bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of Nutritional Intake and Nutritional Knowledge of Rural Post Menopausal Women
Authors: Kashyap Anjali , Chhabra Pankaj
Published: October 2019

Menopause is one of the most challenging periods for every woman. Balanced diet and healthy life style have a great bearing on their future health. The objective of the study was to assess nutritional intake as well as nutritional knowledge in rural post-menopausal women. The study included 140 disease free post-menopausal women, non-users of HRT recruited from November 2018 to February 2019.Variables including socio-demographic and anthropometric factor, calorie and nutrient intake, food frequency as well as the nutritional knowledge were recorded for each woman. In order to determine dietary intake, information of 24-hour dietary food recall was recorded for three successive days. The results of the study revealed that majority of the respondents belonged to the age group of 45-55 years having mean age at menopause was 50.21±4.05 (45%) of them were belonged to agriculture. Actual mean food and nutrient intake of the respondent was found to be more than RDA which may be due to their eating habits and economics status. BMI of the study population showed that 35.1% overweight and 14.4 % had grade II obesity. The findings showed that rural postmenopausal women, aged 51.65±5.40 years had Energy Intakes (EI) 2226±395 (1.43%) above the RDA, consisting protein (1.2%) and calcium (5.2%) less than RDA and fat (42.8%) above the RDA. Food habits of the respondent indicate insufficient knowledge of nutritional need and recommendation. Low nutritional knowledge was seen in most of the study population. Nutritional knowledge was positively associated with education and socioeconomic status but in this study area most of the women (56.4%) were illiterate and (44.9%) women belongs to lower income group.
Development of Barnyard Millet Based Products, their Acceptability and Nutritional Composition
Authors: Nisha B. S. , Prabhavathi S. N. , Prakash Jamuna
Published: October 2019

Barnyard millet is one of the hardest millet. The grains can be used as food and can be cooked similar to rice. The carbohydrate content is low and slowly digestible. This property makes the barnyard millet a natural designer food. The objective of the present investigation was to develop barnyard millet based products and to determine their nutrient composition. A total of seven products using barnyard millet, viz., fruit cake, paddu, instant dosa, puliyogare, gulab jamun, nutri bar and maddurvada were developed. Three of the above products were analysed for nutritional composition, while for remaining the nutritional value was computed for developing a nutrient database. All the prepared products were subjected to sensory analysis by 30 untrained panel members for evaluating the acceptability. Sensory analysis of all millet incorporated products showed that they were acceptable in comparison to control products prepared with traditional cereals. Nutritional composition of millet-based products was similar to control products for macronutrients and showed a higher content of micronutrients. Maddurvada was a baked product with a lesser fat content than the commercial fried product. Puliyogare prepared using only millet was found to be highly acceptable and was nutritionally superior. The sensory parameter of instant dosa prepared with millet was also acceptable. The study showed that preparation of various traditional products using barnyard millet did not affect the sensory parameters; hence, its use can be promoted for health benefits.
Extraskeletal Myxoid Chondrosarcoma of the Midfoot Presenting as Charcot Arthropathy
Authors: Wilson John T. , Pitts Charles , Hess Matthew , Phillips Sierra G. , Siegal Gene P. , Johnson Michael D.
Published: October 2019

Case:

Extraskeletal myxoid chondrosarcoma (EMC) is a rare soft tissue malignancy that very seldomly presents in the foot or ankle and as a result is not commonly in the differential of patients presenting with foot pain. We cite a case of EMC presenting in the atypical location of the midfoot. Because of its location and similarities, this tumor was initially misdiagnosed and mistreated by multiple medical providers as midfoot Charcot arthropathy.

Conclusions:

Neoplastic etiologies, including EMC, should remain in the differential for atypical, refractory foot pain that presents in a manner similar to Charcot foot.
Capacidades Analíticas no Processo de Produção de Políticas Públicas: Quais Fontes de Evidências Utilizam o Serviço Civil da Administração Pública Federal?
Authors: Macedo Alex Santos , Viana Rafael , Nascimento Maricilene Isaira Baia
Published: October 2019

O objetivo central deste estudo foi identificar quais fontes de evidências usa o serviço civil da Administração Pública Federal brasileira (APF) no processo de produção da política pública. A partir da análise estatística descritiva e multivariada, recorremos às informações de 2000 servidores da APF sobre o uso de evidências, considerando (1) as características demográficas do serviço civil da APF; (2) tipos de função na política pública; (3) diferentes órgãos da administração federal; (4) tipos de cargos na administração federal e (5) áreas de política pública. Os resultados apontam que, em média, a depender da função exercida na política pública e da natureza da política pública, diferentes fontes de evidência são recorridas. Além disso, os órgãos se diferenciam no grau de recorrência a essas fontes.
Depletion Efficiency Estimation for Edge-Typed Oil Rims
Authors: Samolovov Dmitry Alekseevich , Varavva Artem Igorevich , Polkovnikov Fedor Igorevich , Sandalova Ekaterina Evgenevna
Published: October 2019

