bluuebunny/crossref_metadata_2025 huggingface dataset:
Uncertainty Analysis and Integrated Modeling Application During Field Development
Authors: Dmitruk V. V. , Mironov E. P. , Mulkamanov A. A. , Kharkovskiy A. , Bayguzov R. , Komin M. , Timakova O. , Chernyak V. , Shakhov D. , Krivokorytova M.
Published: October 2019

Severneftegazprom OJSC is the operator of the Yuzhno-Russkoye field. In accordance with the field development strategy, in 2018 the commercial development of the Turonian formation began, envisaging the drilling of more than 100 wells to a formation with abnormally high pressure and low permeability and their tie-in to the existing gas gathering network. The task that faces the company is to assess the attainability of the planned targets on the basis of the existing field development concept and surface facilities configuration. A separate focus is on the geological uncertainties analysis of the Turonian formation and their impact on the gas production profile.

For the uncertainty analysis, a sector hydrodynamic model was built and history matched, which included the first launch clusters with the U-shaped wells and the multistage hydraulically fractured wells (MSHF). The assessment was made for the impact of geological uncertainties, the alternative well locations, as well as the number of hydraulic fracture stages and fracture parameters on the cumulative gas production.

To study the interference of new wells with the existing network, an integrated model was created, which combined the full-scale Black Oil hydrodynamic models of the Cenoman and Turonian reservoirs with the unified compositional gathering network with more than 250 wells.
Conceptual Approach to Field Drilling – Minimizing Risks And Economic Costs
Authors: Freze Aleksandr
Published: October 2019

The existing, until recently, design system provided no connection of the surface and underground parts of the field in a complex, as a result of which further implementation of design solutions had problems with placement of well clusters on the surface and well profiles drilling. The introduction of a conceptual approach in the design of the field allows you to accurately determine and optimize the cost of construction of wells and construction of oilfield at the design stage.
Pre-FEED CAPEX Evaluation: Speed Through Complexity?
Authors: Chizhikov Sergey , Dubovitskaya Ekaterina , Tkachenko Marina
Published: October 2019

This paper gives riteria for developing successful expenditure estimation models for development of hydrocarbon deposits, as well as tools available to improve the estimation accuracy. The paper describes practical cases supporting efficiency of the proposed approaches.
Comprehensive Evaluation of Costs at the Early Stages of Project Development: Costs of Equipment not Included in the Construction Estimate
Authors: Maksimov Yuri , Skudar Oleg , Yanina Irina , Pashkevich Lev , Sandler Ilya , Ulyashenko Vladislav
Published: October 2019

This article describes the method developed by Gazprom Neft to evaluate capital expenses required to purchase the equipment not included in the construction estimate using the automatic calculation module. Work in this direction is to Gazprom Neft a relevant and logical continuation of the cost engineering development vector. Having a methodology and tool for calculating the costs of equipment not included in the construction estimate will optimize the decisions made by increasing the accuracy and substantiation of the CAPEX amount evaluated for the newly introduced and developed assets.

The method of calculating the costs of equipment not included in the construction estimate includes itemized decomposition by well type and method of well operation. The full list of equipment is defined, the algorithms of equipment selection depending on the technological pre-requisites are described, the cause-and-effect relationships are established according to the principle "technical parameter x cost", an economical and mathematical mechanism is suggested.

The tool for evaluating the costs of equipment not included in the construction estimate includes full automation of the calculation process in accordance with the methodological provisions as relates to the region under consideration where the asset is located. Engineering modules are integrated which calculate the frame size, capacity, length and other characteristics of equipment. The tool helps to perform calculations for both individual well types and in general in accordance with the fluid / oil / associated gas production / water injection.
Impact of Compressibility Change due to Overpressure on HC Volume on Karachaganak Gas Condensate Field
Authors: Ibragimov Abdulmalik , Kan Andrey , Kalmuratov Nurbolat
Published: October 2019

Inappropriate surface infrastructure sizing due to overestimation of initial reserves may lead to financial losses for a company. One of the many reasons why surface facilities are inappropriately sized is due to lack of subsurface understanding, misinterpretation or lack of data [1]. The current work is dedicated to give more understanding on possible expected behavior of the Karachaganak field based on hard data and its implications on hydrocarbons in place.

The Karachaganak gas condensate field is 20% overpressured reservoir. Current production is mainly focused on oil rim. Gas production is delayed to later times, as a blow down process. Based on real cases in the past for overpressured gas reservoirs there was developed a special material balance equation where it assumes different compressibility for a reservoir before and after reaching hydrostatic pressure. There are two main theories that explain the causes of overpressured reservoir material balance calculations [2]. Rock collapse theoryShale water influx theory

The Karachaganak field is a carbonate field with negligible amount of shale which excludes the shale water influx theory. Repeated well test data measured on the same well during a different period of the well life clearly show how rock collapse theory works in the field thus supporting the first theory occurrence on the field.

