Background. The high geological heterogeneity of complexly built reservoir rocks with textural clayey rocks necessitates the creation of special geological modeling techniques that allow us to account as accurately as possible for all the risks associated with the development of productive reservoirs of this type. It is especially urgent for 2D constructions, applied for conceptual modeling, because during calculation of oil-saturated thicknesses maps under-saturated areas remain in the volume of reservoir and may contribute to both overestimation of reserves and incorrect assessment of prospective areas during drilling planning.

The article proposes a new approach that allows quantitative assessment of undersaturated thicknesses of low-permeability reservoirs within deposits with “fritillary” texture, an essential part of which is creation of an addressed petrophysical model.

Aim. The purpose of this technique was to develop certain criteria for correct prediction of reservoir development zones with “ripple” texture in well sections and prediction of their saturation character. Materials and methods. As part of the work, core material, GIS and seismic data was used.

Results. An integrated approach has been implemented to select criteria for identifying undersaturated thicknesses and take them into account in a 2D geological model.

Conclusion. Building a petrophysical model of AB₁² formation is a non-trivial task and is associated with a number of difficulties, such as the presence of banded saturation, low permeability properties, high vertical heterogeneity, the effect of electric current shunting by thin interlayers of clays and carbonate-clay cement on the readings of electrometry methods. The main criteria for distinguishing these objects in the well are low values of effective thicknesses, as well as their location above the water-oil contact. Boundary values for these criteria were determined on the basis of neural network analysis, based on the results of capillarimetric studies by semipermeable membrane method and relative phase permeabilities on the core.

Aim. Efficient production of hydrocarbons from brown fields becomes more and more important with each year due to the depletion of existing fields and a decreasing number of new fields being discovered. This task cannot be solved without organizing an effective reservoir pressure maintenance system and analyzing vertical and lateral sweep. The article presents the results of the application of an advanced technology for analyzing a large array of data available to solve this problem.

Materials and methods. Traditionally, to solve the problem of improving the efficiency of the reservoir pressure maintenance system and increasing reserves recovery, costly studies are used, including production logging, multi-rate well-tests, cross-well tracer studies, cross-well pressure interference tests and others. At the same time, advanced analysis of the available field data has a high potential for providing useful findings.

The article shows that in many cases, a simple correlation of water cut with well flow rate can suggest whether the produced water contains an unproductive production due to the presence of behind-the-casing cross-flows from water-saturated formations or water production through the casing leakage.

Conclusions. Based on the results of the presented analysis of well water cut historically, production wells with operational problems and unproductive water production are identified. For these wells, it becomes possible to make decisions on adjusting their production targets, which can help in the case of water coming along dynamically opening and closing fractures in reservoirs with non-standard geomechanics. In addition, based on the results of the analysis, decisions are made on conducting targeted production logging and well-testing, which makes it possible to exclude their conduction in wells without problems which results in significant savings for oil and gas companies. In addition, in a number of cases, based on the results of this analysis, it becomes possible to immediately make decisions of workover planning, which increases the economic efficiency of field development, extends the life of fields and increases reserves final recovery.

Introduction. The changing of the productivity index during the life cycle of a oilfield is important. As it allows an objective assessment of the  potential productivity of wells, which can later be used for special types of analysis and production control.

Goal. Assessment of the impact of reservoir development on the current productivity index of wells

Materials and methods. Materials of Welltesting. The productivity index is determined by steady-state and non- state flow well testing. Methods of processing initial data by methods of mathematical statistics are applied

Results. The results are shown on the example a oilfield of the Western Siberia. Estimates are based on the correlation between actual productivity index and a complex parameter. The results show allow determining the potential productivity index of vertical and horizontal wells, predicting the current productivity index of horizontal production wells, and testing the effectiveness of Wellwork.

