bluuebunny/crossref_metadata_2025 huggingface dataset:
A Comparative Study to Assess Knowledge, Attitude and Practices among Cases of Recently Diagnosed Diabetes and Known Cases of Diabetes
Authors: Vinotha V. , Hema T. H. , Hemamalini A. J.
Published: October 2019

A good knowledge of disease management is necessary in promoting health. Diabetes Mellitus is a major health problem with individual, social and economical consequences. Knowledge, Attitude and Practice (KAP) surveys are effective in providing a baseline for evaluating intervention programs. This is a comparative study to assess KAP among case of recently diagnosed diabetes and known case of diabetes. A cross-sectional survey comprising of 112 patients (56-recently diagnosed and 56-known cases) was conducted in Sri Ramachandra Hospital and volunteers from the community for a period of three months. A structured closed ended questionnaire for KAP on DM with demographic information was formulated. A pilot study was conducted to compute the scoring of adequate >75, moderately adequate 50-75, inadequate <50. The collected data was analyzed using descriptive and inferential statistics. The mean age was 49.2±8.4 years and BMI 25.41±4.82 kg/m².Mean score of knowledge in known cases, 12±2, was comparatively higher than recently diagnosed diabetes (10±3). Mean score of attitude in known cases, 13±2, was comparatively higher than recently diagnosed diabetes (11±4). Mean score of attitude in known cases, 10±2, was comparatively higher than recently diagnosed diabetes (9±3). Significance was shown between both knowledge and socio- demographic data in the known cases and attitude practice with socio-demographic data in recently diagnosed diabetes. When KAP was compared between the two groups, known cases had a higher score. They had good knowledge and attitude but poor practices related to diabetes than recently diagnosed subjects.
Can Iron and Folic Acid-IFA and Ca & Vitamin D Supplementation in Pregnancy be Fitted into Habitual Pattern of Three Meals A Day?
Authors: Ramachandran Prema , Pramanik Amrita , Kalaivani K.
Published: October 2019

In India prevalence of anaemia and vitamin D deficiency in pregnancy are widespread. National programmes recommend that two tablets of iron and folic acid (IFA) and two tablets of calcium and vitamin D (Ca & Vit D) to be given every day from second trimester till delivery. To minimize the side effects and increase compliance, it is advised that each tablet should be taken after a meal. Most households follow a three meal pattern. A study was taken up to find out how IFA and Ca & Vit D supplementations can be fitted into the habitual three meal pattern. A short term crossover supplementation study was carried out on 38 pregnant women to assess side effects following consumption after lunch of one or two tablets containing 500mg elemental calcium (as calcium carbonate) and 250 IU vitamin D or 60 mg of elemental iron as ferrous sulphate. Prevalence of side effects was higher in women who received iron supplements as compared to Ca & Vit D supplements. Taking two tablets of Ca & Vit D together after meal was associated with significantly higher prevalence of side effects as compared to taking one tablet after meal. Taking two tablets of iron together after meal was not associated with any significant increase in prevalence of side effects as compared to one tablet. Giving two tablets of iron together after one meal and giving one tablet of calcium and vitamin after two meals is feasible option for providing two tablets each of iron and Ca & Vit D to pregnant women who habitually follow a three meal pattern.
Compras Públicas no Brasil: vertentes de inovação, avanços e dificuldades no período recente
Authors: Fernandes Ciro Campos Christo
Published: October 2019

Este artigo é um balanço dos avanços, limitações e perspectivas para o fortalecimento das compras públicas na administração pública brasileira. A pesquisa se baseou no levantamento, categorização e análise de trabalhos sobre temas de compras públicas. A pesquisa focalizou a produção científica apresentada nos congressos anuais da administração pública, entre 2008 e 2016, promovidos pela associação que congrega os líderes responsáveis pela gestão pública dos Estados brasileiros. Uma amostra de trabalhos que tratam especificamente de compras públicas foi selecionada. Apresenta-se uma visão sistemática das principais mudanças e inovações, destacando as seguintes tendências: marco legal e regulatório, sistemas informatizados e portais na internet, reestruturação dos formatos de compra e contratação, terceirização, metodologias e ferramentas de gestão das compras, uso do poder de compra, ciclo do suprimento, centralização das compras e institucionalização da área.
Scientific and Methodological Approaches to Improve the Development of Low-Permeability Oil Reservoirs Using Horizontal Wells with Multiple Hydraulic Fracturing on the Territory of LLC RN-Yuganskneftegaz Activity
Authors: Kolonsky Alexander , Toropov Konstantin , Sergeychev Andrew , Murtazin Ramil , Topolnikov Andrew , Antonov Maksim , Khadiyev Ruslan
Published: October 2019

The paper presents the results of: 1) various technologies testing for the development of low-permeability reservoirs using horizontal wells with multi-stage hydraulic fracturing of formation (HW with MHFF); 2) the increase of the repeated fracturing operations efficiency in vertical wells by taking into account geomechanical effects.

