bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computation of Absolute and Relative Permeability Full Tensors for Fractured Reservoirs
Authors: Blonsky A. V. , Mitrushkin D. A. , Kudryashov I. Yu. , Plynin V. V 
Published: October 2017

Abstract
In this paper, we consider the issue that come from flow modeling in fractured reservoirs. We review modern approaches applied for accounting the influence of fractures on flow behavior in both single porosity and double porosity models. We describe in details a DFN type two–phase flow model accounting for non-uniform fracture apertures, flow exchange between fractures, capillary and gravity forces. The Yang-Laplace model was applied for capillary forces. We have developed algorithms of absolute and relative permeability (water-oil) full tensors evaluation for fractured reservoirs. Finally, we present results for a section of field with fractured reservoir.
Study of Vertical and Areal Heterogeneity of Gas Composition in a Gas Condensate Field using Numerical Simulation Model
Authors: Khamzin Timur K. , Reitblat Elena A. , Lomukhin Alexander Y. 
Published: October 2017

Abstract
Development of Achimov formations is one of the most promising prospects to increase gas and gas condensate production for ROSPAN INTERNATIONAL Inc.
Despite large amount of fluid data for Achimov formations, marked by abnormally high pressures (55-60 MPa) and temperatures (104-115 °С), considerable uncertainties still remain, owing to areal and vertical heterogeneity of formation gas within single formation: gas condensate content varies more than twice in a range 150-330 g/m3.
Given that the current reservoir pressure has fallen below the dew point pressure for the most part of the license area, it is impossible to acquire new data on the initial gas composition, and existing data is not sufficient to eliminate the uncertainty.
Under these circumstances simulation modeling becomes a powerful tool, enabling an engineer to reduce uncertainties by the consistent use of all existing data from various sources, such as geological, lab and production data.
Application of 3D Geomechanical Modelling to Optimize Drilling and Completion on Active Exploration Drilling Phase
Authors: Kreknin Sergey , Tryasin Evgeny , Lushev Mikhail , Korelskiy Evgeny , Pavlov Valeriy , Maximov Danil , Strakhov Sergey , Zinovyev Aleksey , Grachev Oleg 
Published: October 2017

Abstract
The paper demonstrates the application of 3D geomechanical modeling results for: identifying zones of increased and lowered risks for entire area of the field, optimizing trajectories of production wells, and forecasting sand production in various productive horizons.
Synthetic cubes of the «safe drilling window» have been modeled for the typical design of the production wells in order to determine the intervals of increased risks from breakouts and mud losses point of view. Finite element method was used for 3D geomechanical modeling of the entire area of the field with usage of Local Grid Refinement (LGR) within the areas of active production drilling. The results of numerical modeling and elastic-strength properties of rocks was used for creation maps of drillability (gradient of pore pressure, gradient of breakouts, gradient of mud losses and fracture gradient) for various horizons over the entire area of the field to determine the safest zones in terms of drilling and zones where optimization of trajectories or well designs is necessary. Creation of the maximum possible depression maps before sand production occurs along the area of the field was made. Based on the drilling maps analyses, an example of the field demonstrates distribution of increased risks areas from drilling point of view and changes in the required mud weight or well design. Within the framework of the article will be shown the influence of existing tectonic faults on changes in the "safe mud weight window" and pressure before sand production will be determined. Based on the numerical modeling results, optimization of the field development system was proposed to reduce drilling related risks, optimize hydraulic fracturing design and reduce the probability of sand production.
The necessity of using geomechanical modeling results on every «life-cycle» of the field and actualization of the created geomechanical models is shown.
The example of the field in Eastern Siberia shows the possibilities of using 3D geomechanical modeling results to optimize drilling techniques, to reduce the probability of drilling related problems and problems related to sand production and completion system.
The influence of geomechanical factors on different processes during field development is shown, which ultimately can lead to the optimization of field development plan by collaboration work with geologists, drilling and development engineers.
West Salym ASP Pilot: Surveillance Results and Operational Challenges
Authors: Volokitin Y. , Shuster M. , Karpan V. , Mikhaylenko E. , Koltsov I. , Rakitin A. , Tkachev I. , Salym M. Podberezhny 
Published: October 2017