Findings. Approach of the interpretation allows to evaluate the impact of development on current well productivity index (within the confidence intervals)

Background. An integrated model (IM) is a unified digital model of a field, consisting of related models of a reservoir, wells, and a surface infrastructure model, it is indispensable tool at all stages of major projects, because it allows finding system solutions and takes into account the maximum possible number of factors and constraints. The integrated approach is especially relevant for reservoirs with oil rims, gas and gas condensate assets, when the produced fluid contains a large amount of associated petroleum gas and natural gas and system “reservoir — wellbore — gathering and hydrocarbon treatment network” is inseparable, so need to take into account the mutual influence of components to production forecast, to search optimal development solutions. However, when working with integrated model, requirements for the initial data increase, labor costs and computing power both for the creation and for model maintenance increase, speed of model calculations and taking decisions decrease. One of the major strategic challenges of the company is ensuring the optimum value created, thus need the balance between model detail and calculation accuracy.

In practical cases, it is more correct to speak not about a single integrated model, but about a hierarchy of integrated models or integrated modeling tools. We use a compositional principle of using IM tools, which implies building of ready-made component models and combining them into a full model of the field in a configuration necessary for solving specific problems. It makes sense to use the Pareto law to select the configuration of the integrated model: for individual tasks, we can somewhat simplify the model (component models), having lost only 20% of its properties, and it is possible that the lost properties will not have any effect when addressing this research problem.

Aim. The article object is the matrix of application integrated models of varying degree of detail development, article is based on long-term experience of professional engineers.

Materials and methods. The article presents the case study of a multi-reservoir gas condensate field X as an example of the integrated modeling tools development, which have varying degree of detail depends on project stage and solving problems:

• An analytical (“balance”) integrated model of a field based on a mathematical model;
• Simplified integrated model based on a detailed gathering network model and a simplified analytical reservoir model;
• Integrated model with a “Network” option based on detailed reservoir model and simplified gathering network model (VLP);
• Integrated model in the integrator software (Resolve) based on combining a gathering network simulator (GAP) and a reservoir flow simulator

Various types of integrated models are compared with each other, advantages and disadvantages, solved task and place in hierarchy of integrated models are highlighted. The tools and approaches of integrated modeling used by the authors in practice are generalized in the form of integrated modes applicability matrix. Degree of detail integrated models is associated with the initial data, the stage of project development and the tasks solved at this stage.

Results. The article shows that the introduction of reasonable and justified simplifications, the elimination of the shortcomings of simpler models using analytical methods, custom algorithms and Workflow allows to achieve the match of varying degree of detail integrated models with high accuracy.

Introduction. Improvement of field development efficiency is the key issue at any operation stage, and is the most critical for Vietsovpetro, considering the declining production at the offshore fields. Production levels are maintained through the generation and implementation of well intervention programs. Main portion of incremental oil comes from drilling well interventions (new wells, side tracking). Well intervention planning for the offshore fields has some peculiarities, which should be considered at every stage of decision-making — from geological criteria for well selection to interventions. Such peculiarities may include approaches and technologies for well construction and casing. 

Materials and methods. The offshore fixed platforms (MSP) and mini MSP — wellhead platforms, are widely used in Vietsovpetro to operate the wells and technological equipment in Vietsovpetro. Well drilling on the wellhead platform is performed through the jack-up rigs, while MSPs engage drilling facilities. Most of MSP drilling facilities are currently dismantled.

MSP wells with low production rate, high water-cut and absence of promising overlaying formations decrease the production profitability, and the impossibility of side tracking negatively influences the efficiency of residual reserves production and ultimate recovery. The residual reserves are spread out across the area in a way, that drilling from the wellhead platform, using a jack-up rig, is impossible due to a significant offset, while poor residual reserves make construction of a new offshore facility economically inefficient. These reasons accompanied with the lack of available positions result in an impossibility of commencing new wells from the available MSPs. This trend negatively effects the current efficiency and may influence the production levels later on. 

Results and conclusions. The experts of the Research and Engineering Institute have developed the new technical decisions, previously never applied in Vietsovpetro, for organizing the additional well positions on MSP without involvement of a derrick barge for further well drilling with a jack-up rig. This decision allows developing the residual reserves and improving the oil recovery.

Introduction. During the life cycle of the well, the occurrence of sustained casing pressure in the well (SCP) is very possible. In practice, various regulatory requirements and approaches to working with such wells have been developed in the worldwide oil and gas industry.

The aim of this work is to describe the evolution of regulations and approaches of oil and gas companies well operations with SCP, including conditions of the regulatory and methodological recommendations absence, or their inconsistency.