Based on the current simulation model with implementation of changing compressibility to reflect pore collapse, authors provide calculations and its impact on original oil and gas in place volumes.
Multiphase Inflow Monitoring in Horizontal Wells Producing from Oil Rims Based on the Advanced Production Logging Suite Data
Authors: Minakhmetova Roza , Aslanyan Irina , Nagimov Vener , Shigapov Llnur , Kosolapov Vladimir , Virt Vitaliy
Published: October 2019

Today, oil reservoirs with a gas cap on top are mainly developed by drilling horizontal wells of various design. In the course of well operation, early increase in gas-oil ratio or water cut can often be observed. These may be caused by both well integrity failure and the geology feature of the target formation when formation water breaks through from the bottom of the producing formation and gas inflows from the top of the reservoir as a result of coning.

One of the ways of controlling unwanted water and gas production sources and reservoir fluid production rates is monitoring of production profiles along the horizontal sections of the well using a reservoir-oriented production logging survey. This paper describes an example of such monitoring at a horizontal well drilled into the oil-rim reservoir at the Novoportovskoye field. The paper provides the results of a series of logging surveys performed in 2, 18 and 24 months after the well commissioning. The first (reference) survey was performed at the earliest stage of the well production; the second and the third ones - when the gas-oil ratio started to increase. The advanced production logging survey included high-precision temperature logging, distributed capacitance measurements and spectral acoustic logging. The spectral acoustic logging data identified the producing intervals of the reservoir along the horizontal section of the well. According to the first survey results, the production fluid was flowing uniformly along the wellbore. The third and second surveys had identified the intervals of gas breakthrough in the reservoir. After all the survey results had been compared to one another, it was identified that the gas breakthrough could have been localized even during the first logging survey. In each survey, the multiphase inflow profiling was perfomed using a temperature modelling.

Information generated as a result of production logging survey in the horizontal well allows localizing and predicting gas breakthroughs in wells drilled in oil rims. Using this data, such gas breakthroughs may be immediately prevented. The data can also be used when designing new wells to increase the efficiency of development of such fields.
Creation of a Source Rocks Integrated Petrophysical Model Based on a Special Core Analysis Results
Authors: Alekseev Aleksey
Published: October 2019

Integrated petrophysical models have been broadly applied in geological and petro-elastic modeling to forecast hydrocarbon accumulations and to estimate resource potential. Methodological basis of building those models have been well developed for conventional terrigenous and carbonate reservoirs; as regards the so-called "shale-type" hydrocarbon-bearing rocks, however, there are objective difficulties determined by a range of various factors that may include multi-component composition of rocks, core recovery problems, as well as process-related peculiarities of laboratory methods. This paper offers a program of special laboratory core analysis of the samples from the Bazhenov formation and an algorithm for the processing of the results with the view to build an integrated petrophysical model of an unconventional "shale-type" oil pay.
Permeability and Porosity Study of Achimov Formation Using Digital Core Analysis
Authors: Yakimchuk Ivan , Evseev Nikolay , Korobkov Dmitry , Varfolomeev Igor , Dinariev Oleg , Khan Vladimir , Koroteev Dmitry , Orlov Denis , Muravleva Ekaterina , Belozerov Boris , Krutko Vladislav , Kondratev Artem
Published: October 2019

The first application of digital rock technology (digital core analysis) with direct hydrodynamic modeling based on density functional theory for the Achimov formation is described. The technology consists of imaging core samples by X-ray microtomography, construction of corresponding digital rock models of pore space geometry, and multiphase hydrodynamic simulation on a pore scale by the density functional method. Despite the extremely low permeability values (less than 1 μd), digital measurements of relative permeability curves were completed successfully for model oil and water in steady-state flow mode whereas laboratory measurements in steady-state flow regime were unfeasible for the studied samples. The required spatial resolution of the digital rock models for the studied samples was about 1 μm and higher. At the same time, for a reasonable selection of a representative sample, it is desirable to conduct a larger sample scan with a coarser resolution. For the first time in the industry, a direct two-phase relative permeability simulation was performed on a record-size model of 1300 × 1300 × 1500 voxels. Also, for the first time, two-phase filtration experiments were carried out on a core miniplugs in the permeability range of less than 1 μd.
Seismic Survey Capability for Oilfields Development Monitoring Using SAGD Technology
Authors: Nevmerzhitskiy Yan , Bykov Alexander , Semaka Vadim , Polnikov Evgeny , Zavyalov Ivan , Zavyalova Natalya , Miroshnichenko Dmitry , Sayfutdinov Rauf , Grinevsky Anton
Published: October 2019

