bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Fluid Structure Interaction Model for Hydraulic Fracture Simulation on Vaca Muerta Argentina Shale Formation
Authors: Alderete I. D. , Sosa-Massaro A. , D'Hers S. 
Published: May 2017

Abstract
Vaca Muerta Formation in Neuquén Basin, Argentina, is one of the great worldwide promises given its potential as a non-conventional reservoir. Because of the intrinsic heterogeneity and low permeability, hydraulic fracturing is a required operation to stimulate the reservoir for better production. Simulation becomes a desirable tool to make fractures more efficient and get predictable outcomes. For this purpose, a 3D finite element analysis is performed using ADINA software to model reservoir response during the hydraulic fracturing process.
This iterative, fully coupled model uses fluid structure interaction (FSI), porous elastic media and stratified materials with transversely isotropic (TI) properties. The allowed fracture distribution is proposed beforehand. A cohesive model is added via non linear springs placed along the fracture proposed path. Material models are calibrated using data from well logs and microseismics taken from one well located in the field. All the information obtained from that well is then filtered for a particular region of interest in depth, determined by the mechanical properties observed.
Regarding the calculation procedure, as initial condition for the stimulated reservoir volume (SRV) the stress strain state measured in the field is adopted. Then hydraulic fracture process is simulated pumping fluid through punched holes and then fracture opening is analyzed, based on nodes displacement along the proposed path, to characterize fracture's opening and extension. The resulting state of stress developed after the fracture is updated at every calculation step. Key information such as resulting pore pressure and effective stresses can be easily computed along the fracturing process.
Once obtained results are compared to analytical solutions and experimental data obtained from fractures performed in similar soil conditions with good agreement. The developed model can tackle a variety of reservoir volumes, considering stratification, geomechanical properties, fracture fluid, fracture paths and the initial state of stress. Natural cracks can be added in a rather simple fashion by adding fractures to the proposed distribution with adequate fracture strengths.
Reduction of Opex Costs and Increase of Oil Production by Means of Production Deferment and Pump Failure Prevention with a Cost-Effective Well Monitoring System
Authors: Armacanqui Samuel , Eyzaguirre Luz , Lujan Cesar , Tafur Yeltsin , Marticorena Harol , Rodriguez José , Paccori Hancco , De La Cruz Ruben , Yataco Sheyla , Sueldo Freddy , Cuestas Francis 
Published: May 2017

Abstract
A system of well monitoring in real time was developed, that is cost-effective and reliable. It allows the the obtained the real time data gattering.
Among the advantages of this system is the low price and effectiveness; as it uses low cost electronic components and an inexpensive communication network. The main electronic components used, are the Arduino controller and the wireless information transmitter using the free bandwidth in the world: 2.4GHz, which allows programming a more effective communication network (ZigBee Network); the power supply is based on photovoltaic cells (5V). The ZigBee Network Technology achieved its goal of keeping all interconnected points. The limited range of the transmitters (1500m) was overcome by the use of interconnected network points, which can build a grid to cover the entire field. The tested prototype was composite of four points in a transmition station – simulating a control room
The system is based on good quality and low cost equipment, that aims to reduce the production deferment and artificial lift equipment failures; by the implementation of a system that generates alerts according to the monitored parameters.
Hybrid Method with a Probabilistic Approach to Estimate Reserves in Mature Fields
Authors: Cervantes Bravo Reynaldo J. , Savioli Gabriela , Estrada José 
Published: May 2017

