bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of Reservoir with Gas Cap and Underlying Water on Srednebotuobinskoye Field
Authors: Ivanov E. N. , Akinin D. V. , Valeev R. R. , Nikulin E. V. , Sultanov R. B. 
Published: October 2016

Abstract
The Srednebotuobinskoe Oil Gas Condensate Field (SBOGCF) is one of the largest fields in East Siberia (the Russian Federation). It is characterized by the presence of massive gas cap and bottom water. The analysis of early production data indicated the key challenges in developing formations containing contact reserves: gas coning and early gas breakthrough in producers, as well as small production levels. Development of such fields entails geological risks and uncertainties with drilling and well operation.
The paper looks at the evolution of development approaches: drilling horizontal wells in complex Bt Horizon of the Srednebotuobinskoe Field. System-based geological and production data analysis method is employed in the study.
The solutions envisage the use of various drilling and well operation strategies depending on saturation zones in complex fields, which provides flexibility in regulating the development strategy in the field through the application of horizontal wells.
Modeling Gas Condensate Well Productivity in Consideration of Trapped Phases
Authors: Mikhailov N. N. , Voronich I. V. , Shelepanov S. S. 
Published: October 2016

Abstract
This paper is devoted to the providing more accurate modeling of the hydrodynamic processes in the gas condensate reservoirs and investigates the influence of near-wellbore region on the gas condensate well deliverability.
For increasing of accuracy it was used Forchhamer's equation as filtration law. As opposed to Darcy law this equation simulates properties of flow at high Reynolds numbers that typical to gas condensate reservoir. As the nonlinearity coefficients in Forchheimer equation were taken functions of porosity and permeability, proposed by different authors. In addition, there were simulated such effects as the capillary trapping of phases, the formation compressibility and the mudding of the near-wellbore area. The capillary trapping effect was simulated by empirical dependence of the residual saturation as function of the capillary number. Residual saturations were arguments of the function of relative phase permeability.
The studies showed that the difference in productivity of wells can overcome 50 per cent in case of using in numerical model the nonlinearity coefficients proposed by various authors. The importance of modeling the capillary trapping effects was corroborated. An essential nonadditivity of considered factors affecting the productivity of wells was shown. It was found that a depression increase in hydrophobic reservoirs leads to a greater relative increase of well deliverability in contrast to hydrophilic reserviors. Furthermore, in the research was simulated the change of the wettability in parts of borehole area from hydrophobic state to hydrophilic and vice versa. It was shown that well deliverability as function of a radius of area with modified wettability has extrema. From the analysis of the data obtained it was concluded that the changes of wettability in near-wellbore area can improve well deliverability, but the optimum size of the area with modified wettability depends on the presence in the formation of capillary trapped water. Thus, radius of the area with modified wettability may be optimal for one configuration of the trapped water or lead to a decrease of deliverability in other cases. Such effect should be considered during attempts to increase deliverability by modifying type of near-wellbore area in terms of wettability of the formation.
Complex Research of Bazhenov Formation Samples Using Digital Rock Approach
Authors: Shklover V. Ya. , Artemov N. A. , Rashkovskiy A. I. , Dmitrieva T. G. , Zagvozdin V. P. 
Published: October 2016

Abstract
The rocks of the bazhenov formation are hard to recover reserves. One of the problems related to the calculation of reserves of hydrocarbons confined to deposits of the bazhenov formation is the lack of a comprehensive approach to the detailed study of the properties of these rocks. Challenge of industry is to develop an approach to the definition of the parameters needed for the assessment and calculation of oil and gas deposits related to deposits of the bazhenovfFormation.
In this paper, the authors propose a multiscale approach to the study of the bazhenov formation samples, which allows us to characterize the different levels of the void space, structure and composition.
The aim of the study was to determine the possibilities of modern bulk multiscale microscopy for solving problems on the properties of bazhenov formation samples and improve the accuracy of input data for reservoir properties modeling.
To achieve this goal it was necessary to solve the following problems: Clarify and complement the structural information obtained by traditional methods (X-ray microtomography), by mineral composition and porosity of the core in the micron and submicron scale.Assess the reservoir rock properties in a wide range of scales with division of different types of porosity.
The work served as a multiscale assessment process for bazhenov formation samples.
Selection of Unconventional Core Workflow Depending on Field Goals
Authors: Karpov I. , Mamyshev T. , Kostin D. , Zhukov V. , Strizhnev K. 
Published: October 2016

