simulation framework, we model the physical processes involved in activation of a fault and the effects of hydraulic communication and pressure change factors. We use the finite element method for mechanics sub-problem, the finite volume method for the flow sub-problem and the fixed-stress sequential solution strategy to solve the coupled sub-problems. We use the Mohr Coulomb failure criterion to determine mechanical stability of the fault against shear failure.
Our study provides key observations for long-term oilfield management in stress-sensitive and faulted reservoirs. We find that during injection pore pressure changes dominate the stability of a fault when it is in hydraulic communication with the well, whereas total stress changes dominate the stability of the fault when it is hydraulically isolated from the well. Injection-induced seismicity is a canonical example of the former case. In terms of the sign of pressure change, production from one side of a sealing fault always destabilizes the fault regardless of hydraulic communication between the fault and well whereas injection can stabilize a fault that is not in hydraulic communication with the well. In conclusion, we propose a novel approach to classify induced seismicity events as a function of reservoir geology (fault-to-well hydraulic communication) and reservoir operation (injection or production). The framework can be applied to monitor reservoir performance in faulted and stress-sensitive fields such as the ones in California.
Operational Experience with Fiber Optic Systems in Horizontal Steam Injectors
Authors: Shirdel M. , Buell R. S. , Wells M. 
Published: April 2017

Abstract
Horizontal steam injectors have a high-temperature, hostile wellbore environment which can result in sand influx, low cycle fatigue failures, packer failures, and liner hanger failures. This paper provides a case history analysis of five fiber optic installations in two wells that were used to evaluate, diagnose and address a variety of tubing-deployed equipment integrity and wellbore conditions. Distributed temperature sensing (DTS) and distributed acoustic sensing (DAS) were used to evaluate integrity of the liner and completion equipment performance in the horizontal section of the wellbore.
Application of a robust fiber data analysis methodology is presented that is focused on determining if the completion equipment is performing consistent with the basis of design assumptions. Examples of basis of design assumptions includes determining : 1) are packers or liner hangers leaking, 2) are steam flow control devices providing both the design steam mass flow rates and uniform quality splitting of wet steam, and 3) is the liner intact and directing steam as expected.
Steam flow in horizontal injectors is a complex two-phase system that cannot be readily predicted from simple multiphase flow models. Fiber optic surveillance provides important insights and understanding of the complex flow behavior in the annulus for tubing-deployed flow control devices (FCDs) in horizontal wells. Two-phase steam flow in horizontal injectors can create various flow regimes that can impact steam distribution and wellbore integrity (e.g. caustic and chloride stress corrosion and scale deposition).
Flow diagnostic tools, the acoustic energy spectrum and steam flow regime models were used to understand nozzle sonic flow, packer integrity, tubing and liner integrity by visualizing the acoustic data in both time and frequency domains. Using advanced signal processing and separation techniques, the liquid and vapor zones were uniquely characterized within the wellbore. The reliability and integrity of the packers and the injection string were also evaluated utilizing DTS and DAS data in combination. The characterization of flow control devices and their performance at the down-hole condition is provided, including identification of slug flow regimes and water pooling in low spots in the horizontal section of the well.
Design and Interpretation of an Interference Test for Determination of Formation Compressibility in a Deepwater Reservoir
Authors: Suleen Fnu , Urbanczyk Chris , Williams George , Kamal Med 
Published: April 2017

Abstract
The design and interpretation of an interference test for determination of formation compressibility in an offshore waterflood is presented. Interference well testing resolves some of the limitations posed by laboratory measurements of formation compressibility, i.e. the sample size is bigger, measurements are made in-situ and the method can be applied reliably in unconsolidated formations. Analytical and numerical PTA (Pressure Transient Analysis) models were used to select the active and observation wells and to design the interference test in terms of lag and lead times associated with the opening and closing of these wells. Some neighboring wells remained on production in between active and observation wells while the interference test was performed due to production constraints. This led to the challenge of unravelling the interference signal from the noise of continued production. Permanent downhole gauge data were utilized in seeking out the interference response at the observation well. Once the interference response was identified, the storativity (porosity-total compressibility product) was determined using the flow capacity (permeability-thickness product) calculated from the pressure and rate history at the active and observation wells. Formation compressibility was then calculated using log derived porosity values. Interference test analysis showed that the formation compressibility was significantly smaller than the pre-test estimates from the lab. The analysis resulted in narrowing of the uncertainty around formation compressibility that was later utilized in field production forecasts. Presence of high frequency high resolution data was critical in deciphering the interference signal. The breakthroughs came by using a range of the calculated flow capacity and total fluid compressibility in determining in-situ formation compressibility, which was in line with an offset analog field that had reliable laboratory measurements. The major impact of this work is in proposing a method for determination of formation compressibility in complex reservoirs and production systems from interference well tests utilizing permanent downhole gauge data.
Asphaltenes: What Do We Know So Far
Authors: Al-Qasim Abdulaziz , Bubshait Ahmed 
Published: April 2017

