bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Fully Coupled Model for Hydraulic Fracture Growth During Multi-Well Fracturing Treatments: Enhancing Fracture Complexity
Authors: Li Sanbai , Zhang Dongxiao 
Published: February 2017

Abstract
Multi-well completion techniques, such as sequential fracturing, zipper fracturing and simultaneous fracturing, have been proposed to improve fracture complexity and connectivity. Critical geomechanics behind the multi-well-frac techniques include pore pressure propagation, cooling stress, tip-induced shear stress, and reversal of stress anisotropy. To optimize multi-well-frac treatments, we numerically investigated fracture growth from the perspective of thermo-hydro-mechanical coupling. The coupled geomechanics and fluid-heat flow model is based on a mixed finite element and finite volume method, which is capable of simulating multi-fracture growth in heterogeneous reservoirs. In this study, both hydraulic fracture propagation and natural fracture reactivation in opening or shearing patterns were taken into account. Particularly, an elasto-plastic fracture constitutive model was adopted to predict permanent enhancement of fracture aperture. The effects of perforation cluster spacing, well spacing, and the fracturing sequence of multi-well completion upon fracture-complexity were studied, where the total hydraulically fractured area was treated as the primary indicator of hydraulic fracturing effectiveness. By numerical parametric studies, we found that: (1) there is an optimal cluster spacing for maximizing the total fracture area for a stage with a given length. Cluster spacing mainly impacts stress distribution during hydraulic fracturing, which subsequently affects the path of newly created fracture propagation and crossing behaviors (i.e., crossing, arresting, or offsetting); (2) a suitable well spacing should be chosen carefully to avoid the hydraulic interconnection between the tip-to-tip stages, as well as to make use of tip-induced shear stresses; (3) the fracturing sequence for multi-well completion is of critical importance. Among three multi-well completion schemes, i.e., sequential, zipper, and simultaneous fracturing, the zipper fracturing technique achieves the best fracturing effectiveness for this case study; and (4) the effect of stress perturbation on natural fractures can be quite different, depending on the relative position to the created SRV. The coupled model significantly improves our understanding of multi-well-frac treatments and then provides us with a means to optimize the multi-well completion, enhancing fracture complexity to effectively improve productivity.
Hierarchical Coarsening of Simulation Model for In-Situ Upgrading Process
Authors: Fucinos Raul , Voskov Denis , Burnham Alan K 
Published: February 2017

Abstract
Oil shales are sedimentary rocks containing organic matter in form of kerogen which account for more than 5 trillion barrels of oil in place according to Birol (2010); therefore, oil shale production represents a plausible solution for the constant increasing demand for hydrocarbons. In this work, first we describe the model for chemical decomposition of kerogen. The prototype of the model is implemented in ADGPRS. The model is based on the most recent understanding of pyrolysis process and contains very precise descriptions of coupling chemical kinetics to heat and mass transport. Due to the high number of species, variations of porosity as consequence of the transformation of solid species into fluid products and complex multi-scale structure of porous media, the simulation performance of the high-fidelity model is limited. As the second step of this work, we introduce a hierarchy of coarser models to improve the run-time of forward solution without significant reduction in accuracy. We applied coarsening in time, space, and chemical representation, and quantify errors introduced at each coarsening level. In conclusion, we provided recommendations for large scale modeling of in-situ upgrading process.
Fully Implicit Mixed Hybrid Finite-Element Formulation for General-Purpose Compositional Reservoir Simulation
Authors: Abushaikha Ahmad S. , Voskov Denis V. , Tchelepi Hamdi A. 
Published: February 2017

Abstract
We present a fully implicit mixed hybrid finite-element (FE) formulation for general-purpose compositional reservoir simulation. The formulation is locally conservative, and the momentum and mass balance equations are solved simultaneously; including Lagrange multipliers on element interfaces. The method utilizes automatic differentiation for the Jacobian construction. This hybrid FE approach accommodates unstructured grids, and we present black-oil and compositional test cases with permeability tensors. We also discuss the accuracy and computational efficiency for the new formulation. For all tests, we compare the performance and accuracy of the proposed approach with the Multi-Point Flux Approximation (MPFA-O) method.
Low-Dimensional Tensor Representations for the Estimation of Petrophysical Reservoir Parameters
Authors: Insuasty E. , Van den Hof P. M. , Weiland S. , Jansen J. D. 
Published: February 2017