Abstract
In the West Salym field, a mature waterflood is ongoing with increasing water cuts and declining oil production. To counter the decline a tertiary oil recovery technique called Alkaline-Surfactant-Polymer (ASP) flooding was selected. Earlier studies indicated 15-20% potential incremental oil recovery due to ASP injection. An injection/production pilot to demonstrate oil recovery potential of the ASP flooding and collect information to decide on the subsequent commercial ASP projects was started with the preflush injection in February 2016. ASP injection started in July 2016 and was followed by the injection of polymer slug in February 2017. By the end of 2017 polymer injection is to be followed by the injection of postflush till the end of the project.
As the project is still ongoing the paper focuses on the pilot status, progress achieved, and plans for the remaining part of the project. To meet project objectives and collect data on the ASP flooding performance a dedicated surveillance program was developed and the results of the program are discussed below. Technical challenges encountered during the operation phase and the solutions applied to resolve those challenges are also the focus of this paper. Additional studies were performed to assess the performance of ongoing ASP flooding and their results are presented. Finally, laboratory data and field observations collected during the pilot operation phase are presented to support our conclusions.
An Innovative EOR Method for Waterflooding Heterogeneous Oilfield ---- Graded Diversion-Flooding Technology and Verification by Field Comparison Tests
Authors: Wu Xingcai , Wu Hongbiao , Bu Zhongyu , Bai Lei , Zhang Song , Yu Zhentao , Xu Hanbing , Zeng Qingqiao , Jiang Yuzhu 
Published: October 2017

Abstract
XJ6 is a conglomerate reservoir, with oil viscosity 80mPa.s. The reservoir is quite heterogeneous, and seriously uneven sweeping exists. For exploring high efficiency EOR method, three types of EOR models were designed, utilizing continuous phase crosslinked polymer gel (LPG), nano-micro grade particle type polymer SMG dispersion, and millimeter grade pregelled swellable particle (SLG). And field comparison tests were conducted.
In field tests, the chemical slug injection started in April 2013 and ended in January 2015. The injection liquid amount was 0.2PV. Model 1 features preset plugging slug of LPG carried SLG and the following oil displacing slug of LPG slugs with different viscosity, and the pilot consists of 25 injectors and 42 producers. Model 2 features preset plugging slug of LPG carried SLG and the following 4 times of alternate injection of SMG slug and small LPG slug, and SMG dispersion is the main slug in the model. Model 3 features three times of alternate injection of water and high viscosity LPG combined with SLG slug.
Model 1 and Model 2 obtained obvious effect quickly. For Model 1, due to continuous injection of viscous fluid, both of oil flowing resistance and water flowing resistance greatly increased, leading to low liquid supplying capacity for the producers, so the effect of oil increasing and water cut decreasing could not be further improved or sustained for a long period. For Model 2, the small slugs of SLG and LPG pluged or inhibited the macroscopic and midscopic scales of prevailing flowing, and the main slug of low apparent viscosity SMG dispersion was used to deal with the microscopic scale uneven sweep, in which, with the SMG particles temperarilly inhibiting the big pores or high permeability area, the water was diverted into small pores or low permeability area to efficiently displace the relatively high saturated remaining oil there. So Model 2 obtained better effect of oil increasing and water cut decreasing. During chemical injection in Model 2, the daily oil rate increased by 2.9 times, and that of Model 1 is 1.1 times. And the maximum water cut decrease of Model 1 and Model 2 was 32.2 and 46.2 percent respectively. Model 3 did not show obvious EOR effect.
The field comparison tests verified the advancement of Model 2, which features multi-grade diversion and displacement, and the scientific nature of syncronouse diversion and displacement mechanism. It also obtained economical success. Therefore, for waterflooded reservoir with complex pore structure and high heterogeneity, the multi-grade divertion and displacement technology can be used to greatly improve utilizing efficiency of the injected water, achiving the aim of oil recovery enhancement.
Reconstruction of the Initial State of a Gas-Condensate System Based on a Limited Set of Field Data; A Case Study of One of the Fields in South Caspian Basin
Authors: Dmitry Olenchikov , Alexander Semenov 
Published: October 2017