Abstract
Asphaltene precipitation becomes a serious problem especially when it causes plugging of the formation, wellbore, or production facilities, which will significantly affect the productivity and final recovery of the area. This paper presents an overview of asphaltene properties, structure, and its impact on oil production operations. It also specifically, discusses different available modeling approaches used to analyze and predict asphaltene precipitation, flocculation, and deposition in oil reservoirs. We will review asphaltene in crude oil systems: asphaltene properties and their impact on oil production, including the effects of pressure, temperature, and composition.
Potential Use of Oil-Field Produced Water as Base Fluid for Hydraulic Fracturing Operations: Effect of Water Chemistry on Crosslinking and Breaking Behaviors of Guar Gum-Based Fracturing Fluid Formulations
Authors: Saini Dayanand , Mezei Timea 
Published: April 2017

Abstract
Though, only few hundreds of hydraulic fracturing jobs are carried out in California, however, the use of oilfield-produced water resulting from conventional oil production operations for preparing fracturing fluid formulations appears a great alternative for unlocking the potential of Monterey shale without putting burden on precious fresh water resources of the region. The present experimental study reports on the crosslinking and breaking behaviors of guar-gum based fracturing fluids formulations prepared using synthetic but representative oil-field produced water samples.
The results suggest that the base fluid composition had little effect on the crosslinking behavior when crosslinked formulations were subjected to high shear rate. On other hand, breaking behavior of the studied fracturing fluid formations was affected by the guar gum concentration used for preparing the formulations. The efficacy of a commercially available bio-degradable breaker in breaking in cross-linked formulations was also evaluated at elevated temperature up to 185°F. The crosslinking and breaking behaviors of fracturing fluid formulations prepared using oil-field produced water as base fluids were comparable to the behaviors of typical fracturing fluid formations prepared using 2% potassium chloride solution as base fluid.
The results of this study are encouraging as conventional oil and gas production operations in California can provide an alternative source of water for base fluid to use in hydraulic fracturing based exploitation of Monterey shale resource in near future. Use of sea water for preparing fracturing fluid formulations for offshore applications will also help in reducing the need of treated sea water for any futre growth of hydraulic facturing technology in offshore environment.
It is noted here that the paper is a derivative work of the original paper first published in the Energy and Environment Research Journal (Vol. 6, No. 1; June 2016).
Errors Associated with Waterflood Monitoring Using the Hall Plot for Stacked Reservoirs in the Absence of Profile Surveys
Authors: Qi Qianru , Pepin Sophie , AlJazzaf Abdula , Ershaghi Iraj 
Published: April 2017

Abstract
It is common to use the slope of Hall plot as a tool for monitoring changes in well injectivity. Loss of injectivity at a given well head pressure may relate to a build-up of reservoir pressure or a gradual build-up of skin. In this study, we focus on injectivity losses caused by the wellbore skin development. Based on actual field data, we had noted errors in detection of permeability losses when later profile surveys were consulted. Our objective of the study was to examine the problem and then introduce an improved analytical formulation for layered systems and assess the limitations and meaning of slope changes observed on the Hall plot for stacked reservoirs. For calibration purposes, we used both an extended analytical model and a simulation approach to demonstrate the weakness of the Hall Plot for multi-layered cases. In simulating the cases, we used a cumulative injection dependent function to model the permeability losses for a given layer in a stacked system, and examined the limitation of estimated slopes in regarding to indication of the location and extent of the damaged zones in a stacked reservoir for remediation measures. We included a case study to exemplify the situation.
Optimization of Recovery in Waterfloods with Bang-Bang Control in Reservoirs with Subsidence and Uplift
Authors: Balaji Karthik , Suhag Anuj , Ranjith Rahul , Yegin Cengiz , Saracoglu Onder , Hendroyono Arief , Dhannoon Diyar , Temizel Cenk , Aminzadeh Fred 
Published: April 2017

