bluuebunny/crossref_metadata_2025 huggingface dataset:
What Is Cost and Is It Always a Bad Thing? Furthering the Discussion Concerning College-Aged Students’ Perceived Costs for Their Academic Studies
Authors: Johnson Marcus Lee , Safavian Nayssan
Published: October 2016

In this article, we present 2 studies with the primary objectives of (a) identifying college-aged students’ perceived costs for their academic studies and (b) exploring college students’ descriptions of “beneficial” aspects of costs. In Study 1, 10 cost concepts were identified from 2 focus groups, including stress, lost opportunities, effort, financial, and lost interest, to name a few. In Study 2, 98 undergraduates were surveyed on their perceptions about possible “beneficial” aspects of cost. Some of the beneficial aspects of costs that were reported included gained rewards and the development of time management skills. Implications of our findings are further discussed, along with avenues for future research.
Legitimating Social Inequality: Political Elites, Ethnic Peddling and Dislocated Constituencies
Authors: Che Fonchingong Charles
Published: October 2016

Political cronyism has been flagged up as a trigger for state dysfunction in post-independence Africa, resulting in escalating social inequality. This paper lays out elite (mostly elderly) dislocation of political space; polarizing communities with constituents feeling distant from governmental machinery with constituency representation under siege. Using case studies, backed up with documentary analysis, framed in conjunction with the conceptual thinking of deliberative democracy; this study engages with the elements of dislocation. Constituency misrepresentation is laid out through a triangulation of case study material drawn from newspaper reports, discourses and counter narratives, amplified by process tracing and inferential analysis. Elite manipulation of political spaces exacerbates social inequality, creates fractured communities; undermines democratic mandate, social advancement and broad citizen consensus. From media coverage of glib slogans, elite pledge generic support for the regime in place whilst constituents are giving false expectations that seldom materialize into concrete development. There are no clear-cut manifestos that reflect the voices of constituents against bogus claims to state institutions with the political elite purportedly speaking on behalf of their constituents -‘the people’. The ensuing inertia creates a false sense of representative governance as projects promised are rarely delivered. Slogans should usefully channel the development needs of constituents, permitting government to calibrate a robust development portfolio and citizen assemblies factored into policy design and service delivery. Developing a stakeholder approach and building the capability of social development professionals, in order to filter through pressing concerns with measurable outcomes, bolstering youth employment and fostering social protection would remove the lock jams in constituencies. Strategic spending in public services and essential infrastructure such as health, roads, transport, water, power supply and education are crucial in reducing inequality.
Effect of Job Status, Gender, and Employees’ Achievement Motivation Behavior on Work Performance: a Case Study of Selected Local Government Employees in Ekiti State, Nigeria
Authors: Ogunleye Adedeji J. , Osekita Damilola A.
Published: October 2016

This study investigated the effect of job status, gender, and employees’ achievement motivation behavior on work performance. Two hundred and seven (207) local government employees’ opinions were sampled using the achievement motivation questionnaire and the perceived work performance questionnaire. Seven hypotheses were developed and tested using 2 x 2 x 3 Analysis of Variance (ANOVA) statistics. Results confirmed that job status [F (2,206) =5.05, p05]. A significant interaction effect of gender and job status; gender and level of achievement motivation behavior; and job status and level of achievement motivation behavior were also found on work performance. However, there was no significant interaction effect that existed between gender, job status, and the level of achievement motivation behavior on work performance [F(2,206)=.217, p>.05]. Findings were discussed in the light of available literature and it is recommended that efforts should be made to discourage discriminative behavior among sexes while also closing gaps in level managers’ hierarchies and categorizations. This is particularly in terms of derivable incentives, benefits, and pay on their jobs to have a significant impact on the work performance of employees.
The Need For a Contemporary Nigerian Philosophy to be Taught at Every Level of Nigeria’s Educational Programme
Authors: Iwuagwu Emmanuel Kelechi
Published: October 2016

This paper while acknowledging the importance of an in-depth study of Western philosophy as well as African philosophy for students of philosophy department holds that this content will not bring about the ethical, socio-political and economic reengineering very much needed in Nigeria. It is the contention of this paper that there is great need for social value reorientation in Nigeria and philosophy should provide the hub for this reengineering of the Nigerian society. The paper argues that there is a big vacuum at the base of Nigeria’s educational system where the students lack any philosophical sense of direction and do not as much as know the philosophy that underlies the societal way of life. The paper employing a critical philosophical appraisal of the current state of affairs argues that philosophy should not only be merely introduced to university students as one of the general courses studied for one semester, it should be studied from the nursery/primary school level through the secondary school to the university level. The content according to this paper should be well articulated as Contemporary Nigerian Philosophy with emphasis on moral leadership training with focus to incorporate future leaders into national values as well as inculcate in them a sense of patriotism which will help address the current ethical, socio-political and economic problems confronting the present day Nigerian society. The paper concluded by advocating the philosophical formulation of a generally acceptable value design to be copied by every segment of the society which will be taught as Contemporary Nigerian Philosophy at all levels of the Nigerian educational program and for all students whether in public or private schools.
Does gender diversity in the boardroom influence Tobin’s Q of Croatian listed firms?
Authors: Pavic Kramaric Tomislava , Milun Toni , Pavic Ivan
Published: October 2016

