bluuebunny/crossref_metadata_2025 huggingface dataset:
Análisis De La Internacionalización De Una Universidad Pública Estatal A Través De La Movilidad Estudiantil
Authors: García Divad Dinorah García , Franco Fabiola de Jesús Mapén , Castro Jorge Alberto Rosas
Published: May 2017

Internationalization in higher education is a complex process derived from the new social, cultural, and economic dynamics that was generated in national and international context. It was conceived as a strategy to guarantee society with better job opportunities. It starts with the social relevance of the curriculum and the development of institutional programs that favors it. For Higher Education Institutions (IES) to enter into this dynamic process, Knight (1994) describes the integration of the international and intercultural dimensions in the teaching, research, and service functions of the institution. In this sense, the objective of the present investigation is to study the incursion of the Autonomous Juarez University of Tabasco (UJAT) based on the process of internationalization. This is done by analyzing the statistical information of the institutional program of the mobility of undergraduate students in period 2012-2016. The research approach is qualitative based on the documental analysis of the information contained in the Institutional Development Plans (IDP) 2012-2016 and 2016-2020, as well as in the annual reports of activities included in the study period. Statistics show that each year, the number of students increased with an increase of 69.6% when comparing the first year of the study with the year 2016. In order to determine the results of this study in absolute terms, the total enrollment of the UJAT in undergraduate degree in the years 2012 and 2016 was compared with the number of participating students, resulting in 0.17% and 0.53%, respectively.
Contrôle De L’inflation En Regime De Change Fixe: Le Cas De La Communaute Economique Et Monetaire d’Afrique Centrale (CEMAC)
Authors: Robert Tangakou Soh , Arsѐne Mba Fokwa , Johnson Akanga Reuben
Published: May 2017

This paper focuses on the determinants of inflation under different policy rules and fixed exchange rate regime, the example of the CEMAC zone. The purpose of this paper is to check the behaviour of inflation in fixed exchange rate regime for a flexible targeting period and a period of strict targeting. The data used are mainly from the World Bank, in «the book of world development indicators» contained in the CD -ROM (WDI 2015). Working for the periods 1977-1994, 1995-2012 and 1977-2012, the analyses was done with a dynamic panel that has the distinction of being among the independent variables, the endogenous variable lagged one or more periods. The endogenous variable is the rate of inflation. Estimates made from the Arellano and Bond (1991) method, it is clear that during the period (1977- 1994) of flexible inflation targeting, money supply, trade balance and the exchange rate are the main determinants of inflation. During the period (1995-2012) of strategy of strict inflation targeting, the main determinants of inflation are the benefits of natural resources, the trade balance and the economic crisis. The determinants of inflation have opposing effects of a match type to another and it is the combination of these effects for each variable that shows the different effects of the determinants of inflation over the period. The exchange rate increased the rate of inflation over the first sub-period (1977-1994) and throughout the entire period (1977-2012). In times (1995-2012) of strict inflation targeting, these negative effects were mitigated at the expense of economic growth. Countries with fixed exchange rate regime should not adopt a strict policy of inflation targeting, but should alternate with the growth objective by facilitating financing for investments.
Influence of Attachment Styles on Academic Performance of Adolescents in High Cost Private Secondary Schools in Nairobi County, Kenya
Authors: Majimbo Evelyn
Published: May 2017

The purpose of the study was to determine the effect of adolescent attachment styles on academic performance in high-cost private secondary schools. The specific objectives were: to establish the attachment styles exhibited by the adolescents, to determine the relationship between attachment styles and academic performance of students in selected high cost secondary schools in Nairobi and to assess the role of parental bonding on adolescent attachment. Descriptive research design was used. The target population was students drawn from high cost private secondary schools in Dagoreti, Langata and Westlands constituencies in Nairobi County, Kenya. Data was collected by aid of a structured questionnaire with closed and openended questions. Data was analyzed using correlation technique and Mann- Whitney U test. The results showed that there was a weak positive correlation between academic performance and secure attachment style and a negative correlation between academic performance and insecure attachment style. In overall, securely attached adolescents performed better than their insecure attached counterparts. Parents placed too much expectation on their adolescents which increased their anxiety and stress during exams. The implication of this is that parents unknowingly cause psychological harm by pushing their adolescents too much to excel in their education. Counseling practitioners attached to high cost private secondary schools should adopt a tripartite framework of guidance and counseling that involves the participation of parents through mutual understanding and child-centered engagement. Parents of these children should also be realistic even when they set their well-intended bar high for their adolescent children.
Etude Archeothanatologique De La Sepulture Protohistorique Du Monument Funeraire Mbii (Boulmane, Moyen Atlas, Maroc)
Authors: Khaddouje Benlamine Lalla , Mohammed Benabdelhadi , Aicha Oujaa , Nassareddine Azzouzi , Soumaya Benabdelhadi , Michel Fontugne
Published: May 2017

