bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mitigating Risks in Hydraulic Fracture Design for a Complex Carbonate Reservoir
Authors: Izadi Ghazal , Barton Colleen , Cruz Leonardo , Franquet Javier , Hoeink Tobias , Laer Pierre Van 
Published: January 2018

Abstract
We use advanced modeling techniques to optimize wellbore landing, completion configuration, and stimulation treatments in a complex carbonate reservoir in the Middle East. The reservoir, where target formations are highly laminated, naturally fractured, and stresses are transitional as a function of depth, presents conditions for which a more sophisticated stimulation design approach is required. A meticulous analysis of wellbore image logs and detailed forward modeling of the geometry of the drilling induced tensile fractures revealed that in situ stresses rapidly transition between strike-slip and reverse faulting as a function of depth. The log-derived geomechanical model was calibrated against wellbore failure observations, laboratory measurements, and mini-frac test results. The stresses and rock properties were mapped to the 3D reservoir volume assuming a horizontally layered formation. Models of hydraulic fracture propagation in the presence of natural fractures and laminations under vertically heterogeneous stress conditions were investigated using a 3D simulator that couples geomechanics, fracture mechanics, fluid behavior, and proppant transport. Modeling results reveal hydraulic fracture propagation is profoundly influenced by the complex stresses and structures in this reservoir. Simulation results indicate that vertical hydraulic fracture propagation (height, growth) is controlled by stress contrasts, stress state, elastic, and strength variations between adjacent formations, and the frictional strength of weak bedding discontinuities that are ubiquitous in tight formations. Results also show limited height growth within a reverse-faulting zone where modeling predicts a tendency for the development of horizontal limbs ("T-shaped" fractures). Hydraulic fracture geometry is significantly different in the presence of weak bedding compared to bedding with sufficient strength to transmit crack tip stresses across the interfaces. Significant amounts of fluid and proppant can be diverted into created horizontal fractures in this reservoir. Increasing fluid viscosity improves the propped surface area and controls the height growth within the zone of interest. Capturing such subsurface complexities and using them to simulate hydraulic fracture propagation helps us to improve treatment designs, reduce operational costs, and ultimately improve hydrocarbon recovery. This study illustrates that for more complex reservoirs where spatial heterogeneities, preexisting natural fractures, or transitional stress states are present, using advanced 3D modeling is essential. Through parametric stimulation modeling, design parameters can be refined to achieve optimal solutions to better manage the controllable drilling, completion, stimulation, and production parameters that present the primary risks to development in tight/unconventional reservoirs.
Mapping Proppant Distribution in Hydraulic Fractures in Cased Wellbores Using Low Frequency Downhole Electrical Measurements
Authors: Zhang Peng , Sen Mrinal K. , Sharma Mukul M. , Gabelmann Jeff , Glowka David 
Published: January 2018

Abstract
A tool concept using downhole electrical measurements for mapping electrically conductive proppant in hydraulic fractures is presented in this paper. The method relies on direct excitation of the casing, which overcomes the severe limitations of induction tools in cased wellbores. An array of insulating gaps is installed and cemented in place as a permanent part of the casing string. The electrical measurements are done by imposing a voltage across each insulating gap, one at a time, before and after hydraulic fracture operations. The voltages across other insulating gaps near the transmitter gap are recorded.
The proposed tool's response to the geometry of a single fracture was modeled by solving for the electrical potential using a finite volume method. Preliminary results have shown that the electrically conductive proppant alters the path of the electrical current in the formation and this is recorded as differential signals by the string of insulating gaps surrounding the source gap. The measured differential signals are highly sensitive to a fracture's location, size, and orientation, and less sensitive to the fracture shape. However, to enable the implementation of such a practical system, various aspects of the tool need to be further investigated. Following our previous work, this paper focuses on forward modeling of the tool's response to multiple fractures, which demonstrates the influence of these fractures to the signals and provides important guidance for inverse modeling. Parametric inversion of fractures from synthetic data, generated by exciting various insulating gaps, is solved by using Very Fast Simulated Annealing (VFSA).
Simulation results show that when multiple hydraulic fractures are present, the voltages measured at the receiver gaps are primarily determined by the geometry of the fracture, which is in direct contact with the excited section of casing. When two fractures touch the same casing section, they induce very similar voltages to those from a single fracture with equivalent conductance. Preliminary inversion results from synthetic data indicate that the proposed VFSA can solve for the multiple fractures' conductance and size at the same time, without requiring a large number of forward simulations. Even with noisy synthetic data, VFSA is able to make good estimates of the fractures' geometries. This indicates that the VFSA technique is a proper and robust inversion technique for the measured voltages at various receiver gaps.
Experimental and Numerical Investigation of Shear Stimulation and Permeability Evolution in Shales
Authors: Ye Zhi , Sesetty Varahanaresh , Ghassemi Ahmad 
Published: January 2018