The paper is devoted to the investigation of possibility of seismic methods using for steam chamber growth monitoring during heavy oil fields development using steam assisted gravity drainage method. For this purpose a program for simulation of compositional flow of high-viscosity viscoplastic oil as well as a program for simulation of acoustic wave propagation in three-dimensional heterogeneous medium. The features of steam chamber influence on the seismic wavefield are detected and technique of their interpretation is developed.
Oil and Gas Bearing Complexes of the Sedimentary Cover of the Arctic Zone of the Siberian Platform Marginal Zones of the North of the Siberian Platform?
Authors: Dmitrievsky Anatoly , Eremin Nikolai , Shabalin Nikolai
Published: October 2019

The report discusses issues related to the assessment of the resource base and the development potential of the Arctic zone of the Siberian platform along the Northern sea route, the region of Russia with a high concentration of oil and gas resources. The basic concepts on the geological structure and the oil and gas potential of the Arctic zone of the Siberian platform are based on seismic data tied to existing deep exploratory wells. To date, five petroliferous complexes have been described in the Yenissei-Khatanga (the Yenisei Bay, the Yenisei-Khatanga regional trough) Anabar-Khatanga (Anabar-Khatanga saddle, Khatanga bay) Anabar-Lena oil and gas regions (Anabar-Lena trough and adjacent shallow shelf of the Laptev Sea) and the South Laptev sea promising oil and gas region for the main oil and gas complexes: Riphean, Vendian, Vendian-Middle Paleozoic, Upper Paleozoic and Mesozoic.

The report considers the results of the analysis of estimates of the filtration-capacitive properties of the sedimentary cover rocks in the marginal zones of the north of the Siberian platform available on 01/01/2019. Open fields are briefly described. The obtained results allow for the adjustment of state programs for the development of the Arctic zone of the Siberian Platform (Yenisei-Khatanga, Anabar-Khatanga and Anabar-Lena oil and gas regions, South-Laptev Sea promising oil and gas region).
Green Seismic
Authors: Nazyrov Dmitry , Dakirov Valikhan , Tarasov Sergey
Published: October 2019

Today we can clearly see that the world's leading oil companies strive to improve not only the quality of explorations but also tighten industrial and environmental safety requirements to this work. Green Seismic is a complex of methodologies, technical means and organizational measures applied to seismic explorations to ensure they efficiently achieve the following goals: Narrowing the width of the signal reception and excitation linesReducing personnel injuries in the course of seismic surveysGetting access to restricted exploration areas and improving seismic data qualityReducing the number of seismic crew personnel

The need for this project is caused by the technology challenges faced by Gazprom Neft's seismic operations. These challenges, that significantly complicate seismic work when it is performed by standard methods, include a large number of industrial facilities, infrastructure networks, residential areas, agricultural lands, thick forests, mountainous terrain and everything else that makes it impossible to deploy seismic crews, does not allow achieving sufficient density of seismic lines, extends the time for preparation of driveways for heavy equipment, increases the risk of injury to personnel when performing tree cutting work, and generally affects the Company's image in aspects related to the introduction of environmentally friendly technologies.

The main purpose of this project is the establishment of an innovative technology that would allow the Company to remove or minimize negative factors of seismic operations performed by standard exploration methods.
Borehole Acoustic Reflection Survey in Horizontal Wells: High Resolution Reservoir Structure to Guide Properties Distribution
Authors: Karpekin Yevgeniy , Orlova Svetlana , Tukhtaev Rustam , Ovchinnikov Alexey , Kuntsevich Vitaly
Published: October 2019

The article discusses the method of borehole acoustics reflection survey for detecting the presence and reconstructing the position of various reflecting surfaces, such as of large fractures, faults, bed-boundaries, in the near-well space at a distance up to 30m or more. The measurement principles, data processing, visualization and interpretation workflow developed by us based on the best published practices and supplemented by our solutions that significantly improve the quality and usability of the images are explained. A study of fractured zones identification and characterization in three horizontal wells based on the electrical microimager and the reflected acoustic survey is presented. Possibility of imaging the bed-boundaries of the host layers above and below the wellbore and specifying their position relative to the well's trajectory is demonstrated. Confinement of rocks with different reservoir quality within certain sub-layers of the target productive strata, identified with acoustic reflected survey, brings possibility to populate these properties more accurately in a refined structural model.
Conditions of Secondary Fracture Reorientation for Cases of Vertical and Horizontal Wells
Authors: Martemyanov Andrey , Shel Egor , Bratov Vladimir , Chebyshev Igor , Paderin Grigory , Bazyrov Ildar
Published: October 2019

