bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nanoscale Free Gas Transport in Shale Rocks: A Hard-Sphere Based Model
Authors: Xu Jinze , Wu Keliu , Yang Sheng , Cao Jili , Chen Zhangxin 
Published: February 2017

Abstract
Shale gas is a very important energy resource for humans in the 21st century. However, the mechanism underlying the transoport behavior of shale gas in nanopores (typically 1 nm to 100 nm) remains a huge challenge in industries, as well as in research. In this study, we investigated the free gas transport in nanopores of shale rocks by using the real gas equation of state (EOS) and elastic hard-sphere (HS) model. Excellent results were obtained from the validation of the real gas model on the basis of molecular simulation and experimental data. This paper discusses the following: (1) the model efficiently and reasonably describes the known gas transport behavior in nanopores by establishing the relationship among real gas effect, molecular interactions and collisions, and gas transport behavior; (2) the use of real gas HS EOS considers repulsion, which reduces Knudsen diffusion and laminar slip flow conductance. In addition, packing fraction in EOS provides minimum boundaries for Knudsen number and flow regime; (3) the molecule-wall collision is mainly dominated by pore diameter, and the intermolecular collision is mainly dominated by pressure in nanopores. Under 10 MPa, the molecule-wall collision dominates in nanopores. Otherwise, the intermolecular collision dominates; (4) the laminar slip flow conductance increases with the corresponding increase in strength of intermolecular collision. With increased strength in the molecule-wall collision, Knudsen diffusion conductance increases, thereby improving the transport efficiency, as shown by apparent permeability.
An Evaluation of EOR Potential in the Elm Coulee Bakken Formation, Richland County, Montana
Authors: Todd Burt J. , Reichhardt David K. , Heath Leo A. 
Published: February 2017

Abstract
Low primary recovery percentages from unconventional reservoirs have long motivated interest in Enhanced Oil Recovery (EOR) for these reservoirs, resulting in numerous simulation studies and injection pilots. However, performance from injections pilots has typically been disappointing compared to the simulations, suggesting that reservoir permeability and heterogeneity are not adequately described in the reservoir simulation models.
In this study, a simulation and history-matching approach was used to quantify the permeability matrix over a six-section, nine-well area. Twelve years of production data were history-matched, using a combination of pressure-dependent permeability and enhanced permeability to represent natural fractures or other high-permeability features. Also, the performance of a failed injection pilot was history-matched to determine the level of reservoir heterogeneity needed to explain the pilot failure.
Based on this study, a reservoir description capable of matching twelve years of production and injection history has been developed. Formation properties in the high-permeability streaks capable of causing the disappointing injection pilot performance have been quantified. Recovery has been forecast to depletion, and EOR under hydrocarbon gas injection has been forecast for a variety of scenarios. Optimal operating strategies and recommendations for technology development to mitigate early breakthrough are made. Realistic cost estimates were made for each scenario, and economics were run for each recovery method. These results give insight into the economic potential of enhanced oil recovery in the Elm Coulee Bakken formation. Recommendations for favorable tax treatment and scheduling of expenses/investments are made.
Developing the permeability matrix using the history matching approach is a novel and versatile way of quantifying unconventional reservoir properties. However, it is important to match both injection and production data, since the permeability vector appears to have pressure-dependent effects. The effect of controlling injection thief zones by controlling local wellbore outflow is quantified, and a need for in situ permeability modification of fracture thief zones has been determined.
Improved Oil Recovery in Tight Oil Formations: Results of Water Injection Operations and Gas Injection Sensitivities in the Bakken Formation of Southeast Saskatchewan
Authors: Ghaderi S. M. , Clarkson C. R. , Ghanizadeh A. , Barry K. , Fiorentino R. 
Published: February 2017

