bluuebunny/crossref_metadata_2025 huggingface dataset:
Efecto del enriquecimiento ambiental en un grupo de monos araña (Ateles geoffroyi) en cautiverio
Authors: Márquez-Arias Alejandra , Santillán-Doherty Ana María , Arenas-Rosas Rita Virginia , Gasca-Matías Marco Polo , Muñoz-Delgado Jairo , Villanueva-Valle Javier
Published: July 2016

Los animales que viven en cautiverio padecen problemas relacionados con el estrés y la falta de estimulación. El enriquecimiento ambiental (EA) proporciona a los animales en esta situación un conjunto de actividades que los alienta a presentar conductas típicas de su especie. El objetivo de este trabajo fue analizar el efecto de un programa de EA en la conducta de una colonia de siete monos arana (Ateles geoffroyi). Se esperaba que la agresión, la coprofilia y las estereotipias fueran menos frecuentes entre los monos, mientras que la exploración y el juego se presentaran con mayor frecuencia. Para ello, la investigación se dividió en dos etapas: una etapa previa al EA y una etapa durante el EA. En cada etapa se registraron las siguientes categorías conductuales: agresión, coprofilia, estereotipias, exploración y juego. Se utilizo un muestreo focal por conducta en registros continuos de 1 hr., obteniéndose en cada etapa 40 hrs. de observación. Al comparar la frecuencia de dichas conductas con la prueba de los signos de Wilcoxon, se encontró que la agresión, las estereotipias y la coprofilia disminuyeron durante el EA. La exploración y el juego se incrementaron significativamente con el EA. No se observaron diferencias significativas al comparar el sexo de los individuos. El EA disminuye los problemas causados por el confinamiento, por lo que debe contemplarse como una herramienta indispensable que de manera constante mejore las condiciones de vida en individuos confinados.
Role of high resolution computed tomography in the evaluation of temporal bone lesions: our experience
Authors: C. Jyothi A. , H. Shrikrishna B.
Published: July 2016

Background: High resolution computed tomography (HRCT) is a modification of routine computed tomography. It provides visual information of the minute structural details of the temporal bone. The present study aimed at studying the pathological processes of the temporal bone and their extent using HRCT.

Methods: This prospective study was done by taking HRCT of the temporal bone in 50 patients who presented to us with clinical features of temporal bone diseases. Both contrast and no enhanced images were obtained by taking 2mm sections using ultra high algorithm in both coronal and axial planes. The results were then analysed statistically.  

Results: Amongst the 50 cases, infection was the most common pathology affecting the temporal bone.  Neoplasms formed the second largest group of lesions with acoustic neuroma being the most common tumour.

Conclusions: HRCT is a revolutionary imaging tool in evaluating the various pathologies affecting the temporal bone. It identifies the hidden areas of the temporal bone. It also lays down an anatomical roadmap for the surgeon preoperatively. 
Latin American Thinking in International Relations Reloaded
Authors: Frasson-Quenoz Florent
Published: July 2016

In the midst of uncertainty –generated by the narratives of the decline of the United States– academics are looking for answers and cerebral stimulus in the heart of the academic Terra Incognita that is the “Global South”. Building on this interpretation, I formulate a simple question: Does a Latin American school of thought exist in International Relations? In order to respond to this question I will propose a model that will allow for an assessment of the existence of a Latin American school of thought in International Relations. Additionally, this model will enable me to distance myself from the air du temps; that is, to celebrate the existence of a school of thought before even being certain that it actually exists. For sure, the assessment done here will only stand as a first attempt, and is in no way exhaustive. Nonetheless, it will allow me, firstly, to demonstrate that the eagerness to promote any kind of academic proposal to the status of “school” is detrimental to the central goal of generating knowledge and, second, to stimulate others to think about the subject along the same lines.
Central Banking and the Crisis. A Comparison of the Federal Reserve and the European Central Bank Measures, and the ECB’s Changing Role in the EU Economic Governance System
Authors: Roman Czubala Marcin , Puente Regidor Mónica
Published: July 2016

The European Central Bank (ECB) has received a lot of criticism for its too little, too late performance to ease market pressures during the economic crisis. At the same time, the ECB and the Federal Reserve (FED) have managed the new economic realities that have emerged in the international context differently. Despite the criticisms, the European Central Bank is the European Union institution that has assumed more control due to the new model of economic governance of the EU. Why did the Federal Reserve act so nimbly and quickly to calm the markets, while the ECB was so cautious in managing monetary policy? The aim of this paper is to perform a comparative analysis of the management of interest rates and other monetary policy measures undertaken by the Central Bank and the Federal Reserve during the economic crisis, as well as to understand the changes in the context of the ECB and the emergence of its authority within the European Union’s economic governance model since 2011. Thus, in order to carry out a scrupulous exposition, we will also limit the time frame of this study to the 2007-2014 period.
Historical background of the population biology of the swimming crab Arenaeus cribrarius (Crustacea: Portunidae) in the Ubatuba coast, southeast Brazil
Authors: PINHEIRO Marcelo Antonio Amaro , PARDAL-SOUZA André Luiz
Published: July 2016

