bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Generalization of Geomechanical Model for Naturally Fractured Reservoirs
Authors: Myasnikov A. V. , Vershinin A. V. , Sboychakov A. M. 
Published: October 2016

Abstract
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

Abstract
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

Abstract
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.
Electric Prospecting Will Help
Authors: Geletii P. P. 
Published: October 2016

Abstract
With the development of science and technology geophysical methods of prospecting and mineral exploration have changed a little. Owing to reliable equipments, designed by modern technologies, field observations have become more accurate and owing to a powerful mathematical apparatus of modeling and interpretation, as well as software, the final geophysical data has gained perspective, faithfulness and informative value. But, at the same time, requirements to geophysical information have changed, as well as cost of work which under the conditions of oil crisis is not entirely acceptable. Another important point is that "geophysical evolution" lies in perfection and modeling of old ideas, physical essence of the methods and approach to an observation system construction, as well as the measuring principle have practically remained the same. I am falling under the impression that such methods of geophysical exploration as electrical prospecting and magnetic survey the world has completely forgotten. In essence, it does make some sense, as it is very difficult to compete with information obtained as a result of seismic exploration. But, is it always beneficial and necessary to use such expensive work? The experience in geophysical practice tells us that this question has an unambiguous answer: alternative solutions are possible nearly always.
This article describes one of such alternative solutions, i.e. a method of directional electromagnetic reception. This method was developed by analyzing already–existing methods of Applied Electric Logging, by examining their physical nature, equipments in use, methods of field observations, the efficiency and faithfulness of the information being obtained, problems and shortcomings, as well as a field of application.
The aim of this work involves drawing attention of the oil world to new methods of geophysical exploration, which are full methods of Applied Geophysics, have a number of advantages and are relatively cheap in comparison with the methods used today.
The article is organized in such a way that the reader is given an opportunity to consistently get acquainted with the method and then to find out its actuality and to draw certain conclusions, no matter whether he is a specialist in the field of geophysics, or not.
Validating Mixing Models for Dielectric Logging
Authors: Kouchmeshky Babak , Fanini Otto , Nikitenko Marina 
Published: October 2016

Abstract
An important element of dielectric logging is validating the mixing models that can predict a formation's electromagnetic response over a wide frequency range. The main petrophysical outputs from dielectric log interpretation include water saturation and water resistivity. The resistivity of water as an output of the interpretation provides an advantage for formations where this information is not available or varies over short depths.
The electromagnetic properties of a formation show a variation with respect to frequency that is called dispersion. To relate the dispersive behavior of a formation to petrophysical properties, certain mixing models are used that relate the properties of the aforementioned elements of the rock to that of their collective effective behavior. Interpretation success depends on the application of a suitable mixing model. This work provides a comparative study of different mixing models and their validation with respect to experimental results on sand and carbonate rocks.
Results of experiment on dielectric dispersion of rock cores are used to study the performance of commonly used mixing models. Experimental results for various values of water saturation and water resistivity at different frequency ranges are used in pursuing two goals. First, the ability of the mixing models to recreate the rocks' dielectric dispersive behavior is considered. It is shown that selecting an appropriate mixing model requires experimental data on a wide frequency range. Second, the fitted mixing models are used to invert for petrophysical parameters. These parameters are compared with known values from experiment to quantify the error associated with using each mixing model.
Dielectric Logging service is poised to play an important role in Formation Evaluation of unconventional and/or non-Archie environments, only if appropriate mixing models are developed and applied. Paper provides guidelines on choosing the appropriate mixing model to improve accuracy of dielectric data processing.
New Life for Old Fields: Identification of Bypassed Productive Zones, Formation Evaluation and Formation Testing Through Casing with Modern Wireline Tools
Authors: Zozulya A. , Petrakov Y. , Karpekin Y. , Blinov V. , Weinheber P. , Karipov I. 
Published: October 2016

Abstract
The Volga Urals basin of Western Russia has a very long production history and consequently many of the original target reservoirs have become depleted. The Uzenskoe field is no exception. Originally placed on production in 2008 the original target layers in the lower Cretaceous formations have since depleted. It was assumed that potentially productive reservoirs exist in the overlying layers; however, these had never been evaluated. Using a variety of through-casing measurements these layers were investigated for productive potential. Integrated interpretation of the acquired data was used evaluate lithology, rock composition, saturation and porosity to identify potentially productive layers. These layers were then perforated and tested with a wireline conveyed formation tester inside casing. Fluid type was verified, samples were acquired and pressure transient analysis was performed to determine layers permeability. The entire evaluation took less than three days of rig time comparing very favorably with alternative methods.
In this paper we discuss the planning, execution and interpretation of this evaluation exercise.
Competent Utilization of Multistage Acid Fracturing Technology to Increment Well Productivity during Stimulation of Low Permeability Gas Carbonate Reservoirs – Case Study
Authors: Guizada Pablo 
Published: October 2016