Abstract
Conventional oil production has occurred from the Bakken Formation in Saskatchewan since the mid-1950s. However, with successful implementation of multi-fractured horizontal well (MFHW) technology, the low-permeability (unconventional) Bakken has experienced ever increasing E&P activity on both sides of the US/Canada border. Prior to 2005, the Bakken in Saskatchewan had less than 100 active producers in the region but has increased to more than 2,500 producing wells since then (Sekar, 2015).
Although improvement in hydraulic fracture properties and infill drilling remain the focus of recovery enhancement from the Bakken, low oil recoveries and steep initial oil decline rates are experienced using primary recovery operations, even after application of MFHW technology. Therefore, many pilots have been executed to determine the viability of waterflooding for maintaining oil rates and improving recoveries through reservoir pressure maintenance and sweep efficiency enhancement.
This paper presents the performance results from one of the waterflood pilots in the Viewfield Bakken. MFHWs were used as both injectors and producers for this pilot. Five years of production/injection volumes for these wells, along with pressure data, were matched using a black-oil simulator. The calibrated model was then used to predict the long-term performance of the pilot. Finally, this model was used for further investigation of parameters affecting the performance of the waterflood operation along with assessment of EOR (gas injection) schemes applicable to the Bakken Formation.
Two important conclusions can be derived from this study: 1) waterflooding can be effective in tight oil reservoirs using MFHWs as injectors and producers and, 2) careful characterization of vertical changes in reservoir quality using laboratory-based measurements are important for improving the quality of the history match and resulting forecast scenarios. For 2), permeability heterogeneity was quantified using profile permeability measurements corrected to ‘in-situ’ stress conditions.
Evaluation of Downhole Multi-Cycle Sleeve Technology for Re-Frac Completions in Southwest Manitoba
Authors: Swain Curtis , Kozelj Chris , McArthur Kevin , MacArthur Nils , Stadnyk Shawn , Powell Jesse 
Published: February 2017

Abstract
A new down hole multi-cycle sleeve completion system that was run in a well allowed the operator to re-frac all previously stimulated zones along the horizontal section of a wellbore with relative ease. The technology utilizes sleeves that can be closed and opened for the life of the well and re-defines the way re-frac completions can be done. Risks are significantly reduced and efficiencies improved compared to other re-completion techniques
Coiled tubing (CT) equipped with a resettable frac plug bottom hole assembly (BHA) was deployed in a well that was originally fractured from the toe interval back to the heel. Unlike conventional completion systems where the frac sleeves are left open after each stage, these particular sleeves were closed immediately after each frac was complete. Once all the stages were stimulated, CT was then moved back down the well to re-open all the sleeves from the toe to the heel and allow the well to produce. This method is described as the Shift-Frac Close (SFC) sequence and is discussed in more detail in the paper. Both the original and re-completion were done in this nature. Well details along with original and re-frac designs will also be discussed in the paper
The subject well consisted of 25 stages along the HZ section. The original completion from start to finish took ~ 56 hours to complete where each interval was fractured successfully with fairly small tonnages and low rates. After poor production results the operator decided to re-frac all intervals with a more aggressive frac design placing more sand in each interval at faster rates and higher bottom hole sand concentrations. It was estimated that the re-frac completion took ~38 operating hours. This represents significant improvement when compared to other systems where trying to re-complete a well may require drilling out ball seats, re-perforating and/or using risky isolation or diversion techniques. In addition, being able to close the sleeves after each frac has shown added benefits in the prevention of proppant flow back. This was noted in both the original stimulation and re-completion performed on this particular well that in turn saved money in potential sand cleanouts and possibly eliminated the use for resin coated sands.
The paper documents this first ever application of executing re-fracs through re-closeable sleeves, and discusses the importance of sleeve reliability and longevity. Having the flexibility with this completion system also allows customers the option to frac intervals out of sequence, which has been hypothesized to reduce effective fracture spacing and effectively tap into a natural fractured network (Sharma et al 2013).
Comparison of PKN, KGD, Pseudo3D, and Diffusivity Models for Hydraulic Fracturing of the Horn River Basin Shale Gas Formations Using Microseismic Data
Authors: Yousefzadeh Abdolnaser , Li Qi , Virues Claudio , Aguilera Roberto 
Published: February 2017