Materials and methods. This article comprehensively reviews industry regulatory and methodological documents, as well as local regulatory and methodological documents (LRD) from various oil and gas companies. In the absence of a single database on wells with SCP, disparate sources of information have been collected and summarized, allowing you to see the overall picture of working with the well stock with SCP in the world.

The results of the performed analysis demonstrate the evolution of regulatory and the current situation in the domestic oil and gas companies, which, in the absence of a unified approach to working with the well stock with SCP, choose different options for harmonizing LRD with the current requirements of regulatory authorities and the best world practices to ensure the integrity of wells.

Conclusions. The article shows real examples of LRD of oil and gas producing companies, as well as trends in further improvement and harmonization of industry standards and regulatory documents of various countries. 

Background. This article is devoted to the automation of engineering tasks, taking into account the probabilistic nature of the active, in the face of a huge number of fluid production profiles, using MEFS technology.

Aim. Development of original algorithms for calculating facilities at the early stages of the project life, determining the physical and cost characteristics of capital construction objects, taking into account the uncertainty of the volume of the resource base, variations in the exploration program, determining the optimal solutions for the concept of development and field facilities under current economic conditions.

Materials and methods. Automation of calculations in terms of development at payback levels MEFS I and II was implemented by estimating the costs per unit well on a well pad. Further, the costs are multiplied by the number of wells in accordance with the well construction and commissioning schedule, as a result of which the total cost of infrastructure facilities for these payback levels is formed. At the MEFS III level, the costs for the construction of facilities for the preparation of well products and external transport of marketable products are added to the costs of the previous level. The task of automating the development block at this level is to correctly scale the physical and cost parameters of infrastructure facilities for the selected development concept.

Results. To perform probabilistic calculations of infrastructure, specialists of the Center for Project Evaluation and Analysis developed the calculation module “Arrangement”. This tool allows you to create an integrated probabilistic model “development-infrastructure-economy” for the “Access” stage. The calculation time for one option is about 5 seconds.

Conclusion. The tool proposed by the authors makes it possible to perform infrastructure calculations with sufficient accuracy and speed during probabilistic assessment in the early stages of a project’s life using MEFS technology.

Purpose. Description of effective methods of killing wells with AHFP using intelligent systems. Search for solutions for new approaches and breakthrough technologies in the field of well killing.

Materials and methods. Now, various technological solutions have been tested and approaches have been determined for each type of wells, allowing to regulate the technological process. However, working with the Achimov formation requires high-tech methods. Killing wells is the first preparatory stage before the start of the well life cycle or already in the process of production before planned workovers, and it is at this stage that it is necessary to concentrate on new technologies, calculations and the operational process. This article proposes for consideration one of the promising methods of killing wells using digital products and automated equipment. Examples of killing process modeling and obtaining data on completion of work in the form of graphic images are given. A comparative analysis of indicators of actual and planned performance of work was carried out. The convergence of results during well killing was 99%.

The proposed method improves the quality of well killing operations and is a technological breakthrough. In addition, killing wells using digital products will make it possible to more accurately generate calculations, reduce the impact of the human factor, preserve the production characteristics of the well and ensure an increase in the turnaround time.

Results. The development of a software package for well killing will make it possible to eliminate the overspending of the solution and reduce the cost of additional volumes in the process of well killing.

Conclusion. Thus, the software is necessary for modeling the process of circulation and well cleaning, hydrodynamic losses, and performing calculations of effective replacement of solutions with other process fluids. Additional field trials are required to introduce this product.

Aim. The paper describes a method for increasing the yield of stock-tank oil by reducing oil carryover with associated petroleum gas (APG) to the flare system and decreasing natural gas liquids content in associated gas separated at the central processing facilities (CPF) of the oil field in Iraq by cooling the feed stream in air cooling (AC) units.

Materials and methods. An integrated model (IM) of the field was built including: a well lift models, a wellhead choke models, a model of an oil gathering network, a models of AC heat exchange, a model of material and heat balance of an CPF. The AC performance in oil treatment was estimated. The main advantages and disadvantages of using the proposed technology are shown.