Abstract
Tight gas reservoirs and specifically low permeability gas-bearing carbonate formations require stimulation to produce commercial gas rates. Certain carbonate reservoirs in Saudi Arabia are highly heterogeneous and the degree of heterogeneity changes over the field and within well drainage areas. Horizontal multi-stage acid fracturing technology has become the preferred completion method in such reservoirs to stimulate these carbonate formations to maximize reservoir contact and enhance well productivity. Due to the degree of heterogeneity of these formations, a number of factors should be considered and a set of best practices should be implemented to overcome the reservoir challenges and achieve the expected results.
Maximizing stimulated reservoir volume is one of the key aspects of the success of this technology. To maximize the stimulated reservoir volume, effective placement of the hydraulic fractures for every stage must be achieved, which is one of the most challenging factors. Effective placement of hydraulic fractures depends mainly on the following factors: placement of the horizontal wellbore along the minimum-stress direction and proper annular isolation to induce independent fractures across each stage. This goal becomes even more challenging to achieve with acid fracturing treatments. Failure to isolate the stages can lead to hydraulic communication between the fracture stages, allowing the pumped frac stage to propagate to the previously open frac stage, preventing the creation of separate fractures, affecting the well's productivity and ultimate recovery. A second factor that governs multi-stage completion effectiveness is the use of swellable packers to ensure proper isolation between the various stages, which was observed in the field.
This paper describes the application of Multi-Stage Fracturing (MSF) completion technology. Field cases describing the deployment of the MSF completions and the obtained results after stimulation is presented, as well as the main conclusions and recommendations for successful implementation of this technology are highlighted.
Maximize Efficiency of Coiled Tubing-Conveyed Perforation with Advanced Gun Deployment System and Real-Time Correlation in High-H2S/High-Pressure Wells
Authors: Panferov Rostislav , Burov Anton , Zhandin Alexander , Ghioca Gelu , Boulter Derek 
Published: October 2016

Abstract
Well completion and commissioning operations offshore present a variety of technical and operational challenges in the quest to maximize well productivity and optimize the economic value together with focus on safety. This is very relevant to the perforation operations performed in hostile and high-pressure reservoir conditions encountered in a complex development project in the Caspian basin. We provide description of the project and the innovative solution applied, including challenges faced, experience gained, and lessons learned.
To overcome challenges, we selected electric-line-enabled (e-line-enabled) coiled tubing (CT) for precise depth control, and the latest advanced gun deployment system for conveyance of long gun strings under pressure. Innovative solutions implemented throughout the project included the perforation-shock-resistant bottomhole assembly (BHA), two independent emergency disconnects, and tuned software to predict and evaluate shock load and dynamic underbalance. Some of the unique technical solutions were designed specifically for this project: high-pressure and H2S-rated connectors; specialized tool deployment stack; 15,000-psi working pressure 5.12-in. ID H2S-rated rounded scallop guns; shock-resistant electrical disconnect; and high-tensile CT logging head disconnect weak points.
To date, more than 10 well commissioning operations were successfully completed with this innovative method—e-line-enabled CT perforation under high pressure. This perforation technique proved to effectively minimize operational time, associated risks, improper equipment use, and footprint on location. Such approach allowed safe and efficient perforation in a controlled well environment that resulted in accurate depth control and managed detonation shock load and overbalanced conditions, which avoided any well fluid influx or H2S release. The developed solution required seamless integration of innovative techniques and hardware, including e-line enabled CT, the CT logging head, the gun deployment system for pressurized well conditions, wireline tools and specialized perforation equipment. The design was optimized to perforate the well in three or four runs at overbalanced condition (squeeze mode) in a single rig-up job instead of more than 20 wireline runs. Additionally, the use of CT granted flexibility and increased operational safety to perform pumping operations for well displacement and well control, injection of H2S scavenger, and stimulation, as per Operator's plan, without or with only partial rig-down.
This is the first time that the described CT perforation operation using such techniques has been performed in the Caspian region. The experience demonstrates a method to safely and efficiently facilitate perforation jobs under challenging conditions in the future.
Successful CT Intervention for Re-Frac on Horizontal Oil Well After 2 Years of Production Completed with Full Bore Liner with Frac Ports Controlled by Shifting Tool
Authors: Mazitov M. R. , Valiullin A. S. , Burdin K. V. , Starodubtseva K. A. , Demenchuk I. A. , Serikov D. A. 
Published: October 2016