Abstract
The objective of this work is to present a novel methodology – Hybrid Method - to estimate reserves and resources in mature fields. The Hybrid Method consists of combining the probabilistic reserve estimation by volumetric method with the Arps´ decline curve analysis, also including a probabilistic approach. The understanding and managing of uncertainties in reserves and resources estimation are two of the most important problems in the oil industry, because the final figures might add value to the capital of a company and might influence the economy of a country.
The best way to deal with uncertainties in hydrocarbon in place and EUR estimations is to assign a probability distribution function to each variable involved in the computation and to apply the Monte Carlo approach. The Hybrid Method starts with the estimation of reserves obtained by the probabilistic volumetric method including a drilling portfolio. Porosity, initial water saturation, area, net pay, formation volume factor are the main variables used. Three levels of reserves are obtained: 1P, 2P and 3P. Then, the Arp´s decline curve analysis is applied. A probability distribution function is assigned to the Arp´s curve parameters, "b" and "D". Again, three levels of production performance are obtained and the proved reserves 1P (base curve + drilling portfolio) are defined using the cumulative production principle. The final step consists of normalizing, correlating and integrating the two distributions independently obtained by the two methods in the 1P and 2P zones. In this way, a unique distribution function, its percentiles and the location of "boundary reserves 1P/2P" (minimum value to be considered proved reserves) are determined. The "boundary reserves 1P/2P" might differ from the PRMS definition (2011) [6], that uses 90 % certainty to classify 1P proved reserves.
The described methodology is applied to a mature field in Talara Basin (Perú) using the production history and average petrophysical properties from Pariñas Inferior and Mogollón formations. A portfolio of four infill wells is incorporated in the calculation. In this case, the Hybrid Method obtains a better estimation of reserves in mature fields through risk reduction of up to 80 % compared to traditional methods.
The results show that this methodology has a great potential to provide consistency, transparency and reliability to the financial decisions [13].
Assessing the Long-Term Energy Landscape Using a Global Energy Market Model
Authors: Aguilera R. F. , Aguilera R. 
Published: May 2017

Abstract
The objective of this paper is to estimate the long-term energy mix – i.e. the combination of resources including solids, liquids and gases that will satisfy energy demand to the year 2040 – with a Global Energy Market model (GEM). The GEM provides a close match of the historical energy mix dating back to the year 1850 and is then used to make forecasts for the future. Originally developed in 2007, the GEM was used to project the energy mix to the year 2030. In the present paper, the validity of the original projection is tested against the most recently available data.
The GEM estimates the fractional contribution of different primary energy sources to the global market. In total, there are six parameters that allow the GEM equation to give the best possible match of the historical energy mix. Using the estimated parameter values, the model can then be extended into the future, providing a reference case and alternative scenarios of the energy mix based on evolving unconventional, conventional and renewable resource quantities, costs, technologies, economic growth, population and policies.
The original GEM findings from 2007 forecasted a "2030 1/3 forecast", indicating that solids, liquids and gases would each occupy a third of the energy market in the year 2030. After further disaggregating the categories, it was found that liquids, mostly, oil would experience a declining market share by 2030 while natural gas would see a rapid rise. The share solids, mostly coal, was relatively flat by that time. Our new results show continued penetration of natural gas in the energy mix – a result consistent with efforts to reduce carbon emissions.
Our proposed paper is novel in that it uses the most recent statistics of the last 10 years on consumption of different energy sources to verify the accuracy of the original GEM projections carried out in 2007. Once the results are proven reasonable, new scenarios are developed with an extended time horizon to the year 2040.
Evaluation of Water Oil Relative Permeability of Fractured Rock under Variable Conditions of Hydrostatic Effective Stress and Capillary Number
Authors: Restrepo A. , Lopera S. H. , Diez K. 
Published: May 2017

