bluuebunny/crossref_metadata_2025_split huggingface dataset:
Using NMR Relaxometer in the Study of Unconventional Rocks Characteristics
Authors: Vavilin V. , Galiyev T. , Kunakasov A. , Sorokina E. 
Published: September 2014

Abstract
NUCLEAR MAGNETIC RESONANCE (NMR), NMR RELAXOMETER, STRUCTURE OF VOID SPACE, "FRITILLARY", "WEATHERING CRUST", "BAZHENITE" (OIL SHALES), BI-MODAL NMR DISTRIBUTION, ROUTINE CAPILLARY METHODS
This paper presents the results of NMR studies of structure of void space of rocks from unconventional reservoirs.
Objects of the study - "fritillary", "weathering crust", "bazhenite". These rocks are difficult for studying by conventional methods due to their high heterogeneity, low porosity and permeability, presence of large amounts of clays. Therefore we have used NMR relaxometer to study the structure of void space of such rocks.
We have studied more than 200 samples of the three rock types, made more than 500 NMR measurements on 100% saturated and dry samples.
The nuclear magnetic resonance (NMR), accurate and non-destructive technique, was selected for these rocks,, because the standard methods for capillarity of rocks investigation (capillary pressure by porous plate and by centrifugation) do not reveal the characteristic features of the void space structure which are inherent for these rocks.
These standard techniques doesn't allow to determine the pore sizes and pore channels of less than 0.1 microns, and by these methods it is impossible to study the so called "clay bound water" as a component in the fluids distribution in the rock.
Same samples, were also undergone through routine core analysis measurements (permeability and porosity),, as well as detailed lithological studies using a scanning electron microscope and gas chro-matograph.
Examples of Mini-Frac Test Data Interpretation in Low-Permeability Reservoir
Authors: Makhota N. , Davletbaev A. , Federov A. , Asmandiyarov R. , Afanasiev I. , Sergeychev A. , Yamalov I. 
Published: September 2014

Summary
When dealing with ultra low-permeability reservoirs, one comes across a certain problem of choosing low cost way of getting reservoir pressure data. Classical well test implies long-lasting shut down of production wells (up to several months) due to low permeability and presence of extended hydraulic fractures. The paper contains examples of surveys carried out using hydrodynamic logging. These tests show significant restrictions of the method applied in low permeability resevoirs.
Well pressure based on minifrac test data was evaluated here for ultra low permeability reservoirs. Then the data was then compared with the results of average pressure at hydrodynamic logging. Fracture closure pressure data was used to enrich correlation dependencies for fracture closure pressure (spontaneous growth of fracture) in injection wells using well pressure fall-off curve interpretation methods during minifrac test. Each minifrac test in horizontal wells with multi-stage fracturing was analysed, the results of injection efficiency ratio were gained that are in agreement with production profile according to PLT and allow to test the most productive well influx intervals.
Competencies Transfer for Offshore Russian Operators
Authors: Lavrov Vladimir V. , Fedorov Konstantin M. , McMorren Paul D. , Nalimov Gennady P. 
Published: September 2014

Abstract
Breakthrough in techniques and technologies in oil and gas recovery onshore and offshore changed the reqirements to the personell of operators all over the world. For Russia Petroleum industry the main professional deficit is desplyed in offshore field development. The problem is complex because Arctic challenge incorporates morden offshore technologies and undissolved objectives of their adaptation to severe north conditions.
Two ways of offshore competencies transfer from leading centers to Russian personell market are considered. Future perspectives of Russian shelf development defines the way of formation of own Russian competencies through involvement of professional courses from foreign Universitites and internships in production and service companies. The experience of integration of academical knowledge and professional practice in training and engineering clusters is outlined.
The utiliuzation of State Universities and private initiatives are compaired. The experience of OIL-TEAM Company and its Academy in competencies tranfer are considered. Key aspects of successful development of educational project are analized.
Advantages of Fluvial Reservoir Object Modeling
Authors: Shishmanidi I. , Martynov M. , Kozlov A. 
Published: September 2014

Abstract
The article presents object-based method for creating three-dimensional geological model of continental deposits (Tyumen formation case study). The input dataset of geological and geophysical information to support spatial, morphological and compositional characteristics of the facilities and principles of data implementation in the model are determined. The methodology allows to integrate in a model concept of the sedimentation and create geologically validated reservoir bodies. The results are applicable for reservoir connectivity analysis, well placement, waterflooding optimization.
Estimability of Heavy Oil Viscosity by Nuclear Magnetic Resonances Researches
Authors: Musin Kamil , Bobb Irina , Abdullin Timur , Khisamov Rais , Skirda Vladimir , Gizatullin Bulat , Zaripov Timur 
Published: September 2014