Abstract
In 2016 it was received the first experience of Coiled Tubing Intervention for Re-frac on horizontal oil well after 2 years of production completed with full bore MSF liner with frac ports operated by CT shifting tool.
The main tasks for Coiled Tubing service setted by customer were effective wellbore preparation of horizontal oil well after 2 years of continuous production, the following frac ports opening and closing by CT in predetermined order for selective fracturings and final clean out and nitrogen kick-off for getting well into production.
Drilling Waste Reduction During Well Construction in the Fields of LLC LUKOIL-West Siberia
Authors: Khalimova Aliya , Shcherbakov Andrey 
Published: October 2016

Abstract
A group of wells of TPE "Pokachevneftegaz" LLC "LUKOIL-WEST SIBERIA" (given in 2015) were selected as an object of study. A comparative analysis of the volume of drilling waste (DW) formation has brought to light that the actual values exceed the normative values. To determine a reason for the excess is currently difficult due to the absence of accounting of the formation of DW during the process of drilling wells in the fields of LLC "LUKOIL-WEST SIBERIA".
The goal of this research work is to decrease the volume of DW formed during construction of wells in the fields of LLC "LUKOIL-WEST SIBERIA" by setting up controls over the volume of their formation, specifically: carrying out a unique calculation of norms of DW formation for each well when developing the project documentation;accounting the formation of DW during the process of drilling.
An analysis of the effective governing documents (GD) that are used in the calcuation of the norms of DW formation has shown that: the following documents do not take into account the use of modern and effective equipment and drilling solution systems that are used during well construction on the fields of LLC "LUKOIL-WESTERN SIBERIA";the empirical coefficents of the losses of drilling solution due to the use of cleansing systems (CS) found in the GD are outdated and using them is inexpedient.
"Regulation of accounting of drilling waste during drilling wells in the fields of LLC "LUKOIL-WEST SIBERIA" is developed in 2016 in the framework of which: works on the development of forms of calculation of the norms of DW formation were made, coefficients of losses of drilling solution when using CS were established, and actions in regards to accounting of DW formation during the process of drilling wells were suggested. The document is approved and brought into action on 14.3.2016.
A trial calculation of the volumes of DW formation is made for the researched group of wells in compliance with the methodology layed out in the regulation. A comparative analysis in regards to the volumes of DW formation has shown that actual values exceeded that predicated values (using the regulation) by 34.6%. Actions for the introduction of accounting of DW formations should allow correct values for the actual volumes of DW formation to be established during the process of well construction and allow their manipulation in the direction of the normative values.
According to the acquired results, and also data in regards to the volumes of DW formation, an assessment of the economic effectiveness is made and a positive effect is established. The introduction of control over the objects of DW formation should allow for the elimination of heightened unplanned expenditures in the future. On the basis of the regulation calculations of norms of DW formation are made for every well during the preparation of the projection documentation for the well construction since March 2016.
The Kosmos Innovation Model - Using Integrative Processes to Redefine Social Investments for Greater Social Impact in Ghana
Authors: Adashie Ruth , Gyan-Kesse Benjamin , Sarpong George , Boakye-Agyei Kwame 
Published: October 2016

Abstract
This paper examines the Kosmos Innovation model that demonstrates impactful results combining integrative but innovative social investment approaches altogether for an impactful social change.
The Kosmos Innovation model was applied to a set of young entrepreneurs with ICT and Agribusiness background. They went through the three main tenets of the model, which are Collaboration, Incubation and Acceleration. Through observations and analysis, these components were deployed to facilitate connections for knowledge sharing, excite and inspire budding entrepreneurs to use technology as a conduit for development and engage small holder businesses to scale up private sector solutions. Processes are compared and impactful approaches were identified.
This long-term project has just begun but key impact indicators and KPIs on social change, business change and market system changes are beginning to emerge. The goal of investing in one entrepreneur at a time within the innovative but integrated approach of providing collaborative and synergistical platforms, incubation of new ideas and ideals, the acceleration of potential on-going projects have energized stakeholder perceptions about agriculture. Combining the three pronged approach at the same time is creating positive social, business and market changes.
This paper describes the processes and results of the model and discusses the novelty of the new approach and its ability to combine integrative approaches all at the same time, to develop both start-up and small scale entrepreneurs.