Gender diversity has attracted attention of scientists and practitioners of different fields. Despite the efforts and progress that has been made towards achieving gender equality in the workplace this has remained the weak point especially in the context of management and supervisory board positions. Therefore, the authors wanted to investigate whether this is true for Croatian listed companies. The hypotheses that women in leading positions has a positive impact on performance Croatian listed companies is tested using Tobin’s Q indicator for the year 2014 whereas explanatory variables comprise different corporate governance variables such as Shannon index, Blau index, gender of the president of the management and supervisory board, share of women etc. The analysis is performed by using different empirical research methods including linear regression. The main findings are that women acting as the presidents of the management board positively influence performance. Moreover, having more women in the management board also has beneficial effects on financial success of the firm.
Acetabular Fractures in the Elderly
Authors: Manson Ted , Schmidt Andrew H.
Published: October 2016

➢ In the physiologically compromised elderly patient with an acetabular fracture, nonoperative treatment is associated with functional outcomes (as indicated by the Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC] scores) similar to those seen in healthier patients who undergo open reduction and internal fixation, with similar mortality and lesser need for late conversion to total hip arthroplasty.

➢ Open reduction and internal fixation of displaced acetabular fractures in patients older than 60 years of age is an excellent option provided that the patient does not have risk factors for failure such as acetabular dome (roof) impaction, femoral-head impaction, or a posterior-wall component. Specific techniques to treat quadrilateral plate involvement and dome impaction are necessary to ensure a durable result. More limited operative approaches and percutaneous fixation have a role in this patient population to minimize the morbidity associated with more extensive exposures.

➢ The clinical and radiographic outcome of posterior-wall acetabular fractures that have associated comminution, marginal impaction, and/or femoral-head impaction fractures is predictably poor, with rapid onset of posttraumatic arthritis. Immediate total hip arthroplasty in this population is simple and has outcomes equivalent to those of total hip arthroplasty for coxarthrosis. Total hip arthroplasty should be considered for patients who are ≥60 years of age and have posterior-wall acetabular fractures and perhaps even in younger patients when there are multiple injury factors that predict a poor outcome.

➢ The published clinical results of the use of acetabular reconstruction rings, bone graft, and revision arthroplasty techniques appear to be similar to the results of combined internal fixation and insertion of uncemented acetabular components. Surgeons should choose an operative plan that is appropriate to their particular training and skills, the patient’s particular fracture, and hospital resources.
Methane-Hydrate-Formation Processes in Methane/Water Bubbly Flows
Authors: Shimizu T.. , Yamamoto Y.. , Tenma N..
Published: October 2016

Offshore natural-gas production from methane-hydrate (MH) reservoirs has received considerable attention. In this study, the offshore production method is briefly described, followed by the flow loop experiments performed to investigate the formation processes of MH in methane-in-water bubbly flows. Transient processes of phase transformation are characterized by phase paths, flow morphologies, pump heads, and in-situ particle-size measurements. It is realized that an MH slurry is generated by MH shells covering unconverted bubbles, whereas it can be transformed into a colloidal flow with fine crystalline particles under an intense turbulent shear. This study suggests that, in practice, the flow pattern under MH formation would be determined by the phase path and the flow velocity in the pipeline, which is one of the important factors considered in the evaluation of flow-assurance risks.
A New Approach of Gas Lift Wells Production Optimization on Offshore Fields
Authors: Lubnin A. A. , Yudin E. V. , Fazlytdinov R. F. , Khabibullin R. A. , Grishchenko E. N. , Bovt A. V.
Published: October 2016

This article deals with developing production mode of gas lift operation of production wells. A method for solving the issues associated with immediate assessment of the potential flow rate of a large number of wells, as well as for the search of candidates for wellwork is presented. A method for solving optimization problems that arise in operation of gas lift wells on offshore is proposed. Examples of using the proposed method at offshore oil fields of the Socialist Republic of Vietnam that are operated by JV Vietsovpetro are shown.
Selection of Thermo-Chemical EOR for a Large Carbonate Reservoir with Heavy Oil Based on Results of Laboratory Experiments
Authors: Taraskin Evgenii , Ursegov Stanislav
Published: October 2016