Abstract
This paper presents the results of laboratory and nuclear magnetic resonances researches of seventy-seven crude oil samples from the Devonian, Carboniferous and Permian formations of Tatarstan oil fields with a wide range of viscosity varying from several cps to 60,000 cps.
The results can be used to estimate the viscosity of the oil, including in situ viscosity. It has been found that the NMR relaxation characteristics of the tested samples presented in the form of T2 time distribution spectra confirm that crude oil is multicomponent. Numerical characteristics resulting from the analysis of the spectrum of spin-spin relaxation time T2 have been determined, which show good correlation with the viscosity of the hydrocarbon fluid. The paper presents the obtained experimental correlations between the rheological properties and NMR characteristics for oil samples studied.
Evaluation of Thin Laminated Reservoirs - Hidden Problems
Authors: Oshnyakov I. , Khabarov A. , Malshakov A. 
Published: September 2014

Abstract
The depletion of the majority of mature fields with the best reservoir properties and the easiest extracted reserves determines the necessity of involvement in the elaboration structurally complex reservoirs of different kind.
Among them a special place occupy laminated sands, which can contain and produce oil and gas. However, ther is a number of problems associated with determination of their reservoir properties, reserves volume and effective development.
In this context PK formation of Russkoye field in Western Siberia is the classical example of such kind of objects (Pic. 1.). The main problem is that the shale microlayers are not resolvable on the logging curves, as their thickness is much less than the resolution of the main well logs. The logging methods characterize integral rock properties (sandstone and shale alternation). The usage of classical approach does not allow determine the real properties of sandstones, and net thickness estimated by conventional log evaluation is not real, as it contains impermeable shale microlayers.
So, the petrophysical model of homogeneous reservoir, made previously, does not correspond to the results of hydrodynamic modeling. There was no success in its adaptation without significant increase of permeability and oil and gas saturation.
Geology and Petroleum Potential of the Gulf of Mexico, Cuba
Authors: Ananev V. V. , Verzhbitskiy V. E. , Obukhov A. N. , Borisov D. V. , Nortsev G. V. 
Published: September 2014

Abstract
Oil-and-gas potential of Cuba is ascertained by discoveries among which there are the most large-scale deposits, such as Boca de Jaruco and Varadero fields of heavy oils. Currently the petroleum and petroleum products needs of the island state are satisfied by own sources by less than a half. Prospects of the hydrocarbon resource base development are connected with the adjacent water area of the Gulf of Mexico where foreign companies have been granted license blocks for geological study and further development since 2001. Two Russian companies – JSC Gazprom Neft and OJSC Zarubezhneft among others took part in the development of the Cuban part of the Gulf of Mexico. Since 2004 5 oil wells have been drilled by various companies in deep water of the exclusive economic zone of Cuba. Commercial oil-and-gas bearing prospects have been established in neither of them for both geological and technological reasons. However, only a small part of the water area has been covered by drilling and the productivity of the drill core has been tested at the depth of Cretaceous sediments only. In our opinion, oil-and-gas bearing prospects of the exclusive economic zone of the Republic of Cuba in the Gulf of Mexico remain undervalued and the mentioned water area needs additional geological exploration. Planning of exploration work in this poorly explored region shall be carried out systematically and it shall be based on the results of the regional scientific research.
Oil Viscosity Impact on Invasion Zone Structure and Resistivity Measurements
Authors: Karpov Igor , Makarov Alexander , Eltsov Igor 
Published: September 2014

Abstract
The invasion zone structure and its radial depth depend on formation properties and fluid parameters. Previous research described a methodology for invasion zone reconstruction established from logging data and mud filtration simulation. Fluid mobility in porous media is affected by viscosity; therefore, it is important to understand the effects of oil viscosity on mud filtration. The study presents how oil viscosity and its dependence on formation conditions affect formation resistivity measurements.
Buckley-Leverett equations are used to simulate the invasion process established from drilling and formation parameters pertinent to true reservoir conditions. At the end of the invasion process, the resistivity radial profile (from borehole wall to undisturbed formation) strongly depends on oil viscosity: for example, increasing oil viscosity from 1 cP to 25 cP increases the resistivity of the invaded zone by three times. Resistivity is computed via the Archie equation by taking into account water/oil saturation and salinity. The resistivity profiles are used as input data for forward modeling of the induction logging tool (IL). High-frequency probes (2 MHz) are very sensitive to variations in oil viscosity. The responses of short-spaced (23 inches) probes vary from each other by approximately 21%, with signals of long-spaced (35 inches) IL probes varying by approximately 7%.
Detailed understanding of formation oil properties reduces the ambiguity of resistivity models in the inversion of electromagnetic data. Particularly, knowledge of oil viscosity influence on a resistivity profile is useful for improving the quality of formation evaluations using resistivity logs.
Practical Approach in Planning Well Testing in South Tyumen Region for Improving Data Quality
Authors: Kulyatin O. Yu. , Kulik A. P. , Sosnovskikh A. I. 
Published: September 2014