In this article the horizontal wells productivity analysis has been hold in respect of edge-typed oil rims developed with depletion recovery drive with gas breakthrough. There are several methods that may help to calculate producion rate of the wells in underlayng oil rims without gas breakthrough (so called critical rate). These methods were obtained due to the relatively simple well drainage area. Considering the of edge-typed oil rim geometry with different saturation zones we get much more complicated boundary conditions and the numerical solution is needed. Main criteria that influence on the character of filtration flows in underlaynig and edge-typed oil rim were formulated. Various simulation runs on 2D "X-Z" model were perfomed to investigate coining peculiarities especially different coning regimes and it’s influence on the oil production rate. Main results of the work are the corrleations between dimensionless oil rate and geometrical parameters of edge-typed oil rim that also may help to calculate economical efficiency of the oil rim development.
Waterflooding East-Messoyakhskoe Heavy Oil Field in Unconsolidated Reservoir – Challenges and Proactivity
Authors: Ilyasov Ilnur , Podkorytov Alexander , Gudz Anton , Komarov Vladimir , Glushchenko Nikolai
Published: October 2019

The main objective of this paper is to share experience obtained from waterflood implementation in unconsolidated reservoir PK1-3 with heavy oil in East-Messoyakhskoe oil field.

Key geological features of PK1-3 reservoir are presented, on which attention should be paid during waterflooding organization in unconsolidated reservoir with heavy oil. Typical effects are described, which are observed during waterflooding of such reservoirs, their analysis is made, based on world experience and actual field results.

The history of waterflood implementation from the design and pilot stage to the full-field implementation stage and obtained results are highlighted.

Waterflooding strategy and tactics used at this field development stage are described in details: analytical tools, selection and justification of injection pressure, selection of target VRR, individual injection rates selection, investigation program, tactical waterflood management.

In addition, proactive actions to improve waterflooding efficiency and field development of PK1-3 reservoir are described.

We hope that our experience will be useful to colleagues - reservoir engineers who already started or only plan to start field development with waterflooding of similar fields.
Optimization of Micellar-Polymer Drive in a Stochastic Reservoir
Authors: Canbaz Celal Hakan , Temizel Cenk , Palabiyik Yildiray , Deniz-Paker Melek , Ozyurtkan Mustafa Hakan
Published: October 2019

Micellar – Polymer drive process is one of the effective, proven and widely used non-thermal EOR methods which classified under chemical flooding. The process is preferable in reservoirs that don’t have enough aquifer assistance and also in depleted reservoirs. A successful micellar-polymer flooding operation can be enabled by having correct data of parameters like reservoir pressure, mineral types in the reservoir, phase behavior of microemulsions, reservoir temperature, salinity data, buffer stability, micellar slug, and concentrations of the surfactants.

In this study, A comprehensive literature review regarding on above parameters studied with field case studies worldwide. A Micellar-polymer drive process is applied on a stochastic reservoir and the optimization of the case performed by considering the mechanisms and limitations of micellar-polymer drive process, selection and design criteria, as well as the phase behavior changes during the process to have the most effective residual oil recovery. Parameters that enables an optimal recovery is described and used as optimization parameters in a full-physics commercial reservoir simulator.

Typical Injection sequence that includes water flooding, polymer injection, polymer drive, polymer taper and chase water is applied for selected time periods. Changes of Oil saturation, water viscosity, adsorbed fluid, surfactant and polymer adsorption is simulated by using the optimal values of selected optimization parameters. General solution results are given with the optimal solution and all compared with the base case. It clarified that the Micellar-polymer drive optimization maximizes cumulative oil recovery in a reservoir that has a stochastically generated permeability distribution.
A/S-P Alternating Flooding, A Modified ASP Flooding Technology
Authors: Huang Wenqing , Dong Yeliang , Zhao Jinyi , Liu Xiaobo , Fan Yu , Bai Hongjun , Hao Jinsheng
Published: October 2019

A modified ASP flooding technology, in which polymer and alkali-surfactant solution are injected alternatively for several turns, rather than being injected simultaneously as the traditional way, is studied by both lab experiments and a field test.

Experimental results show that the viscosity of polymer solution will be reduced by 30% if alkalis and surfactants are added, while the dynamical interfacial tension is much higher in ASP-oil-water system than in AS-oil-water system. To give full play of these three chemicals on oil recovery, we alternatively inject polymer and alkali-surfactant slugs, and this modified ASP flooding is named A/S-P alternating flooding. A pilot test is then carried out in a water flooded reservoir since November 2008, which is employed in a block of 28 injection wells and 40 production wells.