This work summarizes the results obtained during the laboratory tests carried out to choose the most efficient thermo-chemical EOR for the further development of the Permian - Carboniferous reservoir of the Usinsk field which is the largest object with heavy oil (its viscosity is around 710 mPa*s) in the Timan-Pechora oil and gas region located in the North European part of Russia. The laboratory experiments were conducted using the stacked models of full-sized and standard-sized core samples of carbonate rocks of the reservoir. Due to the oil-wet characteristic of the carbonate formations, the large volume model was initially imbibed by oil without modeling the water connate saturation. The results of these studies suggest that the combined use of hot water with a temperature of 250°C and a NOP surfactant increases the oil recovery factor up to 38 %. The reason of this relatively low efficiency of the considered thermo-chemical EOR is connected to saving the hydrophobic characteristic of the carbonate formations even upon their heating above 200°C.
An Integrated Approach to the Effective Completion of Horizontal Wells with Multistage Fracturing Based on Petrophysical Analysis, Geomechanical Modeling and Reservoir Simulation. Examples from Western Siberia.
Authors: Kovaleva E. , Vishnivetskiy A. , Naumov Yu. , Lavrenkova N. , Ahmedsafin S. , Rybalchenko V. , Varyagov S. , Kreknin S. , Borovinskiy Yu.
Published: October 2016

This paper describes the integrated approach to decision making on the optimized horizontal well completion with multistage fracturing (MSF) based on petrophysical, geomechanical and numerical modeling. This approach is pertinent in case of insufficient target exploration including absence of a full scale geo&hydromodel (FSGHM). The basic work process of the proposed approach is based on consistent efforts of a petrophysicist, geomechanical engineer, fracturing engineer and reservoir engineer and thus includes petrophysical and geomechanical modeling, fracturing design, numerical modeling and final planned well flow rate evaluation. The role of geomechanics in the production chain is to determine zones with the lowest and the highest fracture gradients to control fracture location and analyze fracture geometry. The basic objective of the proposed approach is to develop a set of recommendations to select: Optimized frac sleeve spacing to increase production during a certain period of well production;Optimized proppant injection volume in general and for each fracture;Recommended horizontal well paths for efficient multistage fracturing completion and reduction of the most probable risks;Frac sleeve placement with provision for the horizontal well path through the section (vertically) to optimize fracture initiation points and maximize reservoir coverage.

Besides, according to the base history, costs of new target development using available production technologies can be estimated based on the completed work package.

An additional objective of this approach is identification of interdependent parameters for further facilitation of downhole surveys and laboratory studies and excluding of non-informative methods.

This paper gives an example of the developed method application for a prospecting and appraisal well at one of the West Siberian fields with a target characterized by extremely low permeability and uncertainty.
Application of Open Hole Gravel Pack OHGP among the Technical Solutions for Successful Drilling and Completion of Horizontal Wells, North-Komsomolskoye Field, PK1 Formation
Authors: Salyaev Vadim V. , Sitdikov Suleyman S. , Nuykin Andrey M. , Arzamastsev Georgiy G. , Pilgun Pavel S. , Safin Ayrat F. , Gashimov Roman R. , Susoev Anton S. , Gruzdov Dmitry , Gromovenko Alexander , Kapkaev Alexander , Rezanov Ivan
Published: October 2016

Well completion using technology enabling to improve performance and life time is an important objective in the development of PK1 productive reservoir of North Komsomolskoye field. The main challenge of the development of this productive horizon lies in the fact that the reservoir is shallow (1,120 m TVD) and consist of poorly consolidated sandstone, which results in massive production of solids during operation. In addition to that, proximity of GOC and WOC together with high oil viscosity in reservoir conditions results in early gas and water breakthroughs when using standard completion technology.

Basic PK1 formation characteristics could be found in Table 1.

Remote location of the field and impossibility to use all-year-round road transport of materials, equipment and personnel are additional operating problems which had to be resolved to ensure that the project is delivered successfully and without extra costs.

Main questions which the project team had to deal with: What is the long-term solution to limit solids production at target drawdown to a level that would be safe for pumps and surface facilities?How to prevent early water and gas breakthroughs?How to drill a long horizontal section in poorly consolidate rock without any incidents knowing that previously several wells were lost in this zone due to well caving during drilling?

To tackle these problems, we chose a completion technology for the open horizontal section using screens equipped with autonomous inflow control devices (AICD) and inflow tracers. To ensure sand control, we injected gravel packing in the annular space between the screens and the open well bore. In addition to that, we built a 1D rock mechanic model to calculate well bore stability.

During the project execution we drilled 2 long horizontal sections without any incidents; tested completion technology with gravel packing (well A) and without gravel packing (well B); obtained the planned oil inflows; confirmed that the approaches adopted can be successfully used in the Full Field Development.