Abstract
In the study of fractured systems petrophysics, the concept of relative permeability is of primary importance as it integrates into a characteristic curve, the net effect of complex interactions between matrix, fracture and fluids as a function of the state of saturation. In most practical applications, this curve is assumed invariant to the state of stresses and / or to the relative magnitude of viscous and capillary forces, normally represented by the capillary number concept Nc. In coupled simulation schemes, some approaches incorporate geomechanical effects to petrophysical attributes such as absolute permeability, porosity, fracture width and fracture permeability and others; incorporate variable capillary number to the relative permeability functions. In a practical sense, the assumption of invariant Kr with the stress and / or the capillary number actually simplifies computational requirements but can underestimate known physical effects that variable stress regime and variable viscous-capillary forces field induce over multiphase flow and of special relevance in the context of naturally fractured reservoirs subject to fluids injection and production.
In this work, results of water-oil relative permeability curves, measured over a single fractured Berea core by the unsteady state JBN method, with variable hydrostatic effective stress and capillary number are shown. The aim of the present study is to advance towards the prediction of complex dynamics in systems were matrix-fracture deformation occur due to stress changes, and variable flow regime exist as a function of relative variations of the field of viscous-capillary forces across the reservoir. The methodology is based on the exploration of the variations of Corey relative permeability parameters with both hydrostatic effective stress and capillary number outlining that literature reports studies about the independent effect of these two variables but not of its combined effect.
Results to date indicate that the features of relative permeability curves of fractured rocks (e.g. ranges of mobile saturation, curvature, endpoints) get modified when changes on the effective hydrostatic stress, the capillary number or both are induced. It is herein proposed, that the degree and configuration of the variation of the curves with respect to a reference curve is a function of the level of flow transfer between the matrix and fracture which in turn is determined by the relative incidence of the capillary, viscous and deformation effects over both domains. Further phases of the investigation shall include additional variables such as anisotropic stress regime, other types of fractures and wettability conditions towards the derivation of empirical correlations for Kr prediction.
Successful Introduction of the First Worldwide 30 Casing while Drilling Job Saves 1.31 Days in an Exploratory Well in Shallow Waters, Mexico
Authors: Luna Gonzalez O. , Van Balen A. , Bavidge M. , Mafla J. , Karimov J. , Hurtado Cardenas P. , Karrer C. , Sotelo Fonseca M. , Gil Rodriguez P. , Mora A. , Noguez M. , Gomez G. , Garcia Lopez J. R. , Zamudio Lopez L. A. , Perez Cabrera J. C. , Gomez Tapia M. , Perez Ibarra R. , Olcese F. , Carranza J. A. 
Published: May 2017

Abstract
In exploration wells in shallow waters of Mexico, the challenge of reducing drilling time and enhancing efficiency of well construction had become a problem on a daily basis. The continued use and success of Casing while Drilling (CwD) led the operator and service companies to embark upon a more ambitious project. Using the learning curve of previous 20″ CwD conductor sections, the first 34″ PDC drillable drill bit was designed and the first Casing Running Tool (CRT) for 30″ casing was utilized. These tools were used to apply the technology in the conductor sections of wells targeting Mesozoic formations.
A technical feasibility study was performed by the operator and service companies involved to analyze the viability of executing this whilst creating new products. This saw the implementation of CwD using 30″ casing, an integral drilling system using casing as the drill string and a PDC drillable bit that allows drilling and casing of the section to take place simultaneously and eliminates the need to assemble a 36″ drilling BHA and, subsequently run casing. Once the CwD BHA (Casing + Drillable drill bit) reaches the final depth of the section, the hole is already cased and ready to cement. This challenged the service companies' engineering departments to develop the custom made tools for the application.
In the first well, the original plan was to drill the 30″ section using a 36″ roller cone bit, drilling from sea bed (+/-78m) to 250 mts. This was the candidate well that the operator chose to utilize an ″unconventional″ drilling system to ensure reaching TD in a single run prior to cementing the casing.
The 30″ × 34″ conductor section was drilled and cased at a depth of 256 meters, drilling a total of 178 meters with the PDC drillable drill bit (4 blades + 19 mm cutters) in 9:52 hrs., with an average rate of penetration (ROP) of 18.04 m/hr., and then preparations for cementing the 30″casing began. This entire operation represented a 26.3% time reduction compared with a conventional drilling operation
This document will show the methodology and technology used in Mexico Marine Exploratory fields to reduce and mitigate the risk of not setting the casing at TD, focusing on the pre-planning stage, proper bit selection, Torque & Drag (T&D) analysis, casing fatigue life analysis and the use of new technology with a high success ratio on the operations in order to add value and ensure the customer' satisfaction.
Primary mitral valve regurgitation: Update and review
Authors: Maslow Andrew D , Poppas Athena 
Published: May 2017