In the pilot test, alkali-surfactant slugs and polymer slugs are alternatively injected for five turns after a leading polymer slug. Injecting pressure increases in each polymer slug and decreases in the following A/S slug. In the following polymer slug, the injecting pressure of test area is 1.5MPa lower than contrast area and the injection rate per well is 9m3/d higher, while the production is 18% more. Profile tests show that the proportion of injectable thickness to total effective thickness keeps 80% or higher during the whole flooding process of the test area, while the proportion of contrast area is only 70% in the late stage. The minimum water cut during A/S-P alternating flooding is 82.0%, which is 6.1% lower than ASP flooding. However, the water cut increases significantly when A/S slugs are injected, which is an important weakness of A/S-P flooding. When chemical flooding is over, 17.8% of the original oil in place (OOIP) has been exploited by A/S-P alternating flooding, which is more than 7% higher than the contrast area flooded by ASP, while the total chemical cost is 11.3% lower. Therefore, A/S-P alternating flooding can be a cost effective enhanced oil recovery technology.

A/S-P alternating flooding has more injection and production, displaces more zones, gets a higher oil recovery and uses fewer chemicals, which can be a cost effective technology.
Selection of Effective Surfactant Composition to Improve Oil Displacement Efficiency in Carbonate Reservoirs with High Salinity Formation Water
Authors: Kornilov Alexey , Zhirov Aleksey , Petrakov Andrey , Rogova Tatiana , Kurelenkova Yulia , Afanasiev Igor , Sansiev George , Fedorchenko Gennadiy , Fursov Grigory , Kubrak Mikhail , Altmann Thomas , Lichterfeld-Weber Nicole , Bittner Christian , Oetter Guenter , Helwig Ekaterina
Published: October 2019

The paper includes the scheme of surfactant composition selection and the approach to evaluate potential results of injection for Central-Khoreiver Uplift (CKU) fields with carbonate reservoirs. Several scenarios of surfactant composition injection were studied, using high salinity treated formation water (up to 210 g/l) without applying salinity gradient. The first step of surfactant composition selection included testing of water solution stability in formation water that is characteristic for CKU conditions. Then interfacial tension of surfactant water solution with oil was measured, as well as adsorption properties. The target values of interfacial tension were set in the range around 10-2, and not higher than 10-1 mN/m.

Filtration experiments on composite core model were conducted to evaluate the efficnency of selected composition. Development and tuning of linear model for the filtration experiment matched the laboratory results. Obtained parameters are included into the sector model of field development unit, considering the conversion of one of the wells to injection of chemicals. The paper presents preliminary evaluation of technological efficiency for the selected scheme of composition injection.

The approach presented in the current paper can be used to plan injection of surfactant-based compositions into carbonate formation with properties that are similar to investigated values. Applying surfactants that are compatible with high salinity formation water makes possible to use treated produced water as injection medium and it decreases the costs of mix water preparation.
Using Spectral Inversion to Build Acoustic Impedance Exemplified by an East Sibirian Field
Authors: Fagreeva Veronica , Butorin Alexander , Krasnov Fedor
Published: October 2019

The present time is characterized by increased number of features with complex geology and poor exploration maturity where the target interval is represented by thin pays and heavy lithologic heterogeneity.

In most cases, seismic inversion is used to prospect such features; however, quality seismic inversion calculation is quite a labor-and-resource intensive process; given the increasing demand for the acceleration of exploration projects and fast provision of spud-in locations, the need arises for the development and provision of an inversion-building method whose quality would be no worse than that of syncronous inversion and which could be done faster.

This manuscript aims at the developing and benchmarking of a new approach to acoustic impedance forecast. The manuscript describes an acoustic impedance reconstruction algorithm built on wavefield spectral inversion and allowed for low-frequency model based on well logs. To prove its applicability, we tested it using model data, as well as based on an East Siberian field case as part of which the accuracy of reconstruction properties was benchmarked using standard and suggested approach.
Choosing Optimal Standoff for Horizontal Well Profile with High Cavernosity to Achieve Better Mud Removal
Authors: Tcibulskii Mikhail , Vavilov Mikhail , Afletunov Vladimir , Orlov Sergey
Published: October 2019

Cement bond logs in the Messoyakha field indicated only 65% achieved mud displacement, which resulted in poor zonal isolation, resulting in annular pressure and remediation. Casing standoff is the most important factor to achieving better mud displacement from the annular space. The wellbore profile and the presence of caverns have significant impact on casing standoff. At the same time, increased centralization, in some cases, has a critical impact on running the casing to planned depth.