Abstract
The shearing of pre-existing fractures plays an important role in the permeability enhancement of shale reservoirs during hydraulic fracturing or refracturing treatments. The process reactivates pre-existing fractures around a hydraulic fracture causing them to slip and dilate and can also cause fracture propagation in the shear and tensile modes creating secondary cracks resulting in increased permeability. However, laboratory data on fluid flow and fracture slip in reservoir rocks particularly shale rocks are rare, and the mechanisms of permeability evaluation with shear slip and dilation are still not well understood. In this work, we present the results of laboratory scale shear stimulation tests and numerical simulations to illustrate fracture permeability changes with fracture shear slip and complex network formation. Eagle Ford shale samples containing a natural fracture have been used to run triaxial shear tests and injection-induced shear tests. The multistage triaxial shear test has been performed to measure fracture mechanical properties including shear strength, friction angle, normal stiffness, and shear stiffness; the injection-induced shear test has been used to investigate fracture dilatant shear slip and the coupled permeability evolution. The multistage triaxial shear test show that this type of Eagle Ford fracture has a 37° friction angle, and average 1.39*106 psi/in. normal stiffness and 1.11*106 psi/in. shear stiffness. In the injection-induced shear test, we achieved 6 times increase in flow rate even with only a small induced shear sliding (&lt;0.1 mm or &lt;0.004 inch). Furthermore, permeability evolution during injection-driven shearing tends to linearly evolve with the shear slip and dilation. The irreversible behavior of shear slip was found to explain the permeability hysteresis during shear sliding. The relevant laboratory data has been used in numerical simulations to quantify the impact of shear slip along natural fractures during stimulation. This has been achieved using a newly developed complex fracture network model which robustly simulates hydraulic fracture propagation in a naturally fractured reservoir. The numerical results indicate that shear slip induced permeability enhancement in ultra-low permeability reservoirs is a critical component of stimulation particularly when most of the natural fractures are mechanically closed and may not be favorable for proppant placement.
Seismic Attributes Application for the Distributed Acoustic Szensing Data for the Marcellus Shale: New Insights to Cross-Stage Flow Communication
Authors: Ghahfarokhi Payam Kavousi , Carr Timothy , Song Liaosha , Shukla Priyavrat , Pankaj Piyush 
Published: January 2018

Abstract
Recently, oil and gas companies started to invest in fiber optic technology to remotely monitor subsurface response to stimulation. Distributed Acoustic Sensing (DAS) and Distributed Temperature Sensing (DTS) record vibration and temperature around the fiber, respectively. In this research, we introduce new seismic attributes calculated from the DAS data that could suggest cross-stage fluid communication during hydraulic fracturing. The DAS data covers the entire 28 stimulated stages of the lateral MIP-3H well close to Morgantown, WV. We calculated the energy attribute for the DAS data of the studied stages. Subsequently, a Hilbert transform is applied to the DAS data to evaluate the instantaneous frequency of each trace in the DAS. In addition, we applied a fast Fourier transform to each trace for all the SEGY files to calculate the dominant frequency with a 30 second temporal window. The dominant frequency is compared to the DTS data and energy attribute for the stages in the horizontal MIP-3H well. The DTS analysis shows that stimulation of the stages 10 causes a temperature rise in the previous stage 9; in contrast, stage 18 stimulation does not affect stage 17 temperature. We suggest that the common low frequency zone identified in instantaneous frequency and dominant frequency attributes between stages 10 and 9 is related to presence of fluid and gas that transferred cross-stage during hydraulic fracturing. The fluid and results in the frequency damping of the vibrations around the fiber. We show that the frequency attribute reveals increases detail about the stimulation than conventional signal energy attribute of the DAS data.
The Impact of Stress on Propped Fracture Conductivity and Gas Recovery in Marcellus Shale
Authors: El sgher Mohamed , Aminian Kashy , Ameri Samuel 
Published: January 2018

