bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of the Analysis on the Characteristics of Learning Style of the Students of the Vocational Education of Building Construction Study Program, Faculty of Engineering, Jakarta State University
Authors: Sri Handoyo S , Iriani T , Septiandini E
Published: March 2019

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Bugih Cloth As Traditional Hermeneutics in Minangkabau
Authors: Prabawati M , Wesnina W , Haryono M
Published: March 2019

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Development of Electronic Learning Design 3 Vocational Education Program in Electronics Engineering Jakarta State University
Authors: Setyowati A
Published: March 2019

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Effect of Competence Teacher and Student Learning Environment Program on Student Achievement Light Vehicle Engineering
Authors: Rudy Prihantoro C , Wafirul Hadi M , Amilia Avianti R
Published: March 2019

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The Effect of Transformational Leadership and Organizational Commitment to Organizational Citizenship Behavior (Ocb) in Building Construction Companies
Authors: Purnomo A , Hadi W
Published: March 2019

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Microstructure and Mechanical Properties Analysis of Quenched and Tempered AISI 4340 Steel
Authors: Basori I , Surocaena A , Titik Dwiyati S , Sari Y , Singh B
Published: March 2019

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”ASICT” Learning Model in Vocational Education in 3T AREA’S
Authors: Nurhidayat D , Dudung A
Published: March 2019

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Study of Urban Drainage Network Performance in Maximum Discharge Storage in the City of Bandung
Authors: Yusuf R
Published: March 2019

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Implementation of Integrated Quality in the Manado State Politechnic Tourism Department
Authors: D Polii B , Tangian D , Kumaat H
Published: March 2019

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医药合成过程DCS自动化控制系统设计
Authors: 洪金 杨
Published: March 2019

随着我国加入WTO后，国民经济得到了飞快的发展，广大民众对身体健康这块提出了更高的要求。对药品的要求也越来越严格，那么这就对医药工业的生产提出了更为苛刻的要求。同时加入WTO后，我国医药工业的生产也要求符合国际规范，如美国FDA等。为了达到这些要求和标准，改进我们国家以前医药生产中存在的一些落后现象，就势必需要去在医药工业中推广应用现代化的控制系统，使得控制更为精确，更有追述性。那么作为现代工业自动化控制系统的代表产品，DCS控制系统就在医药工业生产中得到了更为广泛的应用。

本文根据某医药公司合成车间的工艺要求，采用和利时公司的KM控制系统，以及和利时公司MACS6.53版本软件,设计了友好的监控画面。从而工艺参数得到了很好的控制
In the Shadow of Ghadar: Marxism and Anti-Colonialism in Colonial Punjab
Authors: Jan Ammar Ali
Published: March 2019

The Ghadr Party, an eclectic group of diasporic Punjabis, was perhaps one of the most significant political movements led by emigre Indians in the early twentieth century. Designated as one of the biggest threats to colonial rule in the 1910s, the Ghadr Party spread its operations over five continents, and repeatedly committed acts of sabotage aimed at colonial officials from India. By the 1920s, however, the birth of popular movements in India marginalized various groups that believed in the spectacular actions of a vanguard as a strategy for overcoming the stifling impact of colonial rule. Members of the party, eager to find a foothold in the changed political scenario, opened discussions for building a popular front in Punjab, with many returning to the country to participate in such an endeavour. In this article, I study the encounter between the Ghadarite tradition and the communist movement in colonial Punjab through the writings of Sohan Singh Josh, who attempted to bring these two traditions together to produce a viable political project. I argue that Ghadar's encounter with Marxism not only influenced the former, but also radically transformed Marxism itself, particularly on questions of History, violence and volition.
The Madness of Jodh Singh: Patriotism and Paranoia in the Ghadar Archives
Authors: Chopra Rohit
Published: March 2019

My paper focuses on Jodh Singh, a marginal figure in the archives of the Ghadar Party, who was arrested for High Treason against the United States for his role in the “Hindu Conspiracy” plots aimed at the British government of India. Incarcerated in a California prison, Singh was moved to a sanatarium on displaying symptoms of insanity. Through a close reading of a web of archival documents and scholarly reflections—at the center of which lies the report of a commission appointed to inquire into his mental condition—I examine the account of the madness of Jodh Singh as a statement about patriotism and paranoia. In engagement with the work of Foucault, Guha, and scholars of the Ghadar movement, I describe how the record of Singh’s experiences indicts the juridical-legal-medical framework of American society as operating on a distinction between legtimate and illegitimate madness. I also examine how Jodh Singh points to the glimmers of a critique of the self-image of the Ghadar Party as a revolutionary movement committed to egalitarian principles. I conclude with a reflection on what Jodh Singh might tell us about the relationship between madness, political aspiration, and the yearning for solidarity.
DECOLONIZING GHADAR
Authors: Dhami Mandavni
Published: March 2019

