bluuebunny/crossref_metadata_2025 huggingface dataset:
Technology For Oil Production Wells Drawdown and Gor Control For Oil Rim Reservoir Development on the Yurubcheno-Tokhomskoye Field.
Authors: Dadakin Nikita , Nukhaev Marat , Rymarenko Konstantin , Grishenko Sergey , Aitkaliev Galymzan , Kabanov Vasilii , Gusachenko Tatyana , Zaitsev Alexandr
Published: October 2021

One of the critical tasks during the oil rim development is to control production wells to prevent water breakthroughs and gas outs. Key factors are control over drawdown and on-time choke restriction of the well in case of a gas out and an extreme gas factor increase.
Evaluating Efficiency of Multilateral Producing Wells in Bottom Water-Drive Reservoir with a Gas Cap by Distributed Fiber-Optic Sensors and Continuous Pressure Monitoring
Authors: Maltsev Andrei Konstantinovich , Kudlaeva Nailia Vladimirovna , Aslanyan Artur Mikhailovich , Krichevsky Vladimir Markovich , Gulyaev Danila Nikolaevich , Surmasheva Leysan Vladislavovna , Solovyeva Viktoria Vitalievna
Published: October 2021

The main goal of the pilot job is to assess the risks of production by horizontal wells and multilateral wells with a close gas cap above and water layers beneath the main formation. The objectives are to monitor the total producing length of the wells using temperature and pressure surveillance. The results of monitoring were analyzed at different stages of development.

An analysis was carried out by combining pressure and temperature data obtained while monitoring the production of multilateral wells. The well properties were determined using RTA and PTA.

To assess the inflow profile, distributed temperature sensors in the wells were analyzed for the entire period of appraisal production. A feature of the research was the low contrast of temperature anomalies associated with fluid inflow. In addition, it was also revealed that the DTS absolute readings at the depth of the formation were affected by surface temperature, which required corrections and the use of relative readings in the calculations instead of absolute ones.

The main feature of the pressure analysis was the short period of production. With such well completion geometry and reservoir properties of the layer, the radial flow could not be achieved during the whole test period. Despite these limitations, the dynamics of the total producing length of the well was determined. The initial value of the producing length was about 70% of the drilled length, then there is a slight decrease after 7 to 10 months of well production.

By analyzing the fiber-optic temperature profile, an inflow profile was assessed. Based on the analysis of changes in relative temperature anomalies, the shares of inflow from the sidetracks were estimated.

Several memory temperature / pressure gauges set along the horizontal section were used as an additional data source to monitor well parameters during the whole period of production. The difference in their readings was due to, among other things, the average flow rate in the section between the sensors, which made it possible to give an independent assessment of the inflow profile.

Based on the results of the job performed, a number of risks and uncertainties were removed, including information on the total flowing horizontal length dynamics, which is a valuable input for full-field development planning. In addition, an express method of DTS data analysis has been developed for assessing the wellbore producing length without significant temperature changes associated with intervals of inflow.
Novel Integrated Approach for Complex Carbonate Reservoirs Testing with Wireline Formation Tester: Yurubcheno-Tokhomskoye Field Cases Study
Authors: Dzhalatyan Yakov , Charupa Mikhail , Galiev Aydar , Karpekin Yevgeniy , Egorov Sergey , Kishauov Abilkassym , Smetanin Yury , Pushkarskiy Alexey , Arbatsky Timur
Published: October 2021

In the presented paper, the object of the study are carbonate rocks of the Riphean and clastic-carbonate rocks of Vendian-Cambrian ages, uncovered by the well drilled at Yurubcheno-Tokhomskoye field.

These reservoirs are characterized by extremely low porosity (1-4%) and determining saturation nature and fluid contacts cannot be reliably solved by conventional wireline petrophysical logging. Solutions to these problems are provided by interval testing using wireline formation evaluation testing tool (WFT). However, to obtain quality results from WFT testing it is important to identify porous intervals first by using advanced wireline logging services which are sensitive to porosity and fractures.

In order to select the optimal WFT toolstring combination and to prospective testing intervals, advanced petrophysical wireline logging suit ran first. Porous reservoirs were identified from density, neutron and nuclear magnetic resonance evaluation. Saturation evaluated through dielectric and induction-based resistivity logging.

In fracture-vug type reservoir, the main inflow of formation fluid into the well is provided from fractures, so it was very important to allocate conductive fractures to plan test intervals for WFT accordingly.

based on imagers evaluation, fractures and faults were visualized; using Stoneley's wave conductive fractures, not clogged with drilling mud solids were identified; borehole acoustic reflection survey was used to segregate large fractures that propagated in the reservoir;

During WFT logging, a total of 23 intervals were tested, for 8 of which reservoir fluid inflow was achieved, in all others, mainly with low porosity or single non-conductive fracture, the inflow was not achieved or was insignificant.