Abstract
Bazhenov Formation (BF) is a complex study target, not only in terms of getting the flow of oil, but also in terms of studying and parameterization of its implementation on the basis of complex laboratory tests. "Standard" approaches to core studies are not applicable to the BF due to the destruction of rocks over time from exposure to air and liquids. Specialists, who analyze core material, are often encounter a lack of manufacturing capabilities of conditioned samples required for the measurement of physico-chemical and estimation parameters.
The purpose of this work is to optimize the operations with core material from source rocks on the territory of the company Gazprom Neft PJSC, which are aimed at maximum recovery of geological information while ensuring the best preservation of core material.
To address this objective it is required to perform an integrated approach for analysis of the core material at all stages - from the selection of suitable coring technologies, operations with a core "in the well" and transportation of the core to the laboratory to selection of the optimal sequence (algorithm) of the sample preparation and laboratory tests, depending on the set of commercial applications.
It is assumed that the section of the BF can be divided into a series of intervals formed by rocks, differing from each other by physico-chemical and filtration parameters. One group of intervals may be involved in the development by creating a pressure differential in the well-reservoir system, the second - by creating artificial fracture network by applying the fracturing technologies, the third will be the result of thermal effects on the rock. A list of studies was compiled on the basis of the basic assumptions of non-uniform vertical structure of the section of BF, that allows addressing a series of commercial tasks: how intervals with different properties are spread in the sections of the BF, the presence of movable hydrocarbons, filtration-capacity parameters range of intervals. To implement a list of studies, that take into account these features, "a roadmap" for research was composed, including the required handling procedure for core material.
The work shows the influence of the selection of technology, transportation, storage and sample preparation methods on the amount and quality of information obtained from geological core material of source rocks in Western Siberia.
Express-Method of Assessing the Effectiveness of Acid Compositions for Oil Production Stimulation in Relation to Geological and Physical Conditions of Specific Formation
Authors: Silin M. A. , Magadova L. A. , Gubankov V. B. , Tsygankov V. A. , Veremko N. A. 
Published: October 2016

Abstract
As you know, most acid compositions intended for use in oil and gas production stimulation technology contain various surface-active agents (surfactants).
During the filtration experiments the efficiency of surfactant-contained acid compositions is assessed by an increase of core permeability, which may be the result of two processes: dissolution of rock material and washing off the oil from porous medium surface. When both processes are at the same time, it is impossible to estimate the contribution of each of them.
The express-method involves research on single cores. Only in case of the positive result of acid composition application regarding an increase of permeability and porosity of the core sample, you can proceed to the complete simulation on core samples with residual water or oil saturation.
The filtration experiments are performed with a high pressure filtration unit and extracted core samples.
The new approach is to replace a complicated research process of acid stimulation effect in order to select the most effective compositions, and the use of a simple study on a single water-saturated and oil-saturated core. This will reduce the work of testing acid compositions by eliminating the time-consuming research process on a stacked core model, as well as prevent from using the inefficient acid compositions in the field.
In contrast to the experiments to determine the coefficient of oil displacement by water, as well as experiments to determine the curves of phase permeability, in which stacked core models are applied to avoid end effects, in this case a core material single-sample is used, since the main purpose of these experiments is to identify the impact of acid composition on the reservoir properties.
Secondly, the feature of this method is the fact that allows you quickly and without additional expensive studies of the structure and composition of the core material, not only to select, but also to adapt the acid composition to the specific formation and porous medium conditions and characteristics.
Thus, the further research is carried out only with the selected acid compositions excluding the rest of provided testing acids, saving a considerable amount of time and money.
Selection of Adequate Reservoir Models for EOR Laboratory Simulation
Authors: Putilov I. S. , Rekhachev P. N. , Gurbatova I. P. , Barkovsky N. N. , Yakimov O. I. 
Published: October 2016

Summary
The publication reviews the influence of core samples on reliability of data collected during laboratory simulation of formation stimulation techniques depending on the type of reservoirs.
The analysis has shown that, as opposed to composite models, a full-size core displays the interconnection of pore systems in complex reservoirs in the best possible way, and this makes it possible to draw more correct conclusions on the efficiency of techniques such as assessment of adsorption and mechanical destruction of polymer compounds, strength of the built waterproof barrier, pressure dynamics during injection, etc. When selecting full-size core samples, in order to increase reliability of the laboratory simulation data, it is necessary to consider rock anisotropy that is inherent to carbonate reservoirs and is generally associated with rock fracturing.
Based on the obtained knowledge about improvement of EOR simulation efficiency under complex carbonate reservoir conditions, laboratory analyses have been carried out using core material and METКA thermoreversible polymer compound developed by the Institute of Petroleum Science, Russian Academy of Sciences, Siberian Branch. The usage of a full-size core made it possible to assess the efficiency of METКA technology in terms of involvement in the development of not only low-permeability layers, but also high-permeability formation zones which have not been covered before or lightly covered by water-flooding. The analyses carried out using composite models from a standard-size core showed that the obtained data in terms of assessment of water-flooding coverage had low informative value.
Thus, it was found that core samples of the maximum diameter must be used for testing under complex carbonate reservoir conditions due to low representativity of standard samples.
The obtained findings are of practical importance in terms of correct assessment of EOR parameters for wells during field development.
Tight Oil in Oil-And-Gas Source Carbonate Deposits' Gas Saturation Zones of Gas-Condensate and Oil-Gas Condensate Fields
Authors: Skibitskaya N. , Bolshakov M. , Burkhanova I. , Kuzmin V. , Surnachev D. 
Published: October 2016