Analysis in the use of different types of centralizers, their spacing patterns, and placement on the casing in the horizontal wells in this field are detailed in addition to the results of trial operations.
Application of Proportional, Integral, Derivative PID Control Loop Algorithm for Optimization of Equipment Operation Used for Decentralized Water Injection System at West Qurna 2 Oilfield
Authors: Letunov Dmitrii , Nepomiluev Dmitry
Published: October 2019

One of the key drivers in gaining the cost-effective, reliable and low-downtime Operation system for major Oil Fields is implementation of Water Injection System (WIS) with capability of online-automated regulation and control.

This Paper outlines an application of Proportional, Integral, Derivative (PID) control loop algorithm for Decentralized WIS (with direct injection from Water Source wells to Injection wells by means of high capacity ESP's) used in West Qurna-2 oilfield located in Iraq, operated by LUKOIL.

PID control loop algorithm has being used in the industry for the years, but not commonly applied as integral component of Water Injection System allowing to maintain optimal equipment modes. Such limited PID deployment is explained by complexity of operational parameters synchronizing for every Water Injection System component.

The decentralized Water Injection System at the West Qurna 2 project is common and united pipeline system for every WellPad that provides water transfer from Water source wells (3-5 wells per WellPad) to injection wells (3-6 wells per WellPad) with line pressure of 70-130 Barg by means of high-capacity ESP equipped with VSD.

Water injection process is regulated by controlling both the conventional ESP parameters (frequency, flow rate, motor current and load, Intake and discharge pressures), line pressure, required injection rate by means of flow control valves, and implemented PID control loop algorithm.

This paper discusses the techniques of PID control loop algorithm application as the tool for: –Pipeline protection against high pressure without full shutdown of water injection process and–ESP automated regulation to ensure operation inside Recommended Operated Range (ROR) and smoothening of ESP mode when any changes in the system happen (i.e. shutdown of other water source well ESP's at the same WellPad or shutdown of injection well) with immediate feedback to Operator Control Room. Implemented approach allows to decrease number of ESP shutdowns and avoid high jumping of ESP loads that consequently leads to maximizing of ESP run life.

Comparative examples and case studies of submersible equipment operation results before and after the application of PID regulation are specified.

Mainly by implementing PID regulation and control stable and smooth operation of equipment and ESP's used for WIS (direct injection from Water Source Well to Injection Well) has been achieved.

New approach for PID application as a tool for pipeline overpressure protection has been formed, which allowed to reduce Capital Expenses for the WIS construction works. Specified case can be used as example for further development and projects in the oil and gas industry.
Comparison of Various Tracer-Based Production Logging Technologies Application Results in One Well
Authors: Arefyev Sergey , Makienko Vladimir , Shestakov Dmitry , Galiev Marat , Ovchinnikov Kirill , Malyavko Evgeny , Novikov Igor
Published: October 2019

In recent years, oil and gas producing companies have increasingly migrated towards using tracer-based methods to obtain data on horizontal wells operation. The interest in these technologies is largely due to their ability to obtain data over a long period of time with a radical decrease in the required resources, thereby providing new opportunities for well management and increasing cumulative production. The aim of this article is to compare the results of applying different tracer-based systems in one well.

Tracer-based technologies produced by different manufacturers vary in physical principles of operation, as well as in the methods of their injection into the well or reservoir. Tracers designed for long-term work are injected into the reservoir with marked proppant or lowered into the wells in the lower completion cassettes. For the first time, alternative tracer-based systems were applied in one well, ensuring the selectivity of work with oil and water. This allowed us to compare the results and evaluate the technology's advantages and disadvantages. The well was completed by multi-stage hydraulic fracturing with the possibility of subsequent port control using coiled tubing. Each of five well intervals were equipped with two tracer cartridges fixed on an MFrac sleeve on both sides. In addition, proppant with markers was pumped in 3 months. The unique signature of the marker was used for each fracturing stage (5 unique signatures for each of 5 fracturing stages).

As a result of this world-first field application of alternative tracer-based systems, valuable analytical material was obtained related to the quantitative analysis of various tracers, the performance of different polymers, and the stability of the tracers’ allocation in the formation fluid. The data obtained confirmed the character of the marked proppant pack washing out with the formation fluid in comparison with the tracer casings attached to MFrac port on both sides.

The following results were achieved upon completion: additional tools were obtained for the correlation of data on the tracers amount and concentration, and comparative indicators of different tracer technologies in terms of efficiency and work accuracy were identified. It was also confirmed that the marked proppant is not washed out into the well under these reservoir conditions. The authors of this article were the first to compare the technologies with different approaches to the tracers’ placement in a well within one project. Based on the project results, the obtained data allowed us to answer many pressing questions from oil and gas producing companies related to the comparison of tracer systems.
Estimation of the Largest Russian Oil Field Development Efficiency Using the Combination of Hydrodynamic Modeling and Horizontal Well Production Logging Methods Using Markers
Authors: Gurianov Andrei , Katashov Alexander , Ovchinnikov Kirill , Gilev Denis , Vasilyev Vladimir
Published: October 2019

Increasing the pace of oil production to achieve profitability in projects has increased significantly with the transition to the active development of deposits with low-permeable reservoirs throughout the West Siberian oil and gas province. The key to increasing production rates for objects with degraded reservoir properties is to increase the technical and technological effectiveness of the applied solutions. The purpose of the article is to evaluate the project using data obtained by the new, innovative tracer-based methods and contemporary types of well completion in well testing to increase the drainage area, flow rate and improve the operational parameters of the pressure maintenance system.