According to the results of WFT testing, the nature of saturation for clastic-carbonate sediments of Vendian age was determined. Inflow of formation fluid (oil and water) from Riphean fractured reservoirs was achieved from 6 intervals, with identified fractures according to described above advanced logging suit. In addition, pressure transient analysis was performed, to measure the formation pressure, define pressure gradient curves and assess the fluids contact level with high confidence, for the first time for this field.
End-to-End Quality Control of Downhole Samples from the Sampling Point to the Laboratory Unit: This is Possible and Necessary
Authors: Lobanov Alexey Alexandrovich , Fedorovskiy Stanislav Alexandrovich , Promzelev Ivan Olegovich , Tikhomirov Yevgeny Vladimirovich , Zvonkov Mikhail Alekseevich , Kovalenko Vyacheslav Andreevich , Kuporosov Dmitriy Nikolaevich , Bastrakov Aleksandr Aleksandrovich , Nartymov Vladimir Sergeevich , Harisov Arthur Uzefovich , Struchkov Ivan Alexandrovich , Pleshanov Nikolay Nikolaevich , Makarov Sergey Evgenievich , Frolov Artem Sergeevich
Published: October 2021

The services and downhole sampling technologies market in Russia is in deep stagnation. The objective conditions have emerged, wherein the responsibility and leadership in the development and recovery of this area is a prerogative task of major oil and gas companies, rather than the equipment manufacturers. The paper shares the authors’ experience in the development, pilot testing and implementation of novel regulatory and technical approaches and technologies of sampling, transportation, field, end-to-end and laboratory assessment of samples quality in PJSC «Gazprom Neft».
The Efficiency of the Novel Technology Reservoir Pressure Reconstruction Without Well Shut-in and without Production Losses
Authors: Belyakov Alexander Alexandrovich , Gulyaev Danila Nikolayevich , Krichevskiy Vladimir Markovich , Nikonorova Anastasia Nikolaevna , Iskibaev Roman Edisonovich
Published: October 2021

The analyzed oi- gas field is based around Orenburg region, located 40 km away from the Buzuluk city, Russia.

This multi-layered field has a number of domes. 11 productive layers lie within its cross-section. In total, 21 oil and two gas deposits have been identified at this field.

The study layer A4 is confined to the top of the Bashkir layer and has a wide extension. Permeable rocks at this layer include limestone and dolomite, separated by impermeable sublayers. The effective oil-saturated well thicknesses vary between 1.1-38.4 m, and is 11.8 m on average. The caprock of the formation A4 consists of the Vereiskan clay-siltstone sequence.
Optimized Multi-Zone Dynamic Reservoir Evaluation in the Middle Caspian
Authors: Shtun Sergey , Kaipov Yermek , Kamalov Fanise , Akbayev Beibit , Blinov Vlad
Published: October 2021

Caspian offshore is reach for hydrocarbon reserves. The fields are made of multi-zone carbonate and sandstone reservoirs with significant variation of properties having high pressure (HP), high temperature (HT) and high H2S concentration in reservoir fluid. These challenges pose significant challenges to conduct the formation and multi-zone reservoir testing in a safe and informative manner.

The dynamic reservoir evaluation program consists of formation pressure and its profile measurements, fluid pump-out for confirming the fluid type and sampling performed with wireline formation testers (FT) in open-hole and multi-zone well test for productivity estimation with drill-stem test (DST) designed for offshore environment with HP and high H2S.

The project was planned and executed in an integrated manner, where the well construction design and selection of drilling and completion fluids has to improve the chance of success for FT and DST by taking into accound the downhole tool sizes and complex geological conditions.

The open-hole formation testing and well testing in cased-hole were combined to provide enough information for characterizing multi-zone reservoirs by minimizing the drilling rig time. The well testing program was optimized in terms of number of zones for testing and necessity to acidize the reservoir based on formation testing data.

The given methodolgy allowed to efficiently conduct the formation testing and well testing at two recently drilled offshore wells with multi-zone reservoirs.

It was the first integrated dynamic reservoir evaluation project for such complex geological conditions in Middle part of Caspian offshore. This paper demonstrates the lessons learnt from two wells and offers the methodology for planning the evaluation for similar fields.
Comparative Analysis of Tracers Against Pressure Pulse Code Interference Testing based on the Numerical Simulations of the Synthetic Oilfields with Complicated Geology
Authors: Aslanyan Artur Mikhailovich , Farakhova Rushana Rinatovna , Gulyaev Danila Nikolayevich , Mingaraev Ramil Anvarovich , Khafizov Ruslan Ildarovich
Published: October 2021

The main objective of the study is to compare the results of the cross-well tracers survey against the pulse code pressure interference testing (PCT) for the complicated geological structures.