Mitral regurgitation is the second most common valvular disorder requiring surgical intervention worldwide. This review summarizes the current understanding of primary, degenerative mitral regurgitation with respect to etiology, comprehensive assessment, natural history and management. The new concept of staging of the valvular disorders, newer predictors of adverse and controversy of ‘‘watchful waiting’’ versus ‘‘early surgical intervention’’ for severe, asymptomatic, primary mitral regurgitation are addressed.
Food finds its way to a woman’s heart: Campylobacter jejuni-associated myopericarditis
Authors: Veerasamy Manivannan , Alguire Craig T 
Published: May 2017

Campylobacter jejuni-associated myopericarditis (CAM) has been reported infrequently in the literature. We describe a case of immunocompetent young woman presenting with chest pain, with history of recent travel and diarrhea. Evaluation led to diagnosis of myopericarditis associated with this infection. The patient improved with conservative management. The pathogenesis of CAM remains unknown. Patients present with chest pain, heart failure, pulmonary edema and arrhythmias. Diagnostic evaluation includes EKG, cardiac enzymes, echocardiogram, cardiac MRI and stool culture. Conservative management recommended and routine use of antimicrobial therapy is controversial. CAM is a rare but severe complication of C. jejuni infection. It should be considered as a diagnosis in patients presenting with chest pain with associated gastrointestinal symptoms.
Feature extraction of vibration signal using OMP-NWE method
Authors: Xu Juan , Zhang Jianjun , Sun Chunyu , Dong Jianghui 
Published: May 2017

Feature extraction is one of the core problems in condition monitoring and fault diagnosis of mechanical equipment. In this study, an OMP-NWE method of feature extraction is proposed, aiming at the problem of low accuracy of existing feature extraction method. The OMP-NWE method integrates the strengths of orthogonal matching pursuit (OMP) algorithm with the benefits of nonparametric waveform estimation (NWE). Signal feature extraction model is constructed by design of filter bank and adaptive template signal. Then the vibration signal is linearly decomposed into a set of best matching waveform, which solves the problem that the basis function must be chosen in advance in OMP algorithm. The OMP-NWE method is applied to the feature extraction of the simulation and experimental vibration signal of rolling bearing, compared with the traditional OMP algorithm. Results show that the SNR of the extracted feature signal using OMP-NWE method increased by 19.22 % compared with that using the OMP method, which illustrates that OMP-NWE method has a higher accuracy in the feature extraction of unknown complex vibration signals. This work provides a new idea and a successful example for the feature extraction of vibration signal in the condition monitoring and fault diagnosis of mechanical equipment.
Numerical computation for vibration characteristics of long-span bridges with considering vehicle-wind coupling excitations based on finite element and neural network models
Authors: Wang Ling-bo , Jiang Pei-wen 
Published: May 2017