Greater reservoir filtration areas in reservoirs with abnormally low permeability is achieved by using horizontal drilling and fracturing. Modern modeling tools allow for the consideration of uneven development of the horizontal shaft length. Conventional logging methods cannot provide detailed information during the operation of hydraulic fracturing stages, but marker-based methods present a proper production logging alternative, especially given their widespread development in recent years. Using the data of marker diagnostics, it is possible to adapt hydrodynamic models to specify the hydrocarbon production profiles.

The present article brings to your attention sector hydrodynamic model (HDM) calculations that take into account the uneven development of depleting reserves based on marker diagnostics data. A comparison was made with HDM under the assumption of a uniform inflow into horizontal well with MFrac. The model showed several levels of inflow variability obtained through statistical data on the marker production logging of 60 wells performed at various fields.
Application of Time Lapse Gravity Measurements for Oil and Gas Field Development Monitoring
Authors: Kolesov Valentin , Gareev Kamil
Published: October 2019

Time lapse gravity (TLG) technology for producing oil and gas field control involves periodic high precision gravimetric and geodetic measurements at the area of a developed field.

The technology targets the following geological and technological challenges: improvement of field development control by adding independent information from gravimetric variations and finding its relationships with fluid saturation variations in the reservoir;prediction GOC or GWC shifting according to gravity data;precise surface elevation control in time (geodynamics).

TLG is considered as a significant part of the integrated field development control workflow and provides important independent information to be means added to time lapse well log measurements, production data and time lapse seismic where applicable.

The paper describes the methodological basics, provides some results of TLG implementation at a large gas field and estimates of gravity variations during production from a real oil field with a gas cap, which shows the feasibility of TLG application.
Enhancing Efficiency of High-Viscosity Oil Development with Using Autonomous Flow Control Devices. Case Study in Western Siberia.
Authors: Solovyev Timur
Published: October 2019

Most of the new fields in Western Siberia have unfavorable conditions for the development of the field, such as the presence of an extensive gas cap, the low power of oil-saturated oil rim thicknesses, and the underlying water. The field is also characterized by weakly consolidated sandstone and high-viscosity oil. For the deposition of an early breakthrough of water or gas into the wellbore, it was decided to conduct a pilot stage of project on the use of various types of completion (autonomous inflow control devices), which allow controlling the inflow along the wellbore. Formation of completion strategy requires continuous monitoring of wells, evaluation of the effectiveness of cleaning intervals after drilling, interval flow along the wellbore, as well as the detection of water or gas breakthrough areas to identify the ineffective placement of AFCD.

This article presents the results of the use of autonomous flow control devices, an assessment of their effectiveness according to PLT and well logs interpretation and intellectual tracers, as well as analytical methods.

The article also describes general information about the inflow control devices technology, their characteristics and problems that the operators user may encounter when using one or another element of high-tech completion, gives reasons for the use of autonomous inflow control devices at the considered development object.

Analysis of field data and PLT and well logs results revealed that the devices actually work and help to limit water and gas compared to wells that are equipped only with wire filters without inflow control, and also begin to form a unified strategy and concept of well completion based on the data

The results of the work show that currently the use of AFCD for the project is favorable, and the completion of wells without flow control in these conditions is impractical.
Decision Making Process in the Gas Carbonate Reservoir Engineering Based on the Uncertainty Analysis at Various Stages of the Life Cycle
Authors: Ermilov Andrey , Volnov Ignatiy , Zhukov Alexandr
Published: October 2019

Usage of the uncertainty analysis in the carbonate gas reservoir is the most useful instrument for making decisions when changing the field development stages. And it is necessary to use the appropriate approach for each field development stage. The new systems that were used for the fields in Uzbekistan proved their usefulness for the complex reservoir conditions and were based on the deep understanding of the reservoir properties and geological issues as well as clear vison of the project management and criteria for the stage shifting. Carbonate reservoir inherent uncertainties lead to important issue – how to predict the production rate and properly manage the reservoir? Each stage of the field life cycle is characterized by the different approaches towards the uncertainties that must be properly managed.

