bluuebunny/crossref_metadata_2025 huggingface dataset:
New Insights in the Characteristics Required for A Successful Flowback Surfactant and Its Use in Tight and Unconventional Reservoirs
Authors: Rabie Ahmed , Zhou Jian , Qu Qi
Published: April 2019

Hydraulic fracturing has always been associated with significant volumes of fracturing fluid invading the formation matrix, which leads to water blockage and a reduction in relative permeability to gas or oil. In Shale and tight formations, this has become more challenging since capillary forces have profound impact on water retention and hence, water recovery and subsequent oil productivity. Surfactants and microemulsions have been extensively reported as flowback additives to lower surface and interfacial tension to maximize water recovery.

Most of the previous studies focused on a few testing methods to validate a surfactant or a microemulsion formulation for flowback use. In this work, a new environmentally friendly water-based surfactant formulation (Surf-I) was evaluated for flowback and its performance was compared against several industry standards of microemulsions and non-ionic alcohol ethoxylated surfactant. Surface tension (ST), interfacial tension (IFT), contact angle (CA), and coreflood tests were conducted in a wide range of typical field conditions of water salinity, temperature, crude oil type, and surfactant concentration. Core flow testing on 0.1-0.3 md Kentucky sandstone was conducted simulating oil reservoirs following constant-pressure flow schemes of 50-500 psi. Water recovery and oil productivity were determined for each pressure stage.

The new formulation showed a surface tension of 26 mN/m with CMC corresponding to a load of 0.1-0.3 gpt, depending on the water salinity. Interfacial tension measurements varied from 0.17 mN/m to 10 mN/m, depending on the crude oil type and temperature. Contact angle measurements indicated the surfactant ability to water-wet controlled substrates. The coreflood results confirmed the benefit of using surfactants for flowback versus non-surfactant cases, especially at low- to mid-pressure flow and. At 50 psi pressure difference, no oil was observed in the no-surfactant case. At 100, 250, and 500 psi the oil productivity with surfactant was 53, 22, and 20% higher than the base case. The results also showed that a formulation with ultra-low IFT (5E-2 mN/m), can initially recover substantial water volume but did not show a superior performance over the new formulation. The data obtained in this study can be used to identify the optimum criteria of a flowback additive in terms of surface tension, IFT, and wettability requirement to enhance water recovery and maximize oil productivity.
Advanced Modeling of Production Induced Pressure Depletion Impact on Infill Well Using Cloud Computation in the Haynesville
Authors: Zheng Wei , Xu Tao , Baihly Jason , Malpani Raj , Li James , Zhang Rui
Published: April 2019

Since late 2017, the Haynesville Shale has seen an uptick in activity as more operators have started to drill more new shale wells than at any other time since the industry was slowed due to declining oil price at the end of 2014. Some of the new activity has been focused on pushing the economic boundaries of the Haynesville shale out whereas others have focused on drilling infill wells or wells that are drilled between pre-existing wells (known as "parent wells"). Parent wells may cause pressure depletion in the reservoir, potentially hindering the performance of new infill wells. The distance from the parent well to an infill well along with the degree of reservoir depletion caused by the parent well impact, to varying degrees, the production results of the infill wells. It is important to design a completion program in the infill well that minimizes the potential negative impact of depletion. This paper presents detailed studies assessing the impact of the change in offset well spacing and reservoir depletion related to parent wells on infill well performance through modeling in the Haynesville shale.

An actual reservoir dataset was utilized in the Haynesville shale to build the parent well hydraulic fracture and reservoir simulation models to account for fracture calibration and production history matching. The models' results were then used to evaluate the impact of production depletion on the stress reorientation and changes in stress magnitude through a coupled boundary element and finite element model residing in a geomechanics simulator. Three different production depletion times were modeled through the simulation, 0.5, 1, and 3 years, to understand the timing impact on the infill well production. After the stress in the model was updated for each case, a child well pad was added to the model adjacent to the parent well. The well spacing, stimulation job treatment, and fracture stimulation pump rates were all varied for child well simulation and evaluated to understand their impacts on the created complex fracture propagation and total system hydrocarbon recovery.

In this study, more than 200 different scenarios were simulated by using cloud computation, and each parameter was compared for varying spacing scenarios for the three depletion time horizons. This study can help the understanding of well spacing, completion job design, and reservoir depletion impact on the new infill well performance and help the optimization of the infill well completion strategy to achieve optimum production performance for new infill wells and minimize communication or fracture hits to the existing parent wells in the Haynesville.
Modeling Interwell Interference Due to Complex Fracture Hits in Eagle Ford Using EDFM
Authors: Fiallos Mauricio Xavier , Yu Wei , Ganjdanesh Reza , Kerr Erich , Sepehrnoori Kamy , Miao Jijun , Ambrose Raymond
Published: April 2019