The Moudmane Boulama site is a funeral structure located at 10 km South West of the city of Boulmane (Middle Atlas). It is a necropolis made of approximately twenty tumuli implanted on a hill. The MBII funeral monument is a tumulus built on the top of this hill, which culminates at 1970 m. It is an oval formation made of stack of stones and blocks. The funeral space is delimited in its West part by a low wall made of a sharpened stone alignment. The digs undertaken in June 2013 brought to light the burial place of a H3 adult and some remains of another adult as well as an immature subject. The skeleton of the most complete H3 individual is a male adult, buried in a lying dorsal position, oriented towards East West, head towards West and feet East. He is in a hyper contracted position and lays on an oval plane pit with a diameter of less than a meter. The calvarium and the mandible were subjected to a rotation and lay on the right side. The superior members are folded on themselves and laid on the thorax. The inferior members are also flexed. The skeleton is characterised by the maintaining of the connection of a number of labile elements which allows the characterisation of the burial place as being primarily in clogged space. This funeral monument has probably been used at first for the reception of the two individuals (H1 and H2) and then for the burial of the H3 individual in a sepulchral pit. The reuse of the monument could be explained by the three individuals belonging to the same family and that the last buried subject H3 has a more important familial and possibly social role. This tumulus has also released funeral furniture made of a few bones of domestic fauna. They were the object of a radiometric dating, which allowed the attribution of 2290 ± 35 years old to this tumulus14C B.P (GifA15085/ Sac A 41509).
An Investigation of Executive Functions and Cognitive Emotion Regulation in Labor Children Undergoing Training at Educational Centers
Authors: Kashani Shamim Razaghi , Mashhadi Ali , Farahi Seyed Mohammad Mahdi Moshirian
Published: May 2017

The aim of this study is to determine the comparison of executive functions and cognitive emotion regulation between labor children undergoing training at educational centers and normal children. The sample included 29 male children (mean=9.58, SD=0.50) which was selected from a childcare center. For the control group, 27 third-grade children were selected from a normal primary school (mean= 9.40, SD=0.50). Two questionnaires were used: 1-The extended version of executive function deficiency in everyday life (Barkley, 2011); 2-The child version of cognitive emotion regulation (Garnefski et al., 2007). Part one of this study showed that the scale of executive functions revealed that labor children under training in educational institutions were significantly different in terms of self-direction and time management and self-organization from normal children. Part two of this study showed that there is a significant reverse relationship between planning refocusing, self-regulation, and time management (r value < 0.05). Moreover, there was a significant reverse relationship between positive reappraisal and spontaneity (r value < 0.01), and a significant negative relationship between positive reappraisal and executive functions (r value < 0.05). Overall, it can be posited that children undergoing training in educational institutions are not different from normal children in terms of cognitive emotion regulation.
Incentive Package, Employee’s Productivity and Performance of Real Estate Firms in Nigeria
Authors: Oloke Olayinka C. , Oni Abiodun S. , Babalola Daniel O. , Ojelabi Raphael A.
Published: May 2017

The level of motivation received by an employee as reflected in the satisfaction with the base pay package and other incentives goes a long way to influencing the employees’ attitude to work, loyalty, performance and job satisfaction. Employee’s motivation and organization performance has been investigated across different fields and economic sectors. This study takes it further by examining incentive package, employees and organization productivity in real estate firms in Nigeria. Panel survey approach was adopted and three questionnaires administered in each of the one hundred and seventeen (117) estate firms in Ikeja, Victoria Island and Lekki Area of Lagos State. Respondents were two employees and one other in employers’/management capacity. Descriptive tools such as frequency and percentage were used to identify and determine the proportion of firms that make use of incentive package/option while a 5-point Likert scale and ranking were used to determine and rank the options in order of importance among these firms. Panel data regression model was used to determine the strength of relationship between firms’ performance/productivity and incentives whilst holding other factors constant. Findings showed amongst others that there is strong positive correlation between incentive and employee productivity, employees are largely dissatisfied with the incentives offered by majority of estate firms and that incentive package is not the most important determinants of performance in real estate firms. The study therefore concludes that employers in real estate firms pay attention to other factors identified and review remuneration and incentive package to boost the morale of their employees for better performance.
La Evaluación Del Retour En Interpretación Simultánea Árabe-Español: Transmisión Del Discurso Original
Authors: Rayaa Bachir Mahyub
Published: May 2017

Many reasons have boosted the demand for Arabic-Spanish Simultaneous Interpreting (SI), among others the political and economic interdependence and the social and cultural relations between the Arab and the Spanish-speaking world, as well as the growing interest in the contemporary Arabic world for strategic and geopolitical reasons. Meetings and multilateral conferences have proliferated from the second half of the twentieth century. In addition, Arabic and Spanish are official languages at international organizations like the United Nations or the African Union, and they are present in the private international market of SI. However, research on the quality of Spanish-Arabic interpreting (AR-SP) remains limited, raising numerous questions on the evaluation and quality control of a profession that enables communication in an increasingly globalized world. This article, which is part of a wider study analyzing how users of interpreting services evaluate AR-SP SI, focuses on the analysis of two parameters: correct transmission and complete transmission of the Original Speech (OS). For this purpose, we have carried out an empirical study using a questionnaire to survey 25 users of interpreting services, asking them to observe and evaluate AR-SP SI over the course of a 30 minute conference. The data obtained reveals that the users are aware of the concept of quality regards interpreting and, despite not having access to the OS, form an opinion on interpreters and their work. Ultimately, in this article we investigate the elements that influence how users of interpreting services evaluate AR-SP interpreting and the consequences these elements have on the work of the interpreter.
Repenser Le Rôle Des Institutions De Conservation De La Nature À L’ère De La Globalisation En Afrique: À Propos Du Parc National De La Salonga (RDC)
Authors: Salomon Mampeta Wabasa
Published: May 2017