This study presents results obtained 25 years ago on the population structure, sex ratio, and handedness of Arenaeus cribrarius in Ubatuba, North coast of São Paulo State, Brazil. Sampling studies were conducted during two different periods (from November 1988 to October 1989, and from May 1991 to April 1993), one of them performed for pooled data, and other exclusively for Fortaleza Bay (monthly samples from November 1988 to October 1989). Males were larger (CW, average Â± SD: 73.38 Â± 15.78 mm) than females (68.45 Â± 12.20 mm). The size between juvenile and adult stages has an overlap, for males (40-70mm CW) e fêmeas (45-75 mm CW). A prevalence of females was registered for pooled data (1:1.42; P < 0.01), but it was not recorded in Fortaleza Bay (1:1.25; P > 0.05). The sex ratio was close to 1:1 in the smaller size classes, with females dominating in the intermediate classes, and males in larger ones. In Fortaleza Bay, a female biased sex ratio was only noted in transect I (1:3.88; P < 0.05) and in the autumn (1:1.67; P < 0.05), with 73% of the specimens measured were right-handed.
Açúcar refinado como fonte de carbono no berçário de camarões cultivados em sistema de bioflocos
Authors: CHAMORRO-LEGARDA Esmeralda , MENDES Lucas Gomes , BEZERRA Gabriella Garcia de Oliveira , ESPIRÍTO SANTO Carlos Manoel do , SEIFFERT Walter Quadros , VIEIRA Felipe do Nascimento
Published: July 2016

Objetivou-se avaliar o uso de açúcar refinado como fonte de carbono no berçário de camarões marinhos em sistema de bioflocos. Foram utilizados oito tanques de 800 L povoados com 3.000 camarões m-3, sendo que metade dos tanques recebeu açúcar refinado como fonte de carbono e o restante, melaço de cana-de-açúcar (controle). Os valores dos parí­¢metros de qualidade de água mantiveram-se dentro dos limites aceitáveis para o camarão marinho. Contudo, o teor de amônia total foi superior no tratamento com açúcar refinado em relação ao registrado no controle. A alcalinidade e fosfato foram superiores no controle. Os í­­ndices produtivos avaliados (peso final, sobrevivência, conversão alimentar e produtividade) não foram diferentes entre os tratamentos. Entretanto, o custo do açúcar refinado para produção de um quilograma do camarão foi 62% inferior ao do melaço (tratamento controle). O estudo mostra que o açúcar refinado pode ser usado na fertilização do berçário de camarão e auxiliar na redução dos custos de produção.
Suplementação dietética com probiótico e butirato de sódio no pré-berçário de Litopenaeus vannamei
Authors: SANTOS-JUNIOR Marcello Mendes dos , CANDIA Efrayn Wilker Souza , JESUS Gabriel Fernandes Alves de , SEIFFERT Walter Quadros , MOURIÑO José Luiz Pedreira , VIEIRA Felipe do Nascimento
Published: July 2016

Este estudo teve por objetivo avaliar o uso suplementar de probiótico (Lactobacillus plantarum) e butirato de sódio, e a interação deles na dieta de pósí larvas de camarão-branco-do-pací­­fico (Litopenaeus vannamei) em fase de pré-berçário. Durante o experimento foram aplicados nas dietas os tratamentos: (1) probiótico 1x108 UFC/g, (2) butirato de sódio 2%, (3) probiótico 1x108 UFC/g + butirato de sódio 2%, (4) controle (dieta base). Todos os tratamentos tiveram a adição de meio de cultura na mesma dosagem utilizada nos tratamentos com probiótico. Foram utilizadas 16 unidades experimentais de 60 L cada uma, com fundo em formato U, povoadas com 2.880 pós-larvas 5. Após quinze dias, independentemente da presença ou não do probiótico, os camarões dos tratamentos com butirato apresentaram maior sobrevivência (p = 0,0039) e menor peso seco individual (p = 0,0043). Não foram observadas alterações morfológicas no intestino das pós-larvas em nenhum dos tratamentos. Portanto, a suplementação com butirato de sódio na ração aumenta a sobrevivência das pós-larvas de camarões na fase de pré-berçário sem causar alteração morfológica em seu intestino.
Characteristics of a Pneumatic Bellows Actuator for Colonoscopy
Authors: Wakimoto Shuichi ,   Graduate School of Natural Science and Technology, Okayama University, Kametani Hidehiro
Published: July 2016