Abstract
A method is proposed and applied to one of the fields in the South Caspian Basin that allows to reconstruct the initial state of a partially depleted gas-condensate field using a limited set of initial data and assess the prospects of its development.
The method is based on numerical PVT-simulation with sequential stepwise gas saturation with equilibrium condensate to the dew point pressure that corresponds with the pressure at the gas-oil contact (GOC). The obtained composition at the GOC is then used to reproduce the variation of gas composition and condensate content with height above GOC taking gravity into account. At the final stage the obtained results are verified against well production data.
PVT-modeling was based on laboratory studies of recombined gas samle. The residue C10+ was divided into two pseudo components C10+(1) and C10+(2). To adjust the model to the experimental results, the properties of C10+(1) and C10+(2), and the shift-parameter of methane (Sv) were modified.
PVT-modeling allowed the following gas compositions to be calculated: –at the sampling depth and time;–at the sampling depth in the initial state;–at GOC depth in the initial state.
The calculation of gas composition variation with height above GOC was performed. For each of the compositions obtained, the potential content of C5+ was calculated.
From the development point of view, not only the initial state is of interest, but also the change of gas-condensate ratio (CGR) with reservoir depletion. To model this process, a constant volume depletion (CVD) experiment is generally used. The obtained dependencies allowed us to compare the results of calculations with the historical data.
Actual values, on the whole, correlate well with PVT-modeling data, and values that do not fit into the general paradigm of the obtained regularities are a reason for more in-depth studies of the reasons that led to such a difference.
The approach used allows to: –partially fill the lack of research by taking into account the physical principles of reservoir formation;–build an initial equilibrium reservoir state taking gravity into account;–reduce the uncertainty of reservoir production data.
System Approach to Justification of Gas Wells Pattern Arrangement under High Geological Uncertainty Conditions
Authors: Yazkov A. V. , Kadochnikova L. M. , Ramazanov R. R. , Martynov I. V. 
Published: October 2017

Abstract
The work deals with the problem of choosing the optimal of gas and gas-condensate wells pattern. Numbers of three-dimensional hydrodynamic models based on multi-variant calculations and economic analysis select the optimal wells pattern. However, creating a full-scale models is not always appropriate, for example, in case of low exploration at the initial development stage, the lack of investigation methods of reserves difficult to recover. In this case justification of the wells pattern should be based on other principles.
The article suggests a method of justification of the pattern arrangement, based on sectoral hydrodynamic models calculations. The advantages of sectoral models in case of low-data are the creation of local geological model based on the exploration wells data, little calculation time, interactive model changes. However, sectoral modeling has a several questions, for example the size of the sector or the boundary conditions. In the solution of the well location problem the modeling sector size determines the distance between the wells, which influences on the dynamics of wells technological parameters, the development time, cost effectiveness of the project.
The main idea of the proposed methods is to analyze of wells production in non-stationary filtration models (the maximum production rate in a minimum development time). The pseudo-stationary radius is based on the economic analysis.
Methods to Improve the Efficiency of Development of a Multi-Layer Offshore Gas Condensate Field: Thien Ung Case Study
Authors: Lubnin Aleksandr , Yudin Evgeniy , Sansiev Georgiy , Karimov Talgat , Bondarenko Viacheslav 
Published: October 2017