Given all the particular features of the field and the well design, this operation can be rightly considered one of the most complex onshore operations that have been performed in the Russian Federation.
Special Features of Casing Running and Cementing in ERD Wells
Authors: Netichuk Igor , Suvorov Anton , Galimov Amir
Published: October 2016

ERD drilling is associated with both technical and technological issues that need to be considered from the first planning stage which directly affects the job successful execution. The Paper summarizes the best practices and solutions related to casing running and cementing in ERD wells, describes the importance of geomechanics modeling, special features of casing running and cementing in ERD wells. The purpose of this Paper is to develop an understanding of recent solutions and best practices related to ERD wells construction from the very beginning.
Optimization of Oil and Gas Production Based on Integrated Planning
Authors: Volkov S. V. , Karandashova I. I. , Kagarmanov E. V. , Mogilnikov S. I.
Published: October 2016

One of the key directions for improving the efficiency of oil and gas production is the development of production management techniques. In the last 15 years, there has been a trend in the oil and gas industry toward introducing integrated organizational and management techniques and suitable tools into the production process. The world's leading participants in the oil and gas production sector are implementing programs to introduce "integrated operations" into the production process. In this article, the authors address one of the basic elements of integrated operations, i.e., integrated planning, including: key elements of the Integrated Planning process;key functional components of an Integrated Planning solution;examples of the use and optimization of an integrated plan.
Compressive Strength of Polymer Nanogels Used for Enhanced Oil Recovery EOR
Authors: Suleimanov B. A. , Dyshin O. A. , Veliyev E. F.
Published: October 2016

This paper presents the effect of light-weight metal nanofiller onto compressive strength of polymer gels used in Enhanced Oil Recovery. Non-destructive method based on ultrasonic-wave passing was applied for compressive strength evaluation. The investigations revealed effect gain in strength of gel system by 65% when addition of nanoparticles. The evidence of nanoparticles uniform distribution was utilized by measurements of electrical conductivity changes and percolation task. The kinetic mechanism of nanofiller effect on gel forming and determination of inflection points has been presented and proved. On the basis of polymer consumption due to nanofillers usage, it appears that it is economically efficient.
Investigation of Thermodynamic Processes During Multiphase Fluid Filtration to the Well with Perforation Channels in Damage Reservoir for Determination of Near Wellbore Zone Properties
Authors: Gaidukov L. A. , Novikov A. V. , Posvyansky D. V.
Published: October 2016

In this paper, new models of numerical simulation of non-isothermal multiphase inflow to the well are introduced. These models take into account a damaged near-wellbore zone with low permeability, perforation channels. With the models, it is investigated an opportunity of near-wellbore zone characterization and estimation its parameters (radius, permeability) based on the study of non-stationary downhole temperature and pressure data. Main factors of uncertainty are determined, their influence on the estimated parameters is analyzed.
Modeling Non-Equilibrium Dynamics of Condensate Recovery for Mature Gas-Condensate Fields
Authors: Lobanova O. A. , Indrupskiy I. M. , Yushchenko T. S.
Published: October 2016

Theoretical and experimental studies, as well as actual data of gas-condensate fields development, indicate non-equilibrium phase behavior at low reservoir pressures. However, matching of pVT-models and prediction of condensate (group C5+) recovery dynamics are performed on the basis of equilibrium constant volume depletion (CVD) experiments and simulations. This results in unreasonably high expected values of the condensate recovery factor and in selection of unappropriate technological regimes for reservoir development.

To simulate properly the actual dynamics of C5+ content in reservoir gas during revaporization (regular evaporation) at low pressures, one should consider non-equilibrium phase behavior of hydrocarbon mixtures. In this study, a numerical algorithm for simulation of the non-equilibrium constant volume depletion (NCVD) process is developed on the basis of the previously proposed model for non-equilibrium phase behavior and the non-equilibrium flash algorithm for calculation of phase fractions and compositions.

The NCVD algorithm and two pVT-models of reservoir hydrocarbons are used to simulate the dynamics of condensate recovery at Vuktylskoye field. A special procedure is used to match the pVT-models to lab and field data.