This paper confronts the unspoken/unwritten patriarchal and settler colonial roots of Ghadar and its history through Toni Morrison’s ([1987] 2008) method of using imagination to construct re-memories of the truths that dominant histories erase.  To do this, this paper draws on feminist critiques of the state, the private/public divide, the individual/citizen, and manhood/masculinities (Bederman [1995] 2006; Kaplan [2002] 2006; Pateman [1983] 2006; Pettman [1996] 2006) and thereby genders Radha D’Souza’s discussion of the colonial/imperial disconnecting of people from places (2014, 63).  Focussing on the Punjabi context, this paper takes up Ghadarites’ employment of the private/public divide, their manipulation of patriarchal power, their appropriation of women’s bodies/voices, and their participation in “logic[s] of genocide” (Smith 2011, 51)  as means of claiming access to citizen/political rights. Ultimately, it is argued that Ghadar was a movement for access to manhood power, whiteness and settler coloniality.
Workers and militant labour activists from Punjab in Bengal (1921-1934)
Authors: Chattopadhyay Suchetana
Published: March 2019

Sikh migrants joined post-war strike-waves, formed unions and turned left in the 1920s and early 1930s in and around Calcutta, in the South Bengal region under British rule. To them, an unofficial commemoration of Komagata Maru’s voyage and the militancy associated with the Ghadar movement during First World War, became inseparable from contemporary resistance to the domination of colonial capital and British colonial state in India. They engaged with, worked upon and simultaneously moved beyond the boundaries of ethno-linguistic and religious identities as well as the social content of anti-colonial nationalism by focusing on a self-aware identity based on organised class action. This understanding was linked with the lived experiences of migration and imperial exploitation, the components of identity that had come to the forefront during the war. The diasporic identity of the Sikh migrant workers converged with the wider labour movement and was politically reshaped in the post-war context as livelihood issues took on the form of systematic protests in the city and beyond.
The effect of hemodialysis on glycemic variability
Authors: Pruś Grzegorz , Firlej-Pruś Magdalena , Śnit Mirosław
Published: March 2019

Stały wzrost zapadalności na cukrzycę typu 2, będącą główną przyczyną schyłkowej niewydolności nerek u chorych hemodializowanych, stał się przedmiotem wielokierunkowych badań. Wiele uwagi poświęcono wpływowi hemodializy na wahania glikemii w trakcie zabiegu hemodializy oraz w okresach między zabiegami, jak również na różnice między zmiennością glikemii u chorych z rozpoznaną cukrzycą oraz bez tego schorzenia.
Dużą grupę stanowią badania dotyczące metod monitorowania poziomu glikemii oraz przydatności poszczególnych biomarkerów. Wyniki badań jednoznacznie wykazują istotny oraz odmienny wpływ hemodializy na zmienność glikemii u osób z cukrzycą oraz bez tego schorzenia. Wykazano również, że z uwagi na liczne czynniki interferujące przydatność HbA1c do monitorowania poziomu glikemii u chorych hemodializowanych jest mniejsza niż u osób niehemodializowanych, nadal jednak pozostaje ona głównym biomarkerem służącym do monitorowania poziomu glikemii.
Przedmiotem badań stały się również metody leczenia cukrzycy u chorych hemodializowanych, zalecenia dietetyczne oraz próba opracowania standardów opieki nad tymi chorymi. Wyniki pojedynczych badań nad otyłością i zaleceniami dietetycznymi różnią się od pozostałych, sugerując korzystny wpływ na jakość życia chorych, przebieg niewydolności nerek oraz sam zabieg hemodializy. Wyniki te nie zostały dotychczas potwierdzone.
VALIDACIJA SRPSKE ADAPTACIJE SKALE REAKCIJA NA ISPITIVANJE
Authors: Avramović Miša
Published: March 2019

Ciljevi ovog istraživanja bili su usmereni ka proveri faktorske strukture i proceni nekih metrijskih karakteristika srpske adaptacije Skale reakcija na ispitivanje. Pored toga, kreirana je i skraćena verzija skale, sa idejom da se na taj način popravi loš fit originalne verzije instrumenta, kao i da se skala učini ekonomičnijom za zadavanje. Uzorak istraživanja činilo je 300 prigodno odabranih studenata, prosečne starosti 22.73 godina. U konfirmatornoj faktorskoj analizi testiran je fit dva modela. Prvi je imao korelirane faktore prvog reda, dok je u drugi model uveden faktor drugog reda. Puna verzija skale imala je loš fit. Međutim, skraćena verzija skale (od po 5 ajtema u svakoj subskali) imala je odličan fit prvog modela (CFI = .96; RMSEA = .048) i neznatno slabiji fit drugog modela (CFI = .95; RMSEA = .055). Skraćena verzija skale sačuvala je zadovoljavajuće koeficijente interne konzistencije (.78 do .91 za subskale i .92 za celu skalu). Skraćena verzija skale pokazala je visoku konvergentnu validnost, kroz visoke korelacije sa Inventarom ispitne anksioznosti. Kao takva, skaćena verzija skale ima svoju upotrebnu vrednost, kako u istraživačkom tako i u obrazovnom kontekstu.
“Zimniaya Vishnia” and the “Yadrovo” landfill as two sides of the same coin: difficulties in comprehending the obvious
Authors: Nikitina Bela A.
Published: March 2019