The study was based on the numerical simulations on the synthetic 3D models with popular geological complications, such as faults, vertical and horizontal reservoir anisotropy and pinch-outs.

The study has set a special focus on quantitative analysis of the reservoir properties estimated by tracers and PCT as against the known values.

This provides a text-book examples of advantages and disadvantages of both surveillance methods in different geological environment.

Pulse code testing is specific implementation of pressure interference testing by creating a series of injection/production rate changes accordingly to a preset schedule to create a "pressure code" and monitoring the pressure response in the offset wells. The use of high-resolution quarts gauges is highly beneficial in case of large cross-well intervals scanning or poor reservoir quality in case of regular inter-well spacing.

The tracer survey is based on injecting a liquid with chemical markers and subsequent capturing the markers at surface samples in the offset wells. The modern markers are relatively cheap and can be captured at very low concentrations thus making the cross-well scanning available even for high inter-well spacing.

For synthetic models with vertical inhomogeneity the PCT provides a close estimate for compound dynamic reservoir properties (transmissibility and pressure diffusivity).

For synthetic models with lateral inhomogeneity the PCT provides an accurate estimation for effective reservoir thickness and permeability.

Tracers survey is not able to assess the reservoir thickness.

The popular methods to assess reservoir permeability from tracers survey show a substantial deviation from the true reservoir permeability for synthetic models with vertical and lateral heterogeneity.

This leads to conclusion that the most reliable application of racers survey is a qualitative assessment of cross-well connectivity and quantitative estimate of permeability in homogenous reservoirs.

The first study of quantitative comparison of tracer survey against pressure pulse-code interference survey. Tracer survey and PCT efficiency was compared on 3D numerical models. Presence of synthetic models, describing geological complications, which may be seen very often on real reservoirs, provides a reliable basis for comparison.
Localisation and Recovery Planning of the Remaining Hydrocarbon Reserves
Authors: Aslanyan Artur Mihailovich , Popov Arkadii Yurievich , Zhdanov Ivan Aleksandrovich , Pakhomov Eugeny Sergeevich , Ibryaev Nikolay Petrovich , Kuznetsov Maksim Aleksandrovich , Krichevsky Vladimir Markovich , Garnyshev Marat Yurievich , Guss Rodion Vladimirovich
Published: October 2021

The paper presents the results of a study project of 60+ well block of the large (> 1,000 wells) mature (30 year old) oilfield in Western Siberia with objective to localise and characterize residual recoverable reserves and propose the optimal economic scenario for further depletion.

Low permeability, heterogeneous reserve structure along the cross-section, numerous induced hydraulic fractures in producing wells and numerous spontaneous fractures in injecting wells with dynamic behavior, aggravated by numerous behind-the-casing crossflows in almost every well have resulted in a very complex conditions of remaining reserves.

The conventional methods of production analysis and surveillance (well testing and production logging) do not provide a consistent picture of the current distribution and conditions of the remaining reserves and required a deeper and more complex analysis.

Development Opportunities Management workflow was chosen for this particular holistic study, which includes a set of interconnected studies, field surveillance, geological and flow modelling and culminated in field development planning based on the digital asset twin. (Ganiev, B., 2021)

Digital asset twin was constructed based on results of this workflow with a full-range economical model, flow simulation over the thoroughly calibrated fine-grid 3D dynamic model and production complication model (dynamic behavior of the fractures and behind-casing channeling).

The 3D model has been calibrated on results of the cross-well pressure-pulse surveillance, reservoir-oriented production logging and was validated by the results of the drilling of the transition wells.

The digital asset twin was used to find the optimal investment scenario based on multivariate calculations with the help of digital assistants.

Due to simplicity of the user interface and client-server design, the digital twin was made available for various corporate engineers and managers without any modelling skills to play around with their own ideas on possible production/investment scenarios which gave another level of validation of the ultimate field development plan.

All activities carried out within the digital twin automatically generate a complete package of investment metrics (NPV, PI, IRR, MIRR, Cash Flow and many correlation graphs) to assess the economic efficiency of each package and select the most appropriate solution for further ultimate choice.

The approved scenario was based around drilling 6 producing side-tracks in specific locations/trajectories, performing workovers on specific offset injectors and re-scheduling of the production/injection rates in all block wells.

The results of the field development's activities implementation will be the subject of a future publication.
Stuck Pipe Early Detection on Extended Reach Wells Using Ensemble Method of Machine Learning
Authors: Rakhimov Rushad Ravilievich , Zhdaneev Oleg Valerievich , Frolov Konstantin Nikolaevich , Babich Maxim Pavlovich
Published: October 2021

The ultimate objective of this paper is to describe the experience of using a machine learning model prepared by the ensemble method to prevent stuck pipe events during well construction process on extended reach wells. The tasks performed include collecting, analyzing and cleaning historical data, selecting and preparing a machine learning model, testing it on real-time data by means of desktop application. The idea is to display the solution at the rig floor, allowing Driller to quickly take actions for prevention of stuck pipe event.