Abstract
In this work, the application of tensor methodologies for computer-assisted history matching of channelized reservoirs is explored. A tensor-based approach is used for the parameterization of petrophysical parameters to reduce the dimensionality of the parameter estimation problem. Building on the work of Afra and Gildin (2013); Afra et.al. (2014); Afra and Gildin (2016), permeability fields of multiple model realizations are collected in a tensor form which is subsequently decomposed to derive a low-dimensional representation of the dominant spatial structures in the models. This representation then is used to estimate an identifiable reduced set of parameters using an ensemble Kalman filter (EnKF) strategy. This approach is attractive for the parameter estimation of permeabilities because it increases the ability to represent channelized structures in the updates resulting in an improved predictive capacity of the history-matched models. In particular, channel continuity is better preserved than with a Principal Component Analysis (PCA) parameterization.
An Integrated Case Study of the Frio CO2 Sequestration Pilot Test for Safe and Effective Carbon Storage Including Compositional Flow and Geomechanics
Authors: Jung Hojung , Singh Gurpreet , Nicolas Espinoza D. , Wheeler Mary F. 
Published: February 2017

Abstract
CO2 geological sequestration is one of the most efficient and direct ways to reduce the CO2 emissions to the atmosphere. Understanding reservoir capacity and geomechanical implications of CO2 injection are necessary for safe and effective storage. Large pore pressure increases from injection may induce fault reactivation and seal failure, and compromise storage integrity. Several studies examined the Frio brine pilot CO2 sequestration project conducted in Dayton, Texas. However, geomechanical implications were not fully evaluated at that time besides calculations required for a class V well permit. This article presents a comprehensive case study to evaluate pore pressure increase due to CO2 injection at the Frio injection site. The work includes new laboratory experiments and well-logging data analyses. The results are consistently assimilated into a numerical reservoir model which includes compositional flow. A fine-scale reservoir model of the Frio pilot test is developed in our in-house reservoir simulator IPARS (Integrated Parallel Accurate Reservoir Simulator). We perform history matching of the pressure transient data of Frio pilot test, and the history-matched reservoir model is used to predict the implications of larger CO2 injection volumes. Reservoir simulation results show that injection rates adopted during the actual pilot test very likely did not upset the mechanical integrity of the storage complex. Higher and sustained injection rates may increase pore pressure beyond limits for fault reactivation and hydraulic fracturing. A change of over a few-hundreds-psi could cause the sand to reach the shear yield stress. However, tested rock samples exhibit ductile deformation at in-situ effective stresses suggesting that reaching shear yield stress in neighboring faults may not jeopardize the sealing integrity of faults.
A General Purpose Reservoir Simulation Framework for Multiphase Multicomponent Reactive Fluids
Authors: Qiao Changhe , Khorsandi Saeid , Johns Russell T. 
Published: February 2017

Abstract
Reservoir simulation models describe the flow of various fluid models, such as black oil, compositional, reactive transport, and chemical flooding. Implementing new fluid models in reservoir simulators requires significant manpower to rewrite the simulation code, especially if the original simulator was not designed properly. One such example is to include geochemical reactive transport processes. In this paper, a general modeling framework is developed for easy implementation of new fluid models including time-independent (equilibrium) and time-dependent (kinetic) correlations. The approach is physically sound, robust and naturally extends black oil and compositional models to multiphase reactive systems for a variety of complex flow processes.
The fundamental physical laws (including conservation laws of mass/momentum/energy and thermodynamics laws) govern multiphase flow in porous media. Here we consistently applied the general principles under different assumptions to obtain the mass conservation equations for various processes. The framework includes a definition of components under the instantaneous phase and chemical equilibrium, mass conservation equations, a volume balance equation, and equilibrium relations. That is, primary equations for various fluids are represented by a unique set of mass conservation equations with different secondary algebraic constraints. The differential equations do not need to be changed as new processes are added. IMPEC and FIM are used to solve for flow. A robust algorithm is developed to calculate the phase equilibrium together with chemical equilibrium.
The simulator was validated with SPE comparative solution projects using Eclipse 300 and CMG-GEM. Large-scale reservoir models including SPE 10 and a field case from Europe were compared with various commercial simulators, showing that the simulator is significantly faster and more robust. New coupled reactive phase behavior models were implemented, including low salinity waterflooding, CO2 WAG with reactions, alkali/surfactant/polymer (ASP) flooding with the HLD-NAC EoS model, and fines migration. Those models have been implemented with minimal additional coding owing to the novel and consistent framework. The modeling framework provides a handy and powerful tool to understand the detailed interaction between species, easily update the physics as needed, and to better predict its impact on the ultimate oil recovery. This framework differs from previous research because the equilibrium chemical reactions are included without changing the structure of the compositional model. Similar to conventional compositional models, the flow, transport and local interactions are treated in two parts. This paper generalizes the simulation technology (named PennSim) that we have used in various applications. The novel formulation also enables fast linear solver performance due to the natural decoupling techniques.
A Discrete Imaging Formulation for History Matching Complex Geologic Facies
Authors: Khaninezhad Mohammad-Reza , Jafarpour Behnam 
Published: February 2017