Results. The decision to implement the pilot project using the leased equipment was made based on the results of a integrated assessment. Estimated improvements in the operational mode of the CPF and oil quality were confirmed by analysis of subsequent practical experience in the use of AC: a decrease in the gas factor of oil, unloading of separators, minimization of carry-out of gas condensate, a decrease in density due to retention of condensate in the liquid phase, while the Reid vapor pressure (RVP) remains within acceptable export specification values. It is important that the values of the True vapor pressure (TVP) were recalculated for climatic conditions: this parameter sets the minimum allowable cooling temperatures, and also ensures the safety of transportation by trucks in a hot climate (≥ 55 °C) without evaporation.

Conclusion. An AC unit considered in the article was originally designed for use in another field. Therefore, one of the tasks was to validate the applicability of this AC unit in the oil treatment process for a field with completed infrastructure. The novelty of the study lies in the non-standard use of an AC unit in the oil treatment oil treatment process.

The results of simulation of using AC units in oil treatment and the actual operation of an AC showed increased output of stock-tank oil at the CPF at low capital and operating costs. The decision to replicate the technology in the field was taken following the results of a successful pilot project to maximize the yield of stock-tank oil.

Background. With an increased removal of mechanical impurities (sand, proppant, etc.) from production wells, the largest amount of these impurities accumulates (precipitates) in the inlet separator, as in the first capacitive apparatus in the direction of well production. Typical oil and gas separators do not provide for the possibility of accumulation and removal of mechanical impurities. This leads to the ingress of mechanical impurities into the apparatus of the oil treatment plant and disruption of the operation of these apparatuses.          

Aim. To trap the settling solid particles of impurities, it is proposed to create a stationary water zone in the lower part of the separator by placing the inlet of the liquid outlet fitting at a certain height from the bottom of the apparatus and remove the mechanical impurities accumulating in it from the apparatus together with water through special outlet pipes.

Materials and methods. Mechanical impurities are removed from the separator along with part of the water through the drain fittings and sent to the drainage tank, which consists of two compartments. The sludge settles and accumulates in the first compartment of the tank, from where it is pumped out for disposal by a special submersible pump. After the first compartment is filled, the top layer of desludge-free water flows through the partition between the compartments and fills the second compartment. From the second compartment, the water purified from sludge is recirculated by a submersible pump into the water zone of the apparatus to the inlet of the sludge-washing nozzles.

Results. The technological calculation of an apparatus of design size for the ability to separate and trap mechanical impurities consists in determining the time of sedimentation of mechanical impurities from a moving liquid layer into a stationary (underlying) layer of water (τ_os), and comparing this time with the potential residence time of the liquid in the apparatus (τ_lw). To ensure the precipitation of mechanical impurities, it is necessary that the residence time of the liquid in the apparatus be longer than the time for the particle to reach the surface of the water layer, i.e. τ_lw > τ_os.

Conclusions. Calculated dependences are given to determine the rate and time of sedimentation of mechanical impurities in the modified inlet separator, depending on the modes of its operation and the physical and chemical properties of well products.

The results of calculations of the settling time of mechanical impurities (true density ρ³, depending on the size of the deposited particles _pr = 2500 kg/m³) in oil separated from gas in the inlet separator with a volume of 100 m at various flow rates of the liquid, are presented.

Background. The article provides algorithms for calculating the size of the apparatus and provides an example of constructing diagrams to determine the diameter of the apparatus at a given flow rate and temperature of the separation process.

Aim. In the initial data on the physicochemical properties of the liquid, on the basis of which the technological calculation of oil and gas separation equipment is carried out, as a rule, the rheological properties of oil-water emulsions are not given. Therefore, at the beginning of the calculation, the residence time of the liquid in the apparatus is set, focusing on the known density of oil and the specified water content in the oil-water mixture, which can be achieved during operation. After determining the size of the device according to the specified residence time, the actual time of the liquid in the degassing zone is estimated and compared with the specified one. To determine the actual time of the liquid in the degassing zone, it is necessary to calculate the rate of ascent of gas bubbles in the liquid, for which it is necessary to know its density and viscosity.