Abstract
We present a comparison of three different hydraulic fracture models as well as an anisotropic diffusivity model with the observed microseismic data from shale gas reservoirs in the Horn River Basin of Canada. We investigated the validity of these models in the prediction of hydraulic fracture geometries using tempo-spatial extension of microseismic data. In the study area, ten horizontal wells were drilled and hydraulically fractured in multiple stages in the Muskwa, Otter Park, and Evie shale gas formations in 2013. The treatments were monitored by downhole microseismic measurements.
We integrated microseismic analyses, geomechanical information extracted from well logs, and fracturing treatment parameters performed in the area. We compared fracture geometry predicted by Perkins-Kern-Nordgren (PKN), Khristianovic-Geertsma-de Klerk (KGD), and a Pseudo-3D (P3D) fracturing models as well as an anisotropic diffusivity model with actual fracture geometries derived from microseismic records in more than one hundred fracturing stages.
For the study area, we find that there are no barriers to hydraulic fracture vertical growth between the Muskwa, Otter Park and Evie shales. Therefore, the fracture height to length ratio is higher than unity in many stages. Large fracturing heights suggest that the PKN model might be more suitable for fracture modeling than the KGD model. However, our analyses show that the fracture length predicted by the KGD model is closer to, but still far less than the fracture length illustrated by microseismic events. Pseudo 3D model also predicts fracture lengths which are slightly larger than the modeled fracture lengths by the KGD and PKN equations and still significantly smaller than the microseismic fracture lengths.
These differences are observed throughout all stages suggesting that these methods are not able to perfectly predict the hydraulic fracturing behavior in the study wellpad. Vertical extension of microseismic data with linear patterns into the Keg River formation below the shale formations suggests the presence of natural fractures in the study area.
This study presents a distinctive insight into the complex hydraulic fracture modeling of shales in the Horn River basin and suggests that diffusivity mapping is a simple, but powerful tool for hydraulic fracture modeling in these formations. Observed microseismic fracture lengths are significantly higher than lengths predicted by the geomechanical models and closer to diffusivity models, which suggests the possibility of increasing well-spacing in future development using diffusivity equation for improving treatment design.
Suppression in the Bubble Points of Oils in Shales Combined Effect of Presence of Organic Matter and Confinement
Authors: Pathak Manas , Kweon Hyukmin , Panja Palash , Velasco Raul , Deo Milind D. 
Published: February 2017

Abstract
The shale plays have drastically increased production of oil and gas in the US and North America in general. In the past couple of years, there has been tremendous research on understanding the dynamics and phase behavior of fluids at the pore scale in shale rock. The change in bubble point of oils in liquid rich shale play because of the effect of confinement of oils in nano pores has caught attention of the researchers. Our prior research based on modeling and experiments show that kerogen interacts with the oil that leads to changes in bubble point of oils. There has not been any experimental work to account for the presence of kerogen (organic matter) in vapor-liquid equilibrium calculation. Experiments have been performed in this work that show the combined effect of kerogen presence and confinement on oil bubble point.
In the current work, kerogen is isolated from a shale sample by series of acid treatments. The shale rock sample was collected from a prolific US shale play. The isolated kerogen is nano porous and was swelled with light sweet Wyoming crude oil. Differential Scanning Calorimetry is used to measure the changes in bubble point of oil in kerogen. The work, thus accounts for the effect of oil confinement and kerogen-oil interactions on the pressure-volume-temperature (PVT) properties of oil. Results show that the bubble point temperatures are suppressed in the nano pores and in the vicinity of kerogen. The changes in the bubble point of oils in shales affect properties like produced gas-oil ratio, volumes and rates of recovery of petroleum reserves.
A Computational Fluid Dynamics Study of Proppant Placement in Hydraulic Fracture Networks
Authors: Kong Xianhui , McAndrew James 
Published: February 2017

Abstract
This study aims to study the driving mechanism of proppant transport from wellbore to hydraulic fracture networks (HFN) by fracturing fluid, using computational fluid dynamics (CFD). We simulated multiphase slurry flow containing proppant based on the Euler-Euler multiphase flow model. Foam rheology was modeled using non-Newtonian power-law model in simulation. We investigated the propping performance of different fluid and proppant for various types of fracture network, such as T- shaped and cross-shaped. Sensitivity studies show that the fracture width, fluid viscosity, and sand load has the most significant impact on final proppant placement in the fracture networks. The sand particle size and density are secondary factors in the distribution of proppant in fracture networks. The fracture network shape (i.e. factors such as bends and angles) does not impact proppant movement to an appreciable extent. We also confirmed the benefit of using high proppant load on proppant placement.
EXPLICANDO O DISSENSO: UMA ANÁLISE EMPÍRICA DO COMPORTAMENTO JUDICIAL DO SUPREMO TRIBUNAL FEDERAL E DA SUPREMA CORTE DOS ESTADOS UNIDOS
Authors: Almeida Guilherme da Franca Couto Fernandes de , Nunes José Luiz , Chaves Filho Luciano de Oliveira 
Published: February 2017