Russia was affected by a waste management crisis at a later point than developed countries, due to the fact that during Soviet times everyday consumption was limited by a shortage of goods. After our country made the transition to capitalism, especially during the years of abundance, Russia’s population strived towards compensating the deprivation of the past by actively consuming goods with no regard for the affects on the environment. The reason for such behavior lies in the population’s peculiar system of values, defined by our country’s history. Meanwhile the government had been completely ignoring the need for developing a waste management system which would suit the people’s new lifestyle. It is quite obvious that such a crisis was imminent. However, its nature came as a surprise to government and municipal management. Due to this fact, the decisions they make are very much flawed, and they do not contribute to stability in our society, but rather postpone the resolution of the issue in question. Actual change to the situation lies not at the end of a product’s life cycle, but rather at its beginning. Which is why the experience of European nations must be taken into consideration, where they actively implement circular (cyclical) economy principles into social and economic activity. This means that goods can not only be purchased, but also repaired, reused, modernized, passed on or resold etc. In order to implement such actions, there is a need for specific infrastructure, with the internet being a key component of such. We are already witnessing the spontaneous advancement of sharing platforms, where people swap goods or give them away for free, but this is not enough. Similarly to centers of overconsumption such as the “Zimnyaya Vishnya” shopping mall, dispersed prosumerism platforms need to appear, where people would engage in the various stages of reproducing goods for personal or public use. Such public spaces would allow for developing activities which consolidate local communities and family groups, and which eliminate consumers’ detachment from produced goods by means of developing an understanding of their content and their reproduction life cycle. One of the conditions or manifestations of transforming society’s lifestyle would be a shift in city infrastructure, away from widespread centralized consumption. This would decrease the environmental and technological risks, as well as increase the population’s living standards.
Patriotism as a component of public consciousness: a generational measurement perspective
Authors: Ivchenkov Sergey G. , Sayganova Elena V.
Published: March 2019

Following the results of a sociological study conducted in 2018 by means of questionnaire method with a probability quota sample (N=420), this article analyzes the various interpretations of patriotism according to public opinion in the city of Saratov. It has been established that, according to its inhabitants, the word “Homeland” most often implies Russia, “small homeland” – one’s own city or family (less often one’s home neighborhood). The meaningful interpretation of this term is associated with socially significant activity, activism, and social responsibility. Basic displays of patriotism, according to respondents, are considered to be army service, patriotic upbringing of one’s children, abidance to the law and diligent work for society’s benefit. Most of Saratov’s inhabitants consider themselves to be patriots to one degree or another. However, what’s concerning is the fact that one out of every three city residents – especially among youths – denies such values. Youth patriotism is more oriented towards love for Russia. The elder generation builds its patriotic sentiments around love for their families, close ones, their home town and the USSR. Meanwhile most citizens (albeit to various degrees) draw a distinction between the terms “patriotism” and “nationalism”. The latter bears more of a negative connotation. Generally citizens (especially among the elder generation) believe that, after the USSR’s downfall, the teaching of patriotic values has “degenerated”, despite the government and the president taking certain steps towards increasing the level of patriotism within society. It is during such periods of change, like we are witnessing today, when the values of preceding generations start to contradict reality, and when the younger generation assumes the role of bearer of new knowledge and aspirations, due to possessing a more acute sense of society’s major issues and the will to openly speak out. Thereby not only the elder generation, but also the younger generation plays an equal role as a subject of developing society’s patriotic values. However, the profound differences between generations are proportional to the dynamics and scale of change within society, and the degree of mutual influence between generations acts as one of the major factors for stabilizing society, which includes establishing patriotic values. Increasing the efficiency of practices in this area, together with more extensive coverage of such practices in mass media and the internet, would aid in the development of historical and socio-cultural memory.
Advanced Maternal Age: Adverse Outcomes of Pregnancy, A Meta-Analysis
Authors: Pinheiro Rosa Lomelino , Areia Ana Luísa , Mota Pinto Anabela , Donato Helena
Published: March 2019