Abstract
Estimation of geologic facies with complex connectivity patterns from limited direct and indirect measurements is facilitated by exploiting recent advances in discrete imaging methods. Classical model calibration techniques have difficulty in honoring solution discreteness and preserving facies connectivity. The existing methods for calibration of facies models either focus on preserving the facies connectivity and incorporate discreteness as a post-processing step, or they attempt to generate conditional samples from a discrete prior model (training image), which can be computationally demanding. In this work, we propose a novel framework for discrete geologic facies reconstruction from dynamic production data by combining connectivity-preserving parameterizations with discrete regularization techniques such as well-potentials that are inspired by recent advances in discrete tomography. For calibration of discrete geologic facies against flow data, we propose a method to promote solution discreteness and incorporate geologic connectivity information. To obtain discrete solutions we invoke well-potential regularization functions that penalize continuous solutions. The regularization penalty function is minimized along with the mismatch between model predictions and observed production data. To incorporate the geologic connectivity patterns, we learn plausible geologic patterns from available prior (training) models. This is done by learning parametric representations of facies connectivity such as the truncated singular value decomposition (TSVD) or learned sparse geologic dictionaries. We solve the resulting regularized minimization problem by implementing an efficient gradient-based algorithm known as the alternating direction method of multipliers (ADMM). Through several numerical experiments, we show that the proposed formulation offers a flexible facies model calibration approach that can be applied to problems with multiple facies types. An important aspect of this method is that it incorporates the discreteness of the underlying structure as a soft constraint in the inversion process, without a requirement for post-processing of the solution, which can potentially violate data match requirements. The implementation is amenable to iterative gradient-based algorithms and allows gradual, systematic, and plausible morphing of a given facies model to match the observed data. We present several case studies that illustrate the superiority of the proposed method to existing approaches in the literature for calibration of discrete facies distribution against production data.
Integritas Akademik dan Kecemasan Akademik dalam Menghadapi Ujian Nasional pada Siswa
Authors: Firmantyo Tyas , Alsa Asmadi 
Published: February 2017

<p class="IABSTRAK"><strong>Abstract: </strong>The objective of this research is to examine the correlation between academic anxiety and academic integrity on facing the state examination among twelfth grade students. This research was conducted in SMAN Y, involving 114 twelfth grade Mathematic and Natural Science students. Data was collected using Academic Anxiety scale and Academic Integrity scale and was analyzed using Spearman correlation technique because of abnormality of data on academic integrity. Result supported the hypothesis that there was a negative correlation between academic anxiety and academic integrity on facing the state examination (r<sub>s</sub> = -0,457; p &lt; 0,01). The determination coefficient of r<sup>2</sup> = 0,209, show the effective contribution of academic anxiety to academic integrity was 20,9%.</p><p class="IABSTRAK"><strong>Abstrak</strong>: Penelitian ini bertujuan untuk mengetahui apakah terdapat hubungan antara kecemasan akademik dan integritas akademik dalam menghadapi ujian nasional pada siswa kelas XII. Penelitian ini dilakukan di SMAN Y dengan melibatkan 114 siswa kelas XII jurus­an MIA atau Matematika dan Ilmu Alam. Pengumpulan data dalam penelitian ini dilakukan dengan skala penelitian atau kuisioner Kecemasan Akademik dan Integritas Akademik. Analisis data dilakukan dengan menggunakan teknik korelasi <em>Spearman Rank</em> karena sebaran data yang tidak normal pada salah satu variabel penelitian. Hasil penelitian ini sejalan dengan hipotesis penelitian, yaitu bahwa terdapat hubungan negatif antara ke­cemasan akademik dan integritas akademik dalam menghadapi ujian nasional pada siswa di SMAN Y (<em>r<sub>s</sub></em> = -0,457, p &lt; 0,01). Koefisien determinasi, r<sup>2</sup> = 0,209 menunjukkan sumbangan efektif kecemasan akademik terhadap integritas akademik siswa dalam menghadapi ujian nasional sebesar 20,8%.</p><p><em> </em></p>
Clío América y su trayectoria en la investigación científica
Authors: García Vargas Oscar Humberto 
Published: February 2017