Since colonoscopic insertion requires a high level of skill on the part of the examining physician, the patient may experience pain if the physician is not so highly skilled. In this study, our objective is to realize an easy-to-execute endoscopic insertion that does not rely on the physician’s skill. We develop a pneumatic actuator that gives the endoscope self-propulsion capability. The actuator is configured with three bellows made of polyethylene film. By applying pneumatic pressure to the bellows in a specific sequence to extend and contract them, the end of the actuator moves elliptically. Thus, the endoscope can be given propulsion performance by attaching several actuators and driving them in different phases. In this paper, the basic characteristics of the actuator are determined geometrically from the characteristics of the bellows, and then those characteristics are compared to the results of experiments. In addition, experiments are conducted in which a rod, used as a dummy endoscope, is transported through a pipe and inserted in an intestinal tract model. The experiments confirm and validate the proposed concept.
Development of Novel Particle Excitation Flow Control Valve for Stable Flow Characteristics
Authors: Hirooka Daisuke ,   Department of Mechanical Engineering, Kansai University, Yamaguchi Tomomi , Furushiro Naomichi , Suzumori Koichi , Kanda Takefumi ,   ,,   Graduate School of Engineering, Tokyo Institute of Technology, Tokyo, Japan,   Graduate School of National Science and Technology, Okayama University, Okayama, Japan
Published: July 2016

The authors have previously developed a compact, light-weight air flow control valve, which realizes continuous flow control. The vibration produced by a piezoelectric device (PZT) was used to excite particles confined in a flow channel to control the valve opening for the developed control valve. Therefore, the voltage applied to the PZT can be changed to continuously control the flow rate. A new working principle was developed for the control valve to stabilize flow rate characteristics. Different types of particles were used to change the valve opening condition. A prototype was manufactured to demonstrate the effectiveness of the control valve.
Non-Resonance Type Linear Ultrasonic Motor Using Multilayer Piezoelectric Actuators with Parallel Beams
Authors: Aoyagi Manabu ,   Graduate School of Engineering, Muroran Institute of Technology, Nakayasu Ryuichi , Kajiwara Hidekazu ,   ,
Published: July 2016

A linear ultrasonic motor (LUSM) with two parallel beams and two multilayer piezoelectric actuators (MPAs) has been developed. The MPAs are aligned across the beams, and the force and displacement generated by the MPAs result in the deformation of the beams in the orthogonal direction. The LUSM has two types of operation modes: dynamic and static. In dynamic operation, the MPAs are driven by alternating voltages with a phase difference, and elliptical displacement motions are generated on the surfaces of the beams. Objects touching the surfaces of the beams can be moved in the same direction by friction. In addition, micro positioning is available over a wide range by combining dynamic and static operations. The characteristics of the LUSM include a maximum speed of 41 mm/s and a maximum thrust of 3.4 N at an operating voltage of 20 Vp-p. A movement range of approximately 8 μm has been confirmed during static operation.
Surface Acoustic Wave Excitation Using a Pulse Wave
Authors: Tamon Ryo ,   Graduate School of Science and Engineering, Saitama University, Takasaki Masaya , Mizuno Takeshi ,   ,
Published: July 2016

Surface acoustic waves (SAWs) excited by bursts of sinusoidal waves have been used in various applications. However, the SAW actuators used for this purpose are expensive because each SAW transducer must be equipped with a radio frequency linear amplifier and a function generator. To simplify the driving circuits of these actuators, SAW excitation using a pulse wave is proposed in this report. Simulated results for an equivalent circuit of a single interdigital transducer and measurements of SAWs excited by pulse waves are presented. The generation of tactile sensations using a SAW excited by a pulse wave is also reported. Furthermore, the power requirements for SAW excitation by a sinusoidal wave and by a pulse wave are compared.
3-DOF Outer Rotor Electromagnetic Spherical Actuator
Authors: Nishiura Yusuke ,   Graduate School of Engineering, Osaka University, Hirata Katsuhiro , Sakaidani Yo ,   ,
Published: July 2016

Conventionally, many single-degree-of-freedom (single-DOF) actuators have been used to realize devices with multiple-degrees-of-freedom (multi-DOF). However, this makes their structures larger, heavier, and more complicated. In order to remove these drawbacks, the development of spherical actuators with multi-DOF is necessary. In this paper, we propose a new 3-DOF outer rotor electromagnetic spherical actuator with high torque density and wide rotation angles. The dynamic characteristics are computed employing 3-D FEM and its effectiveness is verified by carrying out measurements on a prototype. Then, in order to realize further high torque density, the electromagnetic pole arrangement is optimized using Genetic Algorithm (GA) and the effectiveness of the optimized stator poles arrangement is verified.
Designing Multi-Agent Simulation with Big Time Series Data for a Global Supply Chain System
Authors: Tanaka Kenji ,   Department of System Innovation, Graduate School of Engineering, The University of Tokyo, Gu Shen-Ming , Zhang Jing ,   School of Mathematics, Physics and Information Science, Zhejiang Ocean University,   ,
Published: July 2016

Multinational corporations produce products at relatively few factories and then sell those products in all areas of the world. Longer lead times increase the risk of fluctuations in product demand. To reduce this risk, the entire business chain, from production to sale, must be optimized. In this study, we propose, implement, and verify a total optimization system. This system uses multi-agent simulation on big time series data. It consists of management, integrated database, and operation modules.
Ultra-Low-Frequency Vibration Assisted Machining of Ti-6Al-4V Alloy
Authors: Sugihara Tatsuya ,   Osaka University, Enomoto Toshiyuki ,   ,
Published: July 2016