Historical data mining and analysis were performed using software for remote monitoring. Preparation, labelling and cleaning of historical and real-time data were executed using programmable scripts and big data techniques. The machine learning algorithm was developed using the ensemble method, which allows to combine several models to improve the final result.

On the field of interest, the most common type of stuck pipe are solids induced pack offs. They occur due to insufficient hole cleaning from drilled cuttings and wellbore collapse due to rocks instability. Stuck pipe prevention on extended reach drilling (ERD) wells requires holistic approach meanwhile final role is assigned to the driller. Due to continuously exceeding ERD envelope and increased workloads on both personnel and drilling equipment, the effectiveness of preventing accidents is deteriorating. This leads to severe consequences: Bottom Hole Assembly lost in hole, the necessity to re-drill the bore and eventually to increased Non-Productive Time (NPT).

Developed application based on ensemble machine learning algorithm shows prediction accuracy above 94%. Reacting on alarms, driller can quickly take measures to prevent downhole accidents during well construction of ERD wells.
Optimization of the Reservoir Management System and the ESP Operation Control Process by Means of Machine Learning on the Oilfields of Salym Petroleum Development N.V.
Authors: Musorina Anastasia Dmitrievna , Ishimbayev Grigory Sergeyevich
Published: October 2021

Under the present conditions of oil and gas production, which are characterized by mature production fields and the focus shifted towards digitalization of production processes and use of machine learning (ML) models, the issues related to the improvement of accuracy and consistency of the well operation control data are becoming increasingly important. As a result, SPD has successfully implemented the project of using annular pressure sensors in combination with machine learning models to control the well annular pressure as part of the field development program compliance.

Under the field development program, echosounder and telemetry system readings are typically used to control the annular pressure and the dynamic flowing level. Echosounders, however, are not designed as measuring instruments, the accuracy of their readings being low and making it impossible to reliably evaluate the well's dynamic flowing level and annular pressure, as well as to achieve the well's maximum potential, and the telemetry systems used to measure the pump intake pressure may go wrong.

This manuscript describes the approach to the producer well annular pressure assessment based on the machine learning model data. The machine learning (ML) model is a function of the target variable (bottom-hole pressure), which is predicted on the basis of the actual data: static parameters (well schematic, pump design) and dynamic parameters (annular and line pressures, flowrate). The input parameter interpretation results in the most probable value of the target variable based on the historic data.
Multi-Mineral Segmentation of SEM Images Using Deep Learning Techniques
Authors: Alekseev Vladislav Vasilevich , Orlov Denis Mihaylovich , Koroteev Dmitry Anatolevich
Published: October 2021

The approaches of building and methods of using the digital core are currently developing rapidly. The use of these methods makes it possible to obtain petrophysical information by non-destructive methods quickly.

Digital rock physics includes two main stages: constructing models and modeling various physical processes on the obtained models. Our work proposes using deep learning methods for mineral and pore space segmentation instead of classical methods such as threshold image processing. Deep neural networks have long been able to show their advantages in many areas of computer vision.

This paper proposes and tests methods that help identify different minerals in images from a scanning electron microscope. We used images of rocks of the Achimov formation, which are arkoses, as samples. We tested various deep neural networks such as LinkNet, U-Net, ResUNet, and pix2pix and identified those that performed best in segmentation.
Long-Term Forecasting and Optimization of Non-Stationary Well Operation Modes Through Neural Networks Simulation
Authors: Ponomarev Roman Yurievich , Vershinin Vladimir Evgenievich
Published: October 2021

The article discusses the results of long-term forecasting of non-stationary technological modes of production wells using neural network modeling methods. The main difficulty in predicting unsteady modes is to reproduce the response of producing wells to a sharp change in the mode of one of the wells. Such jumps, as a rule, lead to a rapid increase in the forecast error. Training and forecasting of modes was carried out on the data of numerical hydrodynamic modeling. Two fields with significantly different properties, the number of wells and their modes of operation were selected as objects of modeling. Non-stationarity was set by changing the regime on one or several production wells at different points in time. The LSTM recurrent neural network carried out forecasting of production technological parameters. This made it possible to take into account the time-lagging influence of the wells on each other. It is shown that the LSTM neural network allows predicting unsteady technological modes of well operation with an accuracy of up to 5% for a period of 10 years. The solution of the problem of optimization of oil production is considered on the example of one of the models. It is shown that the optimal solution found by the neural network differs from the solution found by hydrodynamic modeling by 5%. At the same time, a significant gain in calculation time was achieved.
Complex Approach to Creation and Maintenance of Integrated Asset Models and Implementation of Digital Data Management Platform
Authors: Markov Pavel Vladimirovich , Gorshkov Alexey Vladimirovich , Shadrin Sergey Vladimirovich
Published: October 2021