Introduction: The risks of pregnancy in women of advanced maternal age are not consensual amongst studies. The aim of this metaanalysis  was to determine whether women of advanced maternal age (≥ 35 years old) had worse obstetrical and perinatal outcomes than non- advanced maternal age women (20 - 34 years old) in singleton, naturally-conceived pregnancies.Material and Methods: We searched PubMed/ MEDLINE, IndexRMP and the Cochrane Database of Systematic Reviews. Ten studies were included according to the following criteria: population of > 1000 nulliparous and/or multiparous women with singleton gestations who did not undergo any type of infertility treatment. Using Review Manager v. 5.3, two meta-analysis were performed: one comparing the outcomes of 20 - 34-year-old vs 35 - 40-year-old women, and another comparing the outcomes of 35 - 40-year-old women vs > 40-year-old women.Results: Women aged 35 - 40 years old were more likely to have > 12 years of education than 20 - 34 years old and > 40 years old women. Advanced maternal age women (35 - 40 and > 40 years old) were more likely to be overweight and having gestational diabetes and gestational hypertension. They were also more likely to undergo induced labour and elective caesarean deliveries. Furthermore, they had worse perinatal outcomes such as preterm delivery, low birthweight babies, higher rates of Neonatal Intensive Care Unit admission and worse Apgar scores. Advanced maternal age women had higher rates of perinatal mortality and stillbirth.Discussion: Most authors present similar results to our study. Although the majority of adverse outcomes can be explained through the physio-pathological changes regarding the female reproductive apparatus that come with aging and its inherent comorbidities, according to the existing literature advanced maternal age can be an independent risk factor per se. In older pregnant women without comorbidities such as gestational hypertension or diabetes there are still worse obstetric and perinatal outcomes, which indicate that advanced maternal age is an independent strong risk factor alone.Conclusion: Advanced maternal age women are at a higher risk of adverse obstetrical and perinatal outcomes. In both comparisons, worse outcomes were more prevalent in the older group, suggesting that poorer outcomes are more prevalent with increasing age.
LC-MS/MS based targeted metabolomics method for analysis of serum and cerebrospinal fluid
Authors: Plewa Szymon , Dereziński Paweł , Florczak-Wyspiańska Jolanta , Popławska-Domaszewicz Karolina , Kozubski Wojciech , Sokół Bartosz , Jankowski Roman , Matysiak Jan , Kokot Zenon J.
Published: March 2019

Introduction. Recent instrumentation and software advancement enabled to develop new, high‑throughput targeted metabolomics methods for in‑depth exploration of metabolome in a quantitative manner.Material and Methods. The presented targeted metabolomics approach allows to analyze both of serum and CSF in the same way, with identical sample preparation procedures. The analyses were carried out using high‑performance liquid chromatography system coupled to triple quadrupole tandem mass spectrometer with electrospray ion source (LC‑ESI‑QqQ‑MS/MS). Results. The applied targeted metabolomics approach enabled to determine a wide panel of metabolites from different chemical classes of compounds including: acylcarnitines, amino acids and biogenic amines, glycerophospholipids, sphingolipids and sum of hexoses. Finally, 148 metabolites in serum and 57 in cerebrospinal fluid were determined.Conclusions. Here we presented the results of successful implementation of the method of analysis of low‑molecular weight compounds in human serum and CSF using targeted metabolomics. The evaluation of selected groups of metabolites resulted in obtaining the mean concentrations of panel of metabolites in serum and CSF, which gives a valuable information about the metabolome of these matrices.
An Analysis of Web Coverage on the 2018 West Japan Heavy Rain Disaster
Authors: Sato Shosuke ,   International Research Institute of Disaster Science (IRIDeS), Tohoku University 468-1 Aoba Aramaki, Aoba-ku, Sendai, Miyagi 980-0845, Japan, Imamura Fumihiko
Published: March 2019

This study analyzed quantitative big data from web news on the West Japan Heavy Rain disaster for a two-month period. The retrieved information was compared with previous natural disaster coverage. The results indicated the following. 1) For natural disasters that had occurred over the past 15 years, the “half-life period for media exposure” (i.e., the period in which the amount of news reporting halves) was approximately one week, while the half-life period of web media exposure on the West Japan Heavy Rain disaster was 24 days. Thus, the West Japan Heavy Rain disaster appeared to be the most significant social concern since the Great East Japan Earthquake. 2) The West Japan Heavy Rain disaster was large enough to affect both the Chugoku and Shikoku Districts, but the available human support was comparable to the extent of the human and material damages as well as the related amount of media coverage. No significant regional differences in the amount of media coverage or support were found.
Robust Fuzzy Timestep Selector for a Fully Implicit Reservoir Simulator
Authors: Crumpton Paul
Published: March 2019

The objective of this work is to avoid wasteful timestep cuts of the reservoir simulator by developing a timestep-selector that controls the linear and non-linear iterations as well as the physical quantities. Using a Fuzzy logic framework, a non-linear timestep selector has been developed that reduces run time, and increases robustness for challenging nonlinear simulations.

From a linear analysis standpoint a fully implicit reservoir simulator has no stability limit on the size the timestep. However, in practice the non-linearity prevents arbitrary timestep size being chosen. Without any theory to guide us the timestep choice it is left to heuristics, usually based on physical engineering constraints such as the previous time steps, maximum pressure and saturation changes. This can be very effective, but can lead to many timestep cuts, and sometimes lead to failure of the simulator. This is especially common for highly non-linear dual-porosity, dual-permeability reservoirs which are very common in the Middle East. Here a Fuzzy logic framework is used to construct a non-linear timestep selector which takes many inputs (linear and non-linear convergence data as well as pressure and saturation changes) and breaks down the complexity. Firstly fuzzification of the inputs into fuzzy sets (e.g. High medium and low) then applications of rules (e.g. if linear high then timestep is low) and de-fuzzification into a crisp timestep to be used for the next iteration. This process provides us with a powerful framework to construct various strategies for controlling the timestep. In contrast, traditional timestep controllers use crisp logic, this is difficult to blend multiple conflicting inputs to a timestep selector.