As titanium alloys such as Ti-6Al-4V provide several benefits, including high-temperature strength and high corrosion resistance, the demand for such materials has rapidly increased, particularly in the aircraft industries. On the other hand, they are known to be among the most difficult-to-cut materials due to their mechanical and chemical properties, which make tool life extremely short. In order to solve this problem, this paper proposes a new cutting method employing ultra-low-frequency (ULF) vibration. ULF vibration ranges from less than 1 Hz to approximately 10 Hz and is generated by using a numerically-controlled machine tool axis and an NC program. The results of turning experiments showed that the developed method significantly reduces crater wear in the machining of Ti-6Al-4V, even under dry machining conditions. Moreover, the mechanism that ULF vibration affects and the effect of actual cutting time and non-cutting time in each individual vibration period on the amount of crater wear were investigated. As a result, it was found that the developed process is a promising method for achieving high performance dry machining of titanium alloys.
High Compressive Strength, Ultra-Lightweight and Lightweight Cement – Formulated with Raw Material Locally Available in Saudi Arabia
Authors: Sarmah Pranjal , Al Tawat Najeeb , Yadav Prahlad , Agrawal Gaurav
Published: July 2016

This paper presents our research on developing new lightweight and ultra-lightweight cement formulations which have resulted in higher cement strength, better adhesion and improved cement bond logs. The resulting formulation could be used for deeper placement in wells. Traditionally, these have been viewed as technology limiters for lightweight cements.

We screened local raw materials, cement available in Saudi Arabia. This in combination with carefully selected glass microspheres, have resulted in unique ultra-lightweight cement formulation. Careful selection of particle sizing and micro-additives has resulted in better adhesion. This paper describes the formulation, lab test results, and structural properties found through use of x-ray diffraction analytical testing. Additionally, it shows a comparison among the various density formulations with different microspheres and additives. Success in formulating with locally available ingredients improves supply chain flexibility – often a key in successful operations.

Our results show nearly double the mechanical strength expected from a lightweight formulation lower than water density. Systematic approach considered during fluid optimization. The Paper will highlight the improved crush resistance of the beads and summarize the robust laboratory tests performed to qualify it for applications in a wide variety of challenging down-hole conditions including lost circulations and weak formations. Due to more predictable downhole density, complete circulation can be achieved deploying this slurry. The set cement mechanical properties, including compressive strength, have significantly improved which is essential for ensuring long-term isolation. Conventional water-extended cement slurries are not considered adequate to isolate unconventional reservoirs such as shale and tight sandstone.

We believe this formulation discovery, when further optimized, could be the basis of high-performance lightweight cement systems that are capable of deeper placement in the wells with improved pumpability and on-location rheology and set time control. Our formulations leverage normally available particulate materials to the best of our knowledge.
How to Make Drilling Operation in Ultra-Deep Water from Better to Best
Authors: Liqiu Ping , Wangxi Wangxi , Yanfeng Wang , Guangfeng Wan , Zouke Zouke , Fujin Fujin
Published: July 2016

X. Block is the exploration ultra-deep water block in Brazil and the average water depth is about 2000m, and the reservoir target zone depth is about 5800m. The major challenges of drilling in X. Block are pipe stuck in shale and salt formation, losses in carbonate formation and low ROP in pre-salt formation that cause too much NPT (about 37% NPT) and sidetracking (1-2 sidetracking points). So the actual drilling duration is longer than the planed and drilling cost is higher than the budget.

This paper discusses the optimization processes of drilling operation in X. Block to cope with the drilling challenges including casing program optimization and drilling fluid system and properties optimization to deal with the stuck in shale and salt formation, MPD to solve losses in carbonate formation and to increase ROP in pre-salt reservoir formation. In addition, advanced drilling ship equipped with double derrick and advanced drilling operation management system to improve drilling efficiency and decrease NPT to make drilling operation from better to best have been mentioned in the paper.

Stuck NPT in shale and salt formation is decreased from 18% to 2% and sidetracking is avoided by optimizing casing program and drilling fluid system and properties. The average flow rate is enhanced 40% and the ROP is increased 37% by MPD in the carbonate losses formation. The average ROP in pre-salt formation is improved from 2.1 m/h to 3.5m/h and the drilling speed is increased by 66.7% by the optimizing bit type. Well drilling duration is sharply shortened by 45% and the total NPT is decreased from 37% to 5.6%-9.5%.

This paper will highlight the ultra-deep water well drilling challenges in X. Block of Brazil, matching drilling technologies respectively for stuck in shale and salt formation, losses in carbonate formation and low ROP in pre-salt formation as well as the application results of optimization. The experiences presented in this paper can give a light to ultra-deep water drilling operation optimization.
Enhance Drilling Performance Using an Optimized Mud Fluid System through Extensive Laboratory Testing
Authors: Al-Ansari Adel , Abuhamed Amr M , Abahusain Abdullah , Pino Rafael , Bialy Moustafa El , Zoghbi Bilal
Published: July 2016

Drilling oil-producing lateral wells often requires the use of an efficient drill-in fluid (DIF). A properly designed reservoir DIF with precise control of its properties is essential to help prevent formation damage that can impede production. This paper discusses the custom use of a DIF to reduce damage while drilling a lateral well to help maximize productivity during later stages.