In the Democratic Republic of the Congo (DRC), the protectionist conservatism influenced by colonialism, which exploited African countries for the prosperity of the colonizing countries, still has a high visibility in the Salonga National Park (PNS). If, in theory, the Central Africans seem to free themselves from the colonial powers on their land, in practice they are still there. The hostility of settlers who have become neo-colonists to the development of Central Africa remains intact, he adds (Ndinga, 2003). This reflects a "logic from above" that has disregarded local values. Yet, in the era of sustainable development and globalization, African protected areas appear to be essential tools for States to reposition themselves in a complex set of actors with the aim of capturing and using the new environmental rent (Giraut, Guyot, & Houssay-Holzschuch, 2003). This is a "bottom-up logic", placing people at the heart of all activities and aiming to reorganize their long-term relationships with the environment. From these two logics, a third "logic from the other side" emerges, reflecting a collective awareness of the fragility of the planet. The restoration of the rights of Africans in the various national frameworks constitutes a major challenge for the contemporary management of African protected areas. Because the protected areas inherited from the different colonial systems must accompany the change in management methods and the redefinition of their functions in order to better serve the local community in the long-term.
Allyn A. Young - Increasing Returns and Economic Progress
Authors: Castro Antônio Barros de
Published: May 2017

Allyn Young parte, no seu artigo de 1928, da constatação de que o progresso econômico havia passado a ser concebido como algo que decorre da “natureza das coisas” e “não algo a ser explicado”.1 Como se se tratasse de um “fenômeno natural”, ironiza o autor. Inconformado com este juízo, Young se propõe a reabrir o tema, a partir de idéias lançadas por Adam Smith em A Natureza e as Causas da Riqueza das Nações. Com este propósito, introduz uma distinção entre dois tipos de mudança que podem ser sumariamente apresentados como se segue...
Innovation, Competition and Growth: Evolving Complexiting or Complex Evolution
Authors: Metcalfe J. Stanley , Fonseca Maria da Graça Derengowski , Ramlogan Ronald
Published: May 2017

Este artigo constitui-se numa investigação fundada na visão evolucionista sobre o crescimento econômico, inovação e competição. Nosso ponto de partida é a idéia de que o sistema econômico é composto por múltiplos agentes, diversos em habilidades e capacidades, interagindo e reagindo uns com os outros de forma a se adaptar ao ambiente em que estão inseridos. Neste processo, os agentes econômicos acabam por modificar os padrões de comportamento e as estruturas que eles próprios ajudaram a criar. O artigo está construído em torno de duas idéias principais. A primeira é a de que o processo de tomada de decisões deve ser analisado através do conjunto de regras e rotinas que os agentes econômicos – em particular, as empresas – dispõem para decidir qual o curso de ação que devem tomar. Este tratamento permite recuperar a questão da micro-diversidade e da relevância de padrões de conduta. A segunda idéia está relacionada à importância do crescimento econômico como um fenômeno emergente. Como tal, os processos de transformação podem ser divididos em três elementos: processos de seleção, processos de criação de novidades (micro-diversidade) e processos de desenvolvimento. A forma de interdependência entre estes elementos vai ajudar a definir a própria relação entre inovação, crescimento e competição. No contexto do artigo, a questão-chave está na especificação da concorrência como um processo de seleção. Para avaliar o crescimento e desenvolvimento de categorias relevantes dentro das populações tomamos como base os princípios de Fisher e seus desdobramentos nas equações de replier dynamics. Acreditamos que o artigo possa ajudar a esclarecer os elementos centrais presentes na teoria evolucionista do crescimento endógeno, estabelecendo seus fundamentos no processo de conhecimento.
Evaluation of the RPC Model for Ziyuan-3 Three-line Array Imagery
Authors: Hong Zhonghua , Xu Shengyuan , Zhang Yun , Han Yanling , Feng Yongjiu
Published: May 2017