To demonstrate the effectiveness of this approach results are presented on a suite of cases, covering a wide range of models including compositional and dual-porosity cases. For some cases a dramatic 3x improvement is observed, however, what is more important, is on average the new timestep selector significantly improves performance, especially for the slow challenging cases; by reducing the time steps wasted due to timestep cuts. Perhaps what is most impressive is that the fuzzy controller did achieve the goals of the fuzzy rules to keep the non-linear and linear iterations under control, which had the benefit of reducing total failures of the simulator.

A fuzzy logic framework is applied to timestep selection of a fully implicit reservoir simulator. A combination of convergence data as well as physical quantities are used as inputs which has led to a robust and extendable timestep selector.
Von Neumann Stable, Implicit, High Order, Finite Volume WENO Schemes
Authors: Arbogast Todd , Huang Chieh-Sen , Zhao Xikai
Published: March 2019

Simulation of flow and transport in petroleum reservoirs involves solving coupled systems of advection diffusion-reaction equations with nonlinear flux functions, diffusion coefficients, and reactions/wells. It is important to develop numerical schemes that can approximate all three processes at once, and to high order, so that the physics can be well resolved. In this paper, we propose an approach based on high order, finite volume, implicit, Weighted Essentially NonOscillatory (iWENO) schemes. The resulting schemes are locally mass conservative and, being implicit, suited to systems of advection-diffusion reaction equations. Moreover, our approach gives unconditionally L-stable schemes for smooth solutions to the linear advection-diffusion-reaction equation in the sense of a von Neumann stability analysis. To illustrate our approach, we develop a third order iWENO scheme for the saturation equation of two-phase flow in porous media in two space dimensions. The keys to high order accuracy are to use WENO reconstruction in space (which handles shocks and steep fronts) combined with a two-stage Radau-IIA Runge-Kutta time integrator. The saturation is approximated by its averages over the mesh elements at the current time level and at two future time levels; therefore, the scheme uses two unknowns per grid block per variable, independent of the spatial dimension. This makes the scheme fairly computationally efficient, both because reconstructions make use of local information that can fit in cache memory, and because the global system has about as small a number of degrees of freedom as possible. The scheme is relatively simple to implement, high order accurate, maintains local mass conservation, applies to general computational meshes, and appears to be robust. Preliminary computational tests show the potential of the scheme to handle advection-diffusion-reaction processes on meshes of quadrilateral gridblocks, and to do so to high order accuracy using relatively long time steps. The new scheme can be viewed as a generalization of standard cell-centered finite volume (or finite difference) methods. It achieves high order in both space and time, and it incorporates WENO slope limiting.
A Compositional Model for Gas Injection IOR/EOR in Tight Oil Reservoirs Under Coupled Nanopore Confinement and Geomechanics Effects
Authors: Tian Ye , Xiong Yi , Wang Lei , Lei Zhengdong , Zhang Yuan , Yin Xiaolong , Wu Yu-Shu
Published: March 2019

Gas injection has become the top choice for IOR/EOR pilots in tight oil reservoirs because of its high injectivity. The effects of nanoconfinement and geomechanics are generally considered as non-negligible, but its coupled effects and resulting flow and displacement are still not well understood for gas injection. We hence present a general compositional model and simulator to investigate the complicated multiphase and multicomponent behaviors during gas injection in tight oil reservoirs.

This compositional model is able to account for vital physics in unconventional reservoirs, including nanopore confinement, molecular diffusion, rock-compaction, and non-Darcy flow. The MINC method is implemented to handle fractured media. The nanopore confinement effect is modeled by including capillarity in VLE calculations. The rock compaction effect is represented by solving the mean stress from a governing geomechanical equation which is fully coupled with the mass balance equations to ensure the numerical stability as well as a physically correct solution. The equations are discretized with integral finite difference method and then solved numerically by Newton's method.

The simulator is validated against a commercial compositional software (CMG-GEM) before it is applied to simulate gas injection. Huff-n-puff with dry gas in Eagle Ford is investigated. The simulation result shows that if the reservoir pressure is much higher than the bubble point pressure, the nanopore confinement effect will have a minimal impact on the recovery factor (RF) for both the depletion and the first few cycles of gas huff-n-puff. Geomechanics is found to be an influencing factor on RF but not always in a detrimental way, as enhanced rock compaction drive could offset the reduction of permeability in certain scenarios. Gas huff-n-puff would improve the RF of each component compared with the depletion. The heavy component would first have a higher recovery than the light component at the first few cycles of huff-n-puff, but its RF will be outpaced by the light component when the gas saturation in the matrix surpasses the critical gas saturation. Lastly, considering the nanopore confinement effects would slightly reduce the RF of the light component but increase the RF of the heavy component after huff-n-puff when combined with the critical gas saturation effect in the matrix.