Oil-based mud (OBM) with density of approximately 67 lbf/ft3 was formulated based on reservoir data by optimizing the particle size distribution (PSD) of the bridging materials used to effectively bridge against the average pore throat sizes. It was tested in the laboratory at simulated reservoir conditions and applied in the field at the target well. The fluid was continuously monitored at the rig for PSD and fluid loss control using the particle plugging test (PPT). The hole cleaning and equivalent circulating density (ECD) were simulated with proprietary hydraulics software.

Using nondamaging specialty products that reduce fines and fluids invasion is an essential prerequisite for a reservoir DIF. This paper describes the case history of drilling a horizontal well in a sandstone formation in Saudi Arabia and also shows the successful use of a reservoir DIF on lateral wells. It presents an approach that helps minimize formation damage, mitigate differential sticking, and drill a hole without having any hole problems. Implementation of this optimized fluid in the field while using specially designed practices to maintain the quality of the DIF during drilling led to a higher level of production rates.

This paper concludes that close monitoring of mud properties, optimization of PSD design, and the use of nondamaging specialty products helps minimize fluid invasion and deliver maximized production.
A Business Intelligence Approach to Maximize Value of I-Field Data by Managing Data Quality
Authors: Al-Ghamdi Reema , Abdulal Haider
Published: July 2016

With the advent of I-filed (Intelligent Field) data and the increasing volume of various data sources, reservoir simulation engineers aim and work on capitalizing on all of those data in addition to the regular monthly averages. Due to the time scale variation and data frequency, a tool is needed to assist engineers to maximize the value from the data sets and at the same time ensure accuracy and representativeness of the simulation input. This paper discusses a workflow that utilizes Business Intelligence capabilities to compare both data sets, the I-field and monthly averages, and visually identify the anomalies.

Several issues can be recognized in and between the data sets that are of different sources and timescales, which will create a struggle for simulation engineers to synchronize both data sets and select the reliable data source to be incorporated into the simulation model, especially when they are working on I-fields where they will be represented with two sets of data. The developed workflow capitalizes on Business Intelligence functionalities that will use an equation to compare the data sets against each other and represent the results in charts to graphically identify the discrepancies. Since the average monthly measurements are stored in monthly format and daily measurements, I-field real-time data, are stored in daily format, the workflow will transform the daily measurements format to match the monthly measurements before the comparison.

The workflow will assist simulation engineers to QC (Quality Check) the large sets of data automatically and graphically by locating the areas to focus on in the data, which will reduce human errors, the time needed to examine the data sets and the time needed to alter the format of the daily measurements. Simulation engineers need to QC the data sets before they are integrated into the simulation model to enhance the quality of the model, produce accurate results and reduce the time for simulation engineers to manage the data quality.

There are many methods to manage data quality; however, Business Intelligence offers a wide range of data acquisition and mining techniques for QCing. This paper will present how these techniques are used to enhance and streamline the process of data QC for the monthly and daily measurements.
Computational Fluid Dynamics Study of a Centrifugal Downhole Oil Water Separator CDOWS for Potential Use in High Water Cut Wells
Authors: Hashem Mohamed Hossni , Belhaj Hadi , Abukhalifeh Hadil
Published: July 2016

With the decreasing price of oil nowadays, the need to develop techniques to reduce operational costs in a field is inevitable. Formation water is a by-product obtained during oil production which is produced is produced in higher quantities than hydrocarbon. This is a major concern for oil and gas industry as separating, treating and reinjecting of the produced water into the reservoir formation requires a large amount of energy, money and time.

This paper proposes a new technique for downhole separation of oil and water using a tubular centrifuge which can be integrated of the casing or the tubing string. This centrifugal downhole oil/water separator (CDOWS) will introduce the feed to a large centrifugal force which will separate both fluids based on density differences. The technology is designed for different well configurations satisfying several conditions in the industry.

This paper shows and tests the model using Computational fluid dynamics (CFD) study for different designs and configurations. To validate this process in a downhole configuration, a computational fluid dynamics (CFD) study is conducted on a CAD model which was designed using a 3D modeling software.

The study investigates the separation efficiency using various diameters, RPMs of the CDOWS as well as different flow rates and water cut. Furthermore, different possible designs are considered in this study. The results are then used to optimize the design of such tool in order to produce a physical model.
Real-Time Estimation of Flow Rate in Dry Gas Wells – A New Field
Authors: Al-Kadem Mohammad S. , Al Dabbous Mohammad S. , Al Mashhad Ali S. , Alsadah Hassan A. , Al Shehri Dhafer
Published: July 2016

There are well-known correlations and technologies which estimate the flow rate in dry gas wells. Measuring the surface rate is challenging, especially when there is no measuring equipment. Nevertheless, the choke equation and some well-known correlations can provide an estimate of the flow rate whether the gas at the surface is single-phase or multi-phase but with a certain accuracy and basic assumptions.