Ziyuan-3 (ZY-3) satellite is the first civilian stereo mapping satellite in China and was designed to achieve the 1:50000 scale mapping for land and ocean. Rigorous sensor model (RSM) is required to build the relationship between the three-dimensional (3D) object space and two-dimensional (2D) image space of ZY-3 satellite imagery. However, each satellite sensor has its own imaging system with different physical sensor models, which increase the difficulty of geometric integration of multi-source images with different sensor models. Therefore, it is critical to generate generic model especially rational polynomial coefficients (RPCs) of optical imagery. Recently, relatively a few researches have been conducted on RPCs generation to ZY-3 satellite. This paper proposes an approach to generate the RPCs for ZY-3 imagery from RSM. Three scenarios experiments with different terrain features (such as ocean, city and grassland) are designed and conducted to comprehensively evaluate the replacement accuracies of this approach and analyze the RPCs fitting error. All the experimental results demonstrate that the RPCs is suitable for ZY-3 imagery and can be used as a replacement for the RSM of ZY-3 imagery.
Unamuno and Ortega's Ideas of language and translation
Authors: LÓPEZ FOLGADO Vicente
Published: May 2017

En este trabajo me propongo abordar algunos pasajes en los ensayos de dos destacados pensadores españoles cuyas ideas han ejercido un gran influjo sobre otros escritores sobre todo en la primera mitad del siglo XX. No cabe atribuir, no obstante, sus reflexiones sobre la lengua y las lenguas a la originalidad de su pensamiento, sino a la asimilación de lecturas foráneas, en especial a la filología alemana decimonónica. A pesar de tal influencia, sus ideas representan una renovación en medio del erial de la cultura española de entonces en esa materia. Me parecen asimismo pertinentes sus reflexiones sobre el papel que desempeñó la traducción en la cultura occidental.
Enhancing Optimization of Reservoir Simulation Processes in Next-Generation Reservoir Simulators
Authors: Temizel Cenk , Saputelli Luigi , Nabizadeh Mehdi , Balaji Karthik , Suhag Anuj , Ranjith Rahul , Wijaya Zein
Published: May 2017

In field development and management, optimization has turned out to be an integral component for decision-making. Optimization involves computationally intensive complex formulations but simplifies making decisions. For reaching the optimal solution to a defined objective function, optimization software can be combined with a numerical reservoir simulator. Hence, robust and faster results are imperative to optimization problems.

To maximize cumulative recovery and net present value (NPV), the reservoir simulator works on maximizing these predefined objective functions that can be multi-objective leading to Pareto sets with "trade-offs" between objectives. In optimization algorithms with predefined objective functions, there is a need for these objective functions to be flexible by using conditional statements through procedures, since generally they do not provide the flexibility required by the physical reservoir fluid flow phenomenon to "maneuver" throughout optimization iterations.

In this study, a commercial reservoir simulator is coupled with an optimization software. As the need was discuss earlier, conditional statements are implemented in the simulator as procedures. Operating the software/simulator combination under pseudo-dynamic objective functions is achieved through these procedures. Highest recovery for the time period mentioned in the conditional statement for the simulation is achieved by trying sets of combinations of parameters, which also makes the optimization process faster and more robust. Throught the use of these conditional statements, the procedures are able to implement piecewise objective functions as codes for a given time frame.

The objective function to be maximized by the optimization process in this study cumulative production. The optimized recoveries with pseudo-dynamic objective functions provide an enhanced recovery, as compared to that of an optimization case with predefined constant objective function in the optimization software throughout the iterations of the optimization and simulation process.
Numerical Modeling of Magnetic Nanoparticles Transport in a Two-Phase Flow in Porous Media
Authors: El-Amin Mohamed F. , Brahimi Tayeb
Published: May 2017

In this paper, the problem of magnetic nanoparticle injection into a water-oil two-phase flow under an external permanent magnetic field is investigated numerically. The mathematical model of the problem under consideration has been developed. We treat the water- nanoparticle suspension as a miscible mixture while it is immiscible with the oil phase. The magnetization, density, and viscosity of ferrofluids are obtained using immiscible mixture relations. On the other hand, the magnetized phase pressure will have additional pressure terms relative to the conventional thermodynamic pressure, namely, the ferrofluid phase dynamic pressure, the fluid magnetic pressure, and the magneto-strictive pressure, while, the magnetic normal pressure is neglected in this study. Physical variables including water-nanoparticle suspension saturation, nanoparticle concentration, and pore wall/throat deposited nanoparticle, are investigated under the influence of the magnetic field. From our results, we found that magnetic field has a significant effect on the physical quantities of the model. Therefore, a magnet can be implemented for enhanced oil recovery.
Sourceless Porosity-Density and Geomechanics with Logging-While-Drilling Tools in Carbonate Sequences
Authors: Chen Chao , Abd El-Aziz Sabry , Abdulkarim Anar , Aki Ahmet
Published: May 2017

Azimuthal acoustic logging-while-drilling (LWD) sensors have recently been used in a bottomhole assembly (BHA) to evaluate the viability of sourceless formation evaluation compared to conventional density-neutron data acquired in the same run in a horizontal well across a carbonate sequence.

Borehole deterioration and significant pore pressure variations across the reservoir layers pose wellbore stability risks during the drilling phase, which has historically requireddrilling deviated pilot-hole sections for evaluation purposes. These sections were then plugged, backed, and sidetracked.