Abstract
Research is based on conception about field as not only migrating fluids trap with formed pore volume and shielding cover but as self-assembling oil-gas source system on one or another oil-gas generation stage.
In order to study oil-and-gas source carbonate rocks in detail a core studying laboratory investigations complex was developed. Core samples, salt exhausted but not extracted, were studied by petrophysic, geochemical, electron microscope and physicochemical methods.
Complex treatment to investigations allowed to discover regularities of carbonate oil-and-gas source deposits' catagenetic transformations. These regularities were put into created hearth-clustered algorithm for rock properties modeling. A hearth-clustered conception taking into account oil-and-gas source rocks' transformation regularities would allow to differentially estimate and classify hydrocarbons reserves and also choose directed recovery technologies in hearths' pay zones which correspond to different organic matter and rock-forming matrix catagenetic transformation stages.
Geological hard-to-recover oil reserves in gas-saturated zones of gas-condensate and oil-gas-condensate fields are traditionally not considered in estimation of reserves, nor in field-development program but they represent tremendous unaccounted and not realized resource base of Russian Federation in regions and fields with wholly developed infrastructure. They should be necessarily considered in design estimates as on early so on late field development stages.
Probabilistic Assessment of Single Well Source Rock Oil Recovery in Terms of Geological and Technological Uncertainties
Authors: Nenasheva M. , Demo V. , Zhukov V. , Shevchuk T. 
Published: October 2016

Abstract
The Bazhenov formation contains huge hydrocarbon reserves and covers the most of West Siberia territory. In most cases its productivity is assosiated with the presence of permeable layers ensuring natural inflow of oil. Both global and Russian experience in development of unconventional reserves has shown that the stimulation process is the key method of introducing previously inaccessible reserves into development.
It should be noted that current level of multi-stage fracturing technology development does not provide the cumulative production required for payback of a drilled well. In the near future fracturing technology development should be focused on the increase of stimulated reservoir volume by creating artificial fracture network in relatively ductile source rocks.
The authors believe that Bazhen wells productivity calculations should consider not only geological, but first of all technological uncertainties and risks. This work shows a shift from the deterministic 2D forecast of the well production profile to the probabilistic 3D forecast making it possible to take into consideration a significant range of technological uncertainties related to development of source rock deposits in the Bazhenov formation.
Meeting the technological challenges, such as creating high density fracture network and reduction of the well cost, is the key target for projects of Bazhenov formation investigation.
High-Frequency LWD Electromagnetic Measurements Applied to Studying Macroanisotropic Properties of Thin-Bedded Sedimentary Deposits
Authors: Nikitenko M. N. , Glinskikh V. N. , Eremin V. N. , Epov M. I. 
Published: October 2016