This study presents a 3D multiphase, multicomponent simulator which is a practical tool for accurately modeling of primary depletion as well as gas injection IOR/EOR processes in unconventional oil reservoirs. This simulator is not only of great importance for assisting researchers to understand complex multiphase and multicomponent behaviors in tight oil production but also of great use for engineers to optimize gas injection parameters in field applications.
Continuous Relative Permeability Model for Compositional Reservoir Simulation, Using the True Critical Point and Accounting for Miscibility
Authors: Martin Petitfrère , Romain De Loubens , Leonardo Patacchini
Published: March 2019

Compositional simulators conventionally use Li's correlation to approximate the critical temperature (Tc) of hydrocarbon mixtures, used to arbitrarily label them as ‘gas’ or ‘oil’ outside the two-phase (gas/oil) envelope. Tc also feeds into the calculation of hydrocarbon-to-water relative permeabilities, typically interpolated between oil-to-water and gas-to-water based on the parameter Tc/T. This approach is clearly inconsistent when crossing the phase envelope in case of incorrect phase labeling.

We here propose to replace Li's correlation by a rigorous calculation of Tc using Michelsen's (1984)'s algorithm when phase identification is required. Using the gas-oil interfacial tension (IFT) within the phase envelope, and a fictitious gas-oil IFT computed at the saturation pressure (psat) outside the envelope, the hydrocarbon-to-water relative permeability is then built by interpolation between oil-to-water and gas-to-water relative permeabilities. The derivatives of psat (hence the IFT) with respect to the primary variables are computed analytically, to ensure robust fully implicit simulations.

In order to address the observation that gas/oil relative permeability curves tend to straight lines when approaching to the critical point, a second level of interpolation with respect to the IFT is applied within the phase envelope between miscible and immiscible three-phase models. Continuity is, by construction, guaranteed at any possible phase-state transition.

The proposed relative permeability model is first tested standalone (i.e., on a single cell) with different hydrocarbon mixtures, by analysis of the dependent parameter (true or fictitious IFT) and the relative permeabilities at different p-T conditions; in particular, continuity at each relevant interface of the p-T diagram is illustrated.

The model is secondly implemented in our In-House Research Reservoir Simulator (IHRRS), and tested on a synthetic 2D cross-section undergoing near-critical gas injection. We observe that with conventional models based on Li's correlation, discontinuities in the relative permeability model when crossing the phase envelope occur, as well as spurious phase flipping. No such unphysical behavior is observed with the proposed approach, while requiring the same input data.

There is of course a computational cost involved in properly calculating Tc, which is partly offset by the improved model convergence; because it is a cell-by-cell calculation, the overhead however scales down very well with parallelization.
Sequential Implicit Newton Method for Coupled Multi-Segment Wells
Authors: Li Jiawei , Wong Zhi Yang , Tomin Pavel , Tchelepi Hamdi
Published: March 2019

Accurate and robust well modeling is essential for performing reservoir simulations of practical interest. The Multi-Segment well (MSWell) model is able to describe the well topology and accurately represent the multiphase multicomponent flow and transport behavior in the wellbore. The fully coupled method (FC) has been developed and widely applied on coupled reservoir and MSWell modeling due to its unconditional stability and consistent implementation. A local well solver can be applied to provide a better nonlinear precondition for MSWell variables in order to accelerate the nonlinear convergence of the FC method.

However, solving the coupled MSWell and reservoir model in a fully implicit scheme can still present limitations on some practical applications. First, the well or surface facility solver can be separate from the existing reservoir simulator, making it challenging to employ the fully implicit method. Second, complex linear and nonlinear solvers need to be designed to pair the specific wells and reservoir models. These solvers have to account for the different flow characteristics and discretization domains between reservoir and MSWell. A sequential coupling scheme can become preferable in such situations.

Sequential fully Implicit method (SFI) splits the fully coupled reservoir and MSWell equations into two parts and solves them sequentially. In spite of accomplishing an implicit coupling in a sequential scheme, SFI suffers the slow outer loop convergence rate especially when reservoir is strongly coupled with the wells, which is very often the case. The slow convergence is caused by the linear convergence rate of the fix point iteration used in the SFI. Here, we developed a sequential implicit Newton's method (SIN) for coupled MSWells. SIN incorporates a Newton update at the end of each sequential step to achieve a quadratic convergence of outer iterations, while require a limited extra computational cost. Numerical results show that SIN attains comparable nonlinear Newton iterations with the FC in the coupled heterogeneous reservoir and complex MSWell problems.
Production Data Integration into Complex Geologic Facies Models: Exploiting the Behavior of Multiple-Point Statistical Simulation for Effective Data Conditioning
Authors: Ma Wei , Jafarpour Behnam
Published: March 2019