Previous experiences in the same geological setting also encountered extreme borehole enlargements. LWD helped acquire high-quality data before borehole enlargement occurred. Additionally, possible rock anisotropy indications were observed, and rock mechanical moduli were derived. The results were then correlated and normalized to existing field geomechanics knowledge and offset well data.

Azimuthal acoustic tools, free of radioactive sources, were run in an LWD tool combination, with the primary objective of measuring porosity, pressure prediction, and possible anisotropy using a four-axis acoustic caliper sensor.

This paper discusses the planning, design, and execution of an LWD azimuthal acoustic tool in the case study well. Additionally, the viability, integrity, and robustness of logged data as well as interpreted results are discussed. Optimization of real-time drilling operations and petrophysical dataacquisition requirements are also investigated to help optimize future field development data-acquisition requirements and overall reservoirmanagement strategies.
Computational and Experimental Study of Microfracture Conductivity in the Eagle Ford Shale Using Microproppant Pillars
Authors: Madasu Srinath , Nguyen Philip D.
Published: May 2017

Proppant conductivity in fractures at closure is crucial to ultimate hydrocarbon recovery from reservoirs. The proppant distribution inside the fracture determines the conductivity. This paper presents the application of solids-free channel fracturing treatment in microfractures. Microproppant (MP) agglomeration forms mini-pillars that support the microfractures to help prevent their complete closure and to provide conductive flow paths. Mathematical modeling of the conductivity that results from the microproppant pillars is presented and compared with the experimental data for validation using split cores of an Eagle Ford shale outcrop sample. Proppant embedment caused by the fracture deformation is estimated using the numerical model.

This paper presents a new three-dimensional (3-D) mathematical model that couples the solids and produced-fluids fracture-flow fluid mechanics with the deformable proppant pillars. MP aggregates/pillars are modeled as deformable cylindrical agglomerates, and the particles are modeled as deformable aggregates that deform under the closure stress. The fluid flows inside the fracture when there is a pressure differential. The propped microfractures are modeled as deformable solids that interact with the fluid flow. The fracture deforms as a result of closure and fluid stress. The model captures the fracture and pillar deformations using moving-mesh capability.

Simulations of closure stress with multiple pressure differentials for flow through the solids-free channels were performed to compare the conductivity obtained from the experiments using the split Eagle Ford shale core. MP aggregates, with less supporting surface area, must support higher closure stress compared to the conventional packed-proppant fracture, which has higher stiffness and lower embedment. Core samples treated with MP droplets were tested to obtain the experimental conductivity data. The results showed that the MP aggregates provided better conductivity than the partial monolayer of MP particulates were uniformily distributed and the number of droplets was properly limited. This was validated both qualitatively and quantitatively during the experiments. An uncertainty analysis using the simulation model revealed that the MP aggregate height significantly influenced conductivity and, therefore, should be optimized to enhance production.
Application of the Superposition Principle for Pressure Build-Up Analysis at Variable Rates Compared with Horner's Method
Authors: Mohammed Akram F.
Published: May 2017

The pressure build-up equation derived by Horner is applicable to wells that produce at a constant rate. However, as a constant flow rate does not exist in practice, the Horner equation is not expected to yield accurate results. Because of this limitation, an alternative method must be used to account for a variable production-rate history. The principle of superposition enables the generation of pressure behavior solutions for variable-rate cases based on the constant-rate pressure behavior solutions. The superposition solution and its application in pressure build-up analysis are herein presented and are compared with the Horner method for different interpretation cases. Finally, the accuracy and reliability of the calculated results are discussed.
Analytical Solutions for Temperature Transient Analysis and Near Wellbore Damaged Zone Characterization
Authors: Mao Yilin , Zeidouni Mehdi
Published: May 2017

Productions from oil and gas reservoirs can induce significant pressure and temperature changes at the wellbore. The temperature signal is sensitive to reservoir properties and production parameters which can be very useful in characterizing the reservoir. In this work, we introduce novel analytical solutions to determine the temperature signal associated with theproduction of slightly-compressible hydrocarbon from a vertical well, and apply the solutions to the production from oil and gas reservoirs. Our procedures to obtain the analytical solutions from the governing equation involve making relevant assumptions that allow rigorous solutions to be constructed using Laplace transform. We extend the analytical solutions to include the near-wellbore damage, and to characterize the damaged zone.

Our results of the analytical models are benchmarked with those from a commercial numerical simulation software. We substantiate that the Joule-Thomson effect on the temperature profile is significant in near-wellbore region, and adiabatic expansion effect extends the radius of investigation of the transient temperature signal. The damaged zoneanalytical solution shows that damaged zone radius and permeability separately affect thetemperature transient signal. This isunlike the pressure transient response for which the effect of damage zone properties is lumped into a single parameter, i.e. the skin factor. The analytically derived equations for slopes of Joule-Thomson and adiabatic expansion effects in undamaged and damaged reservoir present very close agreement with those obtained numerically. We provide semi-log temperature interpretation techniques to determine the reservoir permeability and porosity, and damaged zone radius and permeability.
Dynamic Fractures in Tight Low-Permeability Oil Sandstone Reservoirs
Authors: Li Jiahong , Song Xinmin , Yu Tao , Hou Jianfeng , Lei Zhengdong
Published: May 2017

So far in China, unconventionally low-permeability oil sandstone resource has become the first contributor of proved reserve, and is occupying the most important section of oil production in near future. The low-permeability reservoirs have been primarily developed by waterflood, and therefore display a series of new and specific features. Among them, dynamic fracture, an important factor influencing waterflood performance, was studied in this paper.