Abstract
It is commonly observed that the production rates from unconventional reservoirs decline rapidly as compared to conventional reservoirs. The net stress increases with the production because the pore (fluid) pressure decreases while the overburden pressure remains constant. This leads to the fracture compaction and conductivity impairment due to proppant embedment. Even though advances in technology have unlocked considerable reserves of hydrocarbon, the impact of the net stress changes on proppant conductivity, i.e. stress-dependent propped fracture conductivity, is not well understood.
The objective of this study is to investigate the impact of the net stress propped fracture conductivity from the horizontal wells with multiple hydraulic fractures completed in Marcellus Shale. A commercial reservoir simulator was used to develop the base model for a Marcellus Shale horizontal well. The model incorporated various storage and production mechanisms inherent in Shales i.e. matrix, natural fracture, and gas adsorption as well as the hydraulic fracture properties (half-length and conductivity). The core, log, completion, stimulation, and production data from wells located at the Marcellus Shale Energy and Environment Laboratory (MSEEL) were utilized to generate the formation and completion properties for the simulation model. MSEEL is a Marcellus Shale dedicated field laboratory and a research collaboration between West Virginia University, Ohio State University, The National Energy Technology Laboratory, and Northeast Natural Energy. Precision laboratory equipment was utilized to determine rock petrophysical properties such as permeability and porosity. Additionally, the natural fracture closure stress values were determined by an innovative experimental technique using core plug samples. The relation between fracture conductivity and the net stress were obtained from published studies (SPE 181867) on core plugs collected from Marcellus shale at two different locations. This relation was incorporated in the model to investigate the geomechanical impact of hydraulic fracture on the gas production. The model was used to perform a number of parametric studies to investigate geomechanical effects for fracture conductivity on gas recovery from Marcellus shale.
The production data from two horizontal wells at the MSEEL site, were utilized for production history matching both with and without geomechanical effects. The inclusion of the geomechanical effect in the model improved the predictions particularly at the early stages of the production. Simulation results show geomechanical effects of fracture conductivity on gas production performance for Elimsport and Allenwood samples, which were cut parallel and perpendicular to the bedding planes. Moreover, the results indicate that the geomechanical effects have a significant impact on gas production when the pressure in the vicinity of the well has declined.
Anaesthetic management of parathyroid crisis in a paraplegic patient during parathyroidectomy
Authors: Gu changping , Li Guanjun , Hou Ming , Feng Hai , Bi Yanbin , Wang Yuelan 
Published: January 2018

SummaryChronic renal failure is often accompanied by secondary hyperparathyroidism that can be effectively treated by parathyroidectomy. However, there is a risk of parathyroid crisis during the operation. A 64‐year‐old patient with paraplegia and chronic renal failure showed progression to hyperparathyroidism and developed parathyroid crisis during parathyroidectomy. Emergency treatment included rehydration, calciuresis, intravenous injection of vasoactive agents and bisphosphonate therapy to mitigate the life‐threatening complications of hyperparathyroid crisis. The case shows that special attention needs to be paid to paraplegic patients undergoing parathyroidectomy.
Introducing modified version of penguins search optimization algorithm (PeSOA) and its application in optimal operation of reservoir systems
Authors: Mansouri Afshin , Aminnejad Babak , Ahmadi Hassan 
Published: January 2018