The paper presents a complex approach based on the experience of the authors of this article for creating and maintaining integrated asset models (IAM) and implementing a digital data management platform. Problems of using IAM for the operational management of field development and production are that the data is not accurate, the measurements are spaced in time, and there is not enough data to understand the physical phenomena taking place. The complex approach is that to provide integrated asset models with high-quality data, it is necessary to build new processes, create new specialties and competencies, the key success factor is the combination of the experience of Customer (oil company), Internal oil-related service of Customer (geological and geophysical research), External contractor of oil-related service (the combination of experience in geological and geophysical research, experience in integrated asset modeling and operational support for field development using integrated asset modeling tools and digitalization of data management). The best way to implement the approach of creating joint Integrated Team of External and Internal oilfield service Contractors in the form of Complex Service Engineering Center, the task for which which was the organization of a cyber-physical system for collecting field data, verifying data, identifying problem areas in data, defining approaches to eliminating problem areas using tools of automation tools for working with data, the flexible management of well testing and survey programs, the operational formation of well testing and survey design for non-standard situations. Particular attention in this complex approach is paid to working with initial field data, this article provides a general scheme for verifying the various parameters of well operation and an example of its use for flow rates, as well as examples of the quality analysis of reservoir pressures based on the use of a two-dimensional one-phase proxy reservoir model and the quality analysis of GOR for a well. Based on the developed complex approach, the paper provides examples of strategic and operational problems for a field - the assessment of optimal production for a field and the assessment of oil shortfalls for a well, respectively.
New method for Handling of Infrastructural Constraints for Integrated Modeling in Steady Case
Authors: Olenchikov Dmitry Moiseevich
Published: October 2021

Recently, more and more reservoir flow models are being extended to integrated ones to consider the influence of the surface network on the field development. A serious numerical problem is the handling of constraints in the form of inequalities. It is especially difficult in combination with optimization and automatic control of well and surface equipment. Traditional numerical methods solve the problem iteratively, choosing the operation modes for network elements. Sometimes solution may violate constraints or not be an optimal. The paper proposes a new flexible and relatively efficient method that allows to reliably handle constraints. The idea is to work with entire set of all possible operation modes according to constraints and control capabilities. Let's call this set an operation modes domain (OMD). The problem is solved in two stages. On the first stage (direct course) the OMD are calculated for all network elements from wells to terminal. Constraints are handled by narrowing the OMD. On the second stage (backward course) the optimal solution is chosen from OMD.
Influence of Rock Plastic Behavior on the Wellbore Stability
Authors: Grishko Elena , Garavand Aboozar , Cheremisin Alexey
Published: October 2021

Currently, the standard approach to building a geomechanical model for analyzing wellbore stability involves taking into account only elastic deformations. This approach has shown its inconsistency in the design and drilling of wells passing through rocks with pronounced plastic properties. Such rocks are characterized by the fact that when the loads acting on them change, they demonstrate not only elastic, but also plastic (irreversible) deformations. Plastic deformations have an additional impact on the distribution of stresses in the rock of the near-wellbore zone on a qualitative and quantitative level. Since plastic deformations are not taken into account in the standard approach, in this case the results of the wellbore stability analysis are based on incorrectly calculated stresses acting in the rock. As a result, it can lead to misinterpretation of the model for analysis, suboptimal choice of trajectory, incorrect calculation of safe mud window and an incorrectly selected set of measures to reduce the risks of instability.

The aim of this work is to demonstrate the advantages of the developed 3D elasto-plastic program for calculating the wellbore stability in comparison with the standard elastic method used in petroleum geomechanics. The central core of the work is the process of initialization of the elasto-plastic model according to the data of core tests and the subsequent validation of experimental and numerical loading curves.

The developed 3D program is based on a modified Drucker-Prager model and implemented in a finite element formulation. 3D geomechanical model of wellbore stability allows describing deformation processes in the near-wellbore zone and includes the developed failure criteria.