During the development of Vuktylskoye field, reservoir pressure has decreased from 36.6 MPa to 2.5 MPa, with the dew-point at 32.3 MPa. Non-equilibrium phase behavior is essential for gas-condensate reservoirs at pressures below the maximum condensation pressure. For the case considered, non-equilibrium effects are expressed in significant deviation of the actual curve of C5+-content in reservoir gas from the results of equilibrium experiments for pressures less than 5 MPa. The NCVD algorithm and the two pVT-models are used to simulate the dynamics of C5+-content in the reservoir gas at low pressures. A satisfactory match to the actual data is achieved for both the models by adjustment of characteristic relaxation time of the gas-condensate reservoir system to the value of about 30 years. This value, considering rescaling, is in good agreement with the experimental calorimetry data for non-equilibrium phase behavior. Equal values of characteristic relaxation time for both the pVT-models certify the possibility of physical simulation of nonequilibrium condensate revaporization by the NCVD algorithm regardless of specifics of a pVT-model previously matched to equilibrium experimental data.
Technology of Integrated Monitoring of Steam Chamber Evolution During the Oil Production from the Shallow Deposits of Super-Viscous Oil
Authors: Sudakov V. , Nurgaliev D. , Khasanov D. , Stepanov A. , Khamidullina G. , Kosarev V. , Galukhin A. , Usmanov S. , Zaripov A. , Amerkhanov M.
Published: October 2016

Currently the super-viscous oil deposits are under active development in the Republic of Tatarstan. The general method of production is Steam-Assisted Gravity Drainage (SAGD).

The problem of creation the complex of methods to monitor and control the reservoir processes caused by steam injection is of a great importance for increasing the development efficiency.

Traditional control methods of shallow deposits development are normally based on seismic survey and whether insufficiently adatped for shallow deposits of super-viscous oil or very expensive. Thus, the special modifications of geophysical methods are required.

The paper discusses general approaches used for creation of complex of methods for steam chamber monitoring the oil production from the shallow deposits of super-viscous oil by SAGD. The methods developed include seismic and geoelectric survey.

In context of integrated monitoring technique creation the set of special core survey was conducted to define the possibility of detection of the steam chamber distribution by seismic methods. The distinguishing feature of the monitoring technology developed is the use of downhole monitoring tools to receive the seismic signal and to perform the geoelectrical field establishing.

The article contains the description of the seismic data obtained processing methods and the results of the seismic data interpretation.

The study was made with the financial support of Ministry of Education and Science of the Russian Federation (project № №02.G25.31.0170)
New Approach for Oil and Gas Reservoir Simulation With Tilted Fluid Contacts
Authors: Mamedov Emil , Zakirov Ernest , Arekhov Vladislav , Ahmetzyanov Atlas
Published: October 2016

Contemporary traditional practice of 3D oil and gas reservoir modelling has severe drawback. Namely, the natural water flow is neglected. The main reason for this consist in complexity of combining two processes - the field development and natural water flow in the reservoir. This paper authors compared carefully four different approaches proposed by arabian and russian specialists for simulation of oil and gas reservoirs with tilted fluid contacts for using in software package of geological and hydrodynamic modeling. Advantages and disadvantages of the proposed approaches are revealed. Additionally, authors propose their own, the most realistic approach to taking into account the natural water flow for 3D simulation of oil and gas reservoirs with tilted fluid contacts and perfoming forecast calculations.
Integrated Approach to the Correlation Polyfacies Objects Deposits
Authors: Potapova A. S. , Finogenova A. S. , Zverev K. V. , Bregida A. A. , Erofeyev D. N. , Parfenova V. A.
Published: October 2016

This work develops and implements the principles of well and seismic correlation for detailing the structure of a target reservoir, BP16, in western Siberia. The authors used an integrated approach for the correlation of deposits based on core samples, which combines the advantages of a standard method of geophysical marker correlation and the correlation of events represented by cycles of sedimentation.

In the process of three-dimensional (3D) modeling of the field, simplification of the actual geological environment usually occurs. This allows the reservoir structure to fit a framework, which can be numerically modeled and then used for practical implementation. Often during problem solving, inversion of the procedures occurs. Using actual production data (oil-water contact, reserves amount, the scheme of well location, etc.), the geological understanding of the deposit is applied to the stratum-arched model because it is easier to understand and develop. Additionally, the accepted procedure is a serial study of geological and geophysical data, beginning with direct core data and not indirect geological materials, such as seismic and log data. The next phase includes well and seismic correlation followed by reserves evaluation and field development planning.

The proposed scheme avoids a situation where a simplified understanding of the field structure results in an incorrect strategy and injection system, breakdown of natural hydrodynamic barriers, increases in water cut, unknown fluid migration paths, and pressure changes in different parts of the oil pool.
A Novel Permeability Model of Naturally Fractured Shale reservoirs
Authors: Mi Lidong , Jiang Hanqiao , Li Junjian , Li Linkai , Killough John E.
Published: October 2016

Extensive pore-structure studies reveal that the fabric of shale systems are comprised primarily of micro-nano meter matrix pores and complex natural fractures. Measured permeability of shale samples containing natural fractures varies significantly with different cores in the same shale gas reservoir. The significant variation is mainly caused by the stochastic distribution of natural factures. These natural fractures’ effects on permeability under reservoir conditions significantly influence oil and gas production. This work proposes a predictive permeability model that considers the gas transport mechanisms both in the natural factures and matrix pores.