The example of LUKOIL's reservoir modeling experience in Uzbekistan addresses the uniqueness of each stage by using the decision-making workflows driven by the model and uncertainty analysis. If the first stages are very uncertain, conceptual and need specific approach to define and manage uncertainties, the developed stages have very detailed and robust prediction calling for the usage of the more advanced uncertainty analysis methods. Usage of the specific approach for each stage for over 10 gas carbonate fields examples provides for the clear understanding of the uncertainty level as well as understanding of the main leading indexes requirement to ensure the shift from one stage to another. The paper reveals the peculiarities of the decision-making process for the reservoir engineering and uncertainty analysis for every field development stage. The novelty of the new decision-making system is based on generalization of the methods and approaches of the uncertainty analysis, clear understanding of the main valued indexes and parameters to estimate the criteria for reaching the right decision.
Understanding Well Events with Machine Learning
Authors: Elichev Vitaly , Bilogan Andriy , Litvinenko Konstantin , Khabibullin Rinat , Alferov Alexey , Vodopyan Alexey
Published: October 2019

The key to successful planning of well interventions and other well actions is to understand the current state and the history of the well. Due to the large spread of telemetry systems with high-frequency (up to 1 measurement per second) measurement of parameters, it is possible to use machine learning methods for well events recognition. In this paper we consider well analysis with, aim to identify equipment failures and other influences affecting the behavior of wells.

Typically, several parameters are recorded at the wellhead with high frequency: wellhead and bottom-hole pressure and temperature, flow line pressure and temperature. Also, readings of downhole measuring devices and well logs are periodically made and recorded. The readings of well parameters can be influenced by many factors: manual manipulations on the well, changes in the composition of the produced products, well integrity issues and others.

This work suggests an approach that allows to identify and classify events at the well. The approach is based on the results of constructed synthetic dynamic models of wells and observation of the real behavior of wells. It allows to identify the behavior of individual measured parameters and classify events using all measured parameters in aggregate.

The proposed algorithm allows retrospective analysis of data and identification of different events, such as well tests that occurred in the past. The algorithm also allows the analysis of incoming data and identification of well events in real time. Retrospective analysis of the data was useful not only for detecting anomalies and malfunctions, but also for building a real log of events at the well, monitoring well interventions and building reports on well performance. The analysis of event records demonstrates that only minor part of well events is normally captured in central databases.

The developed algorithm for natural flowing wells can be easily extended to wells equipped with mechanized oil production systems. For example, for wells with a gaslift or ESP installation. The algorithm can be easily integrated into corporate monitoring systems as an auxiliary tool.
Applying Streamline Method for Viscoplastic Oil Flow Simulation
Authors: Nevmerzhitskiy Yan
Published: October 2019

The work is devoted to the application of the streamline method for modeling nonisothermal nonlinear flow of viscoplastic oils. Two-dimensional plane problem of flow of water, gas and viscoplastic oil. The oil phase consists of two pseudocomponents: light and heavy fractions, which can gasify. The aqueous phase is represented only by one component, which can also gasify. During the simulation, the dependence of oil rheology on temperature is taken into account.

The distinctive feature of the proposed streamline method is consideration of the process of integration of the system of flow equations integrations as a set of quasiequilibrium states, which are achived by simulation on a global grid during the relaxation time. Between these states, the calculation is carried out on the streamlines. This approach allows to account for changes of pressure, temperature, saturations during solving a system, rather than using streamlines to calculate temperature and saturations at a fixed pressure.

Verification of the developed program was carried out by comparison with the results of calculations on commercial software. The convergence of the method when changing the number of streamlines, grids on streamlines, as well as the relationship between the times of calculations on the global grid and streamlines was also investigated.

To study the efficiency of thermal methods of enhanced oil recovery in reservoirs with viscoplastic oils, test calculations were performed on the element of a five-spot pattern. In addition, the informativeness of standard techniques for well tests interpretation for viscoplastic oils has been investigated, and recommendations have been made to determine threshold pressure gradient by well test results.
Creation of Complex Hydraulic Fractures Due to Macroscopic Rock Heterogeneity
Authors: AlTammar Murtadha J. , Sharma Mukul M.
Published: October 2019

Hydraulic fracture complexity in unconventional formations, such as shales, has been predominantly associated with the interaction of hydraulic fractures with pre-existing natural fractures. In this study, we demonstrate a novel experimental evidence that shows complex fractures can be induced in intact specimens that are mechanically heterogeneous in the absence of any pre-existing fractures.

Synthetic materials are used to cast sheet-like, porous test specimens that have strongly-bonded layers with different mechanical properties. The layered specimen is placed between two thick, transparent plates and constant, anisotropic far-field stresses are applied to the specimen. Fracturing fluid is injected in the center of the specimen, and the induced fracture trajectories are captured with high resolution digital images and subsequent image processing.