An approach to determine stress field near wellbore with existing hydraulic fracture accounting for rising pressure and fluid filtration along the crack has been developed. An estimations of secondary fracture initiation time near wellbore as well as moment of primary crack growth start have been produced. Factual data about mechanical rock properties, stress state and pore fluid pressure was used. It has been shown finally that reorientation of secondary fracture in the case of vertical well is improbable during reinjection. Calculations were made with various magnitude and rate of pumping pressure increasing, value of pore pressure inside formation and main tectonic stress ratio acting at infinity. Similar analysis in the case of horizontal well demonstrated several alternative mechanisms of secondary fracture initiation: simulteniously with existing crack growth new fractures along and orthogonal to well trajectory may appear. Which of type will become dominant depends on actual geomachanical conditions and primary fracture characteristics. Obtained estimations have been compared with field observations.
Hydraulic Fracturing Overflush on Conventional Reservoirs
Authors: Chaplygin Dmitry , Khamadaliev Damir , Yashnev Victor , Gorbachev Yaroslav , Chernyshev Alexey
Published: October 2019

After hydraulic fracturing treatment, wellbore clean-out takes significant amount of time, and therefore, the commissioning of the well is delayed. In addition to production losses, production companies CAPEX and OPEX are also increasing proportionally to frac fleet activity. As a common practice, in western Siberia fracturing treatment is underflushed by about 0.5 cubic meters. This is supposed to prevent unintentional overflush and, as a result, hydraulic fracture closure at the wellbore. The loss of contact between the propped fracture and the perforated section of the well can neutralize the effect of hydraulic fracturing. This can happen in the first days of production after the operation or in a long-term perspective.

On the other hand, overflush during hydraulic fracturing is common practice for unconventional formations. It allows to use various well completion technologies with the cemented liners and significantly reduces time required to complete multistage fracturing treatment.

The objective of this paper is to show the approach and experience of the company "Salym petroleum development" (SPD). Positive result was obtained with proppant slurry overflush operation during treatment of conventional reservoirs.
Integrated Approach to Diversion During Acid Treatments in Extended Intervals, High Temperature and Fractured Reservoirs
Authors: Abdrazakov Dmitriy , Kalabayev Ruslan , Stepanov Vladimir , Juldugulov Yeltay , Kinnear Campbell , Bekmakhanbet Darkhan
Published: October 2019

Achieving complete wellbore coverage is a challenge for any acidizing treatment performed in a heterogeneous fractured carbonate formation with long intervals. Openhole sections, high temperature, and the presence of depleted layers make the task of acidizing design optimization even more difficult. Existing acidizing diversion studies concentrate either on strongly theoretical or on purely field applications. Coupling these two directions is complicated because of different perceptions of diversion principles and diverting method classification.

The current study introduces a simple and robust diversion method classification and covers both theoretical and practical analysis of the diversion in the fractured carbonates. It is explained in the given study why the maximized rate method cannot be considered as a proper diversion method in fractured carbonates according to the suggested classification. Theoretical aspects of the study also cover the selection criteria suggested for the amount of acid preceding the diverter stage in fractured carbonate formations. A calculation methodology is introduced for the skin caused by the particulate filter cake, with respect to the different fracture plugging scenarios and for the skin development in time.

Practical aspects of the study cover field cases with successful diversion results in a variety of extreme conditions: very long openhole intervals (>1,000 ft), horizontal sections, depleted layers, extremely vuggy and fractured formations, hot formations (>260°F), and restricted completion entry wells. Diversion examples include pressure increase signatures of up to 1,500 psi for skin-forming diverters and 500 psi for viscosified ones. Each field case contains a quantitative interpretation of the diversion according to the skin calculation method introduced in this study.
High Rate Hybrid Fracturing in South-Priobskoe Field
Authors: Vikhman Ivan , Barinov Alexandr , Kolupaev Dmitry , Chebykin Nikolay , Uchuev Ruslan , Mavletkulov Ural , Vereschagin Sergei , Pavlova Svetlana , Sypchenko Stella , Valnev Dmitry
Published: October 2019

The South-Priobskoe Field is one of the largest oil pools in Western Siberia, with a unique category of reserves. Due to the low filtration properties of the productive formations AS10-AS12 (permeability of which is not more than 3 mD), the drilling of horizontal wells with subsequent multi-stage hydraulic fracturing (MSHF) completion is the most cost-effective way in this case. The use of highly viscous fracture fluids (at least 400 cP at 100 s-1) and 16/20 mesh proppant with a maximum concentration of 800-900 kg/m3 and the slurry rates are not exceeding 4.0 m3/min, became a kind of standard during the MSHF. However, a steady decline of permeability in the newly drilled areas of the field is observed (below 0.5 mD), because of this, an effective half-length of cracks begins to make an increasing contribution to oil production. This paper describes the introduction of non-standard methods of hydraulic fracturing for a traditional reservoir, and an idea was the use of low-viscous fluids with increased slurry rates, which resulted in an increase in well production rates by an average of 7%.
A Hybrid Model for Selecting Horizontal Candidate Wells for Re-Fracturing of Tight Oil Reservoirs—A Case Study in the Baikouquan Formation, North Mahu Oil Field, Western China
Authors: Yang Zhaozhong , He Rui , Chen Jianlin , Li Xiaogang , Xie Bin , Meng Jigang , Li Wenhong
Published: October 2019