Shale field operators have vested interest in optimal spacing of infill wells and further fracture optimization, which ideally should have as little interference with the existing wells as possible. Although proper modeling has been employed to show the existence of well interference, few models have forecasted the impact of multiple inter-well fractures on child wells production to optimize further hydraulic fracture designs. This study presented a rigorous workflow for estimating the impacts of spatial variations in fracture conductivity and complexity on fracture geometries of inter-well interference. Furthermore, we applied a non-intrusive embedded discrete fracture model (EDFM) method in conjunction with a commercial black oil reservoir simulator to investigate the impact of well interference through connecting fractures by multi-well history matching, based on a robust understanding of fracture properties, real production data and wellbore image logging. First, according to updated production data from Eagle Ford, the model was constructed to perform four (parent) wells history matching including five inner (child) wells. Later, fracture diagnostic results from well image logging were employed to perform sensitivity analysis on properties of long interwell connecting fractures such as number, conductivity, geometry, and explore their impacts on history matching. Finally, optimal cluster spacing was recommended considering interwell interference. The simulation results show that well interference is present and reduces effectiveness of the fracture hits when the connecting fracture conductivity, primary fracture conductivity, and number of connecting fractures increase. Because of these interwell long fractures, the bottomhole pressure behavior of the parent wells tends to equalize. Furthermore, the EDFM application is strongly supported by complex fracture propagation interpretation from image logs through the child wells in the reservoir. Through this study, three possible scenarios are shown with robust history matching of the model considering more than 20 complex dominant long interwell fracture hits and more than 2000 hydraulic fractures.

The model became a valuable stencil to decide the well location and spacing, the completion staging, and to optimize the hydraulic fracture treatment design as well as its sequence so that it can be expanded to other areas of the field. The simulation results were applied to the field successfully to afford significant reductions in offset frac interference by up to 50% and reduce completion costs up to 23% while improving new well capital efficiency.
Experimental Study on Surface Frictional Behavior of Materials for Lost Circulation Control in Deep Naturally Fractured Reservoir
Authors: Xu Chengyuan , Yan Xiaopeng , Kang Yili , You Lijun , Zhang Jingyi , Lin Chong , Jing Haoran
Published: April 2019

Plugging natural fractures with lost control materials (LCMs) is the common method to prevent foramtion damage and control fluids loss in In naturally fractured reservoir. The plugging zone strenfth stability is critically important for maintaining long-term plugging quality. Surface friction coefficient (SFC) is proposed as an important parameter for the selection of LCMs based on based on granular matter mechanics and the instability of plugging zone. The force chain network with specific geometry is the basis of the plugging zone strength and supporting external load. The likelihood of shear failure can be increased by decline of SFC. And high strength of force chain can not be formed and it can relatively easy to be broken even if a small shear is applied. Effects of LCMs particle size distribution, circulation abrasion, LCMs combination, working fluids infiltration, and high temperature aging on friction behaviors are analyzed for LCMs with high SFC selection. Results show that the average SFC shows a decreasing trend with the particle size reduction and the difficulty of particle dislocation decreases with the particle size reduction. For deep naturally fractured reservoirs, particle size will degradate due to long-term drilling fluid circulation in the wellbore, thus affecting the plugging effect of drill-in fluid. The mixture of elastic material and fiber into rigid material increases the SFC and elastic material contributes most to the increasing the SFC. The SFC decreases under the condition of fluids infiltration, and the SFC show a higher decline in oil-based condition. The high-temperature aging makes the edge of the organic rigid material more smooth, which reduces its SFC.
Converting Waste Vegetable Oil to Emulsifier for Invert-Emulsion Oil Based Mud
Authors: Ramasamy Jothibasu , Amanullah Md
Published: April 2019

Primary emulsifiers are an integral part of an invert emulsion (water in oil) oil based mud system. These are a class of long chain fatty acids and their derivatives. Primary function of an emulsifier in invert emulsion invert emulsion oil based mud system is to minimize the interfacial tension (IFT) between water and oil to have a stable emulsion which is an important quality of oil based mud. Water droplets are surrounded by these long chain fatty acids like an encapsulation. Fatty acids have hydrophilic head group and hydrophobic head group. The hydrophilic end groups are in contact with the surface of water droplets while the hydrophobic tail groups extend into oil phase thereby forming an osmatic cell. Only water can pass through the osmatic cell wall but not salts. Tall oil fatty acid (TOFA) are the most widely used commercially available emulsifiers which shows excellent emulsion stability even at harsh conditions such as high temperature and high pressure. TOFA is a by product of paper industry. Vegetable oil is also a good source of fatty acids present in the form of triglycerides of saturated and unsaturated fatty acids of varying carbon chain lengths. Our focus on this work is to utilize the abundant availability of used cooking/vegetable oil available for the application of emulsifier by chemical modification. A comparative study has been carried out by formulating invert-emulsion OBM using commercially available emulsifier and the emulsifier derived from used cooking/vegetable oil. The performance of emulsifier developed from waste vegetable oil has been discussed in detail.
Minimise System Upsets in High Oil Production Facility throughout Demulsifier Chemical Trial
Authors: Scarborough James , Mega-Franca Leonardo , Ibrahim Mohamed
Published: April 2019

Process upsets in high oil production facilities can hinder optimal plant performance and result in system shut-ins. Based on several successful demulsifier chemical trials, scientists and engineers have developed a guideline on how to optimize production throughout the chemical trial period. Factors such as chemical injection rate, export crude oil monitoring (basic sediment and water (BS&W) and salt), discharge water quality(from the water-oil separator (WOSEP)), and transformer voltage fluctuation (dehydrator and desalter) plays an important role in minimizing the system upset.