In this work, permeability variation is accomplished by considering that the shale core consists of matrix pores and natural fractures. A simple conceptual flow model with shale gas apparent permeability is developed that couples the cubic flow effects of natural fractures and micro- and nano- scale seepage effects of matrix micro- and Nano- pores based on the principle of equivalent flow resistance and the Tandem -Parallel rules of circuit theory. The matrix apparent permeability is derived based on the dusty gas model (DGM) by considering the contribution of Knudsen diffusion and gas slippage. The fracture apparent permeability is established based on a parallel-plate model by considering the influence of the fracture density. Then the comprehensive apparent permeability of shale samples is achieved by coupling the matrix apparent permeability and the natural fractures apparent permeability.

The matching results with experiment permeability of the Cambrian Niutitang formation from Sichuan Basin in South China show that the naturally fractured shale permeability is strongly affected by the natural fractures’ characteristic parameters. This research proves that shale measured permeability is the result of seepage interaction between the natural fractures and matrix space. The new permeability model, which overcomes the defect of conventional models that only considered the contribution of the fracture system or the matrix system, can accurately estimate the total contributions of matrix pores and natural fractures. In turn, this will enable engineers to complete the shale gas simulation studies more readily. In the future, this new methodology can be used to develop the next generation reservoir simulators for the shale reservoirs.
Lithofacies Modeling Application in Reservoir Simulation of Low Permeability Carbonates
Authors: Suchok Sergey , Obsharov Pavel , Ermilov Andrey , Volnov Ignatiy , Zhukov Aleksandr , Yalalova Venera
Published: October 2016

Nowadays there is observed a global trend of ever-increasing complexity and heterogeneity of hydrocarbon reservoirs. More challenging time makes companies take high-risk decisions based on long-term production prediction. As deterministic approach always gives a single result, it loses its relevance when we deal with risks. Generally probabilistic assessment methodology is coming to the forefront.

A new approach called RE-Status (Reservoir evaluation status) has been developed in this study. The methodology is based on probabilistic assessment and along with normal uncertainty technique it includes lithofacies modeling. RE-Status is based on six key parameters that allow us to understand reservoir complexity and level of project definition in terms of reservoir engineering.

Geological models were created by combining all geological and geophysical data in order to provide the highest-quality 3D representation of heterogeneous carbonate reservoirs. Evaluation of micro-macro heterogeneities and complex analysis of all core studies were used to derive lithofacies. Systematization of stratigraphic analysis, core descriptions and well logging data allowed us to locate facies in reservoir cross-section. It gave us better understanding of the reservoir and nature of filtration processes.

The new approach was applied to two gas fields. Impact of reservoir parameters and lithofacies variability on the dynamics of gas production was described. In the first case RE-Status helped to improve history matching by using facies and uncertainty analysis. In the second case (green field) production prediction based on the results of heterogeneity analysis and facies modeling allowed to locate sweet zones, optimize drilling strategy, increase reliability of forecasting and reduce the uncertainty range.

Novelty of the described approach is application of facies modeling to reduce key uncertainties, match the reservoir model to historical data and provide the most accurate forecast of production.
Strength Properties, Elastic Modules and Compressibility Factors of Rocks from Oil Fields OOO LUKOIL–Western Siberia
Authors: Vavilin V. , Kolpakov V. , Romanov Y. , Pustoshkin R. , Galiev T. , Kunakasov A. , Urazgulov R.
Published: October 2016

The purpose of our work – is to show our version of determining the strength properties, elastic modules and compressibility factors at reservoir conditions on the example of rock fields OOO "LUKOIL–Western Siberia". This paper briefly shows a method of measurement and processing of the results. The paper also shows some results of the determination of dynamic and static elastic moduli of rocks (Poisson's ratio, Young's modulus, shear modulus, compressibility, ultimate strength, elastic limits). This article also shows some results of a comparison of dynamic and elastic Young's modulus.

Static deformation and strength characteristics of the rock were determined by direct measurements of the longitudinal and transverse strains. All measurements were made at reservoir conditions by increasing the axial load until destruction of the sample. The rate of deformation changes was no more than 1.5 • 10-6 s-1, reservoir pressure and temperature were maintained automatically with a high degree of accuracy. Static deformation and strength characteristics are the most reliable, and reflect real properties of both homogeneous and heterogeneous anisotropic rocks.