The marker and geophysical methods for determining the flow profile of the HW with MHFF are compared with the calculations results of the hydrodynamic model. The results were applied to determine the optimal types of well completion, planned to further improvement of approaches to the development of low-permeability oil deposits. Also the technological capabilities of the flow profile research methods of and the directions of their further development were determined.
CO2 Assisted Steam Flooding Technology after Steam Flooding - A Case Study in Block J6 of Xinjiang Oilfield
Authors: Xi Changfeng , Qi Zongyao , Liu Tong , Zhang Yunjun , Zhao Fang , Yu Qingsen , Shen Dehuang , Li Xiuluan
Published: October 2019

Currently Block J6 is in the later stage of steam flooding after 27 years’ steam injection, its recovery factor is about 50%, and the water cut is more than 95%. Particularly, the present steam oil ratio is about 12 m3(CWE)/t which has reached the economic limit and is in ineffective development. Cores from four post steam flooding drilling wells show that only top 2-3m of the total 25-30m pay zone has a steam chamber which is the main steam channel and its residual oil saturation is about 20%, the other 22-27m pay zone is displaced by hot water and its oil saturation is 40-55%. A 3D physical simulation show the conventional steam flooding with full interval perforation quickly broke through from the top of reservoir, and the steam oil ratio rose rapidly from 5 m3(CWE)/t to 10 m3(CWE)/t. The recovery factor was only 20.1% at the time of steam breakthrough, and then it was in the phase of high steam oil ratio for a long time. During CO2 assisted steam flooding the whole perforated producer is switched into a low half perforated well, and the recovery factor increases from 20.1% to 81.1%, the steam oil ratio is 3.3m3(CWE)/t. There are three characteristics in CO2 assisted steam flooding stage, firstly there is a steam and CO2 assisted gravity drainage mode, steam chamber expands from the top 2-3cm to the total 20cm oil layer. Secondly, there is a stable emulsion foam oil, its water cut is 60-70%, CO2 liquid ratio is about 5:1 Sm3/t, CO2 is a kind of dispersed bubble so it is much more than the dissolved CO2 liquid ratio 2:1 Sm3/t. Thirdly, CO2 lows the heatloss to overburden and keeps the formation pressure. The calculation shows that the heat loss can be reduced by more than 10% in the top layer. A pilot test including 9 well patterns(49 wells) has been established, and its recovery factor will be up to 75%, and the steam oil ratio will up to 2 m3(CWE)/t, a good production performance is predicted optimistically.
The First Successful Experience of Directional Casing Drilling Technology in Timano-Pechora Region, Russia
Authors: Fatkulin Sergey , Egorov Petr , Gumich Dmitrii , James Biju , Zabuga Sergey , Karimov Jalal , Konysbekuly Galymzhan , Smelov Dmitry , Merzlyakov Alexander , Ryabov Ilya
Published: October 2019

Well drilling is a very technologically complicated process which consists of different stages and operations. Using different technologies to reduce well construction time is important to optimize well drilling costs. Geological complications can increase the time for pulling out the bottom hole assembly (BHA), condition the well, and running casing. Several studies have shown that nondrilling non-productive time (NPT) is significantly higher than actual drilling time. Casing while drilling (CWD) technology is a unique solution which helps to reduce well construction time in challenging formations while drilling and casing the well simultaneously.

Conventional drilling process involves drilling and casing sections in separate operations. CWD involves integrating the casing run process with the drilling process. In casing while drilling, the bottom hole assembly is attached to the casing using a drill lock assembly (DLA). It is challenging to drill and case directional well because the BHA consists of specialized directional tools such as a bend motor, rotary steerable tools, measuring while drilling tools, etc. After reaching the required depth by using specialized tools, the directional BHA is retrieved and casing is cemented.

Pilot test runs for directional casing drilling with retrievable bottom hole assembly technology were successfully conducted in Timano-Pechora region. Three directional wells were drilled with CWD technology on 244,5 mm (9 5/8") casing. There was no NPT during the operations. Casing while drilling technology alongside a steerable and retrievable BHA enabled the operator to drill a directional section in soft and unstable rock, hold trajectory according to plan and meet necessary dogleg severity, exclude the possibility of stuck pipe, and reduce well construction time by decreasing the number of wiper trips in open hole. The pilot experience helped to determine the advantages of casing drilling with a retrievable BHA in the specific conditions of the Timano-Pechora region. Tips for improvement and optimizations were highlighted for future reference of that technology in the region.
Way to a Perfect Well: Successful Story of Multi-Fracturing Well Completion on Achimov Formation Novo Urengoyskoe Field
Authors: Savelyev Alexandr , Sergeev Paul , Prokhorov Alexey , Nikitin Paul , Khomets Ivan , Leguta Michael , Zakharzhevsky Yuri , Koltypin Oleg
Published: October 2019

Developing Achimov gas condensate deposits with horizontal wells and subsequent multistage hydraulic fracturing has recently become important for the oil and gas industry of the Russian Federation. An abnormally high reservoir pressure and a narrow safe range of mud density values complicate both wells’ drilling and completion. This paper presents a description of a successful design, completion and subsequent implementation of multistage hydraulic fracturing in the Achimov deposits of the Novo-Urengoysky license area (ROSPAN INTERNATIONAL, JSC).