The North Mahu Oilfield in western China contains abundant tight glutenite oil resources. The use of horizontal well fracturing has become the main development method in the region. However, the tight oil reservoirs have poor physical properties. After a period of production, some hydraulic fractures in the horizontal wells close, resulting in rapid decline in production. Therefore, Re-fracturing must be implemented to restore and increase oil production. In this paper, a comprehensive evaluation model for the horizontal well selection of tight oil re-fracturing is established, and a three - hierarchy system including the target layer, the criterion layer and the scheme layer is structured. The analytic hierarchy process (AHP) method, grey correlation (GR) method and entropy weight (EW) method are used to calculate the weights of factors influencing re-fracturing effects, and TOSIS method is combined to quantify the re-fracturing potential of the candidate wells, so that well H is selected to implement re-fracturing construction based on the established mathematical model. From the aspects of oil reserves, reservoir energy, wellbore conditions and reservoir fracability, the feasibility of re-fracturing of well H was carried out, and the degradable granular chemical diverting agent was preferentially used. The design of "re-open old fractures + perforate new holes+ supply reservoir energy+ real time microseismic monitoring" was designed. Re-fracturing construction of well H was implemented smoothly, and the obtained stimulated reservoir volume (SRV) exceeded 107m3. According to the production data, the daily oil production continued to rise initially, which was once over 30t/d.
Increase in Profitability Ratio of Hydraulic Fracturing for Multi-Layer Formation
Authors: Mardamshin Ruslan
Published: October 2019

It is the purpose of this paper to search for options to improve technical and economic efficiency of hydraulic fracturing. The paper presents conventional hydraulic fracturing technologies at multiple development targets and interval frac technology using diverter soluble balls for directional wells under the conditions of multiple development targets. The paper also presents experience of technology application at the enterprise and economic analysis (costs reduction for workover actions).

The technology is based on application of diverter soluble balls and it allows performing selective hydraulic fracturing for two and more productive formations for one packer trip-in and one frac fleet approach thereby enabling considerable reduction in the time and increasing the economic value of actions. The main elements of the process are diverter balls which plug (creating a temporary artificial overlap) perforated intervals of the first development target after fracturing at a continuous process, enabling flow redistribution and deviation of frac drive fluid to lesser permeable second frac development target. The process is continuous as follows DFIT, frac #1, diverter balls injection, frac #2.

Diverter balls have been tested in the enterprise’s labs against characteristics and properties, compatibility of products with formation fluids. Frac technology using diverter balls has been successfully tested as part of the pilot project and it is applied at the enterprise on a commercial scale enabling reduce costs for workover crew’s work by 23%, workover actions – by 20%, increasing profitability of frac workover actions for both an existing producing well stock and at the cost of a new well stock drilling. It is worthwhile noting that the existing conventional frac equipment allows applying the technology. It does not need special upgrading. The technology applicability criteria are identified. Success of works which have already been performed is over 95% and it is approved by well logging to determine flow profile. The technology application allows involving into development all low productive formations of dissected section with a considerable reduction in the time and workover action costs.
Experience in Application of Hydraulic Fracturing Techniques in Carbonate Deposits at the Perm Krai, Republic of Komi and Nenets Autonomous District Fields. Ways to Improve Efficiency
Authors: Sharafeev Ramil , Drozdov Sergey , Novokreshchennykh Dmitriy
Published: October 2019

Most remaining recoverable reserves (more than 62%) of the Perm Territory, Komi Republic and Nenets Autonomous Area (NAA) are concentrated in the carbonate reservoirs, so effective reserve recovery from the carbonate formations is a topical problem at present.

Productive deposits with the carbonate-type reservoirs are confined to the Silurian, Lower Devonian, Upper Devonian-Tournaisian, Serpukhovian, Middle and Upper Carboniferous, and Lower Permian sediments. The production zones are characterized by a wide range of changes in the geological and physical parameters (Table 1).
Expanding Boundaries of Multistage Hydraulic Fracturing with Coiled Tubing at Soft Terrigenous Reservoirs
Authors: Simakov Sergey , Kichigin Anatoly , Kurtsev Sergey , Trifonov Andrey , Karpov Maxim
Published: October 2019

Today, given the deterioration in the quality of proven reserves, a separate and extremely important issue is the possibility of using multi-stage hydraulic fracturing (MSF) in wells with complex geology. A striking example of the successful use of MSF using CT is the experience gained at the Messoyakha oil and gas condensate field, where the MSF was successfully carried out for hard-to-recover (HTR) reserves of viscous oil occurring in weakly consolidated terrigenous reservoir at low temperatures.