Abstract
In the current study, modified version of the penguins search optimization algorithm (PeSOA) was introduced, and its usage was assessed in the water resources field. In the modified version (MPeSOA), the Gaussian exploration was added to the algorithm. The MPeSOA performance was evaluated in optimal operation of a hypothetical four-reservoir system and Karun-4 reservoir as a real world problem. Also, genetic algorithm (GA) was used as a criterion for evaluating the performance of PeSOA and MPeSOA. The results revealed that in a four-reservoir system problem, the PeSOA performance was much weaker than the GA; but on the other hand, the MPeSOA had better performance than the GA. In the mentioned problem, PeSOA, GA, and MPeSOA reached 78.43, 97.46, and 98.30% of the global optimum, respectively. In the operation of Karun-4 reservoir, although PeSOA performance had less difference with the two other algorithms than four-reservoir problem, its performance was not acceptable. The average values of objective function in this case were equal to 26.49, 23.84, and 21.48 for PeSOA, GA, and MPeSOA, respectively. According to the results obtained in the operation of Karun-4 reservoir, the algorithms including MPeSOA, GA, and PeSOA were situated in ranks one to three in terms of efficiency, respectively.
Caracterização da produção artesanal de queijo colonial na região do Vale do Taquari
Authors: DALTOÉ Vanessa Cristina Bouvié , KOLCHINSKI Eliane Maria , PADILHA Rosiele Lappe , BIONDO Elaine , SANT'ANNA Voltaire 
Published: January 2018

A produção artesanal de queijo colonial em municípios do Vale do Taquari é uma herança cultural dos imigrantes italianos. O presente trabalho teve por objetivo iniciar a contextualização do processo histórico e descrever as características da produção artesanal do queijo colonial em municípios da região do Vale do Taquari. Para compreender o contexto histórico da produção artesanal de queijo colonial, optou-se pela pesquisa qualitativa com viés etnográfico. A pesquisa envolveu três produtores artesanais de queijo colonial, dois produtores do município de Encantado e um produtor do município de Relvado, aqui denominados A, B, e C, respectivamente. Através dos relatos foi possível constatar que o processamento do queijo colonial é uma herança cultural, passada de geração em geração pelas matriarcas. Atualmente, a atividade continua sendo desenvolvida com exclusividade pela mulher, contudo, não foi observada a perpetuação do saber-fazer para as filhas ou outros familiares. A descrição do processo de fabricação artesanal de queijo colonial foi semelhante entre as produtoras que participaram do presente estudo sendo possível estabelecer um fluxograma básico das etapas envolvidas no processamento. Observou-se que, apesar da disponibilidade de queijos no mercado formal, a procura por produtos coloniais é constante preservando assim a diversidade, o saber-fazer e o modo de vida, contribuindo para a valorização dos produtos coloniais e, consequentemente, para a permanência das famílias no meio rural. Ressalta-se ainda que o presente trabalho compõe o início do processo de caracterização da produção artesanal de queijo colonial na região do Vale do Taquari com margem para a elaboração de inúmeros trabalhos.
Equation to Fat Percentage Estimation in Women with Reduced Bone Mineral Density
Authors: Oselame Cristiane da Silva , Oselame Gleidson Brandão , de Matos Oslei , Neves Eduardo Borba 
Published: January 2018

Introduction:
The measurement of body fat is a way to obtain information about the characteristics that can lead to a framework of certain diseases. Thus, women in postmenopausal period experience significant variations in the body composition and fat distribution.

Objective:
To develop an equation to estimation of the body fat percentage in women with osteopenia / osteoporosis based on anthropometric measurements easily obtainable.

Methods:
The sample consisted of 74 women participating in the study group of the Physical Exercise Program for Osteoporosis Federal Technological University of Paraná, all in postmenopausal period and with osteopenia or osteoporosis. It evaluated body composition and bone mineral density by absorptiometry Radiological Dual Energy (DXA), anthropometry and body circumferences (waist, abdomen and hips), and nutritional status by the Body Mass Index (BMI) as the World Health Organization classification.