In our laboratory, on by our optimized measurement method were performed investigations of dynamic and static strength properties of more than 500 rock samples from different oilfields of OOO "LUKOIL–Western Siberia". Our Company has received a very valuable information about the rocks in the form of diagrams "Stress–Strain," of Mohr's circles, elastic limits, ultimate strengths, elastic modulus, graphs of compressibility factor and Biot's coefficients depending on the pressures. It should also be noted that we have not been able to find any general and uniform dependence (laws) in all studied formations and fields, between dynamic and static elastic moduli. For solving of some specific tasks (for example, a field development, design of hydraulic fracturing) and for obtaining high–quality and reliable results on the rock mechanics we need use only static strength characteristics of rocks identified at true reservoir conditions.

Our methodology is based on the American Standard ASTM D 3148–93, and the results of our experimental work and the measurement procedure (Owner's Manual) for our equipment, taking into account the specific properties of sedimentary rocks of OOO "LUKOIL–Western Siberia". For concrete oil formations studied fields of OOO "LUKOIL–Western Siberia" we had found quite close links between the dynamic and static Young's modulus. Such petrophysical links is possible to use for obtaining more important information from the results of rocks research by dynamic method.
On One Precise Solution for Mobilisation Geo-physics and Geo-Mechanics of Hydrocarbons in Deformed Low-Permeable Reservoirs
Authors: Popkov V. I. , Khamitov I. G. , Zatsepina S. V. , Mitina E. V.
Published: October 2016

The group of authors considers the new globally area-specific geology of the trans-Volga and cis-Ural regions. It presents the geo-physically complex studies in geo-tectonics and correlated geo-dynamics. The authors provide the model of hydro-dynamic history matching in complex structured cavernous – fractured high-amplitude reservoirs with synergy in compaction of super low-permeable skeleton of porous cell containing organo-genic clusters of productive bioherms. The paper discusses the innovative method in development with due consideration of fracturing effect development in deformed prosody of petro-migration and diagenesis. The group of authors presents the new methods in search, exploration and development of complexly-structured hydro-carbon fields of the Zhiguli dislocation in the cis-Ural region.

They also present the additional complex seismic studies in the attributed of deformed synergy field with geo-physical rhythms, amplitude polarization in resolving the issues with compacted – de-compacted filtration. For complexly structured reservoirs having the deformed porosity and for adequate hydro-dynamic simulation of conjugated tectonics in fractured-cavernous-porous geo-mechanics the authors of the paper propose the complex geo-physical methods of investigation: seismic, laboratory and computer algorithmic geo-informative methods of adaptation. They also present the additional studies of vertically profiled anisotropy in geo-physically complex hydrodynamic models, in hydro-dynamic well studies, well work-over actions, multi-stage hydro-fracturing for low-permeable compacted heterogeneous, high-viscous and high water-cut oil and natural bitumen pools in due with dynamic area-specific capacity filtration properties, dual permeability – triple porosity for viscous-filtration and viscous elastic – diffusive complex development methods and stages for the production of hard-to-recover reserves.
Innovative Geomechanical Approach Lead to Successful Drilling of the First Highly Deviated Well at the Kruzenshternskoe Field
Authors: Zadvornov Dmitriy Alexeevich , Grachev Oleg Valeryevich , Maximov Danil Alexandrovich , Pekshev Dmitriy Vasilievich , Korelskiy Evgeny Pavlovich , Pavlov Valeriy Anatolievich
Published: October 2016

In this paper, we describe the use of an innovative approach in the preparation process of the input log data for predrill geomechanical modeling, as well as real-time wellbore stability model update during drilling. The paper presents the methodology and justification of the solutions found to restore the missing data in "slow" formations with low values of the speed of passage of acoustic waves at shallow depths for geomechanical modeling, detection and prevention of risks during well construction.

In the context of the "slow" formations at shallow depths (up to 1200-1400m TVDSS in the Yamal region), as well as logging tools restrictions, it is often impossible to detect shear acoustic waves, which, along with the compressional acoustic wave and other log data is also necessary for geomechanical modeling. Given these circumstances, and due to the inability of recording full-wave wireline acoustic logging conducting geomechanical modeling for the upper sections of the well is very difficult. Based on the analysis of acoustic logging data in the Yamal region, we have managed to build a regional dependence of compressional and shear acoustic waves and generate synthetic recovery of the shear wave velocities in the zones of missing data, which has been confirmed by the actual loging while drilling data.

The result of the discovered regional dependence of compressional and shear acoustic waves was the restoration of the missing portion of the upper interval logging that has allowed to carry out predrill geomechanical wellbore stability calculations in the absence of the necessary log data. Because of predrill geomechanical modeling during project preparation for the construction of the well it became possible to substantiate the need for adjustments in the project documentation regarding the use of project specific mud weights. According to this model, significant collapse of the borehole wall was possible in the case of expected design specific mud weights. Thus, the specific mud weight have been significantly adjusted for each section. The resulting dependence has also been used during the drilling process, in the cases when it was not possible to obtain correct shear wave velocity logging data due to external factors. These adjustments to the drilling program on the stage of well design, combined with the early identification and prevention of drilling risks based on constantly updated geomechanical model played a key role in the accident-free drilling of the first directional well with inclination angle of more than 70 degrees in the field.