Prior to chemical trial, scientists and engineers analyze the process system to understand individual vessel functions and limitations. Incumbent chemical program provides baselines and key performance indicators (KPIs) set minimum oil specifications before exporting oil to refineries. Demulsifier injection rates are reduced based on the chemical program optimization proposal until it reaches the dosage limit while maintaining stable process throughout the trial. Therefore, scientists and engineers may evaluate the demulsifier’s performance based on the KPIs set with no system upset. Fast fluid separation in the High Pressure Production Traps (HPPTs) is an important strategy in order to improve process system’s performance.

High volume oil production systems typically have two HPPTs in parallel for initial water separation. Downstream of the HPPTs is the Low Pressure Production Trap (LPPT), which is mainly used for gas separation. Oil continues to the dehydrator to finish the dehydration to meet the pipeline BS&W requirement. The dehydrator is where the transformer is located for the electrostatic grid and high amounts of water separation can cause fluid levels to fluctuate and trip the transformers.

Throughout several field trial experiences, demulsifier rates can be optimized (reduced) further when it shows increased water separation at HPPT vessels. Clear water from HPPTs discharge, valves in water leg HPPTs open more (%), stable voltage grid (dehydrator/desalter), and less than 0.2% BS&W with less than 10ptb salt recorded at the export oil gives a good indication that the process is stable. Thus reduced the risk for system upset.

This paper summaries the best approach to optimize chemical rates in high volume oil production systems, analyzes qualitative and quantitative system checks to verify stable operations, and discusses potential risks involved when reaching lower limits of effective chemical rates.
Current Methods and Novel Solutions for Mitigating Lost Circulation
Authors: Ramasamy Jothibasu , Gooneratne P Chinthaka , Amanullah Md
Published: April 2019

This paper presents novel lost circulation materials that are being developed to address and effectively control moderate to severe lost circulation. We also present a thorough analysis of drilling methods, lost circulation scenarios and current lost mitigation strategies that have to be undertaken when drilling in severe lost circulation zones, which could also improve the probability of success of the novel lost circulation materials to cure losses. Recent development on lost mitigation materials comprising of polymers and fibers is also discussed in detail.
Practices and Understanding on the Anti-Sloughing Drilling Fluid Technology of SOilfield
Authors: Wenquan Tang , Chao Xiao , Yuzhi Xue , Tian Lu Zhang Hongbao , Chengcheng Niu , Ruiyao Wang , Qingshui He , Lingjun Kong , Zhifa Wang , Haoya Liu , Yan Li
Published: April 2019

In order to solve the problem of severe borehole instability while drilling in the S oilfield, technical research on drilling fluids has been carried out. Firstly, the paper analyzes the mechanism and technical difficulties of borehole instability in depth. Aiming at the reasons of borehole instability, the reasonable drilling fluid flowrate was defined by considering hydraulic erosion, drilling fluid plugging property, inhibition, etc, and the anti-sloughing drilling fluid system was optimized by way of strengthening the plugging and inhibiting properties of drilling fluid system. This technology has been applied in more than 40 wells in the S oilfield, the problem of borehole instability in the fractured formation was solved successfully, and the drilling speed was increased by 25.3%, which greatly reduced the downhole complexity and achieved remarkable application effect.
Digital Reamers to Mitigate Narrow Margin Drilling Hazards for Deepwater ERD Wells in Malaysia
Authors: Lim Ming Seong , Singh Rajpaviter , Mohd-Radzi Razif , Khor Jonathan , Wong Yau Min
Published: April 2019

In planning for their first TLP deep water project in Malaysia, Shell faced the unique challenge of drilling ERD wells in soft unconsolidated sands with narrow ECD margins. Prior experience suggested the benefit of managed pressure drilling & an additional casing profile with hole enlargement to be implemented for these wells. The formation is also believed to be time sensitive, and reducing the wellbore exposure time between drilling and running liner was considered a priority.

A full suite of LWD services were also planned to be run on these sections, resulting in potentially a very long rat hole as the conventional reamer can only be placed above LWD tools. An additional hole opening trip to minimize rat hole length was not desirable, which in turn leads to concerns of well bore stability due to time exposure as highlighted earlier, as well as increasing potential risk of side tracking in the soft interbedded formations. Flow rate restrictions due to the pressure drop requirements from conventional reamers, was not desirable so as to maintain ECD stability.

In order to address the needs and challenges above, contractor proposed a dual digital reamer solution, in order to ream and drill the hole sections in a single run. The digital reamers, each being powered by the LWD suite, were activated via downlinks, eliminating the lengthy time required by drop ball reamers at high angles. The ability to downlink on demand and perform selective reaming without any pressure drop restriction, had provided added benefits while drilling in narrow ECD margin. As placement of the digital reamers are flexible within the LWD tools, dual reamers were deployed in the BHA. The top reamer located above the LWD tools was activated while drilling to ensure necessary LWD data quality was obtained. A near bit digital reamer was activated post-drilling to eliminate the long drilling rat hole, resulting in minimal rat hole achieved similar to the outcomes of a dedicated trip. Eliminating the dedicated trip also greatly minimized the risk of unintentional side track.