Results:
The sample can be characterized by the following average data: age of 59.32 ± 6.96, 27.14 ± 3 BMI 90, Waist Hip Ratio of 0.85 ± 0.08 and Body fat percentage 40.35 ± 4.04. The proposed equation was Body Fat Percentage (BFP) = 14,419 + (0.405 x BMI) + (0.147 x HC) using only two predictor variables, BMI and hip circumference (PQ).

Conclusion:
The standard error of estimate of the proposed equation was 2.89 (R2 = 0.501) can be considered low average values for the percentage of fat in this population, suggesting that the equation can be used to estimate the percentage of body fat in postmenopausal women.
Relationship Between Knee Valgus and Ground Reaction Force in Soccer Players Using Soccer Boots Landing on an Official Artificial Turf
Authors: Claudino João Gustavo , Mezêncio Bruno , Soncin Rafael , Pennone Juliana , Pinho João Pedro , Borges Eduardo , Castiglio Leonardo , Miyashiro Pedro Sampaio , Pomi Eric , Masuko Wellington , Soares Vinicius , Dias Paulo , Goés Luiz Henrique , Piazzi Alessandro Fromer , Amadio Alberto Carlos , Serrão Júlio Cerca 
Published: January 2018

Introduction:
There is a high incidence of Anterior Cruciate Ligament (ACL) injuries in soccer and 37% of this happens during landing after a jumping event. The measure of valgus knee moment during landing of a Drop Jump (DJ) has been considered a gold standard test to predict the risk of ACL injury in young athletes. Furthermore, researchers have used 2D frontal angle of the knee trying to make a practical tool to evaluate this injury risk, however, to the best of our knowledge, there is no studies about the relationship between mechanical load and 2D dynamic knee valgus parameters.

Purpose:
To verify the relationship between kinetics and kinematics ACL injury risk factors: the GRF and the a) peak knee valgus; b) valgus knee displacement in soccer players wearing soccer boots landing on an official synthetic turf.

Methods:
Twenty Brazilian soccer players, 15-17 years old, with 176.6 ± 6.4 cm of height and 67.4 ± 8.1 kg of body mass participated in this study. Following familiarization, subjects performed the DJ from a height of 40 cm. They landed on two force plates synchronized with Vicon system for kinetic and kinematic analyses, respectively.

Results:
Only valgus knee displacement (-1.4 ± 7.0 °) and antero-posterior component of GRF (-0.402 ± 0.097 BW) presented a significant relationship (r = 0.353; p = 0.025).

Conclusion:
There is a significant correlation between knee valgus displacement and GRF antero-posterior component for soccer players in an official artificial turf using soccer boots.
Acinetobacterspp in Intensive Care Unit: Risk Factors Associated with Infection and Mortality
Authors: Derin Okan , Yıldız Sevgi Dilek , Gunduz Alper , Uzun Kes Nuray , Yeltepe Turk Hacer Sebnem , Togay Alper , Bayraktar Banu , Dökmetaş İlyas 
Published: January 2018

Purpose: Acinetobacter was known as a saprophytic colonizer, yet it is considered an important etiologic agent which is isolated from hospital-acquired infections. In this study, we aimed to investigate fatality rates, factors for fatality of Acinetobacter infections and relationship between combination therapies and survival.Patients and Methods: We evaluated patients with Acinetobacter infection in ICU for demographic and clinical characteristics, combination therapies and adverse effects of these therapeutic options, retrospectively.Results: Ninety-one patients with proved Acinetobacter infection were included in this study. We found that the fatality rate of Acinetobacter infection in ICU was 56%. Advanced age, carbapenem resistance and Acinetobacter isolation from respiratory secretions were significantly related with fatality. We found that carbapenem resistance increased steadily during a 5 year period, fatality rates significantly decreased with combination therapies including aminoglycosides. There wasn’t significant relation between colistin therapy and survival in patients with Acinetobacter infections.Conclusion: The patients should be well-assessed in terms of fatality risk factors in case of Acinetobacter infections that occur in the intensive care units. The empirical antibiotic treatment started earlier based on such risk factors may decrease fatality. The antimicrobial combinations including aminoglycoside may be considered more in order to the local resistance data.