To mitigate the risk of completion equipment failure and to minimize friction pressure due to drilling mud and fracking gel incompatibility, calcium bromide-based heavy brine was used as a completion fluid for the first time in the Company's history.

In order to eliminate a blowout hazard while performing multi-stage hydraulic fracturing, as well as during subsequent well operations, a special upper completion system, which included a subsurface control valve, was used.

Multi-stage hydraulic fracturing with a significant mass of proppant (a large volume multi-stage fracturing) was selected as means of enhanced oil recovery. The average weight of proppant in each fracturing operation was 200 tons, the fluid injection rate was 3.5 m3/min, which ensured placing the designed amount of proppant and creating a planned geometry fracture.
Successful Implementation of Managed Pressure Drilling Technology Under the Conditions of Catastrophic Mud Losses in the Kuyumbinskoe Field
Authors: Galimkhanov Aydar , Okhotnikov Denis , Ginzburg Leyb , Bakhtin Andrey , Sidorov Yuliy , Kuzmin Pavel , Kulikov Stanislav , Veliyev Gurban , Badrawi Maytham
Published: October 2019

This paper presents a study, illustrating results of effective cooperation between the Operator Company of the Kuyumbinskoye field, Drilling Contractor, and Service Company involved in the construction of the horizontal well using the technology of Managed Pressure Drilling (MPD). This article also describes the challenges encountered and successfully implemented engineering solutions permitting to meet these challenges.

The main challenge in the Kuyumbinskoye field is the high risk of mud losses in the productive interval. The complex geological conditions as well as the anisotropy of the productive horizon complicate the prediction of catastrophic mud losses zones location. Approximately 50% of the wells were not drilled to the planned depths.

To solve this problem, in 2017 a pilot project using MPD technology was initiated. The main goals to be reached by the implementation of this technology were drilling efficiency improvement, risk management, and well construction cost efficiency improvement. In order to achieve the goals, equipment was selected, a comprehensive well construction program was developed and detailed work plans were prepared.

As a result of thorough planning and close cooperation at all work stages; the multidisciplinary team successfully completed the construction of 11 wells with an average extension of a horizontal interval of approximately 1000 m, drastically reducing fluid losses and associated non-productive time (NPT). By eliminating NPT and thus increasing the effective rate of penetration (ROP) during one of the wells, the drilling time of the lateral section was reduced to seven days, comparing to an average drilling time of the horizontal section of approximately 20-25 days (with conventional drilling). In addition, the average losses of drilling fluid per well were decreased by more than 1000 m3. The application of specially developed technological solutions during this pilot project not only ensured the attainment of target depths and geological objectives but also confirmed the potential of producing crude oil while drilling. Thus, allow to replenish encountered losses "on the fly" and to save time otherwise required to spend on the drilling fluid preparation.

In addition to a technological breakthrough, it is important to emphasize that a high level of Health, Safety, Quality, and Environmental protection (HSQE) was achieved, and no major incidents or accidents were recorded during the entire project. Based on the lessons learned, several engineering, organizational and strategical resolutions were made to further streamline and optimize the well construction process in the field.
Not Too Hot to Handle: Water Based Fluid Drills High Temperature Wells
Authors: Pino Rafael , Abouhamed Amr , Addagalla Ajay , El Dakroury Hesham
Published: October 2019

Most high temperature (HT) wells are drilled with oil or synthetic-based drilling fluids (O/SBM) for a variety of reasons. These O/SBM drilling fluids are naturally lubricious due to the hydrocarbon continuous phase, which also contributes to improved wellbore stability, as the fluids are relatively inert to the formations being drilled. These fluids also have acceptable temperature stability and drilling performance, which makes them suitable for several applications. Downhole losses with O/SBM can be costly and difficult to cure. Additional O/SBM can be mixed at the rig site, but this requires a supply of base oil to be available and the fluid can take time to prepare. The ideal scenario is to have a facility close to the rig location that can supply the high volumes of premixed O/SBM and base oil required.

Exploratory wells are often drilled in remote locations with no convenient liquid mud plant close by to service the O/SBM requirements. Acquisition of good quality logging data from exploratory wells is crucial to understanding the field potential for commercial development. Some of the more sophisticated logging tools available in the industry are incompatible or difficult to run and interpret in an O/SBM environment. In such cases a water based drilling fluid (WBM) can be the solution. The logistic requirement for WBM is significantly lower than for O/SBM, as chemicals can be stored on location and water can be supplied from a nearby water well. WBM is much simpler to prepare than O/SBM, so WBM can be quickly prepared as required, and WBM downhole losses can often be cured more easily. Typical polymer-based WBM does not have high temperature stability, and is usually restricted to wells where the bottomhole temperature is less than 300°F.