The use of dual digital reamers enabled safe and problem-free drilling, logging, casing and cementing; allowing all of Shell’s objectives to be met in a single run, as well as significant exposure time of the wellbore, up to 3.5 days over 3 hole sections and costs savings, up to 1.2mil USD.
Control of Pore Types and Fracture Intensity on the P-Wave Velocity of Carbonate Rocks
Authors: Abdlmutalib Ammar , Abdullatif Osman
Published: April 2019

The study objective is to determine the major factors controlling on acoustic and geomechanical properties of carbonate rocks of Jurassic D5 Member of Dhruma Formation. The study integrates petrophysical, petrographic, and geomechanical analysis to characterize different lithofacies, diagenetic properties, shear and compressional wave velocity, rock strength, dynamic elastic moduli, porosity and permeability of carbonate rocks. A total of sixty samples were collected, petrographic thin sections and Scanning Electron Microscopic images were prepared, small cubes and core plugs were prepared for porosity and permeability measurements as well as wave velocities and point load index tests. Porosity and permeability exhibited moderate to poor correlations. P-wave and S-wave velocities are moderately correlated with porosity. However, they showed better correlation with permeability. Poor to moderate direct correlation between dynamic elastic moduli (Poisson ratio and Young modulus) and porosity were found. The lithofacies with large fracture intensity are related to small P-wave velocity values. Four classes were found based on pore type and diagenetic classifications control on acoustic properties: Class 1 is characterized by moldic and intraparticle pore types with limited microporosity, Class 2 is characterized by intensive micro-fracturing, class 3 is intensively cemented, and Class 4 is characterized by microporosity. Micro-fractures pore type samples show the best wave velocity versus porosity correlation followed by densely cemented microporosity and finally moldic and intraparticle show the weakest correlation. Vertical semi-variograms were measured for P and S-wave velocity as well as porosity. A spherical model was found for P and S-wave velocities with zero nugget values and sill values equal to 3 meters. Hole effect reflecting the control of cyclicity was found. Porosity semi-variogram shows exponential modeling with zero nugget value and sill value equal to three meters. This difference in semivariogram between velocity and porosity supports weak and moderate correlations between them.
A Real-Time Pipeline Tracking Using a Forward-Looking Sonar
Authors: Tipsuwan Yodyium , Kasetkasem Teerasit , Hoonsuwan Phakhachon , Leangaramkul Apinya
Published: April 2019

The pipeline inspection is one of the most critical tasks in the oil and gas industries. The operation of a remotely operated vehicle (ROV) for the pipeline inspection is very costly since it requires both a human operator and the support vessel to which an ROV must be tethered. Furthermore, this tether also limits the surveillance ability of an ROV. Thus, the use of autonomous underwater vehicles (AUVs) can greatly reduce the operation cost of pipeline inspection since an AUV can freely and automatically navigate without tethering to support vessel. In order for an AUV to navigate automatically under the limited vision in the underwater environment, the forward-looking sonar (FLS) is the essential part since the quality of images captured by an optical camera degrade significantly by the turbid water and the low-light condition whereas images produced from an acoustic sonar

As a result, in this work, we are interested in the use of a 2-D multi-beam Forward-Looking Sonar (FLS) to capture echo images on a frontal vision since acoustic signals can pass through tiny particles in turbid medium water [1]. This deployment ensures that an image of pipelines can be captured regardless of low underwater visibility conditions. Other types of sonars that are regularly used in underwater visual inspection include the side scan sonar (SSS), synthetic aperture sonar (SAS), and multi-beam echo sounder (MBES).

There are a limited number of works that focus on the pipeline detection problem. An optical camera was employed in [2] for visual feedback and heading control, SSS and MBES were used in [3], [4] and [5] for pipeline tracking, and, in [6], FLS was used for linear object detection and tracking.
Integration of Latest Laboratory, Software and Retarded Acid Technologies to Increase Efficiency of Acid Treatments in Carbonates: Case Studies from Central Asia
Authors: Abdrazakov Dmitriy , Ziauddin Murtaza , Vernigora Denis , Beletskaya Anna , Yakimchuk Ivan , Olennikova Olesya , Usoltsev Dmitriy , Nikolaev Max , Panga Mohan , Burlibayev Askhat
Published: April 2019

Acidizing treatments in carbonates often result in significant skin decrease due to high reactivity of the formation with acids. Noticeable production increase or inability to run analysis tools after the treatment may lead to the conclusion that the matrix acidizing job was performed efficiently, when, in fact, the job was not optimized in terms of fluid volumes, acid types, wellbore coverage, and pumping rates. As a result, the final skin is not as low as it could be, and, most importantly, medium - and long-term post-acidizing production decline is faster than it could be with an optimized treatment.

To overcome these concerns, an integrated approach to acidizing treatments was implemented for different oil fields in Kazakhstan. The integrated approach consists of comprehensive laboratory testing, which includes core flow tests with subsequent 3D computer tomography scanning. The tests help to determine wormholing regimes and channel geometry while providing calibration points for acid-rock interaction curves. These coefficients are used in the acidizing modeling software, which enables optimization of fluid volumes, pumping rates, and diversion strategy. The approach suggests the use of a single-phase retarded acid system is the most effective method of keeping the treatment in the dominant wormhole regime, especially at elevated temperature. The integrated approach loop is closed by the analysis of the distributed temperature sensor data to calibrate the efficiency of diversion and reservoir injectivity profile.