At this stage of oil industry development, fields that are considered previously unprofitable, the so-called HTR, are increasingly involved in the development. The experience of Messoyakha oilfield is perhaps the most extensive in Russia in terms of testing various systems and strategies for completing horizontal wells with MSF in viscous oil, occurring in weakly consolidated sandy reservoirs at shallow depths and at low temperatures. Conducted work and conclusions can be used in the design and evaluation of similar in structure hard-to-recover reserves.
The Sakhaling Offshore Field 4D Geomechanical Modeling for Fracturing Planning
Authors: Ganaeva Milena
Published: October 2019

The article presents the practical results of the building of a four-dimensional Mechanical Earth Model of the field on the Sakhalin shelf. An analysis of the stress regimes, both regional and local, was carried out. The model was built on an extensive data set, including core and wellbore studies, special logging and leak test results, and allowed to evaluate the initial and current stress-strain behavior, reservoir compaction, stress re-orientation. The article also details the methodology and details of building a four-dimensional Mechanical Earth Model which can be useful for specialists in this area.

Important practical problems were solved on the model - the technological efficiency of MSHF was proved and the efficiency of expensive compaction drilling was increased in offshore conditions. In addition, the risks associated with the first MSHF planning in the region were evaluated, such as the fracturing of the hydraulic fracturing crack into overlying aquifers, the development of crack in the horizontal direction, as well as uncertainties caused by a limited set of data.
Geological and Hydrodynamic Data 3D-Visualization Library
Authors: Perepelitsa Elena , Sayko Andzhelika , Babichev Emily
Published: October 2019

As part of this work, a three-dimensional interactive visualization library for rendering geological and hydrodynamic models' objects was implemented. The main functional capabilities of the library are described, and a comparison with commercial and free alternatives is made.

The library has been successfully integrated into software products for hydraulic fracturing modeling, geological and geomechanical modeling, and is being used by specialists in daily work.

The performance of our library is comparable to commercial counterparts. This is confirmed by measurements of the screen refresh rate and the amount of RAM usage when displaying models of real reservoirs using our visualizer in comparison with the visualizers of software products of competitors.
Modification of the Unconventional Reserves’ Exploitation Approach Based on the Reservoir’s Stress-Deformed State Management
Authors: Murtazin Ramil , Fedorov Alexander , Savchenko Pavel , Mulyukov Damir
Published: October 2019

Based on the experience of developing hard-to-recover oil reserves in fields, a new technology has been proposed that allows increasing the productivity of producing horizontal wells by creating HFF cross cracks and minimizing the risks of auto-HFF cracks fracturing from injection wells.
Reagentless Preparation of Formation Water for Reservoir Pressure Maintenance System in Low Permeable Oil Reservoirs. Water Ozonation Method
Authors: Shumeiko Andrei , Polubojartsev Dmitriy
Published: October 2019

Currently, oil fields with complex reservoir properties are involved in the development of Russian oil Company (for example, Severo-Danilovskoye, Danenberg, Vostochno-Tokayskoye field (Korotkova M.H. et. al, 1998)), in which high requirements are imposed on the degree of preparation of formation water for injection into the reservoir pressure maintenance system. The supply of prepared water to the reservoir pressure maintenance system significantly improves oil production conditions and slows down the deterioration of reservoir properties. This ensures the displacement of oil from a larger number of pore-fractured channels, which increases the oil recovery factor.

In this connection, the technology capable of solving the problems of preparing formation water for the reservoir pressure maintenance system at fields with low permeability of oil reservoirs is considered for implementation in the present work. Also, the solution of the production problem of cleaning the injected agent into the reservoir pressure maintenance system from hydrogen sulfide is considered to prevent deterioration of reservoir properties of the formation. The reagent-free method of formation water preparation is proposed as the described technology, in this case, the ozonation method.

The main technological advantage of this method is the possibility of simultaneous purification of contaminated formation water from oil products and bacterial impurity, which can cause contamination of the formation with sulfate-absorbing bacteria (SHvelev T.G.,2005).
Divert Technology Pilot on Kharyaga Field
Authors: Trushin Yuri , Aleshchenko Anton , Danilin Kirill , Arsamakov Mark
Published: October 2019

A global trend to introduce enhanced oil recovery (EOR) methods at the early field development stages has been recently observed. Zarubezhneft group is no exception in this regard. Early introduction of EOR methods makes it possible to achieve higher process efficiency, and, first and foremost, economic efficiency.

This article describes a pilot project involving implementation of diverter technologies at the field with complex carbonate reservoirs.

The following aspects have been reviewed: the structure of the Kharyaga D3-III reservoir, main issues related to the reservoir development and ways to resolve such issues. Laboratory studies of the applied compositions’ properties, as well as filtration experiments have been described. The article also presents an overview of the available diverter technologies.

The article also describes field implementation of the operations completed, namely, criteria for interface area selection, injection design development, work progress and efficiency evaluation for the EOR method applied.