EXTRAÇÃOProf. Dr. Carlos Bolonha, Editor-Chefe A equipe editorial da revista comunica a extração do artigo:ALMEIDA, G. F. C. F.; NUNES, J. L.; FILHO, L. O. C. Explicando o dissensso: uma análise empírica do comportamento judicial do Supremo Tribunal Federal e da Suprema Corte dos Estados Unidos. REI-REVISTA ESTUDOS INSTITUCIONAIS, v. 2, n. 2, p. 899-931, 2016.O artigo foi extraído a pedido dos autores devido a um erro material com relação aos dados. As análises veiculadas dependiam de uma pressuposição falsa a respeito da amostra e, portanto, não refletiam de maneira precisa a realidade. Muito embora a correção do erro tenha confirmado as conclusões do artigo, os números mudaram, de forma que as informações publicadas estavam erradas.Para mais informações acesse o endereço <http://bit.ly/2I9b50m>
Keterlaksanaan penilaian autentik mata pelajaran fisika SMA negeri
Authors: Rukmana Tutut , Mundilarto Mundilarto 
Published: February 2017

Penelitian ini bertujuan untuk: (1) mendeskripsikan keterlaksanaan penilaian autentik pada mata pelajaran fisika SMA Negeri di Kabupaten Sleman Daerah Istimewa Yogyakarta (DIY), (2) meng-identifikasi kendala keterlaksanaan penilaian autentik pada mata pelajaran fisika SMA Negeri di Kabupaten Sleman Daerah Istimewa Yogyakarta, dan (3) mendeskripsikan hubungan kebijakan kepala sekolah dan pelatihan yang telah diterima pendidik terhadap keterlaksanaan penilaian autentik. Teknik pengumpulan data penelitian ini terdiri atas: angket, observasi, dan wawancara terhadap kepala sekolah, pendidik, dan peserta didik. Validitas instrumen penelitian diperoleh melalui expert judgments oleh dosen ahli. Hasil penelitian ini adalah sebagai berikut. (1) Keterlaksanaan penilaian autentik mata pelajaran SMA Negeri di Kabupaten Sleman Daerah Istimewa Yogyakarta kategori baik. (2) Kendala keterlaksanaan penilaian autentik mata pelajaran fisika SMA Negeri di Kabupaten Sleman Daerah Istimewa Yogyakarta meliputi jenis materi, waktu, kondisi sekolah, dan kemampuan pendidik yang dipengaruhi oleh beban kerja pendidik. (3) Hubungan kebijakan kepala sekolah terhadap keterlaksanaan penilaian autentik kategori kuat, dan tidak terdapat hubungan antara pelatihan yang telah diterima pendidik dan keterlaksanaan penilaian autentik.Kata Kunci: keterlaksanaan, mata pelajaran fisika, penilaian autentik The Feasibility of Authentic Assessment on Physics Subject at State Senior High Schools AbstractThis research aims to: (1) describe the feasibility of authentic assessment on physics subject at state senior high schools in Sleman regency Daerah Istimewa Yogyakarta (DIY), (2) identify the obstacles of the feasibility of authentic assessment on physics subject at state senior high schools in Sleman regency Daerah Istimewa Yogyakarta, and (3) describe the correlation between the headmaster’s policy and teacher training to feasibility of authentic assessment. The data were collected through: questionnaire, observation, and interview with headmasters, teachers, and students. The validity of research instrument was measured by expert judgements. The results of this study are as follow. (1) The feasibility of authentic assessment on physics subject at state senior high schools in Sleman regency Daerah Istimewa Yogyakarta is in good category. (2) The obstacles of the feasibility of authentic assessment on physics subject at state senior high schools in Sleman regency Daerah Istimewa Yogyakarta include materials, time, school condition, and teacher’s ability which is affected by workload. (3) The correlation between headmaster’s policy and feasibility authentic assessment is in strong category, and there is no relationship between teacher training and authentic assessment implementation.Keywords: authentic assessment, feasibility, physics subject
Взаємозв’язок між гіпотиреозом та ожирінням
Authors: Yuzvenko Т.Y. 
Published: February 2017