This paper is a 5-step study of low-permeability oil sandstone reservoirs (average permeability between 0.3mD and 10mD) in Ordos basin, which is famous for its richness in low-permeability sandstone resources. First, dynamic fractures were identified by production data, injection profile, tracer monitoring and well test data. Secondly, mechanical experiment and discrete numerical simulation were integrated to analyze the forming mechanism of dynamic fractures. Third, remaining oil saturation observation of densely-spaced inspection well cores and unstructured-grid simulations were used in combination to obtain a 3-dimensional sweep scenario influenced by both dynamic fracture and matrix. Based on study above, the impact of dynamic fracture on waterflood was then analyzed. Finally, how to curb and use dynamic fractures to maximize recovery according to their different forming mechanisms were suggested.

The dynamic fracture is defined as fracture that reopen, propagate or close influenced by injection pressure. It can be identified by simultaneous features of drastic watercut increasing, sharp spike in GR curve of injection profile, fast breakthrough of tracer and high permeability anomaly by well test. Core sample mechanical experiment and theory calculation support dynamic fractures propagating on the basis of pre-existence fractures as the predominant forming mechanism. Fresh core observation of newly drilled inspection wells after 20y's waterflood indicates a higher percentage of vertical sweep by up to 30% in the direction of dynamic fracture than that perpendicular to the direction of dynamic fracture. Also dynamic fracture simulations show fast growth of dynamic fractures apparently narrows horizontal sweep and causes earlier drastic watercut increasing by years. A fast growing dynamic fracture deteriorates horizontal sweep, while dynamic fractures of a certain height increase vertical sweep. Moderate injection and stimulated fractures with enough height are conducive to enhance sweep and therefore recovery. If dynamic fractures connecting injectors and producers are unavoidable, a line injection pattern is then proposed.

This paper conducted a systematic study on dynamic fracture, which is a dominant feature and geological challenge for waterflood of unconventional tight oil sandstone reservoirs. It offers a guidance for future waterflood development of similar reservoirs.
Unlocking Billion Cubic Meter of Deep, Tight, Rich and Unconnected Gas Field
Authors: Marhoon Nadhal Al , Masroori Haitham AL , Abdul-Majid Imran , Ajayi Ayotunde , Sandoval Daniel , Khan Raees Ahmed , Qasmi Liali Al
Published: May 2017

The Tight Gas Reservoir (TGR) top structure is well defined in seismic data and can be interpreted across the entire area of North Oman. It is being identified as an extremely tight, disconnected, low porosity, low permeability and High Pressure – High Temperature (HPHT) reservoir, and thus presents unique challenges to harness its full production potential. Therefore, to optimise the subsurface location and ensure placing a successful well, the following approaches were implemented.

Firstly, full 3D geological model was generated to reproduce the reservoir heterogeneities and sedimentological behaviour of the TGR. Secondly, sweet spot identification techniques were used due to the heterogeneity nature of TGR properties in order to locate the optimum subsurface location. Lastly, a well completion strategy centred on hydraulically fractured cased-hole wells with immediate production to mitigate formation damage was implemented. This is achieved via abrasive jetting and thermal conductivity techniques to induce micro fractures that vastly enhanced the fracture efficiency, with velocity strings combined with depletion compression.

Furthermore, the characterization and simulation efforts are aimed to test the longevity of the wells in an Early Production System (EPS) to evaluate the optimal well count and spacing for the full Final Development Plan (FDP). Also, the interference between the wells in this tight formation has been studied. Data gathering activities encompasses formation evaluation logs, core analysis data and well test data.

The surface development concept is based on staged field development, with long term testing as the first milestone. EPS have been selected to provide long term production data gathering opportunity for assessing the reservoir and well performance behaviour in order to aid in defining the FDP.

This paper will highlight the success of unlocking tight, unconnected gas and describe methodologies applied to aid fully integrated subsurface loop development. Reservoir characterization, model creation and simulation challenges linked with the appraisal results will also be discussed.
A Numerical Study of Using Polymers to Improve the Gas Flooding in the Harweel Cluster
Authors: Hinai Nasser. M. , Saeedi A. , Wood Colin D. , Valdez R.
Published: May 2017

Field A, located within the Harweel cluster in southern Oman, has been recognised as a viable miscible gas injection candidate. However, the mobility ratio of such a flood is unfavourable due to the low viscosity of the injected gas (0.01 to 0.04 cP) as compared to that of the in-situ oil (0.24 cP). One approach to overcome this issue is to thicken the injected gas to effectively control the gas mobility and increase the sweep efficiency.