Abstract
This paper discusses the development of interpretation base in case of high-frequency electromagnetic logging-while-drilling (LWD) data acquired from deviated and horizontal boreholes. The aim of the work is to analyze the capability of revealing thinly bedded intervals as potentially hazardous when drlilling highly deviated boreholes and conducting multistage hydraulic fracturing. The main challenges are related to the numerical simulation and inversion of electromagnetic LWD data for determining the electrical macroanisotropy of thinly bedded sequences.
To tackle the problem of detecting such intervals, characterized by the alternation of beds with various lithological compositions, we apply high-frequency electromagnetic LWD. The problem is possible to solve since the interlayers are characterized by different electric resistivities, the high-frequency sondes have fine resolution, and the developed simulation algorithms are highly accurate and effective. The basic model we consider is that of a horizontally layered anisotropic medium, taking into account the tool deviation relative to horizontal boundaries. We perform the numerical analysis of electromagnetic signals in typical models of macroanisotropic layers, as well as the numerical interpretation of practical LWD data from highly deviated boreholes of Western Siberia.
For directional drilling of horizontal boreholes with complex trajectories in thinly bedded intervals and for studying their electric macroanisotropy we have developed highly effective algorithms and software for the simulation, processing and interpretation of high-frequency electromagnetic logs recorded during drilling. To substantiate the possibility of estimation of the electrical macroanisotropy factor we have conducted the numerical simulation and analysis of the electromagnetic signals and their sensitivity functions in typical geoelectric models. In such a way, it is shown that the phase shift and attenuation in a horizontal interval penetrated electrically macroanisotropic section have sufficient sensitivity to the vertical resistivity of a formation, as well as to the locations of its top and bottom. This fact enables revealing thinly layered intervals during drilling. As a result, we have shown that the values of the geoelectric parameters (vertical and horizontal resistivities, positions of boundaries) are determined with high accuracy.
The scientific and practical significance of the work at hand is determined by the necessity of improving the safety of construction of deviated and horizontal boreholes and conducting multistage hydraulic fracturing, as well as the development of interpretation base for high-frequency electromagnetic LWD.
Application of AFR Sensor for the Purpose of Integrated Interpretation of High-Resolution Electrical Images and Geosteering of Horizontal Wells in Carbonate Reservoirs
Authors: Shpilman Evgeniya Sergeevna , Butenkova Anastasia Sergeevna , Kirpischikov Yuriy Vladislavovich , Zaboev Konstantin Olegovich 
Published: October 2016

Abstract
Horizontal wells were drilled for the first time in the survey area. The target formation is mainly composed of dolomites and irregularly dolomitized limestones. Voids in reservoirs include pores, vugs, and fractures. Effective capacity of the reservoir is determined by intergranular and vuggy porosity, while fracturing provides for reservoir properties. In view of insufficient knowledge of the operation area, a decision was made regarding penetration of the target formation throughout the entire thickness and identification of a zone with the best reservoir properties for further positioning of a horizontal borehole in this zone. An azimuthal focused resistivity (AFR) sensor of 4 3/4 in. was used during drilling. This sensor generates high-resolution electrical images of borehole walls, measures at-bit resistivity, and provides laterolog data. This paper describes the process and procedures for interpretation of geological and geophysical logging while drilling (LWD) data for building a petrophysical model of the reservoir, determination of porosity and permeability, calculation of fluid, fracture and mineralogical models, and identification of structural geometry of rock bedding. Electrical microimages were used to update geological and petrophysical reservoir models.
Quantitative Characterization of River Depositional System Employing Detailed Automated Dip Picking Based on Optimized Ridge Filtering
Authors: Tyurin Evgeny , Kusov Anton 
Published: October 2016

Abstract
Interpretation of different types of reservoir genesis in fluvial settings, both from core and logs exposes significant challenges. Currently within industry the electrical wireline imagers are the most detailed logging methods available and provide unique information making solutions possible to resolve this puzzle. However imager data is rarely used to the full extent in geologic modelling due to its ambiguity and subjectivity in dip and azimuth processing.
Current image interpretation most frequently employs a manual dip picking process. This procedure requires significant man hours and potentially introduces human bias. The latter, from our experience, leads to smoothing of the dip and azimuth patterns as well as selecting only the most obvious bed boundary contrasts. Indeed it is critical to capture the entire range of dips for confident sedimentological interpretation. The majority of existing automated dip picking routines are based on pad-to-pad correlation, edge detection and Hough transform. These methods are considerably affected by noise and/or pad depth mismatch and often produce unreliable results. The newly developed automated dip picking routine adopts the ridge filtering methodology to the borehole image data. Data preparation involves overlapping sliding window, stripes removal, pads equalization and morphological filtering. The ridge filter methodology is applied with multiple scale factors creating multiple filtered images to ensure successful boundary picking in noisy or partially noisy datasets. The subsequent contouring routine is the key part of the bed boundary definition process. Apparent dip and azimuth are calculated using minimum least squares fitting of the sinusoid of the contour points. The appropriate bed boundary is selected by statistical analysis of the image area separated by each boundary created from the set of multiple filtered images.
The method presented in this paper allows for characterization of every bed boundary resolved by the high resolution resistivity image. The results show a 4.5 refinement, hence increased resolution in bed boundary definition as compared to the conventional, manual approach provided by logging contractors. The matching of the sinusoids to bed boundaries from both methods is also provided to highlight the improved accuracy of this automated method.
The thorough and robust characterization of the bedding data now permits recognition of sedimentary bodies of different genesis: braided rivers, meandering rivers and crevasse splays/deltas. The detailed dip and azimuth information allowed estimation of bedsets thicknesses and flow direction. The latter information and its distribution were directly used in the geologic sector model providing a valuable constraint on channel belt width and characteristic geometry.