The paper shows a special approach to the determination of the mud window based on well logging data and core tests by taking into account the plastic behavior of rocks. An important result of this study is the determination of the possibility of expanding the mud window when taking into account the plastic criterion of rock failure.
Usage of Geomechanically Consistent Fracture Model for Drilling Deviated Wells
Authors: Dubinya Nikita Vladislavovich , Tikhotskiy Sergey Andreevich , Fomichev Sergey Vladimirovich , Golovin Sergey Vladimirovich
Published: October 2021

The paper presents an algorithm for the search of the optimal frilling trajectory for a deviated well which is applicable for development of naturally fractured reservoirs. Criterion for identifying the optimal trajectory is the feature of the current study – optimal trajectory is chosen from the perspective of maximizing the positive effect related to activation of natural fractures in well surrounding rock masses caused by changes of the rocks stress-strain state due to drilling process. Drilling of a deviated well is shown to lead to the process of natural fractures in the vicinity of the well becoming hydraulically conductive due to drilling. The paper investigates the main natural factors – tectonic stresses and fluid pressure – and drilling parameters – drilling trajectory and mud pressure – influencing the number and variety of natural fractures being activated due to drilling process. An algorithm of finding the optimal drilling parameters from the perspective of natural fractures activation is proposed as well. Different theoretical scenarios are considered to formulate the general recommendations on drilling trajectory choice according to estimations of stress state of the reservoir. These estimations can be provided based on results of three- and four-dimensional geomechanical modeling. Such modeling may be completed as well for constructing geomechanically consistent natural fracture model which can be used to optimize drilling trajectories during exploration and development of certain objects. The paper presents a detailed algorithm of constructing such fracture models and deviated wells trajectories optimization. The results presented in the paper and given recommendations may be used to enhance drilling efficiency for reservoirs characterized by considerable contribution of natural fractures into filtration processes.
Geomechanical Modelling Application to Support Reservoir Selection for Carbon Dioxide Utilization and Storage
Authors: Korelskiy Evgeny , Petrakov Yuriy , Sobolev Alexey , Ablaev Anton , Mylnikov Danila , Melnichuk Dmitriy
Published: October 2021

During recent years reduction of carbon dioxide emission driving development of different technologies for CO2 capturing and utilization. Carbon dioxide injection in underground reservoirs is on of effective methods for storage or utilization as enhanced oil recovery agent. Selection of the potential reservoir for CO2 injection is critically important for long term gas storage. In this paper demonstrated software solutions and workflows for modelling of geomechanical modelling of CO2 injection.

Injection of CO2 into the reservoir entails a change in reservoir pressure and a change in reservoir temperature. In turn, the stress-strain state of the massif changes, which can lead to the destruction of the reservoir rock and host rocks, reactivation of faults, and, as a consequence, the loss of the integrity of the seal and uncontrolled interstratal crossflows. This paper will describe an example of choosing a reservoir for CO2 injection based on the study of the stress-strain state of the rock mass and its changes due to gas injection.

Currently, there are various approaches to CO2 recovery into the reservoir, including injection into depleted gas reservoirs, aquifers and oil reservoirs for the purpose of enhanced oil recovery. For injection planning, it is extremely important to understand both the initial injection conditions and their changes over time.

In the work on the published materials, the world experience of CO2 injection into the reservoir with the aim of its utilization was studied.

Using the tools of combined geomechanical modeling of the reservoir, the modeling of the change in the stress-strain state of the massif during the injection process was carried out and the conditions under which the destruction of the reservoir cap and the reactivation of faults occur. The influence of uncertainty in elastic-strength parameters on the critical state of the rock mass and the potential of the permissible injection volume is shown. Comparison of injection potential into reservoirs with terrigenous and carbonate seals has been performed.
Interdisciplinary Approach for Wellbore Stability During Slimhole Drilling at Volga-Urals Basin Oilfield
Authors: Norkina Anna Vladimirovna , Karpukhin Sergey Mihailovich , Ruban Konstantin Urjevich , Petrakov Yuriy Anatoljevich , Sobolev Alexey Evgenjevich
Published: October 2021

The design features and the need to use a water-based solution make the task of ensuring trouble-free drilling of vertical wells non-trivial.

This work is an example of an interdisciplinary approach to the analysis of the mechanisms of instability of the wellbore. Instability can be caused by a complex of reasons, in this case, standard geomechanical calculations are not enough to solve the problem.

Engineering calculations and laboratory chemical studies are integrated into the process of geomechanical modeling.

The recommendations developed in all three areas are interdependent and inseparable from each other. To achieve good results, it is necessary to comply with a set of measures at the same time.

The key tasks of the project were: determination of drilling density, tripping the pipe conditions, parameters of the drilling fluid rheology, selection of a system for the best inhibition of clay swelling.
Techno-Economic Assessment of the Equipment for Production Carbon Black from APG
Authors: Dimitriev Anton Sergeevich , Bandaletova Alexandra Alexandrovna
Published: October 2021

The present work describes one of the key areas of research activity of the modern oil and gas scientific world: decarbonization and increasing the efficiency of the natural and associated gas usage which is a method for producing carbon black. The technology is characterized by relative simplicity of the technological process and a wide market for the resulting product. This method is also included in the list of BAT (BREFs, 2020). The article presents a techno-economic assessment of the proposed method of using gas, there is also a comparison with other existing methods.
Comprehensive Assessment and Targeted Approach to the Implementation of the Gas-Lift Method of Operation on the Yamal Peninsula Novy Port Field
Authors: Blyablyas Aleksander Nikolaevich , Vershinin Sergey Anatolevich , Afanasiev Petr Nikolaevich , Mingazov Ayrat Anvarovich , Akhmetgareev Rustem Faridovich
Published: October 2021

As geological environment becomes more complicated, specifics of oil fields with high gas content more demanding, and the Company's requirements for assets development efficiency more stringent, new challenges arise that require application of high-tech approaches and new tools to solve the tasks set. The era of "easy" oil is far behind, and there are no "simple" tasks left, so the key goal of oil companies now is to radically improve efficiency of existing "difficult" fields including development of gas condensate reservoirs and oil rims.