Abstract
Present article describes workflow and experience acquired during well testing at exploration wells in Uvat district of Tyumen region. Due to significant remoteness of well site activity from established infrastructure, practical approach with compact and effective technological solutions was developed, and thus, can be successfully employed on wide range of other wells and fields with similar remoteness and conditions.
Optimized workflow based on usage of well test string with jet pump, reverse check-in valve and packer during well clean-up and testing sequence is illustrated. Usage of deployed string ensures effective execution of clean-up works on mid-rate to no-natural-flow zones and provides acquisition of quality data on bottomhole pressure through flowing to build-up. Also, this technical solution allows performing full cycle of hydrodynamics well testing operations on target zone in relatively short period, in order of five to seven days for common geology and well conditions. Simultaneous usage of packer and reverse check-in valve drastically reduces wellbore storage effect and allows obtaining detailed pressure dynamics data, characterizing formation properties within corresponding period and radius of investigation.
Through execution of well testing program on more than thirty target zones in frame of exploration drilling campaign, quality assurance, quality control methodology was developed to ensure quality and completeness of acquired data. In addition, process on preliminary data analysis was implemented to discover any potential flaws in data and materials. Inconsistence, lack of data, hidden technological defects shall be identified and activity to be repeated for good data acquisition prior accomplishing of well site operations on target zone. Thus, quality of final well test data set is drastically improved.
Coupled Geomechanical and Fluid Flow Simulation of the Oil Field Evolution Induced by Reservoir Production
Authors: Garagash I. A. , Dubovskaya A. V. , Korneva D. A. , Ghasemi M. F. 
Published: September 2014

Abstract
This paper presents a coupled geomechancal and fluid flow simulation for a hydrocarbon reservoir in exploitation process. Two simulators have been used: 1. Geomechanical simulation software FLAC3D which uses Finite Difference Method and 2. tNavigator which is a Finite Element solver engin for fluid flow simulation in porous media. The parameters connecting fluid flow and geomechanical simulators mainly are porosity and reservoir pressure.
Pore pressure changes in depletion process of reservoir cause changes in stress and strain tensor in hydrocarbon bearing and adjacent formations. Changes in spherical stress tensor in its turn cause a reduction in porosity, which affects the results of the fluid flow simulation.
To verify the geomechanical computations, calculated stress distribution has been compared with analytical and empirical solutions. With coupled reservoir simulation we can predict flow rate for each well, recoverable reserves and also other required parametrs in reservoir life and production process, more accurate and reliable. We will be able to evaluate tensors of stress and strain for hydrocarbon bearing formations and adjacent layers. These stress data can be used in wellbore stability analysis in whole reservoir life.
Reservoir Monitoring of Hydrocarbon-Water Flood Front by Gravimetry Integrated within Reservoir Simulation
Authors: Dyatlov Gleb , Lyngra Stig , Marsala Alberto F. , Loermans A. M. , Georgi Daniel T. , Vasilevskiy Alexandr , Dashevsky Yuliy , Edwards Carl M. 
Published: September 2014

Abstract
Gravimetry is a physical method with a large depth of investigation. Traditional applications include surface gravity observations for mining and oil exploration and borehole gravity logging for investigating formation bulk density.
A new application of gravimetry is large-scale reservoir saturation monitoring. Replacement of oil or gas by water leads to density changes in large volumes of the reservoir, which causes changes of the gravity field down hole as well as on the surface. Since borehole gravity sensors are closer to the reservoir than for surface acquired gravity data, borehole gravity data has better spatial resolution and are less affected by near surface changes.
This paper focuses on the problems of inversion of time-lapse gravity data for complex multilayered reservoirs and estimation of the accuracy of the reconstructed oil-water flood front. The traditional bitmap approach (dividing the reservoir into blocks) requires a huge number of parameters and leads to the well-known inversion ambiguity. This ambiguity can be reduced by introducing a priori information.
The basic idea of the presented approach is to obtain this a priori information by biasing the inversion with output from a history matched reservoir simulation data set. In this case, reservoir simulation saturation data from an onshore giant Middle Eastern oil field was used as input. By processing the simulation saturation data, it was possible to understand the behavior of the water saturation and oil-water flood front in the different layers of the reservoir. Using this knowledge, a 3D model of density changes was introduced. This model formed the basis of the optimization inversion algorithm used to fine-tune the actual location of the oil-water flood front on the basis of gravity data.
Numerical examples demonstrate how inversion and accuracy estimates work for data obtained from a realistic reservoir simulation. The proposed inversion technique will depict any differences from the history matched reservoir simulation saturation output and the gravity data; thus, the gravity data will allow enhanced precision of the reservoir simulation history match.
New Well-Test Interpretation Method for Carbonates Reservoirs With Rare Long Fractures for Field Development Optimization
Authors: Morozovskiy Nikita , Kremenetskiy Mikhail 
Published: September 2014