La Revista Clío América, desde su creación, ha venido trabajando en los temas relacionados con las disciplinas de investigación de las áreas temáticas de la revista, tales como en Economía, Negocios y Empresas, así mismo ha publicado artículos que han tenido trascendencia en las distintas comunidades científicas, esto lo podemos ver reflejado en las diferentes bases de datos a la cual pertenecemos actualmente en especial a Econlit y Emerging Sources Citation Index. Creando de esta forma un entorno apropiado para la conexión de pares y autores internacionales que al publicar y arrojar resultados en nuestra revista la robustecen para lograr una mayor proyección a nivel internacional y un h como indicador visible de investigaciones destacadas y reconocidas por la comunidad científica
DISPARITAS GENDER DALAM TINGKAT PENGEMBALIAN INVESTASI PENDIDIKAN DI JAWA BARAT
Authors: Megasari Diah Nurulia , Purnastuti Losina 
Published: February 2017

Abstrak: Disparitas Gender dalam Tingkat Pengembalian Investasi Pendidikan di Jawa Barat. Investasi yang dilakukan seseorang akan membawa sejumlah manfaat yang kembali pada dirinya sendiri maupun pada lingkungan sekitar. Kembalinya manfaat pada individu yang melakukan investasi pendidikan sering disebut juga tingkat pengembalian investasi pendidikan. Penelitian ini bertujuan untuk mengetahui seberapa besar tingkat pengembalian investasi pendidikan antara tenaga kerja laki-laki dan perempuan di Jawa Barat Tahun 2014. Model yang digunakan adalah model persamaan pendapatan Mincer. Penelitian ini menggunakan data dari SAKERNAS dan diolah menggunakan teknik analisis regresi linier berganda. Hasil penelitian menunjukkan bahwa tingkat pendidikan, potensi pengalaman kerja, potensi pengalaman kerja kuadrat dan jenis kelamin berpengaruh terhadap pendapatan. Semakin tinggi tingkat pendidikan maka tingkat pengembalian investasi pendidikan yang diterima pun semakin besar. Hasil chow test menunjukkan ada perbedaan tingkat pengembalian investasi pendidikan antara tenaga kerja laki-laki dan perempuan. Tenaga kerja perempuan menerima tingkat pengembalian investasi pendidikan lebih tinggi dibanding laki-laki, kecuali pada tingkat pendidikan Diploma. Kata kunci: Tingkat pengembalian investasi pendidikan, tenaga kerja, laki-laki, perempuan. Abstrak: Gender Disparity in Return to Education in West Java. The investment that one makes will yield a lot of benefits that will return to oneself or the surroundings. The return of the benefits to the individual who makes educational investment is called the return to education. This study aimed to find out the return to education between male and female workers in West Java in 2014. The model employed was the Mincer earnings model. The data in the study were the secondary data from SAKERNAS 2014 with 14,951 selected samples. The analysis technique was multiple regression analysis. The results of the study showed that the educational level, work experience potential, work experience potential squared, and gender affect earnings. The higher the educational level was, the higher return to education was. The results of the chow test showed that there was a difference in the return to education between male and female workers. The female workers had the higher return to education than the male workers, except for the diploma education level. Keywords: return to education, workers, males, females
PENGGUNAAN FACEBOOK OLEH INVESTOR
Authors: Sina Peter Garlans 
Published: February 2017