The approach was introduced for different oil fields in Kazakhstan, with a variety of conditions: depths up to 5000 m and temperatures up to 145°C. The approach helped to optimize acid volumes by as much as 44% to achieve an optimum skin. In the mid-term perspective, this approach helped to reduce the production decline rate by at least 20%, and ongoing post-treatment analysis is even more promising.
Large Liquid Volume Deep Penetration Acidizing in Iraq Missan Oilfield - 3 Case Study
Authors: Gao Jichao , Feng Puyong , Wang Da , Shao Shangqi , Cui Bo , Wang Gui
Published: April 2019

Matrix acidizing is widely used for removing damage of carbonate reservoirs. In 2017, more than 70 matrix stimulation operations have been conducted in Iraq Missan oilfield. However, for wells with no severe damage and low production performance which are influenced by formation energy decreasing, the effect of conventional matrix is limited. In order to stimulate these wells, a new acidizing technique has been developed which is called large liquid volume deep penetration acidizing.

According to the Darcy Productivity Equation, for carbonate reservoir, decreasing the skin factor below 0 would also increase production even if the skin factor is 0. That is the theoretical basis of large liquid volume deep penetration acidizing. The key points of this method are injection volume and acid system characters. Total injection volume is even twice as large as that of conventional matrix acidification. The acid system should have characteristics such as retarded acid-rock reaction rate and low leakoff coefficient. Viscoelastic surfactant based acid PA-VES and gelled acid PA-GL are used in these works.

In high permeability formation, the viscosity of PA-VES [20 wt% HCL and 8 wt% VES-1] reaches a peak of more than 400 cp at a shear rate of 170 S−1 at 120°C, which would drive acid flowing into tight formation. Other characteristics such as corrosion inhibition, surface tension, inter-surface tension, iron control and sludge prevention have been tested. Gelled acid is widely used because of its economic benefit, its rheology behavior is tested too. During injecting procedure, optimizing the injection rate and choosing large acid volume to produce long effective wormhole in formation, in this way the oil and gas seepage resistance are reduced, deep oil and gas reservoir area is connected, and oil production is improved. 3 wells have been stimulated using this technique in Missan oilfield which achieved the good results.

Large liquid volume deep penetration acidizing still belong to matrix acidizing because of non-fracturing formation. So that this method do not need a rig and would save cost. This paper introduces a novel method to stimulate low formation energy wells and low pollution wells, which is used in Iraq Missan oilfield for the first time.
Application of Group Fracturing Technology in the Old Area of Low Permeable Oilfield: A Case from Jilin Oilfield, Songliao Basin
Authors: Xu Jianguo , Zhao Chenxu , Zheng Jiangang , Xuan Gaoliang , Zhang Ruquan , Peng Chong , Liu Hongxia
Published: April 2019

In recent years, the investment of new area productivity construction in Jilin oil field is high, stabilized production becomes more and more difficulty, so the strategic center of oil field transfers to the refracturing of old well, however, the comprehensive water cut and recovery of old oil field is high, and the remaining oil dispersed, increasing production and increasing efficiency by refracturing becomes more and more difficulty. In order to deal with these challenges and realize the benefits of tapping in old area, the new idea of "group fracturing" was proposed basing on the concept of volumetric fracturing, starting from the reconsideration of reservoir geology, injection production unit for the smallest study unit, and integrating multiple fracturing method, we conduct a series of technical studies and field experiment in the old area of Jilin oilfield. The group fracturing technology series mainly includes the following: (1) The high strength positioning and plugging technique for re-orientation fracturing; (2) Energy develop before fracturing and fast energy storage technique in fracturing; (3) Synchronous fracturing technique of multi wells; (4) Synchronous fracturing technique of oil and water well, re-orientation fracturing technique of water well; (5) Fracturing combining with rapid profile control and water plugging technique; (6) "Factory-oriented construction".Since 2016, the group fracturing has carried out a total of 143 wells in 14 blocks in the old area, which has achieved good results. Compared with the conventional fracturing in the same area, the economic efficiency is increased by 10.2%, the oil increase of the single well is increased by 1 times, and the effective period of the measure is raised by 50%. The practice shows that the group fracturing technique is an effective measure to exploit the benefits of the old area in the low permeability oilfield.
Numerical Simulation Study of Focused Borehole to Surface Electric Imaging
Authors: Hu Haitao , Xiao Zhanshan , Zhao Baocheng , Yu Zhennan , Zhu Ruiming , Liu Jianguo
Published: April 2019

Focused borehole to surface electric imaging is researched through numerical simulation in this study, this method makes downhole electrical logging synchronize with three dimensional space electrical exploration near the well, and combines borehole electrical logging with surface electrical prospecting, which can expand spatial scale of well logging evaluation technology and increase vertical resolution of borehole to surface electric imaging evaluation technology. This method can be used for detecting the geological information around well and between wells and wells. It provides a new means for exploration of residual oil distribution and evaluation of unconventional reservoirs fracturing effect. In this method, a new electrode structure, multi frequency focused high power transmission mode and surface reception modes are adopted. Based on the three dimensional finite element numerical simulation method, the instrument response characteristics in homogeneous formation and in homogeneous formation are analyzed. The influences of electrode depth, electrode length, and current return electrode orientation on surface potential distribution are analyzed. The results indicate that borehole to surface electric imaging system can effectively identify formation resistivity anomalies. The larger the spatial scale of resistivity anomaly, the better the recognition effect. Under certain conditions, downhole emission electrode depth is inversely proportional to surface potential distribution distortion, and downhole emission electrode length is proportional to it. When current return electrode B is placed far enough from the wellhead, the influence of electrode B orientation on surface potential distribution is negligible.
Signal to Noise Ratio Enhancement Using Empirical Wavelet Transform
Authors: Lee Wei Yi , Hamidi Rosita , Ghosh Deva , Musa Mohd Hafiz
Published: April 2019