Abstract
This article is devoted to carrying out and interpreting well tests that reveal carbonate reservoirs with a developed system of conducting macrofractures. Relevance of the issue is due to not only the increase the number of such reservoirs in the structure of hydrocarbon reserves, but generally by domestic companies’ low experience in production from such reservoirs.
It was found out that in the presence of rare and extended natural fractures the traditional model of «dual porosity» is ineffective.
The authors studied more complex numerical model, which assumes the existence of a few fractures of different length in the formation as well as fracture systems that are uniformly distributed in reservoir. The cases where the well was at different distances from the fractures or penetrate fracture system were also considered.
The numerical model parameters were adjusted to the results of core analysis, geophysical studies, logging and the history of the wells production history.
The simulation results revealed that the hypothesis of fractured block structure of carbonate reservoirs correlates well with the results of well tests. The technique of determining the parameters of the fracture system according to the well test is validated. The distance to the nearest fractures and the average size of blocks are determined. It is shown that by the well tests in several wells the direction of extended natural fractures can be determined. This gives an indication of the spatial orientation of fractures and their areal distribution.
The obtained results allow to approach the development of new carbonate deposits more rationally, to plan future wells spacing reasonably, to predict well rates and production profile, to consider the consequences of the well interference by the main fractures.
Multi-Criteria Analysis and Optimization of Waterflood Systems in Brownfields
Authors: Voznyuk A. S. , Rykov A. I. , Kotov V. S. 
Published: September 2014

Abstract
This paper describes a methodology for waterflooding pattern optimization based on multi-criteria analysis of the interaction between producers and injectors. This method takes advantage on the use of streamlines which are generated from the post-processing of finite difference simulation results to define the flow paths between injectors and producers and characterize flow allocation between interacting wells. This information is then combined with well production/injection data (oil / water rates, pressures etc.) to calculate parameters like compensation ratio and injection efficiency for each well. Having all this information, a set of cross-plots is used to rank the producers and injectors by their sweep / drainage efficiency.
The results of such analysis allows the planning of workovers, optimization and allocation of the volumes of injected water and ultimately enables a comparative assessment of the efficiency of each individual workover event in terms of incremental oil production, water-cut reduction and decrease in non-effective water injection.
One of the advantages of this method is the use of already available results from finite difference simulation. This fact dramatically increases the time available for the waterflood optimization process and significantly widen the range of scenarios where streamlines technologies can be applied. Moreover, this approach does not require significant or time-consuming computational efforts, which make it a very convenient decision-making tool for field operations planning.
Field Study of Temperature Simulators Application for Quantitative Interpretation of Transient Thermal Logging in a Multipay Well
Authors: Valiullin R. , Ramazanov A. , Sadretdinov A. , Sharafutdinov R. , Shako V. , Sidorova M. , Kryuchatov D. 
Published: September 2014

Abstract
Temperature wellbore studies are widely applied for well testing and logging at the stages of exploration and development. However, in nowadays practice the interpretation is still done mainly qualitatively. In last few years different approaches to joint interpretation of temperature along with pressure and flow rates are discussed more and more widely. In particular, there is a special interest in determination of flow profile and individual properties of near-wellbore zone of perforated wells in multi-layer reservoirs from analysis of transient temperature and pressure during different transitional regimes.
In this work an application of mathematical modeling to quantitative interpretation of field temperature data from multi-layer wells is discussed.
For assessing flow rates and hydrodynamic parameter of individual layers of a multi-layer well, different approaches to inverse problem solution are analyzed. It is pointed out that for reaching higher reliability it is necessary to use for interpretation all available field data, including unsteady temperature logging data. Reasons of disagreement between field and simulation data are discussed.
The analysis of uncertainties arising in interpreting data from deviated wells is presented that indicates necessity to apply additional methods of analysis. It is shown that making use of supplementary simulations allows reaching better agreement between field and simulation data.
Therefore, the complex approach to interpretation of thermal logging data comprising application of sophisticated numerical temperature simulators to interpretation of the full available field data set of temperature logs and fixed-depth measurements accompanied by uncertainty analysis allows, on the one hand, to increase reliability of qualitative interpretation results and, on the other, to provide quantitative analysis of flow profiles and hydrodynamic properties of multi-layer well.