This paper will discuss the design, testing, and field application of a WBM for HT applications. To design a temperature stable HT-WBM fluid requires the use of drilling chemicals that can function adequately in a harsh environment.

These wells required temperature tolerant polymers that provide an acceptable rheological profile and controlled fluid loss, so the wells can be safely drilled with no major complications. The HT-WBM was used to successfully drill, core, log, and case wells with bottomhole temperatures higher than 375°F.
Applying a Resin-Cement System to Help Prevent Fluid Migration in the Annulus: Case Study, Western Siberia
Authors: Baklushin Mikhail , Velikaya Nailya , Zyryanov Viktor , Vologdin Dmitriy
Published: October 2019

Production sections of Western Siberian wells consist of gas, oil, and water-saturated sandstones; therefore, it is extremely important to help ensure zonal isolation to help prevent fluid migration from the overlaid water and gas formations into the oil-producing zones. Isolating the water and gas zones with conventional cement has not been a complete success because fluid migration was experienced through a channel or damage to the cement sheath. A typical solution sets an annular packer in the production casing zone beneath the gas and water-bearing sandstones as backup if the cement fails to provide a full annular barrier.

Using the annular packer has some limitations, and potential risks of early activation or nonactivation of the annular packer often contributes to nonproductive time (NPT). An alternative solution used in Western Siberia combines resin-polymer and cement, which provides a cement sheath with improved mechanical properties, such as reduced permeability, increased ductility, and improved shear bond to casing. The successful use of a resin-polymer cement blend as an alternative to using an annular packer, advantages of using this system, and recommendations for implementing this technology are discussed.
Reduce Well Construction Time by Using PDC with Rolling Depth of Cut Control Element in Carbonates Formations
Authors: Rebrikov Andrey , Koschenkov Anton , Nelaev Artem , Trefilov Maxim
Published: October 2019

In the current exploration and production practices, drilling is entering a new stage of development in which one of the top priorities is the reduction of well construction time with new technologies and innovations. A key component of this effort is the use of the latest achievements in the design and manufacturing of drill bits. To efficiently drill complex well profiles with a bottomhole assembly (BHA), including a downhole positive displacement motor (PDM) and polycrystalline diamond compact (PDC) bits, special attention is paid to controlling and orientating the bit by using the cutters depth of cut control limitations. The bit depth of cut is a quantity that characterizes the bit axial displacement per one revolution and depends on the bit rotation speed and rate of penetration (ROP). The control of the depth of cut enables the adjustment of the reactive bit torque, depending on the weight on the bit (WOB) as a result of the use of different static fixed depth of cut control (DOCC) elements, which have their own disadvantages and limitations.

The rolling depth of cut control (RDOCC) element is an innovation that was used to reduce excessive depth of cut by PDC cutters while drilling medium, hard, and interbedded rock. This technology has enabled PDC bits to achieve the best footage and ROP results because it provides smooth drilling and improved bit steerability.

Field trials of this technology have shown its high efficiency in interbedded heterogeneous rock drilling of different well profiles, as compared to conventional depth of cut control static elements.

The first field trial in Russia proved the effectiveness of RDOCC element technology. The RDOCC innovation helps oil companies to achieve new results and improve drilling performance; the ROP and footage drilled on the bit improved. In some fields, it became possible to drill the entire section interval with one run, whereas two or three PDC bits were typically used previously. This paper describes the benefits of using the new drill bits with the RDOCC elements in challenging drilling applications with complex geological conditions.
Integrated Approach to Construction Wells on the Achimov Deposits
Authors: Shokarev Ivan , Glebov Evgeny , Bannov Evgeny , Erokhin Dmitry , Polchenko Valery , Litvintsev Ivan , Shakurov Rafael , Kravchenko Andrey , Levin Ilya
Published: October 2019

Construction wells on the Achimov deposits was accompanied by many problems: the danger of sticking and oil, gas and water inflow; a serious decrease in the mechanical ROP on dense layers; severe downhole conditions: vibrations on dense interlayers, temperature up to 110°C, drilling mud based on diesel fuel. All of the above issues increased the number of trips due to equipment failures, increased non-productive time and, as a result, increased the well construction period. The integrated approach described in this work has significantly reduced non-productive and well construction time.

The customer was suggested: –Limitation the mechanical rate of penetration (ROP) by 15m/h to control equivalent circulating density;–Control of the equivalent circulation density by the MWD sensor;–Combination of a modular motor with rotary steerable (RSS) system in bottom hole assembly (BHA) to increase the mechanical ROP during drilling in dense layers of the productive horizon;–Optimization of the bit design, taking into account geological features, meanwhile drilling with a rotary-steerable system;–Use of a new generation rotary- steerable system;–Optimization of the BHA;–Modernization of equipment preparation procedures.