First, we show that a bi-wing, planar fracture is induced in the layered specimen along the maximum far-field stress direction when the applied differential stress is relatively high. However, when the applied differential stress is relatively low, the induced fractures become complex with multiple wings and nonplanar trajectories. Fracture complexity can also arise under relatively high differential stress when the hydraulic fracture is induced in a thin layer bounded by thicker and harder layers. When the applied differential stress is zero or extremely low, the induced hydraulic fractures become notably less complex, and the fracture propagation direction becomes controlled by the specimen heterogeneity.

Recent field evidence by coring through a stimulated rock volume (SRV) in the Eagle Ford Shale showed the formation of complex fractures despite the sparseness of pre-existing fractures in the cored sections of the SRV. Using well-controlled laboratory experiments, our results prove that rock heterogeneity is a plausible and important mechanism for generating complex fractures.
Improving Well Stimulation Technology Based on Acid Stimulation Modeling, Lab and Field Data Integration
Authors: Khuzin Rinat , Shevko Nikolay , Melnikov Sergey
Published: October 2019

Formation damage of near wellbore zone, which occurs during different well operations (drilling, workover), has dramatic influence on well productivity. To improve well performance the removal of damage or creation of new channels, which bypass damage zone, is necessary. For solving this issue, the acid matrix stimulation is widely used in carbonate reservoirs. In order to design and optimize stimulation treatments the simulation modeling is widely used nowadays. One of the critical issues, which influence the stimulation efficiency, is estimation of near wellbore damage zone parameters and taking them into account during stimulation design preparation. Usually this zone is described as the uniform zone with permeability, which is different from reservoir permeability. However, in reality its structure is complex and contains at least two damage subzones with significantly different parameters. Moreover, in case of perforation the created channels can have a positive as well as a negative effect on near well bore zone. The influence of these subzones is also not taken into account in used in practice models for calculation of skin factor due to presence of perforation. These factors influence the efficiency of acidizing stimulation and should be taken into account in modeling process.

In this paper, we present details of the approach, which takes into account the complexity of near well bore damage zone and its modification during acid stimulation. For this purpose the combined skin factor is introduced that takes into account the present damage subzones with different permeabilities, perforation channels, wormholes, relative permeabilities and viscosities of pumped fluids and their changes during acidizing process.

The combined skin factor approach was implemented into created simulator for matrix acid stimulation, which is used successfully in designing and optimization of stimulation operations on the Company's carbonate fields.

The paper, in the example of one of the green oil fields, describes the evolution of well completion and stimulation technologies based on acid matrix stimulation modeling and integration of laboratory and field data.

The proposed recommendations allowed to reach the values of skin factor up to −5 and involve into production up to 95% of reservoir thickness.
Beneficial Effects of thoracic epidural anaesthesia on mortality after elective surgery for colon cancer: a survey of 215 consecutive patients
Authors: Moormann Simon , Rübsam Marie Luise , Warnking Eva , Gottschalk Antje , Hahnenkamp Klaus , Aken Hugo Van , Doll Dietrich , Hagemann Olaf , Hönemann Christian
Published: October 2019

Background: Colorectal cancer is a major cause of death in the industrial world. The mortality and morbidity rates depend on the incidence of postoperative complications and cancer recurrence. Data from basic science support the view that regional anaesthesia reduces perioperative stress levels, potentially resulting in a lower risk of complications and cancer relapse.
Methods:  We compared short and long-term outcome data in 215 patients who underwent open colon cancer surgery by the same surgeon and the same oncologist. 83 patients received general anesthesia plus thoracic epidural analgesia (EPI group) and 132 patients received general anaesthesia alone (GA group). Oncological data from a state-wide follow-up database were included. The effects of different perioperative anaesthetic techniques on patients’ short and long-term outcome (36 month) were statistically analysed (Pearson’s chi-squared test, Student’s t-test, Wilcoxon rank sum test) as appropriate. A Kaplan Meyer Analysis for survival was performed and analysed by Wilcoxon rank sum test.
Results: With the exception of a significantly higher prevalence of arterial hypertension in the EPI group in comparison with the GA group, there were no differences in demographic, tumour staging data and cancer recurrence rates between the groups. However, mortality rates were significantly different between the groups. 37 of 132 GA patients (28%) died within 36 months, in comparison with 14 of 83 EPI patients (16.9%, P < 0.05). Patients over the age of 70 in particular significantly benefited from perioperative epidural analgesia and had a significantly better survival compared with patients without perioperative epidural analgesia (p<0.05).
Discussion: Perioperative use of epidural analgesia reduces the 36-month postoperative mortality rate. This effect may be due to systemic effects of local anaesthetics or to a reduced stress response caused by the thoracic epidural analgesia itself.
An updated systematic review and meta-analysis of the prevalence of hepatitis B virus in Ethiopia
Authors: Yazie Teshiwal Deress , Tebeje Mekonnen Girma
Published: October 2019