CA (Cellular Automaton) model was applied to the simulation of random traffic flow to develop a model considering the randomness of traffic flow and apply it to wind-vehicle-bridge coupling vibration. Finite element and neural network models were adopted respectively to numerically compute the vibration characteristics of bridges under wind and vehicle loads, verify the correctness of model. Subspace iteration method was used for the modal analysis of bridges. Natural frequencies of the top 8 orders were 0.21 Hz, 0.27 Hz, 0.36 Hz, 0.45 Hz, 0.56 Hz, 0.66 Hz, 0.87 Hz and 1.02 Hz respectively. The vibration frequency of the long-span bridge was consistent with the vibration characteristics of large-scale complex structures. Natural modes mainly reflected the torsion and bending of main beam and the swinging vibration of side and main towers. Fluctuation wind time-history presented periodic characteristics. The maximum and minimum values of fluctuation wind were about 20 m/s and –20 m/s respectively. The target and simulation values of power spectral density of wind speed were basically the same in change trend, which indicated that the fluctuation wind time-history computed in this paper was reliable. The model of dense traffic flow based on CA more truly described the running status like accelerating, decelerating and changing lanes of vehicles on the bridge, also contained the density information of vehicles and more truly reflected traffic characteristics. Vibration accelerations of the long-span bridge were symmetrically distributed. Vibration acceleration of central position in the left main span was the largest and near 50 cm/s2; vibration acceleration on the main tower was the smallest. The curve of vibration displacement with considering wind loads presented some fluctuations, while the vibration displacement of bridges without considering wind loads was very smooth. In addition, the amplitude of vibration displacement without considering wind loads moved laterally towards the left compared with that with considering wind loads. Therefore, wind loads must be considered when the vibration characteristics of the long-span bridge were computed. Otherwise, the accuracy of computational results would be reduced. It only took 0.5 hours to use neural network to predict the vibration acceleration of the long-span bridge. In the case of the same computer performance, it took 5 hours to use finite element model to predict the vibration acceleration of the long-span bridge. The advantage of neural network model in predicting the performance of large-scale complex structures like a long-span bridge could be obviously found. In the future, we will consider using neural network model to systematically study and optimize the long-span bridge.
Numerical simulation of aerodynamic noises in the far field of the high-speed train with considering bogies and connection windshields
Authors: Lu Wei-te , Wang Yan , Zhang Chun-qin 
Published: May 2017

The paper established a computational model of aerodynamic noises for 3-train formation including 3 trains, 6 bogies and 2 windshields. Based on Lighthill acoustic theories, a wideband noise source model was used to recognize the aerodynamic noise source of the high-speed train. Aerodynamic pressures of the high-speed train were extracted and compared with experimental results. The change trends and values presented a good consistency, which indicated that the computational model in this paper was effective. Large Eddy Simulation (LES) and FW-H acoustic model was then used to conduct numerical simulation of aerodynamic noises of the high-speed train. Aerodynamic noise characteristics in the far field of the high-speed train were analyzed. Analyzed results showed that when the high-speed train was running at the speed of 250 km/h, main energy was concentrated within 1250-3150 Hz, and the noise was a wideband noise in the analyzed frequency. The longitudinal observation point was 25 m away from the track center line and 25 m away from the nose tip, and its sound pressure level reached the maximum value of 89.7 dBA, while the sound pressure level around six bogies reached local maximum. With the larger distance from the track center line, the sound pressure level at horizontal observation points presented a smaller attenuation. Incoming flow had a larger impact on aerodynamic noises around the train than the tail flow. The main noise sources of a high-speed train were located at nose tip and pilot of head train, the second noise source was bogies, and the third noise source was located at train connections.
Projection of Lithuanian river runoff, temperature and their extremes under climate change
Authors: Šarauskienė D. , Akstinas V. , Kriaučiūnienė J. , Jakimavičius D. , Bukantis A. , Kažys J. , Povilaitis A. , Ložys L. , Kesminas V. , Virbickas T. , Pliuraitė V. 
Published: May 2017

Abstract
The aim of this research is to analyse and project the effects of changing climate on Lithuanian river runoff and water temperature. Climate change is expected to affect the extremes of the major river indices that impact fundamental ecological processes in river ecosystems. The available runoff and temperature data of rivers from three different hydrological regions of Lithuania were used. HBV software was applied for modelling of hydrological processes in the selected river catchments. The expected future changes of runoff and water temperature were projected according to a new set of scenarios (called representative concentration pathways) presented in the Intergovernmental Panel on Climate Change Fifth Assessment Report. The projected extreme values of runoff (flood and low flow discharges) and water temperatures in the beginning and the end of the 21st century were compared to the ones from the past period. The results showed a decrease of spring flood discharges and summer low flows and an increase of river water temperature at the end of the 21st century. The results are going to be used for an integrated assessment of the impact of climate change on aquatic animal diversity and productivity.