An integrated approach to drilling wells on the Achimov deposits with new methods and technologies offered to the customer allowed reducing the number of failures by 100-200%, which reduced the number of runs, and as a result, the non-productive time decreased. The reduction in the number of runs allowed taking from 500 − 600 meters to 1200 − 1500 meters per run. Optimization of the bottom hole assembly, including a new bit design in Russian Federation, integration of a new generation of rotary-steerable system with a modular motor, made possible to expand the boundaries of drilling modes, accordingly increase the mechanical rate of penetration. In addition, the adopted methods and technologies allowed reducing the negative impact of vibrations that occur during the drilling of dense layers.

Application of the integrated approach to solve the problems, which took place during the construction of wells on the Achimov deposits, has significantly reduced: the number of equipment failures, non-productive time. Meanwhile increased the mechanical rate of penetration and drilled distance in one trip, which in general has significantly reduced the time of well construction.
Modeling of a Gas-Lift Well Operation with an Automated Gas-Lift Gas Supply Control System
Authors: Yudin Evgeny , Khabibullin Rinat , Galyautdinov Ilyas , Andrianova Alla , Goridko Kirill , Smirnov Nikita , Babin Vladimir , Chigarev Grigory , Lomukhin Igor , Murzaev Yaroslav
Published: October 2019

Gaslift operation faces several challenges - optimizing the amount of gas pumped, ensuring that the gas is pumped to the maximum possible depth, combating salt and hydrate formation and, finally, the instability of the flow. The timely detection of these problems and the optimisation of the system requires information on the dynamics of the main parameters (flow rates, pressure measurements at each unit and the amount of gas pumped). In the conditions of high cost of multiphase flowmeters at the Orenburg field well flow rates are not measured often enough, and the task of identification of the most unstable wells in real time by auxiliary parameters measured with greater discreteness becomes urgent.

Often important production decisions based on monthly data, and less often on daily measurements. In the paper the necessity to go down to the level of analysis of highly discrete information (dozens of measurements per day) is proved by the example of the Orenburg field, because in conditions of unstable operation the averaging inside the day can lead to distortion of the general view of the operating mode. Within the framework of the analysis of dynamic parameters of gas-lift wells operation in unstable conditions, the notion of well operation quality index was introduced, i.e. a normalized metrics reflecting the general state of stability of a gas-lift well operation. This metric considers uncoordinated changes in the main parameters of the system. The wells with the lowest index are the first candidates to search for hidden production losses (not achieving the regime flow rate).

Modelling of well performance, adaptation of models to historical data - a typical approach to production management in the field. But in the conditions of unstable gas-lift wells modeling of their work is much more complicated. In this regard, the authors of the article developed an approach to modeling wells through the approximation relationship between the flow rate of wells and the flow rate of gas-lift gas and linear pressure with further integration of well models with the collection system.

To solve well operation modes optimization problem, an integrated Proxy-model of the asset was created, which consists of a simplified reservoir model, developed well models and infrastructure model. The Proxy model was adapted and verified to the actual operating data. The task of finding the optimal distribution of gas injection between the wells from the point of view of oil production was solved.
Efficiency Analysis of ESP Lifted Wells in the Context of Virtual Flow Metering
Authors: Krylov Ilya , Budennyy Semen , Khabibullin Rinat , Loginov Aleksandr , Andrianova Alla , Kobzar Oleg , Margarit Andrey
Published: October 2019

Due to need for optimal management of a large wells stock with a relatively limited amount of conditioned data, the need for a focus rapid detection of implicit complications in the work (mechanical wear of the working bodies of the pump) and an increase in overhaul period of submersible equipment increases. Real-time monitoring of all wells in the debit is limited due to infrastructure problems and high costs of measuring activities. Despite this, the possibility of such monitoring is not excluded due to the availability of field information that correlates with the well flow rate and the mode of its operation.

The article presents an algorithm that, based on telemetry ESP to estimate the parameters that affect the performance of the well and submersible equipment, such as the coefficient of degradation of the outlet characteristics of the pump, the actual efficiency (coefficient of performance) of ESP and the thickness of the deposition of paraffin on the inner walls of the tubing.