The interest in development of new approaches to improve efficiency of the Novoportovskoye field is caused by the huge potential of the asset. Despite the fact that the field was discovered back in 1964, its remaining reserves are estimated at more than 250 million tons of oil and gas condensate and more than 270 billion cubic meters of natural gas, which are concentrated in five reservoirs. The Novoportovskoye field is the northernmost and largest on the Yamal Peninsula, but the complexity of its development and operation is caused not so much by geography and the lack of transport infrastructure but by the presence of a gas cap, low reservoir permeability, the occurrence of underlying water, and high gas content in produced reservoir fluid.

The high gas content complicates the production process. The main method of operation in the existing fields of the Yamal Peninsula is artificial lift by electric submersible pumps (ESP) on rental basis. Given the remoteness and isolation of the Arctic region, the high cost of equipment rental, and the low efficiency of ESPs in liquids with high content of dissolved gas, it is only fair to ask a question of whether there is a tool that may allow us to predict operation parameters for different lift methods.

The existing models and tools intended to assess behavior of the field are not good enough to fully predict gas breakthrough rates, optimize well operation parameters in case of short-term production forecasting, or select the optimal lift method.

In this paper, we described application of an integrated modeling process for a targeted assessment of well operation parameters at the Novoportovskoye field. Also, in the framework of this paper, we performed a technical and economic estimation of the options under consideration, and formulated some recommendations to improve efficiency of development and operation of the field under the impact of the existing complicating factors.
An Improved Methodology for Gas-Condensate Cluster Evaluations under Uncertainty
Authors: Melnikov Sergei Igorevich , Vershigora Nikita Vladimirovich , Groo Alexander Alexandrovich , Grigorev Denis Sergeevich , Kiselev Pavel Yurievich , Morozov Victor Victorovich
Published: October 2021

A decision to buy oil and gas assets requires a project evaluation (PE) aimed at integrated calculation of numerous possible scenarios of asset development, based on the uncertain resource values, variety of geological exploration program events, the most preferable decisions about the oil field development in the current economic conditions.

The vast amount of calculations determined by the probabilistic nature of the PE and specific timeframes require optimization of the current approaches based on the balance between accuracy and time. This issue is particularly relevant for the evaluation and analysis of gas or gas-condensate field cluster as the profitability of the project can be concentrated in the asset integration into one production cluster. Such option as well as proposal to gather separate fields to the common infrastructure, sequence of fields development with different geological and physical characteristics, calculations of a large number of synergy options, etc. require the multi-disciplinary team to think outside the box while searching for a business case. Thus, this paper is aimed to improve current approaches and the current tools adaptation which will be used to drastically automate cross-functional probability estimate of gas field cluster with technical and economic justification of sustainable integrated solutions.

The results were successfully validated within PE of several perspective gas condensate projects focused on the possibility of integration of the fields into a single cluster that creates additional value from the optimization of the project solutions (exploration, development strategy, gathering and transportation of hydrocarbons, monetization of the products) equal to tens of billions of rubles in a limited period of time.
Multivariant Well Placement and Well Drilling Parameters Optimization Methodology. Case Study from Yamal Gas Field
Authors: Magizov Bulat , Molchanov Dmitry , Devyashina Alisa , Topalova Tatiana , Zinchenko Ksenya , Kovalenko Alexander
Published: October 2021

More and more oil and gas fields are moving into the third stage of development - the stage of production decline. Oil and gas operating companies are looking for the most effective ways of production stabilization and extending the period of well exploitation. The most frequently used approach of improving exhausted reservoirs performance is reducing the pace of pressure and hydrocarbons production decline by well workovers and horizontal sidetracks drilling.

The most widely used type of new producing wells trajectory in low - and medium-amplitude gas fields, which include most of the Western Siberia gas reserves, is horizontal completion. According to the analysis carried out by two major Rosneft scientific centers, in oil saturated reservoirs with thickness less than 20 meters, the efficiency of horizontal wells with 300 meters length is 1.6-4 times higher than for directional wells, depending on the reservoir thickness and permeability. In gas saturated formations, the efficiency of horizontal wells performance relative to the directionally drilled wells in similar geological conditions is 3-6 times higher.