Abstract
Along with the introduction of the Bang-Bang theory, it is known that the on-off controls of injection and production in waterflooding of hydrocarbon reservoirs improves recovery using only switching wells or valves on and off where optimal control theory is applied that employs an optimization procedure is gradient-based with the adjoint formulation. The conditions under which the reservoirs might have improvements in the Bang-Bang controls are also shown. In this study, we extend this concept to include the geomechanical factor in softer formations where subsidence or uplift are observed with injection or withdrawal of fluids.
In this study, the significance of bang-bang control theory is demonstrated on the main reservoir types consisting of different geomechanical characteristics, using a robust commercial optimization and uncertainty/sensitivity software which is coupled with a full-physics commercial simulator. A comprehensive theoretical background is provided to illustrate this approach so that the differences not only in the reservoir characteristics but also the simulation results are shown.
The optimization and uncertainty results prove useful in demonstrating the significance of each decision and risk parameter enabling the decision makers to make sound reservoir management decisions under economically-tight environments, providing not only the optimum values for the amount of injection but also the right combination of injection-production strategy to increase net present value or recoveries. The additional knowledge of temporal and spatial geomechanic behavior and the response of reservoirs proves useful in the application of Bang-Bang control with more realistic expectations, thus, leading to better reservoir management decisions.
Although Bang-Bang control and application of optimal control theory are not new in the industry, there has not been a comprehensive study taking into account the geomechanics. Thus, this study outlines the behavior and performance of reservoirs that experience subsidence and uplift at different levels in the application of this methodology to waterfloods.
Development of a Fully Coupled Thermo-Hydro-Mechanics Simulator Using Automated Solution Framework
Authors: Meguerdijian S. , Jha B. 
Published: April 2017

Abstract
Thermal recovery operations, including those in heavy oil fields and geothermal reservoirs, can benefit from increased understanding of thermo-hydro-mechanical (THM) phenomena. Maximizing thermally-enhanced energy recovery and assessment of thermally-induced seismicity and subsidence risk requires the next generation of coupled THM simulators that are easier to develop and use. We present a computational framework based on automated linearization and solution of multiphysics equations using FEniCS, an open source finite element solver. We validate the simulator on benchmark problems and discuss its application to thermal enhanced oil recovery methods. We conclude that using the FEniCS-based framework can reduce code development and maintenance efforts in existing thermal recovery operations and accelerate the discovery of future improved thermal recovery methods.
Finite Element Modeling of Reservoir Heating By An Electrical Cable
Authors: Medizade M. M. , Summers J. T. 
Published: April 2017

Abstract
Heat, mostly in terms of steam latent heat of vaporization, has been injected into heavy or extra heavy reservoirs worldwide to assist producing the in-situ oils. More recently, heat has been introduced directly into the reservoir by means of placing an electrical cable at the middle of the well in front of the target interval. Design of these electrical cables which supply a specific amount of heat energy per cable length, W/m, when placed in front of the target zone, have been evolving from manufacturing point of view to benefit oil operations worldwide in many ways. The purpose of this study is to investigate the heat transfer effects from the electric cable into stagnant gases of the wellbore media, casing, and reservoir porous media which are surrounding the electric cable. Two types of wells, vertical and horizontal have been studied. The objective is to calculate heat requirement to establish desired temperature distribution beyond the sandface.
The mathematical model used to study the heat transfer effects were built by a finite element model software package. In case of cased hole, the heat transfer from the cable propagates through stagnant gases and enters the casing before entering the porous media. In case of open -hole completion, the heat from the cable is transferred to stagnant gases in the wellbore before entering the porous media. Effects of different heating amounts in W/m on the sand-face temperature and deep into the porous media have been investigated for vertical and horizontal well configurations at different energy input conditions. Finite element model results were compared with other similar studies.
Results of the finite element modeling show that for all cases including vertical and horizontal wells, the sand-face quickly heats up. As time goes on, a distance into the porous media is also heated up which in return assists oil recovery from a larger vicinity from the well. Heating via electric cables can be beneficial in wellbore cleaning from paraffin, wax and hydrate build ups thus initiating oil recovery from near wellbore area. Total reservoir heating can provide In-situ upgrading of the heavy and extra heavy oils.
Characterizing Alaska Overburden
Authors: McNeal Josh , Huhndorf Sid , Craig Jon , Atashbari Vahid 
Published: April 2017

Abstract
As exploratory work in Alaska moves beyond the known petroleum basins, new remote areas will be explored, where little sub surface data is available. This paper examines the overburden of Alaska, and develops a general relationship for determining overburden pressures based on the general geographic location in this region.
To develop such relationships, well logs available to the Public are used. To characterize the overburden on a large scale, three major sedimentary basins of the Alaska, the North Slope, Nenana Basin, and Cook Inlet Basin, are studied. Overburden is estimated by integrating density of the deposits, from using density log data, and using MATLAB to filter false readings. From this data, a regionalized relationship is developed for pressure vs depth, based on geographical location.
The collision of the Pacific Plate and North American Plate has resulted in thrust tectonics, associated with shortening and thickening of the crust at southern part of the Alaska Microplate. The studied basins are located along different locations in this deformation zone and evident with different lithological patterns across a north-south direction. Depending on tectonics and diagenesis of sediments, rocks undergo different compaction processes which make overburden various across this region. As a result of plate tectonics and variation in depositional environments, an increasing trend is observed across the entire Alaska region. Such trend can be used in further exploration work in this region to approximate overburden stress at any location in the state.