Noise is the unwanted energy in a seismic trace opposed to the signals corresponding to reflected energy from the subsurface features. Since it can overlap with the main signals’ energy and conceal the geological information, noise attenuation is one of the most important steps in seismic data processing. The most common method is frequency filtering. However, due to its limitations on separating the noise from signals, this method usually results in hurting the signal. Hence, it is important to develop an alternative method that can attenuate the noise without affecting the signal. Filters based on time-frequency analysis of the data can have a better separation of the noise from signal as they maintain the time localization of events while presenting their frequency content simultaneously.

One of the recent approaches to time-frequency analysis of signals is the Empirical Wavelet Transform (EWT) which provides adaptive wavelet filter bank for signal analysis. In this paper, a filter is designed based on EWT for random noise attenuation and is applied on both synthetic and real data. To evaluate the proposed filter performance, its results are compared with the filters based on Short Time Fourier Transform and Wavelet transform. As the EWT filter separate different seismic features using the adaptive basis wavelets, it can attenuate the noise while preserving the signals with higher precision.
COINFECÇÃO DE HEPATITES VIRAIS E HIV NA REGIÃO NORTE DO BRASIL
Authors: Silva Rafael de Azevedo , Haber de Souza Marina , Pinto de Souza Caldeira Marina , Fecury Tavares Lorena , Santos Oliveira Brito Ana Paula , Paulino Cordeiro Herbert , Nascimentos Pontes Carla Daniele , Cezar Rocha de Garcia Hamilton , Bona Maneschy Rodrigo
Published: April 2019

Esse artigo buscou realizar uma coleta de dados sobre a prevalência da coinfecção entre Hepatites Virais e HIV no Brasil, especificando a região Norte. Foi realizado um levantamento dos descritores nas línguas portuguesa, inglesa e espanhola no DECS (Descritores em Saúde) e no MESH (Medical Subject Headings) para coletar artigos nas bases de dados Scielo, PubMED e LILACS do recorte temporal de 2014 a 2018, além da coleta de informações do SINAN. Foi encontrado um total de 457 artigos e após a exclusão por critérios, remanesceu 13 artigos e 1 Boletim Epidemiológico. Não foram encontrados dados relevantes de Hepatite A, Hepatite Delta e Hepatite E. Na região norte do Brasil foi encontrado 2,0% de prevalência da Hepatite B e 8,9% para a Hepatite C. Logo, reconhecer a epidemiologia da coinfecção das hepatites virais com o HIV na região Norte brasileira é importante para um contexto de agilização do diagnóstico.
Rancang Bangun Model Reflektor Yagi Bolik Terhadap Pengaruh Hasil Penguatan Sinyal Antena
Authors: Wigyarianto F.Trias Pontia , Tjahjamooniarsih Neilcy , Imansyah Fitri
Published: April 2019

Perkembangan teknologi yang semakin pesat, memicu manusia untuk mendapatkan kebutuhan sarana dan prasarana yang lebih praktis, mudah dan efisien. Seiring dengan kebutuhan akan informasi jaringan komunikasi, teknologi WLAN merupakan solusi yang terbaik dalam mengatasi masalah jangkauan sinyal untuk daerah yang jauh dengan menggunakan antena Yagi dengan reflector berbentuk Bolic. Dalam penelitian ini akan dilakukan pengujian pada frekuensi 2.4Ghz untuk meningkatkan daya terima wifi pada proses penerimaan sinyal wireless USBadapter terhadap sinyal wifi. Pengujian antena Yagi Reflector Bolic ini dilakukan pada jarak 80 meter dan 100 meter. Hasil pengukuran nilai level daya terima pada antena yagi reflector bolic untuk sepuluh kali percobaan didapatkan rata-rata sebesar -69,7 dBm pada jarak 80 meter dan -65,75 dBm pada jarak 100 meter. Dari hasil antena yagi dengan reflector berbentuk bolic maka diperoleh nilai penguatan daya (gain) pada jarak 80 meter sebesar 9,15 dBm dan pada jarak 100 meter untuk nilai penguatan (gain) terbaik diperoleh sebesar 37,25 dBm. Dapat dilihat dari nilai penguatan daya (gain) antena yagi dengan model reflector bolic ini telah berhasil dibuat sesuai tujuannya yaitu untuk mengetahui pengaruh hasil penguatan sinyal pada antena.
Synthesis of Elaborate Benzofuran-2-Carboxamide Derivatives Through a Combination of 8-Aminoquinoline Directed C–H Arylations and Transamidations
Authors: Oschmann Michael , Holm Linus Johansson , Verho Oscar
Published: April 2019