У зв’язку зі значною поширеністю як ожиріння, так і гіпотиреозу лікарям слід бути особливо уважними до можливої дисфункції щитоподібної залози (ЩЗ) у пацієнтів з ожирінням. Існує двобічний зв’язок між гормонами ЩЗ і ожирінням: як гіпотиреоз може впливати на масу тіла, так і жирова тканина мoже змінювати рівень гормонів ЩЗ. Рівні тиреотропного гормона і вільного трийодтироніну при ожирінні часто підвищені, що опосередкується впливом лептину. При лікуванні гіпотиреозу препаратами левотироксину незначне зниження маси тіла зумовлюється втратою води, а не жиру. Селективні аналоги тиреоїдних гормонів, можливо, зможуть стати засобом для зниження маси тіла шляхом збільшення витрати енергії у пацієнтів з ожирінням при дотриманні гіпокалорійного харчування.
Стан мінеральної щільності кісток у постменопаузальних жінок різного віку, хворих на цукровий діабет 2-го типу
Authors: Kyryliuk M.L. , Atanova Ya.O. , Dohotar V.B. 
Published: February 2017

Актуальність. Актуальні сть порушення мінеральної щільності кісткової тканини (МЩКТ) у пост­менопаузальних жінок обумовлена високим ризиком виникнення остеопоротичних переломів, особливо на тлі коморбідної патології. Мета дослідження: оцінка впливу цукрового діабету (ЦД) 2-го типу на стан мінеральної щільності кісток у жінок різного віку в постменопаузальному періоді залежно від тривалості ЦД та виду цукрознижувальної терапії. Матеріали і методи. Мінеральну щільність кісток було досліджено у 38 постменопаузальних пацієнток із ЦД 2-го типу (середній вік — 64,36 ± 1,95 року, середня тривалість ЦД — 10,68 ± 1,88 року, середній рівень глікованого гемоглобіну — 9,02 ± 0,29 %). Для оцінки стану МЩКТ використовували двохенергетичну рентгенівську абсорбціометрію (Dual-energy X-ray Absorbtiometry — DXA). Мінеральну щільність кісток оцінювали за допомогою Т-критерію. Результати. Показано, що з віком у постменопаузальних жінок без діабету МЩКТ, що оцінюється за Т-критерієм, закономірно зменшується в усіх зонах дослідження. Так, Т-критерій на рівні поперекового відділу хребта (L1–L4) у жінок 50–59 років становив –0,24 ± –0,02, що відповідає остеопенії. У жінок 60–69 років Т-критерій — –2,20 ± –0,22, що відповідає остеопорозу. Виявлено, що вікові зміни середніх значень Т-критерію за ЦД 2-го типу менш негативні, ніж у групі контролю, проте порівняно з контролем гірші показники денситометричної щільності кісток лише на рівні L1–L4 у віці ≤ 60 років — –0,71 ± –0,09 vs –0,24 ± –0,02 (P < 0,001). Висновки. З віком у постменопаузальних жінок із ЦД 2-го типу та без діабету МЩКТ, що оцінюється за Т-критерієм, зменшується в усіх зонах дослідження. Виявлено, що у постменопаузальних жінок, хворих на ЦД 2-го типу, гірші показники денситометричної щільності кісток (за Т-критерієм) на рівні L1–L4 у віці ≤ 60 років. При збільшенні тривалості ЦД 2-го типу понад 10 років зменшується денситометрична щільність шийки стегнової кістки, а в поперековому відділі хребта зміни МЩКТ за Т-критерієм мають протилежний характер. Інсулінотерапія не призводить до поліпшення МЩКТ стегнових кісткок за Т-критерієм, але позитивний ефект інсулінотерапії на МЩКТ поширюється на поперековий відділ хребта.