When processing field data, the parameters correlating with the well flow rate were revealed, which allowed to build a model of a virtual flow meter to verify the existing flow rate measurements and restore the missing values. The basis of the physical and mathematical approach is an algorithm that connects the parameters of the ESP system with the flow rate through the power consumption and hydraulic calculations of the gas-liquid mixture flow in the tubing. After preliminary calibration of pressure-flow characteristics of ESP for real mode of operation, daily measurements of fluid flow rate with a periodicity of 1 hour were calculated.
Implementation of Different Types Flowmeters for Gas Lift Metering on Orenburgskoe Field
Authors: Rymarenko Konstantin , Nukhaev Marat , Grishenko Sergey , Chernysh Nikita , Titov Sergey , Zaycev Alexander , Dadakin Nikita , Ulyanov Vladimir
Published: October 2019

Gas or liquid flow control is one of the most important technical tasks in the oil and gas industry. The choice of a particular device most often occurs on the basis of the established practice of application in a particular company. This paper presents the experience of Gazpromneft-Orenburg in the use of overhead and stationary flow meters of various types, including ultrasonic and restriction devices for measuring gas-lift gas in the Orenburg oil and gas condensate field.
Successful Application of the Intelligent Inflow Tracers for Monitoring of Horizontal Wells on North Komsomolskoe Field
Authors: Solovyev Timur , Soltanov Dzheykhun , Galimzyanov Artem , Naydenskiy Konstantin , Nukhaev Marat , Mukhametshin Ilkam
Published: October 2019

Most of the new oil fields in Western Siberia have unfavorable conditions for field development such as excessive gas cap presents, oil rims and active water aquifer. The North-Komsomolskoe oilfield is also characterized by poor consolidated sandstone and high viscous oil. Different types of reservoir completion (ICD, ACID, AICV) have been decided to trial test for this field in order to mitigate early water or gas breakthrough along the long horizontal well. During this trial testing of the optimum type of lower completion, the continuous well monitoring is required; clean-up efficiency estimation after drilling, quantitative estimation of inflow per compartment along the wellbore and localization of water or gas breakthrough. Traditional well logging methods like production logging cannot always be easily applied technically and be cost-effective for many surveys during well life. This article presents the result of using a novel technology based on chemical tracer for continuous well monitoring.

Polymer matrix with chemical markers for oil and water have been integrated into different types of lower completion (ICD, AICD, Stand Along Screen) and run into the hole as a part of liner string. Technology of intelligent chemical tracers is used to monitor well performance over a long period of well life, which allows to obtain the following information: effectiveness of clean up operation after drilling, inflow per compartment and water/gas breakthrough localization zone. To confirm interpretation results based on chemical tracer, the traditional method (production logging) was used to measure inflow along the wellbore and compare with result from tracer survey.
Building More Accurate Models for Different Reservoir Types Using Interval and Interference Pressure Transient Testing
Authors: Zeybek Murat
Published: October 2019

Building accurate reservoir models can be quite challenging, especially highly stratified thick intervals in hydraulic communication in reservoir. Presented methodology is based on comprehensive Interval and Interference Pressure Transient Testing (IIPTT) for classified reservoir types with a systematic approach. Classification of reservoir types is based on layering, thickness, and hydraulic communication of layers in the reservoir.

The methodology describes building more accurate anisotropic reservoir models, providing well performance assessment based on integrated comprehensive IIPTT solving with efficient non-linear parameter estimation and modeling with numerical simulation for different reservoir types. The number distributed IIPTTs are optimized to ensure to achieve coverage across total thickness depending on the reservoir type.

It is demonstrated that high resolution accurate reservoir models can be built for relatively thick highly layered reservoirs in a feasible manner. In addition, field examples with classified reservoir types including flow tests supported the methodology.
Unrestricted Pressure-Transient Solutions for Homogeneous and Composite Elliptical Flow Models with Limited and Full Height Inner Boundary
Authors: Larsen Leif
Published: October 2019

Pressure-transient solutions for homogeneous and composite elliptical flow models have been presented by several authors over the past 40 years, but all have computational limitations, either with respect to time range or degree of eccentricity of elliptical boundaries. This paper removes these limitations on time and eccentricity with a new fully flexible computational scheme for unbounded and bounded homogeneous and composite elliptical flow also extended to cases with a limited-height inner boundary, thus also covering horizontal well scenarios in composite elliptic models.

Kuchuk and Brigham's (1979) Laplace-space solution is fully flexible with respect to the shape of ellipses, but has a lower limit on time that does not reach purely linear early data unless slow extended precision computations are used. However, this limitation can be removed with the approach of Riley et al. (1991) using asymptotic expansions for early data and Kuchuk and Brigham's (1979) solution for late data. This works for a fracture as inner boundary but has restrictions on the outer boundary. Another asymptotic expansion was used by van den Hoek (2016) to derive a more flexible but not fully flexible solution, since limitations remain for highly eccentric scenarios. This paper extends results from these references with other asymptotic expansions to achieve full flexibility on time and eccentricity.