Materials and methods. For the technological calculation of oil and gas separation equipment, correlation formulas for calculating the viscosity of oil and oil-water emulsions of Western Siberia, depending on the density of oil, obtained by processing experimental data for more than 35 oils with a density from 810 to 940 kg/m³ at 20 °C.

Results. The correlation dependences of the water content at which the emulsion stratification occurs (stratification points) and on the density of oil are given, by which the maximum value of the viscosity of the oilwater emulsion can be estimated at a given process temperature.

Conclusions. Obtained correlation formulas, under certain assumptions, can be used to determine the size of oil and gas separation equipment.

.Background. Bottom hole pressure prediction is crucial issue in integrated field modeling. The well is connection element between surface network and reservoir. It must describe the movement of a two-phase fluid in the wellbore. To control the well production, it is necessary to describe the dependence of the bottom hole pressure on the fluid and well parameters. The classical approach is direct calculation by empirical correlation — physical equation constructed from experimental data. It requires large computing power, expert opinion and as a result large time resources.

Aim. This article proposes a new approach to well modeling. Using machine learning model describe the well depend on fluid properties and production parameters.

Materials and methods. The well model was implemented using the “Random Forest” assembly of “Decision Trees” using the gradient boosting technique. The model was tested on synthetic and real data from various fields.

Results. The developed model was tested on synthetic and real field data. The proposed approach outperforms current solutions in terms of speed and prediction score. It also allows to reduce usage of expensive licenses.  In case of enough data the need to create models in simulator is lost.

Conclusions. Due to its high predictive ability, the proposed algorithm will be introduced into production processes as a well model for the needs of integrated asset modeling.

Background. Unmanned aerial vehicles (UAV) have a great potential for geological exploration optimization at all stages. This study considers UAV implementation at different exploration stage.

Aim. The purpose of this work is to demonstrate the results of the application of unmanned aerial systems technologies in the entire cycle of geological exploration, from the earliest study to the completion of exploration drilling.

Materials and methods. Integrated approach using unmanned aerial systems shows great effectiveness based on the completed surveys. Low-depth electrical exploration using the shallow electrical exploration method is one of the possible UAVs technologies with great potential. In this study there are several cases describing main field data, processed models and cross-sections.

Results. The main results of the work were obtained as a result of a number of field work using attachments and a complex of unmanned aerial systems. The key indicators of the use of statistical data were the reduced values of the cost of exploration, significant up to one field season, significant up to 50 % of the work, as well as the identification of CO₂ and the anthropogenic footprint in general.

Conclusion. The development of these areas is seen in the development of a scientific and methodological base for field and chamber work, the development of algorithms for processing and enrichment of materials, as well as the improvement of measuring systems with the refinement of unmanned carriers in the event of geological exploration needs.

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Background. The events of recent years (limitation of oil production within the framework of OPEC) show us that it is necessary to develop approaches that will help to find the best options for operating existing fields, necessary to maintain and maximize the economic efficiency of the company’s projects.

Aim. Maximizing the economic efficiency of the company’s assets through the development and implementation of the Cost Pyramid methodology for assessing the profitability of all levels of basic production (well, well pad, cluster).

Materials and methods. In the process of analyzing the existing economic methods of assessment and reporting, it was found that only the levels “Well” and “Field” are provided with an assessment of economic efficiency. However, to improve the accuracy of the calculation results, it is necessary to develop a new methodology that allows you to evaluate the missing levels, for example, “Well pad” and “Cluster”. In order to realize this possibility, firstly, an analysis of the set of costs by items was performed, as a result, 2 new specific indicators were identified: semi-fixed costs for a well site, semi-fixed costs for a cluster. Secondly, the evaluation of injection wells has been added. On the basis of the developed Methodology, a prototype of a digital tool in the Python programming language was created, which can significantly reduce the calculation time.

Results. A methodology for the distribution of costs “Cost Pyramid” was formed and a prototype of a digital tool for assessing the profitability of the fund was developed, on the basis of which the growth potential of FCF (Free Cash Flow, free cash flow) was identified using the example of a number of operating fields.

Conclusions. The obtained results of the work confirm that the developed tool for assessing the profitability of the fund allows you to form a rating of unprofitable objects and focus optimization measures to maximize the FCF of the company’s projects, including within the framework of external restrictions.