Another tool to estimate flow rate is the surface venturi meter, which is being used for dry gas wells. In this paper, a new method was established to calculate and verify measured gas flow rates. An empirical correlation was developed to calculate the real-time flow rate in dry gas wells at the surface utilizing the most appropriate parameters: upstream flowing wellhead pressure, downstream flowing wellhead pressure, upstream flowing wellhead temperature, and choke size. The proposed equation consists of a coefficient for each individual parameter which is fine-tuned in the equation using an advanced non-linear regression method.

Moreover, a comparison between calculated rate using the new method and measured gas rate shows accurate values with an average absolute error of 11%. A comparison between the measured rate, Beggs equation, and Gilbert's correlation showed highly deviated values, with an average absolute error of 60% for Beggs's and more for Gilbert's. It is worth highlighting that there is a major difference between the new correlation and Beggs' equation or any other that the new correlation is customized for the selected field. Another difference that the new correlation uses real and field data whereas the Beggs's equation and Gilbert's correlation used experimental data which might not be applicable to the selected field. Hence, this correlation provides a matching trend to the measured flow rate from venturi readings in dry gas wells.

The new correlation would enable production engineers to enhance their rate validity and furthermore it might replace the meter readings when the meter device become defective. Also, this correlation is aimed at calculating the gas flow rate in real-time measurements of wellhead parameters which enhances the monitoring of the well's performance on a real-time basis.
A New Approach for Modeling Scale Formation during Water Injection into Carbonate Reservoirs
Authors: Lu Peng , Wang Qiwei , Chen Tao , Chang Frank
Published: July 2016

Water injection is commonly used in oil fields for pressure support and productivity enhancement. Injection water, if incompatible with formation water, can induce scale precipitation and impose a significant threat to economic and efficient field operation. Reliable scale prediction is of critical importance for the selection of suitable injection water and development of an effective scale management strategy.

The traditional (thermodynamic) approach for scale prediction only provides precipitation potential at different mixing ratios. It describes the initial and final states of the system and omits some intermediate processes and products that may be important for operations. In addition, it may overestimate the total amount of the scale forms. In this paper, we describe a new approach, the kinetic approach, to facilitate more accurate prediction of scale formation.

We demonstrate the kinetic approach in a parametric study of seawater injection into a carbonate reservoir in Saudi Arabia using Reactive Transport Modeling (RTM). RTM simulates coupled multiphase fluid flow and chemical reactions, and has the capability of predicting time-dependent mineral scales formation and associated reservoir quality deterioration. Formation of calcium sulfate scale in the reservoir and near wellbore is a major concern due to high calcium concentration in formation water and high sulfate concentration in the seawater. We built a two-dimensional RTM using TOUGHREACT v1.2 with GUI pre- and post-processor PetraSim v2015, and simulated scale formation over a 20-year time span. Reservoir heterogeneities was considered in our model. The impact of scale formation on the reservoir and well properties during waterflooding operations was evaluated.

The results indicate that the migration path of the solutes depends highly on the reservoir permeability distribution; preferential flow paths form in the high permeability layers. At 20 years, up to 11.6% anhydrite scale forms in the mixing zones of injection and formation waters and up to 18% calcite scale forms near injection wellbore (~ 10 m radial distance to the wellbore). Severe porosity reduction is predicted near the injection wellbore and in the mixing zones at 20 year due to the formation of calcite and anhydrite scales, respectively. A negative feedback forms between the initial exploitation of preferential flow paths and subsequent reservoir quality deterioration in these paths.

The kinetic approach described in this paper will offers a significant improvement on scale prediction results over the traditional approach for field development and cost-effective scale management strategy.
Design Optimization of Multilateral Wells in Heterogeneous Reservoirs
Authors: Ayokunle Ajayi Temitope , Hashem Mohamed Hossni
Published: July 2016

Maximizing profit with minimal costs is a top priority in the oil and gas industry. With the dynamics of today's oil market, finding economically feasible tools to maximizing the production is vital. Multilateral wells possess the potential of achieving such a goal. To date, different theoretical designs of multilateral wells are proposed in literature. One of the most common designs studied is the fishbone configuration. This configuration maximizes the reservoir contact and thus the productivity of the well. While the merits of the application of multilateral wells are well documented, an understanding of the best operating conditions for the use of multilateral wells is rare thus we answer cogent questions related to the optimization of multilateral wells under different reservoir conditions and well design parameters.

To answer such questions, Design of Experiment (DOE) and Response Surface Methodology (RSM) was utilized. Selected factors to be optimized are the number of laterals, length of horizontal sections of laterals, correlation lengths for heterogeneity indication, reservoir thickness, and permeability anisotropy. These factors were chosen based on literature search, perceptions and deliberations while the objective function is the cumulative oil production. Several experiments were conducted using extensive three dimensional fine scale numerical simulations and the Box Behnken response surface methodology was used to derive the response surfaces. Single effects and interaction plots are made to show the interactions between parameters and the effect of these parameters and interactions on the objective function.