A wide range of examples are included to highlight the flexibility and utility of the new solutions, with cases ranging from damage-zone dimensions to long-time injection-falloff scenarios, but only as stationary cases with emphasis on the dimensions of the scenarios. Contrasts between exact degenerate elliptical models and standard solutions for infinite-conductivity fractures based on uniform-flux models and an equivalent pressure point are also discussed briefly. This concerns a solution artifact that might be overlooked. With a limited-height fracture used as a horizontal well replacement, cases are also included for horizontal wells in composite elliptical models.
Approach to Determining the Optimal Parameters of Well Performance in Fractured Reservoirs with a Gas Cap: Orenburg GCF Case Study
Authors: Yudin Evgeny , Galyautdinov Ilyas , Piotrovskiy George , Morozova Anna , Kolyuk Olesya , Smirnov Nikita
Published: October 2019

The paper deals with the features of well operation at the Orenburg oil and gas condensate field. Our study presents the investigations of the reasons for various complications, which can lead to the reduction of production characteristics of wells for the conditions of fractured reservoirs with gas cap and high gas content of oil. The Orenburg oil and gas condensate field wells are used as an example to present the results of well production optimization in accordance with the obtained results. In this paper we proposed a complex approach to determining the parameters of the fractured formation. At the first stage, based on the mathematical model of Warren-Root fracture reservoir, we found the dependence of the well flow rate on time and parameters of fracture under conditions of maintaining constant bottomhole pressure. The second stage was a generalization of this problem for the case of arbitrary dynamics of flow rates and pressures based on the problem of deconvolution. The search of parameters of double fracture formation was carried out by their variation in the corridor of admissible values in order to minimize the deviation of the calculated flow rate relative to the true one.
Big Data in Field Development Projects
Authors: Gurianov Andrei , Katashov Alexander , Ovchinnikov Kirill , Saprykina Kseniya , Novikov Igor , Malyavko Evgeny , Kiselev Vasily
Published: October 2019

In recent years, new terms and concepts have appeared that describe the digital transformation currently in progress. The world image, including in the industrial world, has been changed by the concept of intelligent enterprise (IE) - a set of technological innovations, including artificial intelligence (AI), intelligent automation (IA), deep learning technologies, predictive analytics and cognitive computing. The increasing complexity of the oil and gas business and the decreasing optimization potential from traditional approaches require the use of new, innovative digital technologies to remain competitive.

Responding to the market conditions of falling hydrocarbon prices, the oil and gas industry is increasingly mastering Big Data to optimize technological processes and prevent accidents. The emergence of Big Data technologies, predictive analysis and machine learning are changing the general image of many industries, and the oil and gas industry is no exception. New players are quickly emerging throughout the industry, and digitalization will affect the entire value chain throughout in the oil and gas industry. Among the most promising segments for the transition to digital technologies are asset management and infrastructure facilities, field development, geophysical services, pipelines and processing.

Digital technology is the most powerful driver for cost reduction. It is expected that implementing these solutions will, by 2030, reduce the costs of E & P projects by up to 30%. Thus, Russia can leverage these new technologies and retain a share in the world energy market for another 50 years. The oil industry has recently passed the most difficult period in the last 30 years. The fall in oil prices since 2014, the reduction of 350 thousand employees worldwide, and fall in production investment are examples of serious challenges that the industry has faced in recent years. These challenges have resulted in new attempts to optimize business through implementing new technologies to improve the efficiency and profitability of companies.
ESP Energy Efficiency Management as a Key to Cost Savings and Runlife Improvement
Authors: Musorina Anastasia , Safonov Bictor , Terebennikov Valery
Published: October 2019

In current conditions of oil and gas production the highest importance is improvement of the company operational performance, and with increase of electric power tariffs in the market the porting of costs for energy in total scope of the Company costs is continuously growing maintaining the trend of such growth. In Salym Petroleum Development (SPD) we pay significant attention to issues of optimization of the Company budget costs, and thus the issue of maintaining oil production energy efficiency becomes more and more important with each new year.

Within limits of developing information technologies development and application of intellectual management systems become more popular with the main objective to optimize oil production, technical solutions, planning processes and operational expenditures.

In SPD we pay significant attention to "digitalization" of the company operational processes, in this relation in the beginning of 2016 we developed and started a program of daily analysis of production well stock and making decisions on optimization of its operation called "Optimization register" (SPE-191553). This software includes an integrated module of energy efficiency allowing to control and optimize daily energy consumption by electrical submersible pumps (ESP). Best and average practices were developed and implemented – indicators of unit power consumption for artificial lift of fluid by ESP system among other companies in the industry.

This system is integration of well and equipment operating parameters in real time mode and technical information from different databases into one base with automatic check of data correctness and dynamics of ESP energy consumption change. This allows to promptly draw attention of analytical engineer to increase of unit power consumption for the well after replacement of equipment (due to implementation of well interventions or failure of downhole submersible equipment); in the process of degradation of head and flow rate parameters of downhole submersible pumps due to plugging/wear of ESP driven bodies; in case of incompliance of actual well potential with ESP capacity, which is the cause of ESP operation beyond limits of recommended operating envelope, etc. The system provides for an opportunity to make requests for optimization of downhole submersible pump operation to reduce unit power consumption. Requests are automatically directed to performers, the systems tracks status of their implementation.