The operations completed on 5 injectors resulted in around 65 thousand tons of incremental oil from the producers.

The operations were found successful; a new program for injection of polymer solution slugs is currently being developed.
Prediction of the Distribution of Reservoir Rocks of Syrachoy Deposits in the Fields Named After R.Trebs and A.Titova
Authors: Gaymaletdinova Gulnara , Dushin Andrew
Published: October 2019

The object of the study is carbonate deposits of the Upper Devonian deposits of the name of the Roman Trebs and the name of Anatoly Titov, which are one of the largest deposits among the explored continental ones in Russia. They are located in the Timan-Pechora oil and gas province, the northeastern part of the Nenets Autonomous District on the territory of the Sadayaginskaya step of the Khoyverhollow.

The purpose of studying the deposits of the Syrachoy horizon is to identify the conditions of the formation of deposits for understanding the structure of the reservoir.

The methodology of the work consists in a detailed study of core material, thin sections, the selection of lithological heterogeneity, their comparison with logging curves, the implementation of intra-layer correlation and comparison with seismic data.

The main result of the work is the construction of a sedimentation model of productive deposits which became the basis for the distribution of reservoir rocks.
Selecting Bridging Agents’ Particle Size Distribution for Optimum Plugging While Drilling in Permeable Zones
Authors: Izyurov V , Kharitonov A , Semenikhin I , Korsunov E , Gassan A , Tikhonov E , Jadan G , Stashko V , Blagonadeshniy I , Manikhin A , Medvedev S
Published: October 2019

Differential sticking problems and drilling fluids losses reducing permeability as a result of deep invasion of drilling and completion fluids are still main challenges. Under the conditions of development of mature fields, these problems become more acute due to the uncompensated drainage of formation fluid from the pay zone. The resolution for one of these problems is a high-quality plugging of permeable formation.

The paper states a wide review of research papers on this topic, laboratory testing of one of the selection methods, an example of technical application of one of the methods, and and prospects for further development of the topic to improve the approaches of practical application.
Digital analysis of shaping ability and topographic changes in M and C wire rotary NiTi systems.
Authors: Aziz Amr Khaled Abd El
Published: October 2019

The primary outcome of this study intends to assess the Shaping ability and surface topographic changes of the 2 rotary Nickel Titanium systems: A) One Curve (Micro Méga, Besançon, France)B) ProTaper Next (Dentsply Maillefer, Ballaigues, Switzerland)What's new in the study is the use of AutoCAD program to assess the shaping ability of both instruments, after using them in a standerdized conditions to evalute the minor differences between the two different alloys used in each instrument.While the secondary outcome of this study is to evaluate the instruments after multiple uses under the SEM to detect any abberrations or deformetiesin the instruments to detect its points of strength and weaknesses.The study is planned for one year and it is not expected to be more than that according to the sample size and the availabilty of the tools needed for the trial.
How knowledge brokering on implementation science can improve implementation outcomes: a case study of a public mental health project
Authors: Hudson Kristian , Lawton Rebecca , Hugh-Jones Siobhan
Published: October 2019

Background Schools need mental health interventions that are deliverable, scalable and effective. However, rates of successful implementation of evidence-based practices in schools is low. An underpinning factor is lack of understanding, and attention, by commissioners, providers and schools, to evidence about what works to bolster effective and sustained implementation. Knowledge brokering is one way to improve use of implementation science for delivery of interventions in complex settings. To date, evidence for the use of knowleldge brokers in public health settings is scarce, and their use for brokering implementation related knowledge is non-existent. The aim of this study was to examine whether it was feasible and acceptable for knowledge about implementation to be brokered to a steering group responsible for a wide scale, public mental health, school-based intervention, and what impact this might have on their implementation decisions.Methods The primary researcher attended 13 monthly steering group meetings during the initial implementation phase of the public mental health program and shared implementation knowledge with them. With consent, meeting notes were taken by the primary researcher, and a journal kept of 12 meetings; 5 meetings were also audio recorded and steering group minutes analysed. All data were amalgamated and ordered into month-by-month summaries. The analysis attempted to identify when implementation knowledge was shared with the group (coded a ‘key moment’) and what the steering group did with this knowledge (coded a ‘key outcome’).Results Over the 13 meetings, 15 key moments led to 14 key outcomes, 10 of which involved implementation decisions being made based on brokered knowledge about implementation science. Discussion The majority of key moments led to a significant number of evidence-informed implementation decisions being made by the steering group. Some brokered knowledge was not acted upon. Implementation knowledge was not shared with the program funders which may have meant they did not appreciate the importance of implementation. Conclusion Knowledge brokering on implementation science to a group responsible for public mental health is feasible and acceptable and a potentially viable implementation strategy for future public health programs.
H 2 O 2 , Ca 2+ , and K + in subsidiary cells of maize leaves are involved in regulatory signaling of stomatal movement
Authors: Zhang Li , Yao Yaqin , Zhang Suiqi
Published: October 2019