This study will present the details of a numerical reservoir simulation study, which assesses the potential benefits of adding polymers to the injected gas to increase the viscosity. Considering the composition of the AG in Field A, we have examined a number of different AG compositions to include different levels of hydrocarbon gas and CO2. We have also evaluated the direct effect of the different gas compositions on the oil properties during the flood.

The simulation was carried out using CMG-GEM and the associated PVT module CMG-WinProp. A full-field 3D geological model has been built based on the typical geological characteristics and the light oil fluid properties in Field A. The simulation model takes into account the reservoir heterogeneities and future design considerations of the enhanced oil recovery (EOR) project to be implemented in the field.

The results confirm that increasing the injected gas viscosity close to that of the oil has a significant effect on the gas mobility, time of breakthrough and the ultimate recovery in Field A. It has also been observed that the oil viscosity reduction with natural gas dissolution is much more pronounced than that achieved with the pure CO2. Such an effect resulted in 4% higher oil recovery by the injection of thickened natural gas (76%) than the thickened pure CO2 (72%). Furthermore, bacause gas breakthrough is delayed, a low gas-oil ratio can be maintained during the injection. These results demonstrate the real advantages of thickening the natural gas over CO2 for improving the gas flood efficiency in a light oil reservoir such as Field A.

The contribution of this study is significant considering the fact that to date there have been limited studies evaluating the effect of thickened natural gas for EOR. Most of the previously completed research work in this area have mainly focused on the identification of thickener polymers for CO2 injection processes.
An Innovative Approach towards Improving the Relationship Between Flow Zone Indicators with Lithofacies: A Case Study in Carbonate Oil Field, Middle East
Authors: Hashim N. S. , Zakaria A. F. , Ishak N. A.
Published: May 2017

F field is located in the Middle East and was discovered in 1980's. The bulk of the proven liquid hydrocarbons are contained in the B formation (carbonate), which averages some 200m in thickness in the study area. The hydrocarbons are contained in a low relief NW-SE trending anticlinal structure. Deposition of the reservoir sequence occurred during the late Cemnomanian to Early Turonian in the Mesopotamian Basin.

Oil production started few years ago and currently there are more than 40 producing wells in the centre of the structure. The uneven well distribution limits the understanding of 3D reservoir characterisation, explicitly in the flank areas. Only one conventional core with good recovery was available for reservoir B, which makes it somewhat difficult to delineate the internal architecture of the carbonate ramp.

A total of seven lithofacies were identified which are Rudistic Floatstone Wackestone, Bioclastic Wackestone, Bioturbated Bioclastic Packstone (BBP), Rudistic Rudstone Wackestone, Bioclastic Floatstone Wackestone, Heterolithic Bioturbated Bioclastic Wackestone and Bioclastic Mudstone. A conceptual depositional environment with lithofacies association was generated by using core descriptions, regional studies and analogues.

A fit for purpose integrated reservoir characterisation study was carried out in 2014 with main inputs from Nuclear Magnetic Resonance (NMR) and image logs in conjunction with digital rock analysis (DRA), conventional open hole well logs, core laboratory analysis, mud logs, pressure and well test data. Several rock typing approaches were developed; including Flow Zone Indicator (FZI) or Rock Quality Index (RQI), Lucia Rock Class, Clerke Pore Size technique from Mercury Injection Capillary Pressure (MICP), multi-variate cluster analysis (biased and normalized), cluster analysis (non-biased and non-normalized) and self-organizing maps (biased but non-normalized). From these FZI, an optimum of seven Hydraulic Units (HU) were selected where FZI 1 being the best flow unit, and FZI 7 is the poorest.

A relationship between FZI with lithofacies was then established by comparing both on depth plot as well as porosity-permeability cross plot. Different FZI can be seen for one lithofacies, for instance BBP consists of FZI 1 to 4 which indicates the changes in reservoir quality within the same lithofacies. The same relationship was extended towards depofacies, and resulted with lateral segregation of depositional environment according to its reservoir quality.

This exercise confirms the heterogeneity within B formation, and it captures the changes in reservoir quality laterally and vertically. This detailed understanding of the carbonate architecture was translated into a 3D geological model in order to minimize the uncertainties for dynamic simulation and future field development plans.
Constrained, Multi-Objective, Steamflood Injection Redistribution Optimization, using a Cloud-Distributed, Metamodel-Assisted, Memetic Optimization Algorithm
Authors: Kyriacou Stylianos , Sarma Pallav , Hunt Ian
Published: May 2017

A cloud-distributed optimization algorithm applicable to large scale, constrained, multiobjective, optimization problems, such as steamflood redistribution, is presented. The proposed algorithm utilizes the so-called Metamodel Assisted Evolutionary Algorithm (MAEA) as its algorithmic basis. MAEAs use a generic implementation of an evolutionary algorithm as their main optimization engine and advanced machine learning techniques as metamodels. Metamodels are utilized through the application of an inexact pre-evaluation phase during the optimization, which substantially decreases the evaluations of the problem specific forward model. Additionally, a unification of global search (GS) and local search (LS) is achieved via the use of Lamarckian learning principles applied on top of a MAEA creating, in essence, a Metamodel Assisted Memetic Algorithm (MAMA). MAMAs profit from the abilities of MAEAs to explore the most promising regions of the design space without being trapped in local optima while also utilizing the efficiency of deterministic methods to further refine promising solutions located during GS. At the end of each EA generation, the most promising members of the current populations are selected to undergo LS using a gradient-based method. Further, integration with scalable cloud-distributed computing allows MAMAs (CD-MAMA) to perform rapid and simultaneous evaluation of tens of thousands of operating plans.