Abstract
This paper systematizes the results obtained in the process of design and development of Thien Ung, a multilayer gas-condensate field located in the continental shelf of the Socialist Republic of Vietnam. It describes approaches to the planning of technical and economic performance and suggests methods for increasing commercial efficiency of the project.
An Additional Method for Gas Fields Development Control
Authors: Chepkasova E. , Silov V. 
Published: October 2017

Abstract
The article presents a new additional method for massive gas fields development control. The method allows to control one of the main parameters influencing on gas production. It’s a position of gas-water contact (hereinafter GWC) nearby production wells, which don’t penetrate into phase boundary. The method’s signature feature is its availability for gas producing companies, since it doesn’t require additional costs to purchase new equipment, increase staff. The method is based on analysis of parameters changing determined at different times during gas well test (hereinafter WT). This type of research is an obligatory element in gas fields’ development control. Graphical display of the method makes it user friendly.
The proposed method is positioned by the authors as a diagnostic, because in comparison with traditional gas saturation methods control, based on direct contact well walls with GWC surface, the new method provides GWC position as a calculated value. The quantitative estimation of method is based on the assumption of reservoir homogeneous structure near investigated well. The method was tested in Gazprom dobycha Noyabrsk LLC (hereinafter the Company) on Cenomanian gas fields characterized homogeneous structure of the reservoir, and presented good convergence with standard geophysical methods (hereinafter logging).
Comprehensive Selection of Reagents and Technologies for Shut Off in Gas Producers
Authors: Dubinsky G. , Andreev V. , Fedorov K. 
Published: October 2017

Abstract
Main part of the offered procedure and approach lays in selection of reagents and technology for limiting of water influx to gas wells taking into account composition of the rock, water source and BHZ condition. We pointed out the typical mechanisms of water influx and performed grouping of wells based on this attribute, developed and chose reagents and targeted technologies of water shut-off taking into account properties of reservoir rocks.
We developed the procedure of identification of the water-flooded well stock and its classification based on the peculiarities of the water flooding development using data mining, which takes into account volume and quality of the geological-physical and physical-chemical data; on the basis of this procedure we pointed out a group of wells with similar nature of water flooding and offered the methods of water influx limitation for each type of water flooding.
We made complexation of the methodological approaches and technologies, which made it possible to set the order of measures on water influx limitation and increasing the depletion of the hydrocarbon reserves on separate productive formations and wells.
We developed the technology of the productive formation temporary blocking without sacrificing the reservoir properties, and the technology of water influx limitation with simultaneous stimulation of productive interval operation.
We performed works on water influx limitation and water shut-off in gas and gas-condensate wells, which represent the various groups based on the geological-technological conditions. The offered procedure is approved on the wells of Astrakhan, Urengoy and Yamburg Gas-Condensate Fields. The present paper analyzes the success and efficiency of the offered approach and the performed works.
Features of Water and Process Fluids Effect on Filtration Properties of Terrigenous Reservoirs of the Nepa Suite of Eastern Siberia
Authors: Gaydukov L. A. , Nikolaev V. A. , Vorobev V. S. 
Published: October 2017

Abstract
Based on the results of the filtration experiments conducted on core samples of terrigenous strata V13 of the Nepa suite of the Ignyalinsky field, the main mechanisms of the effect of water of different degrees of mineralization and process fluids (fracturing fluid, drilling fluid) on the filtration properties of the reservoir (relative permeability to oil), were revealed. It has been shown that the key factors determining the magnitude and direction (improvement/deterioration) of technogenic changes in the reservoir are: the degree of its salinization, mineralization of the stimulating agent and heterogeneity of the pore volume structure. The results of special filtration experiments on dynamic desalinization of V13 stratum during injection of low-mineralized water, study of fracturing fluids and drilling fluids are presented.
New Features of the Experiment to Determine Lateral Anisotropy Filtration and Capacity Properties
Authors: Kadet Valeriy Vladimirovich , Kravchenko Marina Nikolaevna , Pavlovich Tsybulskiy Sergey , Bogdanov Andrey Vladimirovich 
Published: October 2017