Abstrak: Penggunaan Facebook oleh Investor. Tujuan dari penelitian ini adalah memberikan bukti tambahan tentang dampak negatif dari penggunaan facebook sebagai jejaring sosial antara investor dalam membuat keputusan investasi serta bagaimana cara mereduksinya. Hasil menunjukkan bahwa penggunaan facebook mengarahkan pada pembentukan keyakinan yang keliru sehingga bertendensi membuat keputusan investasi yang bias. Pada bagian akhir penelitian ini, dijabarkan cara mereduksinya. Kata-Kata Kunci: investasi, jaringan sosial, facebook Abstract: Penggunaan Facebook oleh Investor. The purpose of this study is to give additional evidence of the negative impacts of the use of Facebook as a social networking between investors in making investment decisions and how to reduce it. The results showed that the use of Facebook leads to the formation of erroneous beliefs that tend to make bias investment decisions. At the end of the study, it was described how to reduce them. Keywords: investment, social network, facebook
Kivándorlás vagy maradás? A hűség szerepe az egyéni döntésekben
Authors: Golovics József 
Published: February 2017

A tanulmányban arra a kérdésre keresem a választ, hogy napjainkban az országok közötti jelentős fejlettségbeli különbségek és alacsony mobilitási költségek ellenére miért tartózkodnak mégis sokan a nemzetközi migrációtól. Álláspontom szerint ez a kivándorlás lelki aspektusaival magyarázható, amelyet újszerű módon nem a mobilitási költségek között tárgyalok, hanem a személyközi kapcsolatokban megjelenő altruizmusra vezetek vissza. Ennek segítségével azt mutatom be, hogy az így definiált hűség a korábban tárgyaltaknál fontosabb szerepet játszhat a migrációs döntésekben, s napjaink megváltozott környezetében ellenösztönzője lehet a kivándorlásnak.
Journal of Economic Literature (JEL) kódok: D01, D03, F22
Lixisenatide Therapy in Older Patients With Type 2 Diabetes Inadequately Controlled on Their Current Antidiabetic Treatment: The GetGoal-O Randomized Trial
Authors: Meneilly Graydon S. , Roy-Duval Christine , Alawi Hasan , Dailey George , Bellido Diego , Trescoli Carlos , Manrique Hurtado Helard , Guo Hailing , Pilorget Valerie , Perfetti Riccardo , Simpson Hamish ,   on behalf of the GetGoal-O Trial Investigators
Published: February 2017

OBJECTIVE
To evaluate the efficacy and safety of lixisenatide versus placebo on glycemic control in older patients with type 2 diabetes uncontrolled on their current antidiabetic treatment.

RESEARCH DESIGN AND METHODS
In this phase III, double-blind, randomized, placebo-controlled, two-arm, parallel-group, multicenter trial, patients aged ≥70 years were randomized to receive once-daily lixisenatide 20 μg or placebo before breakfast concomitantly with their existing antidiabetic therapy (including insulin) for 24 weeks. Patients at risk for malnutrition or with moderate to severe cognitive impairment were excluded. The primary end point was absolute change in HbA1c from baseline to week 24. Secondary end points included change from baseline to week 24 in 2-h postprandial plasma glucose (PPG) and body weight.

RESULTS
A total of 350 patients were randomized. HbA1c decreased substantially with lixisenatide (−0.57% [6.2 mmol/mol]) compared with placebo (+0.06% [0.7 mmol/mol]) from baseline to week 24 (P &lt; 0.0001). Mean reduction in 2-h PPG was significantly greater with lixisenatide (−5.12 mmol/L) than with placebo (−0.07 mmol/L; P &lt; 0.0001). A greater decrease in body weight was observed with lixisenatide (−1.47 kg) versus placebo (−0.16 kg; P &lt; 0.0001). The safety profile of lixisenatide in this older population, including rates of nausea and vomiting, was consistent with that observed in other lixisenatide studies. Hypoglycemia was reported in 17.6% of patients with lixisenatide versus 10.3% with placebo.

CONCLUSIONS
In nonfrail older patients uncontrolled on their current antidiabetic treatment, lixisenatide was superior to placebo in HbA1c reduction and in targeting postprandial hyperglycemia, with no unexpected safety findings.