The proposed algorithm has been statistically validated on two mathematical test cases and, subsequently, used to optimize a field undergoing steamflood under two different oil-price scenarios. Thus, demonstrating that, cloud-distributed MAMAs coupled with efficient reservoir models, allow for steamflood injection redistribution optimization in affordable, by industry, wallclock times (hours). For the field in question production comes from poorly consolidated sands within the Antelope Shale member of the Miocene Monterey formation with porosity averaging 30%, permeability averaging 2,000 mD and net thicknesses typically between 50 and 300 feet. Structural dip is steep at approximately 60 degrees. The reservoirs are shallow, with depths ranging from 200 - 600 feet TVD. Oil gravity is approximately 13° API. Reservoir pressures are well below bubble point and average 50 - 100 PSI. The field has about 200 producers and 30 injectors, producing about 2000 bpd of oil and injecting 8000bpd of steam. The field has been under operation for about 7 years, with most of the continuous steamflood starting about 3.5 years ago.
A Novel Model for Pore-Scale Spontaneous Imbibition Accounting for Fluid Viscosities
Authors: Meng Zhan , Yang Shenglai , Wang Lu , Wang Zhilin , Qian Kun , Lei Hao , Ma Quanzheng , Wang Mibang
Published: May 2017

Horizontal drilling and hydraulic fracturing have been proven to significantly increase production from tight oil formations, however, one of the characteristics of these reservoirs is high production declining rate. In the long term, it is necessary to increase the development efficiency of block matrix, many studies have shown that spontaneous imbibition is a potential way. In addition, precisely predicting the behavior of the imbibition recovery under different viscosity ratios is thus critically important. The goals of this paper include theoretically and experimentally investigating the effect of the viscosity on the imbibition recovery.

In this paper a novel pore-scale spontaneous imbibition model is established by two steps. At first, the spontaneous imbibition equation in a single capillary tube considering that immobile oil is established based on Hagen Poiseuille formula. Then, pore-scale spontaneous imbibition model based on fractal theory has been derived. In addition, the corresponding spontaneous imbibition tests have been conducted on sandstone natural cores collected from Xinjiang oilfield.

The predictions of the imbibition recovery by the proposed model have been validated by comparing them with the experiments conducted. Data of cores H-56 and H-39 are used to comparing the calculated imbibition recovery with the measured imbibition recovery. Under four different oil/water viscosity ratio, 0.5, 1, 5 and 10, the relative errors between calculated data and measured data are less than 7%. And both the theoretical and experimental results show that the viscosity ratio of the mixed oil and brine has a significant effect on the spontaneous imbibition recovery. The predicted and experimental results demonstrate that a higher imbibition recovery corresponds to a lower oil/brine viscosity ratio. In addition, rate of spontaneous imbibition has a significant decline which is the same as the result of the calculation.

In general, since the established model has a high precision, it can be used to analyze the effects of different parameters like the contact angle, the interfacial tension and other structural parameters and the results can be useful for understanding the spontaneous imbibition law. What's more, the conclusion can guide the surfactant screening in surfactant-aided imbibition schemes.
Applying Statistical Learning to Quantitative Well Log Analysis
Authors: Bergman Doron L. , Henning Mark J. , Sarma Pallav , Hunt Ian
Published: May 2017

A method is presented for deducing porosity and saturations from well log data, where key reservoir parameters, such as water resistivity, may be missing. The method combines routine petrophysical methods with statistical learning, allowing for well log analysis to be performed on a wide variety of wells and geologies. By solving a combination of fundamental physical laws and empirical models and exploiting the character and relationship of the physical laws, one is able to calculate porosity and saturations from well log data and to identify oil and/or gas producing zones. The methodology allows for fitting model parameters when additional well log data, such as core porosity and saturation, are available. A statistical learning approach allows for the probabilistic derivation of porosity, saturations, and fit parameters, including formation water resistivity and the Archie cementation and saturation exponents.

The methods have been applied to a number of oil reservoirs and have undergone both manual and automatic validation. The method has demonstrated the ability to quantify porosity and fluid saturations and to identify oil zones, with results comparing favorably to those from traditional petrophysical methods. Because statistical methods are used to derive model parameter fits, output log curves are presented probabilistically. This allows the end user to better understand the range of porosity and saturation possibilities at the zone, well, reservoir, and field levels. The statistical approach also indirectly takes into account noise in the data.