Automatic detection of high ESP unit power consumption compared to the best and average practices in the industry for specific type of downhole submersible pumps, creation and implementation of requests within limits of optimization of unit power consumption now presents a closed cross-functional cycle of information transfer allowing each participant to have actual data and make a correct decision.
Reliability Assessment of PVT-Properties of Reservoir Fluids on the Basis of a Probabilistic Mixture Model of Student's Distributions
Authors: Volkov Nikita , Andrianova Alla , Serebryakova Darya , Budennyy Semen
Published: October 2019

Substantiation of the component composition and PVT-properties (Pressure, Volume, Temperature) of reservoir fluids is one of the most crucial conditions for increasing the reliability of reserves calculation and efficiency of oil and gas field development.

The main tasks of this article are abnormal samples definition and a prediction of some PVT-properties form other ones. In machine learning this tasks names as the anomaly detection and the regression analysis. To solving this task, the model based mixtures of multidimensional Student's distributions was developed, training of which using variational Bayesian inference.

The developed model was tested on data base containing more than 3200 samples of reservoir fluids. The article compares the proposed method by the quality of the predictions with other machine learning methods, for example random forest, artificial neural networks and SVM regression. Using these models, the quality of PVT-sample parameters prediction was significantly higher than the proposed method of probabilistic mixture of Student's t-distributions.
Solving the Problems in the Hydrodynamic Modeling of the Eastern Siberia Field with Salted Deposits
Authors: Komalov Saidabror , Shelest Natalia
Published: October 2019

Maintaining reservoir pressure is one of the prerequisites for ensuring production levels to be achieved. However, its implementation is not always a trivial task. Revised oil field is located in East Siberia and complicated by fault, insufficient level of exploration degree and located at isolated location, on the other hand it has a high hydrocarbon potential. Also target oil filed is characterized by deposits of halite in the reservoir, which significantly reduce the reservoir capacitive characteristic and filtration ability, high mineralization and increased viscosity of the formation water, complicates reservoir pressure maintenance, presence of significant lateral and vertical reservoir heterogeneity. All above factors require nonstandard approaches to field development design and engineering solutions for effective oil and gas recovery.
Geology Driven History Matching
Authors: Matveev Ivan , Shishaev Gleb , Eremyan Grachik , Demyanov Vasily , Popova Oksana , Kaygorodov Sergey , Belozerov Boris , Uzhegova Iuliia , Konoshonkin Dmitry , Korovin Mikhail
Published: October 2019

This paper proposes the method of an automatic history matching (HM) with the ability to preserve geological realism and an example of its application in one of the fields in Western Siberia. The method assumes takes into account all identified uncertainties at the early stages of geological model construction and their synchronized variation within realistic limits during HM.

There are interrelations between petrophysical and geological uncertainties, which significantly affect on the reservoir dynamics. Hence, changes in one of the parameters during HM should influence the synchronous change of the others in order to preserve the geological consistency of the simulation model within the given geological concept. As a result, engineer gets a set of history matched models providing a range of predictions, which can be used for investment decisions.
Coupled Reservoir – Well Model of Sand Production Processes.
Authors: Lezhnev Konstantin , Roshchektaev Aleksei , Pashkin Vsevolod
Published: October 2019

Sand production is often observed during the development of weakly consolidated reservoirs. In this paper the physico-mathematical models of the main processes associated with sand production are presented. These models are combined into a single process that allows calculating the dynamics of skin-factor of the well, estimate the risk of well plugging with sand and estimate the concentration of the solids in the flow at the wellhead. Model can also be used for the optimization of the filter.

Coupled model consists of three parts: geomechanical module for estimating the amount of solid particles flowing out of the formation, module for calculating the filter efficiency, and module for solids transport in the well. To evaluate the geomechanical failure of the formation the radial semi-analytical model was used that considers plastic deformations of the weakly consolidated rocks. Pressure drop in the filter was calculated with the one-dimentional suspension model with multiple solid particle sizes. The evaluation of solids transport the was based on the one dimentional model of the multiphase flow. One-way coupling was used to combine these modules. Information about concentration of solid particles in the flow is passed from geomechanical module to the filter module and then to the well transport module.

Presented coupled model covers most significant processes affecting the oil production from weakly consolidated reservoirs. In the course of the work, the dynamics of the near-wellbore area failure was modeled and the dependence of the concentration of solid impurities in the inflow was calculated over time. This data is used as input parameter for the filter model. Calculation of the filter allows estimating the pressure drop across the filter and well's skin factor. The model takes into account the particle size distribution of reservoir particles, which allows it to be used for the optimization problem of filter selection. The constructed model of sand transport along the well allows calculating the risk of sand blockages formation and find the fluid production rate that is sufficient of carrying solids to the welltop. Further development of the model will allow taking into account the erosion of submersible equipment, estimate the turnaround time and calculate the multiphase flow in the near-wellbore area.