As the consequence of scientifically based well performance analysis the volume of horizontal wells drilling and horizontal side track completions at the assets of PJSC "NK "Rosneft" significanty increased as for the period from 2016 to 2021, Figure 1.
The Results of the Implementation of the Technology for Monitoring the Operation of Gas and Gas Condensate Wells According to Condensate to Gas Ratio to Optimize the Production of Liquid Hydrocarbons on the Vostochno-Makarovskoe Field
Authors: Nukhaev Marat , Rymarenko Konstantin , Baranov Vladimir , Grishenko Sergey , Zaycev Alexsandr , Aitkaliev Galymzan , Kabanov Vasily , Gusachenko Tatyana , Golubtsov Alexsandr
Published: October 2021

Liquid hydrocarbon production optimization is among key tasks in the gas condensate fields development. It depends on changes in gas supply quotas and on seasonal fluctuations in demand. The key point for such an optimization is the need to understand the current condensate-gas factor (CGF) for each well of the field to select the operating modes. Often, there is no sufficient well surveying data as these surveys are conducted not frequently enough. The paper presents an approach that allows monitoring the CGF for each well in real time and control the operating modes of the wells.
Setting a Development Strategy for Low-Permeable Turonian Gas Reservoirs
Authors: Kiselev Anton Nikolaevich , Degtyaryov Il’ya Sergeevich , Andronov Yurij Mikhaylovich
Published: October 2021

Synopsis. The paper describes approaches used when creating a comprehensive strategy for the development of low-permeable gas deposits of the Turonian age. Unlike to common techniques based on the experience of the previous development, the authors propose to optimize each of the constituent components of the development design, taking into account their contribution to the overall designing cycle. The efficient development strategy and technology will allow expanding the resource base of hydrocarbons at the expense of gas targets of the Turonian deposits, substantiating the efficiency of potentially promising areas of unallocated areas of the deposits.
Residual Water Saturation of Source Rocks of the Bazhenov Formation Western Siberia, Russia
Authors: Glotov Anton Vasilievich , Skripkin Anton Gennadyevich , Molokov Petr Borisovich , Mikhailov Nikolay Nilovich
Published: October 2021

The article presents a new method of determining the residual water saturation of the Bazhenov Rock Formation using synchronous thermal analysis which is combined with gas IR and MS spectroscopy. The efficiency of the extraction-distillation method of determining open porous and residual saturation in comparison with the developed method which are considered in detail. Based on the results of studies in the properties of the Bazhenov Rock Formation, a significant underestimation of the residual water saturation in the existing guidelines for calculating reserves was found, and the structure of the saturation of rocks occurred to be typical for traditional low-permeability reservoirs. The values of open porous and residual water saturation along the section of the Bazhenov Formation vary greatly, which also contradicts the well-established opinion about the weak variability of the rock properties with depth.
Seismic Reservoir Characterisation of Tyumen Formation in Frolov Megadepression
Authors: Grinevskiy Anton , Kazora Irina , Kerusov Igor , Miroshnichenko Dmitriy
Published: October 2021

The article discusses the approaches and methods to study the Middle Jurassic deposits of the Tyumen Formation within the Frolov megadepression (West Siberian oil and gas province), which have high hydrocarbon potential. The materials refer to several areas with available 3D seismic data and several dozen oil wells.

The problems of seismic interpretation and its application for geological modeling are considered. We also propose several ways to overcome them.
Reconstruction of the Near-Surface Velocities with Trap Bodies by the Full Waveform Inversion
Authors: Gadylshin Kirill Gennadievich , Cheverda Vladimir Albertovich , Tverdokhlebov Danila Nikolaevich
Published: October 2021

Seismic surveys in the vast territory of Eastern Siberia are carried out in seismic and geological conditions of varying complexity. Obtaining a high-quality dynamic seismic image for the work area is a priority task in the states of contrasting heterogeneities of the near-surface. For this, it is necessary to restore an effective depth-velocity model that provides compensation for velocity anomalies and calculates static corrections. However, for the most complex near-surface structure, for example, the presence of trap intrusions and tuffaceous formations, the information content of the velocity models of the near-surface area obtained based on tomographic refinement turns out to be insufficient, and a search for another solution is required. The paper considers an approach based on Full Waveform Inversion (FWI). As the authors showed earlier, multiples associated with the free surface reduce the resolution of this approach. But their use increases the stability of the solution in the presence of uncorrelated noise. Therefore, at the first stage of FWI, the full wavefield is used, including free surface-related multiples, but they are suppressed in the next steps of the data processing. The results obtained demonstrate the ability of the FWI to restore complex geological structures of the near-surface area, even in the presence of high-velocity anomalies (trap intrusions).