Multiple point statistical (MPS) simulation is a modern pattern-based geostatistical approach for describing and stochastically simulating geologic formations with complex connectivity patterns. In MPS geostatistical simulation, a template containing data patterns around each simulation cell is used to extract and store the local conditional probabilities from a training image (TI). To generate a simulated sample, a random path is generated to sequentially visit all unsampled grid cells and draw conditional samples from the corresponding stored conditional probabilities. The grid-based implementation of MPS simulation offers several advantages for integration of hard and soft data. In the Single Normal Equation SIMulation (SNESIM) implementation of MPS for facies simulation, it has been observed that the integration of soft data can result in many facies realizations that do not provide consistent patterns with the incorporated probability map. This is partly explained by the Markov property that only considers probabilities that are co-located with the simulation node, and hence ignoring spatial information from neighboring cells. In addition to this effect, we show another important mechanism is in play in the SNESIM algorithm that explains the observed behavior. Specifically, at the early stage of the simulation when the first few percentage of the simulation nodes on the random path are visited the local conditioning data are limited and the resulting conditional probabilities that are obtained from the TI are not strictly constrained. Hence the conditional probabilities cover a wide range of values in the range [0,1]. However, after this initial stage, as the simulated data populate more cells in the model grid, they tend to severely constrain the conditional probabilities to assume extreme values of 0 or 1. With these extreme values at the later stages of the simulation the probability values that are included in the soft data (as secondary source of information) tend to be disregarded and the facies types are predominantly determined by the TI. We demonstrate and discuss this behavior of the SNESIM algorithm through several examples and present strategies that can be adopted to compensate for this effect. The presented examples are related to indirect integration of the flow data by first inferring probabilistic information about facies types and using the results as soft data for integration into SNESIM algorithm.
Simulation of Radio Frequency Heating of Heavy Oil Reservoir Using Multi-Physics Coupling of Reservoir Simulation with Electromagnetic Solver
Authors: Li Gary , Guan Xiaoyue , Wang Hanming , Du Song , Wu Dagang , Chen Ji
Published: March 2019

Steam-Assisted Gravity Drainage (SAGD) is one of the popular methods for heavy oil production. The process is efficient and economical. However, it requires the use of large quantity of water and disposal of waste water can be costly. In addition, burning of natural gas for steam generation contributes to additional carbon dioxide generation, a known greenhouse gas, which is also undesirable. A method to heat up the in-situ oil without the use of injected water is highly desirable. Radio frequency (RF) heating of heavy oil reservoir is a potential method for oil recovery without steam injection. The evaluation of the potential of such method requires the coupling of a reservoir simulator with an electromagnetic (EM) simulator.

This paper describes the development and implementation of a flexible interface in a reservoir simulator that allows the runtime loading of third party software libraries with additional physics. Data is exchanged between the reservoir simulator and externally loaded software libraries through memory, therefore there is minimal communication overhead. The implementation allows for iterative coupling, explicit coupling and periodic coupling. This paper describes the mathematical coupling of the mass and energy conservation equations in the reservoir simulator with the Maxwell equations in an external library. The electromagnetic properties in the reservoir are highly dependent on temperature and water saturation, this dependence is accounted for in the coupled code using table look-up properties.

Canadian heavy oil and reservoir properties were used in our simulation investigation. We found that RF heating alone can be effective in heating up the in-situ water and reducing heavy oil viscosity by several orders of magnitude. As the in-situ water near wellbore was vaporized by RF heating, electrical conductivities were reduced to zero and thus allowed the EM wave to propagate further into the formation and heat up the water further away from the wellbore. With properly designed RF heating field pilots and tuning of EM and reservoir parameters, the coupled reservoir/EM simulator can be a powerful tool for the evaluation and optimization of RF heating operations.

The interface is sufficiently flexible to allow different types of multi-physics coupling. In addition to RF heating, it has also been used for reaction kinetics and geomechanics coupling with a reservoir simulator. It has been used for large scale coupled full field simulation with over 30 million cells.
Robust Optimization of ASP Flooding Under Oil Price Uncertainty
Authors: Li Heng , Dang Cuong , Mirzabozorg Arash , Yang Chaodong , Nghiem Long
Published: March 2019

This paper presents a novel workflow to optimize Alkaline, Surfactant, and Polymer (ASP) flooding under oil price uncertainty. ASP flooding is a relatively expensive recovery process and the optimization approach must be able to account for the change in oil price to provide realistic economical predictions. A workflow, combining time-event optimization with Robust Optimization has been developed and applied to the optimization of the NPV of the ASP process under uncertain time varying oil prices. Several forecasts of the future oil price from different energy organizations and financial institutions were used to account for the uncertainty of the oil price in the NPV calculations.