Results show a high dependence of productivity on the horizontal section length and reservoir thickness. This implies that candidate reservoirs for the application of fishbone multilateral wells should possess larger thickness. However, where the reservoir is thin production can be improved using longer horizontal sections. The outcome of this study indicates the importance of the horizontal section and lateral lengths on a fishbone multilateral well productivity from the same reservoir.

This study provides a template for decision making in field development operations thereby reducing uncertainties and maximizing gains.
Coupling Memory-Based Diffusivity Model with Energy Balance Equation to Estimate Temperature Distributions During Thermal EOR Process
Authors: Hassan Amjed M. , Hossain M. Enamul
Published: July 2016

At the end of the primary recovery phase, enhanced oil recovery (EOR) process such as hot water flooding becomes more attractive to reduce the residual oil saturation and to increase the oil production. It is well known that during hot water injection, the heat transfers from the injected fluid to the reservoir matrix, and this transfer depends mostly on the rheological and thermal properties of the formation rock and fluids. Moreover, the injection time and fluid velocity play significant roles on the temperature distribution. Therefore, it is important to investigate the effects of fluid velocity on the temperature distribution during thermal operations. The temperature profile in a reservoir formation is an important indicator of various reservoir conditions, such as type of fluid encroachment, the state of water or gas influx, etc. This information is necessary for better reservoir management. Previous studies assumed constant fluid velocity throughout the reservoir to calculate the temperature variations. However, this work studies the temperature distributions of reservoir rock and fluid during thermal operations by employing the velocity profiles.

The temperature distributions are estimated by coupling a proposed memory-based diffusivity model with energy balance equation. The variations of fluid velocity are produced by solving the memory-based diffusivity equation, and then the temperature distributions are estimated based on the fluid velocity profiles. The proposed energy balanced equation is solved by a newly developed numerical technique. This technique is used to couple the energy balance equation with the memory-based diffusivity model. The model equations are solved simultaneously together by Matlab programming language. The temperature profiles are analyzed for unequal rock and fluid temperatures throughout the reservoir.

Results show that, coupling of the pressure model and temperature model can lead to more reasonable temperature distributions during thermal flooding and then to better design of such operations. In addition, it is found that temperature distributions are affected mainly by the pressure variations and the fluid velocity. The finding of this research will help to improve the performance/efficiency of thermal flooding operations.
Enhanced Petrophysical Interpretation of 3D Electromagnetic Surveys for Reservoir Characterization
Authors: Alsaif Sarah F. , Alkhatib Ali M. , Marsala Alberto F.
Published: July 2016

Increasing the recovery factor of brown fields is one of the key challenge for oil companies. When production is driven by water injection, monitoring flood front movements reservoirs is crucial to optimize field production strategies. Most reservoir characterization and saturation tools provide data at specific locations in the reservoir, with a limited radius of investigation around the wellbore. One promising approach to map and monitor the saturation distribution is to deploy 3D electromagnetic surveys. These methods provide an indirect way to determine the saturation by measuring the spatial distribution of resistivity in the inter-well regions.

One of the main challenges in the interpretation of electromagnetic methods is the uncertainty in our knowledge of the reservoir properties in the inter-well regions. These properties are necessary to derive saturation maps from resistivity measurements. This study introduces a novel approach to interpret electromagnetic surveys, producing robust saturation maps that can guide reservoir management practices. The described workflows apply dynamic simulation and advanced uncertainty quantification. The main uncertain parameter that is considered in the proposed approach is permeability, which is assumed to be a spatial parameter. The probabilistic collocation method was applied to efficiently quantify uncertainty in permeability and its effect on the salinity distribution. The outcome of this method is a polynomial proxy model that can be used to perform statistical analyses using a significantly large sample set with minimal computational cost. The results obtained showed that it is possible to investigate a wide range of uncertainty in a computationally efficient manner, providing more robust saturation maps compared to current practices.
Causal Factor Analysis – The Missing Puzzle Piece
Authors: Perkinson Larry
Published: July 2016

There are few if any systems in use to categorize and analyze the causal factors leading to significant incidents. This presentation explores a new categorization methodology and provides causal factor data analysis of real incidents that shows how the process contributes to improving safety.

Detailed accident investigation reports were reviewed from 40 major incidents containing literally hundreds of causal factors. Repeated passes were made through the causal factors to identify commonalities. Thirty-two discrete categories of causal factors were identified. Detailed definitions were written and multiple examples provided for each category. The categories were then tested with a new set of causal factors to ensure they were both exhaustive and mutually exclusive. The twenty-eight final categories were then put into question form for future conversion to an expert system.