The experience and achievements have also been used in a number of similar projects in the Yamal region, where it was possible to get a satisfactory convergence of the reconstructed and actual data, which enables the use of findings on the other projects of Yamal region.
A Generalization of Geomechanical Model for Naturally Fractured Reservoirs
Authors: Myasnikov A. V. , Vershinin A. V. , Sboychakov A. M.
Published: October 2016

The article discusses the generalization of the model proposed in [1] for the calculation of the effective properties of the rock sample (periodicity cell) made of an elastic material, dissected by groups of plane cracks. In the original version of the semianalytic mathematical model cracks are represented by elastic springs with different rigidities in the normal and tangential directions [2]. At the same time, the effects of dilatancy and shear deformations because of normal stresses acting on crack’s boundaries are neglected in the crack’s constitutive relation specified by a relationship between the components of the displacement vector and the vector of forces (stresses on the surface parallel to the crack) in the normal and tangential directions. Further, in accordance with the concept of an equivalent medium for the fractured rock samples proposed in [3], cracks’ effective modules are calculated based on the spacing between the cracks and the stiffness of the elastic springs. In order to calculate the total effective elastic tensor of a fractured rock sample a small deformations assumption is introduced, according to which the full deformations are a sum of deformations of the matrix and the fractures.

In this paper, by constructing a three-dimensional numerical model of the periodicity cell, we managed to remove both limitations of the original analytical model: a diagonal relationship between displacements and forces in the crack and small deformations. This generalization become possible by modeling a crack as a thin layer of elastic material with Young's modulus and shear modulus computed from the initial normal and tangential stiffness (the original simplified model is obtained by zeroing Poisson's ratio) and taking into account a geometric nonlinearity in the relationship between deformations and displacements of the fracture’s boundaries.

Based on the generalized numerical model a finite element model in CAE Fidesys is built capable of varying the parameters of the cracks: the number, spacing, thickness, hardness, etc. The results of averaging are presented for the periodicity cell, dissected by three groups of plane cracks - the first two groups are orthogonal to the third group of cracks and intersect at a predetermined angle. The results of numerical studies on grid convergence, the impact of the size of the periodicity cell and the thickness of the crack on the results of averaging are given. The coincidence of analytical and numerical solutions for a simplified model and the difference between them in the case of a generalized model, leading, in some cases, to the variation of the effective Young's modulus up to 30%, are presented.
Laboratory Analysis of Capillary and Electric Properties of Rocks in PT Conditions
Authors: Gilmanov Y. I. , Fadeyev A. M. , Salomatin E. N. , Borodin D. A.
Published: October 2016

Saturation evaluation and reserves estimation by well logs requires laboratory determination of capillary and electric properties including evaluation of cementation exponent (m) and saturation exponent (n). Crucial task is to improve reliability of modeling reservoir-rock residual water saturation based on laboratory methods. One of the solutions is to conduct studies under conditions simulating in-situ conditions which will allow more accurate determination of oil saturation when estimating reserves in the accumulation, and more correct prediction of field performance. Capillary pressure curves behaviour in PT conditions is critical for understanding the mechanism of water-oil saturation distribution throughout the hydrocarbon column height.

The problem was solved with using special laboratory equipment on which capillary pressure curves were produced for sand samples based on porous plate method in individual coreholder with simultaneous measurement of electric resistivity.

Main objective of the study was to find out the difference between capillary and electric properties produced in ambient and PT conditions.
Aged Carbonate Cores Wettability Verification
Authors: Kovalev K. , Fomkin A. , Grishin P. , Kurochkin A. , Kolesnikov M. , Levchenko A. , Afanasiev I. , Fedorchenko G.
Published: October 2016

With the question of reliability on the results of standard and SCAL tests on carbonate cores of the Central Khoreiver Uplift (CKU) reservoirs, a study was carried out to develop appropriate core preparation techniques for the rock.

Several tests were carried out on core plugs with cleaning agents like: alcohol-benzene, toluene, chloroform, carbon tetrachloride in the Soxhlet apparatus, cold kerosene in centrifuge and hot kerosene in coreholder. Cleaning effects on porosity, gas permeability, wettability, irreducible water saturation were studied. The influence of each agent on basic core properties is shown. Based on the various cleaning techniques available and the results achieved, the most suitable cleaning method for CKU carbonates was recommended.

Core aging techniques with dead oil at reservoir temperature and set pressure were carried out. Single aging and sequential multi aging at different aging periods and their effects on core properties were shown.

Core preparation techniques, uncleaned core tests evaluation, aging methods and further studies were also recommended.