Background : The stomata of maize ( Zea mays ) contain a pair of guard cells and a pair of subsidiary cells. To determine whether H 2 O 2 , Ca 2+ , and K + in subsidiary cells were involved in stomatal movement, we treated four-week-old maize (Zhengdan 958) leaves with H 2 O 2 , diphenylene iodonium (DPI), CaCl 2 , and LaCl 3 . Changes in content and distribution of H 2 O 2 , Ca 2+ , and K + during stomatal movement were observed. Results : When exogenous H 2 O 2 was applied, Ca 2+ increased and K + decreased in guard cells, while both ions increased in subsidiary cells, leading to stomatal closure. After DPI treatment, Ca 2+ decreased and K + increased in guard cells, but both Ca 2+ and K + decreased in subsidiary cells, resulting in open stomata. Exogenous CaCl 2 increased H 2 O 2 and reduced K + in guard cells, while significantly increasing them in subsidiary cells and causing stomatal closure. After LaCl 3 treatment, decreased and K + increased in guard cells, whereas both H 2 O 2 and K + decreased in subsidiary cells and stomata became open. Conclusions : These results indicated that H 2 O 2 and Ca 2+ were correlated positively with each other and with K + in subsidiary cells during stomatal movement. Both H 2 O 2 and Ca 2+ in subsidiary cells promote an inflow of K + , indirectly regulating stomatal closure.
Isometric strength vs. functional mobility and their relationship with risk of falls in community-dwelling older adults: a prospective study
Authors: Valenzuela Pedro L , Maffiuletti Nicola A , Saner Hugo , Schütz Narayan , Rudin Beatrice , Nef Tobias , Urwyler Prabitha
Published: October 2019

Background: Falls are a major concern for older adults and their care givers. The Timed Up and Go (TUG) test is extensively used to identify individuals at risk of falling, but less is known about the validity of simple isometric strength measures for this purpose. We aimed to assess the potential of isometric strength measures and the different modalities of the TUG test to detect individuals at risk of falling. Methods: Twenty-four community-dwelling older adults (≥ 65 years, 19 females, 88±7 years) performed three variations of the TUG test (standard, cognitive, motor) and three isometric strength tests (handgrip, knee extension and hip flexion) at baseline and at several time points (every ~6 weeks) during a 13-month follow-up. Linear mixed model analyses were then performed to examine differences between those who sustained ≥1 fall during the follow-up and those who did not. Results: Fallers had a worse performance in all TUG variations and a lower strength in all tests than non-fallers in non-adjusted analyses (p<0.05). However, when adjusting for baseline variables (age, gender, body mass index, and previous history of falls), only differences in handgrip and knee extension isometric strength measures remained significant (p=0.019 and p=0.042, respectively). Isometric strength measures related to changes in TUG performance both at baseline and during the follow-up (p<0.05). Conclusions: Isometric strength measures has potential to serve as a simple tool to detect individuals at risk of falling as compared to functional mobility measures (i.e. TUG test).
Early or delayed laparoscopic cholecystectomy after endoscopic cholangiopancreatography and papillotomy- does it make a difference?
Authors: Grosek Jan , Petrič Miha , Plevel Danaja , Tomažič Aleš
Published: October 2019

Background Endoscopic retrograde cholangiopancreatography with endoscopic papillotomy (ERCP/EPT) followed by a cholecystectomy is a standard treatment of common biliary duct stones. It is unclear, however, what is the optimal time interval between ERCP/EPT and cholecystectomy. The primary aim of our study was to evaluate our current practice where patients are mostly operated one to three months after ERCP/EPT. The secondary aim was to determine the optimal timing for the cholecystectomy after ERCP/EPT.Methods A retrospective analysis of 117 patients who underwent a preoperative ERCP/EPT followed by a cholecystectomy was performed. Associations between demographic characteristics, type and duration of operation, conversion rate, postoperative complications and interval time were tested using multiple linear regression. The optimal interval was studied by drawing receiver operating curve (ROC) and studying the area under curve (AUC).Results The time interval between cholecystectomy and ERCP/EPT was not associated with the number of conversions to open surgery, duration of the operation or postoperative complications. There was no statistically significant association between any independent variable and time interval. No threshold interval could be found that would discriminate whether a patient had either operation conversion or complications or not.Conclusion No statistically significant associations between the timing of cholecystectomy after ERCP/EPT and the rate of conversions, complications or operation duration are seen in the group. Our current practice is safe, as the time interval in our study does not affect the rate of conversions, postoperative complications or operation duration. Based on the results of our study, no recommendations regarding the optimal time for the surgery can be given. Larger prospective randomized trials are needed.