Abstract
Background: Hepatitis B virus is one of the major public health concerns globally. It is highly infectious and can be transmitted from person to person through vertically or horizontally via contaminated body fluids. Despite the provision of an effective vaccine, it remains a major problem worldwide, particularly among the developing countries.
Methods: Online electronic databases including PubMed, Google Scholar, Science Direct, African Index Medicus, African Journals Online, and WHO Afro Library were searched and published articles from 2010 to June 8, 2019, were considered. Both authors independently screened articles and extracted the data. Funnel-Plots and Egger’s test statistics were used to determine the presence of small-study effects and publication bias. The pooled prevalence of HBV was analyzed using the random-effects model. The possible sources of heterogeneity was analyzed through subgroup analysis, sensitivity analysis, and meta-regression.
Results: The overall pooled prevalence of HBV was 6% and among subgroups, pregnant women, healthcare workers, and HIV positive patients accounted for 5% for each group. Relatively low prevalence (4%) was obtained among blood donors. The Egger’s test statistics ( p =0.747) indicated the absence of publication bias. In addition, from the sensitivity analysis, there was no influence on the overall effect estimate while removing a single study at a time. The level of heterogeneity was reduced among pregnant women, HIV positive and studies with unknown sampling techniques. After conducting meta-regression, province, study group, screening method, and quality of papers were identified as sources of heterogeneity.
Conclusions: The overall pooled prevalence of HBV in Ethiopia was high. Strengthening and scaling up of the scope of the existing vaccination program and implementing novel approaches including screen-and-treat could be implemented to reduce the burden of the disease. Generally, the study can provide current prevalence estimate of HBV that could vital for intervention to tackle the disease.
Qualitative Evaluation of a Community Health Representative Program on Patient Experiences in Navajo Nation
Authors: Lalla Amber , Salt Shine , Schrier Elizabeth , Brown Christian , Curley Cameron , Muskett Olivia , Begay Mae-Gilene , Shirley Lenora , Clark Clarina , Singer Judy , Shin Sonya , Nelson Adrianne Katrina
Published: October 2019

Background:Community Health Representatives (CHRs) overcome health disparities in Native communities by delivering home care, health education, and community health promotion. The Navajo CHR Program partners with the non-profit Community Outreach and Patient Empowerment (COPE), to provide home-based outreach to Navajo clients living with diabetes. COPE has created an intervention (COPE intervention) focusing on multiple levels of improved care including trainings for CHRs on Motivational Interviewing and providing CHRs with culturally-appropriate education materials. The objective of this research is to understand the participant perspective of the CHR-COPE collaborative outreach through exploring patient-reported outcomes (PROs)of clients who consent to receiving the COPE intervention (COPE clients)using a qualitative methods evaluation.Methods:Seven COPE clients were selected to participate in semi-structured interviews one year after finishing COPE to explore their perspective and experiences. Qualitative interviews were recorded, transcribed, and coded to identify themes.Results:Through qualitativesemi-structuredinterviews, clients revealed that health education delivered by CHRs facilitated lifestyle changes by helping them understand key health indicators and setting achievable goals through the use of accessible material and encouragement. Clients felt comfortable with CHRs who respected traditional practices and made regular visits. Clients also appreciated when CHRs educatedtheir family members, who in turn were better able to support the client in their health management. Finally, CHRs who implemented the COPE intervention helped patients who were unable to regularly see a primary care doctor for critical care and support in their disease management. Conclusion:The COPE-CHR collaboration facilitated trusting client-CHR relationships and allowed clients to better understand their diagnoses. Further investment in materials that respect traditional practices and aim to educate clients' families may foster these relationships and improve health outcomes.
Preference of Traditional Bone setting and associated factors among trauma patients with fracture at Black Lion Hospital in Addis Ababa, Ethiopia: Institution Based cross sectional study
Authors: Worku Nardos , Tewelde Tsegaye , Abdissa Biru , Merga Hailu
Published: October 2019

Objective Despite the access and availability of modern health care, traditional bone setting (TBS) has a big place as alternative health care. Hence, this study was aimed to assess the preference of traditional bone setting and associated factors among patients with a fracture. Results A total of 224 patients known to have fractured at Black Lion Hospital, Addis Ababa was included in the study. This study revealed that 29.9% of the study participants had a preference for the traditional bone setting. Hospital admission (AOR=8.158, 95% CI: 1.179, 56.439), TBS center as first port of call after injury (AOR=0.004, 95% CI: 0.001, 0.090), knowledge (AOR=9.448, 95% CI: 1.481, 60.251) and perception (AOR=0.026, 95% CI: 0.003, 0.215) were statistically significant. The preference for the traditional bone setting is high. Hospital admission, traditional bone setting center as a first port of call after injury, knowledge, and perception were significantly associated with the preference of traditional bone setting. In addition to deployment of trained in trauma professionals, working more on awareness creation and training are recommended.