Benzofurans are everywhere in nature and they have been extensively studied by medicinal chemists over the years because of their chemotherapeutic and physiological properties. Herein, we describe a strategy that can be used to access elaborate benzo-2-carboxamide derivatives, which involves a synthetic sequence of 8-aminoquinoline directed C–H arylations followed by transamidations. For the directed C–H arylations, Pd catalysis was used to install a wide range of aryl and heteroaryl substituents at the C3 position of the benzofuran scaffold in high efficiency. Directing group cleavage and further diversification of the C3-arylated benzofuran products were then achieved in a single synthetic operation through the utilization of a two-step transamidation protocol. By bocylating the 8-aminoquinoline amide moiety of these products, it proved possible to activate them towards aminolysis with different amine nucleophiles. Interestingly, this aminolysis reaction was found to proceed efficiently without the need of any additional catalyst or additive. Given the high efficiency and modularity of this synthetic strategy, it constitute a very attractive approach for generating structurally-diverse collections of benzofuran derivatives for small molecule screening.
ESTRATÉGIAS PARA O ENSINO DO AUTOCUIDADO DE PACIENTES CIRÚRGICOS: UMA REVISÃO INTEGRATIVA DA LITERATURA
Authors: Stadler Debora Viviane , Giordani Annecy Tojeiro , Ezaias Paulino Gabriela Machado , Sonobe Helena Megumi , Zanardo Renata Rodrigues , Valério Maria Aparecida
Published: April 2019

O ensino do autocuidado se destaca como importante estratégia para o enfrentamento das dificuldades que permeiam o processo de reabilitação pós-operatória, possibilitando que as pessoas cuidem de si mesmas subsidiadas por informações e recomendações elaboradas criteriosamente. Assim, este artigo teve como objetivo identificar e avaliar as evidências encontradas na literatura cientifica nacional e internacional, sobre estratégias educacionais para o autocuidado em domicilio de pacientes cirúrgicos, de modo a nortear a assistência perioperatória. Revisão integrativa da literatura, realizada na base de dados LILACS e nas bibliotecas eletrônicas PubMed, DEDALUS e SciELO, com artigos científicos publicados em português, inglês e espanhol entre 2005 e 2016.Foram selecionados quatro artigos científicos que evidenciaram estratégias educacionais para o ensino do autocuidado perioperatório, como computação móvel com módulos educacionais multimídia; acompanhamento telefônico; educação interativa por meio de internet, CD-ROM ou DVD, aulas presenciais, aplicação da Teoria do Autocuidado de Orem, reuniões semanais em grupos, folhetos explicativos e educação permanente dos profissionais de saúde. Estas diferentes estratégias promovem o atendimento das necessidades individuais do paciente, favorecendo o aprendizado sobre procedimento cirúrgico e suas consequências, além do desenvolvimento de habilidades para o autocuidado.
Okul öncesi çocuklarda serum 25-hidroksi D vitamin düzeyleri ile tekrarlayan hışıltı arasındaki ilişki
Authors: KARAHAN Feryal , RAZİ Cem Hasan , BULUŞ Ayşe Derya , ANDIRA Nesibe
Published: April 2019

Amaç: Çevresel faktörlerden biri olan 25-hidroksi D
vitamininin okul öncesi çocuklarda tekrarlayan hışıltı ataklarına etkisini
araştırmak. Yöntem: Çalışmaya
Keçiören Eğitim ve Araştırma Hastanesi Çocuk Alerji Polikliniği’nde tekrarlayan
vizing atağı nedeni ile takipli 77 hasta, kontrol grubuna benzer yaş grubunda
olan çocuk sağlığı polikliniğine başvuran 74 sağlıklı çocuk alındı. Hasta ve
kontrol grubunun dosyaları incelenerek çocukların ağırlık, boy, doğum şekli,
anne yaşı, D vitamini kullanma süresi, beslenme öyküsü ve ayrıca hasta
grubundakilerin ilk vizing atak zamanı, vizing atak sayısı ve vizing nedeniyle
hastaneye yatış sayısı belirlendi. Her iki grupta serum kalsiyum, fosfor ve
25-Hidroksi D vitamini düzeyleri çalışıldı. Bulgular: Hasta grubunun 54’ü (%70.1) erkek, 23’ü
(%29.9) kız, ortalama yaşları 29.5±1.9 ay olup kontrol grubunun 44’ü
(%59.5) erkek, 30’u (%40.5) kız ve ortalama
yaşları 31.7±18.1 aydı. Hasta grubunda serum D vitamini düzeyi ile ilk
vizing atak zamanı, vizing atak sayısı ve hastaneye yatış sayıları arasında bir
ilişki bulunmadı. Hasta grupta astım prediktif indeksi pozitif olanların vizing
atak sayısının negatif olan gruptan anlamlı olarak daha fazla olduğu ancak serum 25
hidroksi vitamin D vitamini düzeyi ile arasında
ilişki olmadığı saptandı. Sonuç: Çalışmamızda serum D vitamini düzeyi ile ilk vizing atak zamanı,
vizing atak sayısı ve hastaneye yatış sayısı arasında ilişki saptanmamıştır.
Per-instance Differential Privacy
Authors: Wang Yu-Xiang
Published: April 2019