The proposed workflow introduces the parameterization of time-dependent events to identify the best time to start the ASP flooding project after the secondary water flooding, and to determine the size and composition of different chemical slugs. The Robust optimization workflow is compared to the Nominal Optimization workflow, which is carried out using the average oil price forecase to calculate NPV. Results show that Robust Optimization increases the project Net Present Value (NPV) by over 18% compared with Nominal Optimization. Robust Optimization generates optimal ASP design with desirable performance under different oil price forecast scenarios. In addition to ASP flooding, the Robust Optimization workflow can be efficiently applied to other recovery processes for both conventional and unconventional reservoirs.
Comparison of Higher Order Schemes on Complicated Meshes and Reservoirs
Authors: Kvashchuk Anna , Klöfkorn Robert , Sandve Tor Harald
Published: March 2019

Scope

Accurate numerical modeling of fluid transport is essential in reservoir management. Higher-order methods help to improve accuracy by reducing the numerical diffusion, which is common for all first order methods. In this paper, we present an implementation of a MUSCL-type second-order finite volume method and demonstrate its capabilities on 2D and 3D unstructured grids. This includes corner point grids that are typically used in reservoir modeling.

Methods, Procedures, Process

A second order finite volume method is compared to standard first order method in terms of accuracy, performance and an ability to handle nonlinearities. There are several ways to build a second order finite volume method. In this paper we choose an optimization-based strategy to compute the steepest possible linear reconstruction. At the same time, a steepness-limiting procedure is included in the optimization as constraint. This ensures that the steepest possible reconstruction that does not lead to oscillations is computed. As a result, sharper fronts compared to standard schemes are obtained.

Results, Observations, Conclusions

The paper demonstrates the described method on several benchmark cases with emphasis on relevant for practical reservoir simulation test cases. In particular, we use Norne field open data set, which enables cross validation with other implementations. We test the method on the transport case, where an analytical solution is known, to verify convergence behavior and to isolate the errors. Furthermore, the performance of first- and second-order methods is compared on multiphase flow problems typical for improved oil recovery: solvent and CO2 injection. The second order method shows superior performance in terms of accuracy.

Novel/Additive Information

This paper verifies the desirable properties of higher order method for reservoir simulation. Moreover, all the described implementations are available in an open source reservoir simulator Open Porous Media (OPM). As a result, these methods are accessible for reservoir engineers and can be used with industry standard modeling setups.
Accelerated Compositional Simulation of Tight Oil and Shale Gas Reservoirs Using Proxy Flash Calculation
Authors: Wang Shihao , Sobecki Nicolas , Ding Didier , Wu Yu-Shu , Zhu Lingchen
Published: March 2019

In this work, we present the development of a compositional simulator accelerated by proxy flash calculation. We aim to speed up the compositional modeling of unconventional formations by stochastic training.

We first developed a standalone vapor-liquid flash calculation module with the consideration of capillary pressure and shift of critical properties induced by confinement. We then developed a fully connected network with 3 hidden layers using Keras. The network is trained with Adam optimizer. 250,000 samples are used as training data, while 50,000 samples are used as testing data. Based on the trained network, we developed a forward modeling (prediction) module in a compositional simulator. Therefore, during the simulation run, the phase behavior of the multicomponent system within each grid block at each iteration is obtained by simple interpolation from the forward module.

Our standalone flash calculation module matches molecular simulation results well. The accuracy of the trained network is up to 97%. With the implementation of the proxy flash calculation module, the CPU time is reduced by more than 30%. In the compositional simulator, less than 2% of CPU time is spent in the proxy flash calculation.

The novelty of this work lies in two aspects. We have incorporated the impacts of both capillary pressure and shift of critical properties in the flash calculation, which matches molecular simulation results well. We developed a proxy flash calculation module and implemented it in a compositional simulator to replace the traditional flash calculation module, speeding the simulation by 30%.
A Framework for Incorporating Nanopores in Compositional Simulation to Model the Unusually High GOR Observed in Shale Reservoirs
Authors: Luo Sheng , Lutkenhaus Jodie , Nasrabadi Hadi
Published: March 2019

The fluid phase behavior in shale reservoirs differs from the conventional fluid phase behavior because of the nanopores in shale rock. In many shale oil reservoirs, the producing gas-oil ratio (GOR) is significantly higher than what would be produced from a bulk-state conventional reservoir. The phase behavior alteration in nanopores arises from the fluid-pore wall interaction within the nano-scale confining geometry. Recently, many approaches have been developed to thermodynamically model the fluid phase behavior in nanopores. An adequate and efficient method to incorporate the nano-confined phase behavior in engineering practice is highly desired.

In this work, we present a practical framework to incorporate the nanopores in compositional simulation for shale reservoirs. This approach enables engineers to incorporate the macro- to nano-scale phase equilibria from a pore-size-dependent equation of state into current compositional simulators, which use cubic equation of state. The procedures include bulk fluid characterization, simulation of multi-scale confined depletion by a pore-size-dependent equation of state, re-training the cubic equation of state, tuning relative permeability and applying in composition simulation. The simulation predicts higher GOR with nanopores, in agreement with the higher-than-normal GOR observed with shale oil wells, and the GOR fluctuations are found in association with various reservoir drainage areas. The simulated production behavior gives mechanistic insight into the effect of nano-confinement fluid behavior on shale reservoir depletions.