Abstract
The development of methods of the reservoir properties laboratory determination is the current task in the complex anisotropic formations development. Current condition of the computational and experimental base allows us to develop new research algorithms that could significantly update the field standards for the study of core material with the inclusion of refined data in reservoir simulators. This paper provides generalization of core research methods developed by the authors in previous works, and improvements that clarify the characteristics and structure of the anisotropic formation have been proposed.
The obtained results of experiments with Achimov core samples permitted to specify the type of the reservoir symmetry, to modify the obtained model which provides with more qualified adaptation to history of field development and then to specify fluid filtration different directions patterns as well as stagnant zones. This method can be used for any other formations.
The essence of the experimental method is based on the analogy of the filtration and elastic properties of the porous matrix of the reservoir. The study of the motion of elastic waves along the axis of a full-size core makes it possible to establish the presence of anisotropy and to refine the type of symmetry of the properties. According to the method modified by the authors, five standard size samples (30x30 mm) were taken for the study.
Three of the five previously produced samples are used to determine the filtration-capacitive properties along the principal directions of the absolute permeability tensor, the fourth sample allows to control properties along any direction, which could experimentally show the tensor nature of permeability. This new method requires additional fifth sample, which is necessary to use in the filtration properties symmetry type experimental determination. Similar experiments were not conducted earlier. To determine the type of symmetry on five samples, high-speed gas filtration studies were performed with an output to the nonlinear filtration law and permeability was determined under the given conditions. It was necessary to carry out measurements in the forward and backward directions. Obtained data analysis made it possible to determine the filtration properties symmetry type.
The developed complex method includes creation of an algorithm for experiments carrying out and core samples filtration-capacitance properties determination and this method is generalization of previous researches. It allows determining the anisotropy type and taking this condition into account when formation modeling is in progress which was impossible previously. If this methodology is included in the modeling standards, it will let to obtain a higher degree of future development periods accurate forecasting.
Impact of Pore Structure on Reservoir Quality of Carbonates
Authors: Yalalova V. , Zhukov A. , Volnov I. , Khakimov A. , Ermilov A. , Djumaev V. , Abdullaev G. 
Published: October 2017

Abstract
Nowadays most of the world's hydrocarbons are extracted from carbonate reservoirs and this trend will continue in the next century. However, despite a significant number of publications and scientific papers, reserves estimation and planning of carbonate reservoir development still involve a significant level of uncertainty.
Complexity of the study of carbonate reservoirs is due to the heterogeneity of pore structure media, which reduces the reliability of porosity determination and also explains the ambiguity in predicting permeability.
The problem of evaluating the pore structure of carbonate reservoirs is solved by attracting actual measurements on the core. According to the accepted techniques for preparing and examining core samples, only absolute permeability values are estimated and not effective values in reservoir conditions. For gas wells, the only reliable method for estimating the effective permeability is based on analysis of well test data and production logging data (PLT).
This article highlights the experience of applying the proposed approach to assessing the permeability and porosity of carbonate reservoirs while gas field development.
The purpose of this work is to determine the effective reservoir properties of the investigated deposits and to estimate the amount of gas initially in place.
To assess the reservoir quality heterogeneity, the analysis of well test data and production logging data were performed and intervals with effective permeability were identified. For each perforated interval the effective permeability value is determined on the basis of the actual gas production and inflow rate. To calculate the porosity of net pay intervals, the relationship between the core plug permeability and porosity was applied. Thus, to evaluate effective reservoir parameters, well test data and production logging data are used the entire life of the well, and the calculation results represent the range of porosity and permeability variation for each production interval.
The practical importance of the work is that this approach to the assessment of effective porosity and permeability allows us to identify and assess the gas reserves that will be effectively involved into the development.