We consider a refinement of differential privacy --- per instance differential privacy (pDP), which captures the privacy of a specific individual with respect to a fixed data set.  We show that this is a strict generalization of the standard DP and inherits all its desirable properties, e.g.,  composition, invariance to side information and closedness to postprocessing, except that they all hold for every instance separately. We consider a refinement of differential privacy --- per instance differential privacy (pDP), which captures the privacy of a specific individual with respect to a fixed data set.  We show that this is a strict generalization of the standard DP and inherits all its desirable properties, e.g.,  composition, invariance to side information and closedness to postprocessing, except that they all hold for every instance separately.  When the data is drawn from a distribution, we show that per-instance DP implies generalization. Moreover, we provide explicit calculations of the per-instance DP for the output perturbation on a class of smooth learning problems. The result reveals an interesting and intuitive fact that an individual has stronger privacy if he/she has small ``leverage score'' with respect to the data set and if he/she can be predicted more accurately using the leave-one-out data set. Simulation shows several orders-of-magnitude more favorable privacy and utility trade-off when we consider the privacy of only the users in the data set. In a case study on differentially private linear regression, provide a novel analysis of the One-Posterior-Sample (OPS) estimator and show that when the data set is well-conditioned it provides $(\epsilon,\delta)$-pDP for any target individuals and matches the exact lower bound up to a $1+\tilde{O}(n^{-1}\epsilon^{-2})$ multiplicative factor.  We also demonstrate how we can use a ``pDP to DP conversion'' step to design AdaOPS which uses adaptive regularization to achieve the same results with $(\epsilon,\delta)$-DP.
Insect Pests Complex of Common Sage (Salvia officinalis L.) (Lamiaceae) and Their Natural Enemies
Authors: ZARKANİ Agustin , TURANLI Ferit
Published: April 2019

Common
sage, Salvia officinalis L., (Lamiaceae) has been economically cultivated in many countries due to
its widely used as food and medicines. The sage’s production, however, is still facing significant yield losses because
of insect pest attacks including other arthropods. This research is aimed to determine insect pests
of S. officinalis and their natural enemies. Insect species were
collected in a year
2016 in the sage fields at Bornova and Menemen,
Izmir-Turkey. In total 47 species consisted of 18 insect pests and 29 natural enemies belonging to 30 families in 11 insect orders were collected. The species namely Aphis
passeriniana (Del Guercio) and Eucarazzia elegans (Ferrari) (Hem.: Aphididae); Dysmicoccus angustifrons (Hall) (Hem.: Pseudococcidae); Eupteryx gyaurdagicus Dlabola and Micantulina (Mulsantina) stigmatipennis (Mulsant & Rey) (Hem: Cicadellidae); Chrysolina (Taeniochrysea) americana (L.) (Col.: Chrysomelidae) and Thrips
tabaci Lindeman (Thy.: Thripidae) were determined
as key insect pests. M. stigmatipennis (Mulsant & Rey) was a new pest hosting for common sage whilst E. elegans (Ferrari)
and D. angustifrons (Hall) were known as the new species recorded for Izmir
province. In addition, the natural enemies of key insect pest were determined
and discussed.
Nearly Injective Semimodules
Authors: Alsaebari Sarah H. A. , Alhossaini Asaad M. A.
Published: April 2019

An injectivity in the category of semimodules over semiring was studied by many authors recently. On the other hand, the concept of injectivity, in the category of modules over ring, was generalized in many different directions. In particular, injective modules relative to preradical were some of those generalizations.

       As an analogue to module theory, in this paper, we introduce  and investigate the notion of "injective semimodule relative to Jacobson radical (namely nearly injective semimodule)".
Capital Adequacy and its Impact on Banking Liquidity Risk Applied Study in the Bank of the Islamic National and Commercial Iraqi for the Period (2012-2017)
Authors: Omran Qassem Ali
Published: April 2019

The aim of this paper is to highlight one of the risks facing the banking system in general and the Iraqi in particular, both Islamic and commercial, resulting from the low liquidity of banks from their safe levels, which expose the bank to a number of effects, especially when exposed to sudden withdrawals through measuring and analyzing the banking liquidity risk of banking and the statement The most important means used to processing  these risks, including the adequacy of capital according to the Basel II Accord. Two banks, the National Islamic Bank and the Commercial Bank of Iraq, were selected and the indicators of liquidity risk were used. Statement of the Effect of the Capital Adequacy Tool as a Tool that Contributes to the Absorption of Banking Risks and their Effects in Mitigating Liquidity Risk The indicators were analyzed and tested by testing F, P-value and impact statement through the R2 parameter using the ANOVA analysis. There is a significant effect of the capital adequacy ratio on the liquidity risk of banks and both banks to varying degrees on the basis of which the alternative hypothesis was accepted. The paper also reached the recommendations of the most important of which is the need to achieve a balance between the size of the balances utilized in the various banking fields and what is maintained, Exceed the capital adequacy ratios for the specified rates by the Central Bank of Iraq.
Reflexión mínima. En torno a la pregunta ¿qué podemos entender por filosofía?
Authors: Freire Hermosilla Antonio
Published: April 2019

Reflexión mínima. En torno a la pregunta ¿qué podemos entender por filosofía?  Brief reflection around the question, what can we understand as philosophy? Reflexão mínima. Em torno da pergunta o que podemos entender por filosofia?
Noticias breves
Authors: Briceño Iván
Published: April 2019

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