The analytical advantages of the categories were tested with a group of five major crane incidents from around the world. The incident reports were reviewed and the causal factors identified. The methodology was used to categorize the causal factors and a Pareto chart was developed. This simple chart allowed the discovery of repeated causal factor categories and uncovered where corrective actions for identified root causes of the casual factor categories were inadequate.

This methodology not only assists the users in categorizing causal factors, it assists in identifying generic causes (cuts across organizational boundaries) and assessing the effectiveness of corrective actions for root causes. It has also formed the basis for building an expert system to identify causal factors, which is currently under development.
Comprehensive Traffic Safety Program of Saudi Aramco Safaniya Onshore Producing Department SOnPD Reduces Fatal Traffic Accidents in the Khafji and Nuayriah Areas
Authors: Rahman Syed Obaidur
Published: July 2016

As directed by the Vice President, Northern Area Oil Operations (NAOO), Safaniya Onshore Producing Department (SOnPD) developed and implemented a comprehensive Traffic Safety Program with the objective to eliminate or minimize traffic related accidents in the Safaniya area. The scope of this committee covered highways and major local roads from Jubail Bridge on Abu Hadriya highway up to Khafji City. Successful implementation of this program has resulted in significant improvement and has minimized traffic related accidents. The reported statistics by six NAOO departments operating in Safaniya have reported a reduction of 90+% in MVAs involving company vehicles, 70+% in private motor vehicle accidents, and over 60% reduction in Fatalities. For Safaniya Onshore Producing Department (SOnPD), the leading Department, fatalities and accidents involving company and private vehicle in the area are eliminated. On the otherhand according to government statistics, between the years 2010-2012 and 2013-2015 vehicles incidents in Khafji and Nuayriay areas saw a reduction in fatalities by 11%, i.e., 10 lives/yr were saved.
A Rigorous Correlation for Quantitative Prediction of Water Cresting in Multi-Fractured Horizontal Wells
Authors: Mahboob Ahmad , Al-Nuaim Sami , Rammay Muzammil Hussain
Published: July 2016

This study uses Artificial Neural Network (ANN) to develop correlations for estimating critical oil rate in multi-fractured horizontal wells (MFHWs) with water cresting issue.

A programming software was coupled with a commercial simulator to develop the correlation using a black oil model with typical rock, fluid and reservoir properties. The effects of reservoir fluid properties, fracture properties, water oil contact, horizontal and vertical permeability and length of the fractures were investigated in comparison with the base case and the results were converged to form empirical equations for calculating critical oil rate.

The proposed correlation is dimensionless and can be used for any multi-frac horizontal well and are function of fracture height, permeabilities, fracture conductivities and fluids' densities. All observations of this correlation complies well with the general trends e.g. low anisotropy ratio, lesser fracture conductivity and high viscosity delayed the water breakthrough. Higher anisotropy ratio and low viscosity increased critical oil rate. The results obtained from this correlation when compared with simulated data set had an absolute percentage error of and standard deviation of for critical oil rate correlation, which is quite satisfactory.

Most of the work in literature has been done for water-coning in naturally fractured reservoirs and in some limited aspects of hydraulically-fractured reservoirs, but there is a need to estimate water cresting in MFHWs in order to support early production strategies. This correlation can add value to oil and gas industry in terms of time and money.
Measurement of Bubble Point Pressures of n-Decane, CO2 and N2 Mixtures
Authors: Hassan Mohamed , Gajbhiye Rahul N. , Sultan Abdullah S. , Abu-Khamsin Sidqi
Published: July 2016

Utilization of carbon dioxide in enhanced oil recovery (EOR) serves two important goals. Firstly, it recovers more oil, which could not be recovered during primary and secondary recovery methods. Secondly, it is one of the carbon capture and sequestration (CCS) techniques that work to reduce the emissions of greenhouse gases into the air and combat the climate change. To design and optimize the process of CO2-EOR, it is crucial for engineers to have knowledge about the reservoir fluids properties and their interaction with injected gases. Bubble point pressure is critical for the description of the reservoir fluid behaviour.

Constant composition expansion (CCE) experiments were performed to measure the bubble point pressures for binary mixtures of n-decane/carbon dioxide (n-C10/CO2) and ternary mixtures of n-decane/carbon dioxide/nitrogen (n-C10/CO2/N2). The n-decane represented the hydrocarbon phase, where the gaseous phase consisted of CO2 and N2. The experiments were conducted at two different temperatures, 30 and 60° C. The gas mole fraction in each mixture ranged from 20-80%. For the gaseous phase itself, N2 and CO2 were mixed in three different proportions: 0, 10 & 20% N2 mole fractions. The work in this paper was set to examine how the bubble point would behave due to presence of nitrogen contamination in carbon dioxide, rise in temperature and changing mixture compositions.

The results shows that bubble point pressure increased when the temperature increased from 30° to 60° C, for all mixtures. These increases in bubble point pressures ranged between 19-35%. The introduction of N2 into the mixture would raise the bubble point by up to 55%. The addition of more hydrocarbon into the mixture decreased the bubble point. Bubble point pressure is a strong function of gas solubility, which is capable to explain these behaviors of bubble points.