Horizontal wellbore production profile evaluation by distributed fiber-optic temperature surveillance

The main goal of the paper is demonstration of permanent downhole long-term monitoring capabilities for oil and gas production profile along horizontal wellbore in case of natural flow. The informational basis of the results obtained is the data of long-term temperature and acoustic monitoring in the borehole using a distributed fiber-optic sensor (DTS + DAS). Materials and methods. At the same time, flowing bottom-hole pressure and surface rates were monitored at the well for rate transient analysis, as well as acoustic cross-well interference testing [1], based on the results of which “well-reservoir” system properties were evaluated, the cross-well reservoir properties of the were estimated, and the possibility of cross-well testing using downhole DTS-DAS equipment was justified. The research results made it possible to assess reliability of DTS-DAS long-term monitoring analysis results in case of multiphase inflow and multiphase wellbore content. In particular, DTS-DAS results was strongly affected by the phase segregation in the near-wellbore zone of the formation. Conclusions. In the process of study, the tasks of inflow profile for each fluid phase evaluation, as well as its changes during the well production, were solved. The reservoir intervals with dominantly gas production have been reliably revealed, and the distribution of production along the wellbore has been quantified for time periods at the start of production and after production stabilization.

Laboratory studies of physico-chemical methods to break emulsions stabilized with surfactant-polymer cocktails

Introduction. Oil field treatment often makes it necessary to combine different methods of well production treatment, taking into account the development regimes and parameters, produced and injected fluids, technical equipment and economic feasibility. The carried-out complex of laboratory tests is aimed at the creation and subsequent destruction of model systems with specified parameters. The list of the considered methods and the temperature regime of the tests are due to the physicochemical parameters and the field specifics. The purpose of this article is to search for an effective method for the primary treatment of well production after SP-flooding — a highly stable oil-water emulsion, additionally stabilized during pumping by means of an ESP. Materials and methods. The laboratory tests helped to develop an optimal mode of creating an artificial emulsion based on oil from BS10-1 reservoir of the Kholmogorsk field in the Yamalo-Nenets Autonomous Okrug, and a surfactant-polymer cocktail, which simulates well production after SP-flooding. The research tested physicochemical methods of destroying oil-water emulsions, such as their dilution with formation fluids, thermal settling, gravitational separation by centrifugation at RPM = 4000–12000 rpm, introduction of demulsifiers, as well as a combined effect, including all of the above approaches. The tested methods were supplied with the calculated values of the oil phase final water-cut, which allowed us to evaluate the effectiveness of the applied approaches to the destruction of model systems. Results. It has been found that not all of the applied approaches provide the extraction of the estimated amount of oil from emulsion systems with varying degrees of dilution by formation fluids. Satisfactory destruction of the emulsion was achieved after 10–20 min of centrifugation at T = 40 °C and RPM within 4000–8000 rpm. The traditional introduction of industrial demulsifiers into the studied systems without additional influences is ineffective. Conclusion. The optimal level of water cut in the oil phase of ≤5% was achieved after diluting the emulsion with formation fluids, with a combined approach to the destruction of the original and diluted emulsion with formation fluids. In addition, the research showed that it is possible to re-use the extracted SP-composition when controlling its physicochemical parameters, taking into account the effect of the introduced additives.

Integrated approach to the typification and localization of deposits of the anomalous section of the Bazhenov formation of the Frolov oil and gas region

Introduction. The subject of the study of this work is the deposits of the anomalous section of the Bazhenov formation (ASB) of Western Siberia, the disturbed occurrence of which was recorded by 2D, 3D seismic exploration and borehole data at many fields of the Frolov oil and gas region. The research area unites the company’s assets in the KhMAO and the Tyumen region, which are part of the large hydrocarbon cluster “ZIMA”. Aim. In order to typify various complexes of rocks of the Bazhenov formation and further localization of deposits, a comprehensive core analysis, GIS and seismic studies were performed. Materials and methods. According to the results of lithological study of the core and petrophysical interpretation of logging diagrams, have been identified various types of rocks in the interval of the Bazhenov formation. According to the results of the interpretation of the seismic survey materials, contoured zones that differ in the wave pattern by different coherence of the axes of common phase. The revealed differences in seismic sections compared with borehole data and geological bodies mapped based on the obtained patterns. Results. Based on a comprehensive interpretation of the core, GIS and seismic studies, established the zonality of the distribution of various types of deposits of the Bazhenov formation, the relationship of the development of ASB zones with the introduction of Early Cretaceous sedimentary bodies and showed the introduction of detrital material from the overlying rocks. Conclusions. The authors of the article conclude that the development of anomalous sections of the Bazhenov formation involves several stages of the introduction of landslide bodies of overlying rocks, according to the gradation of Neocomian clinocyclites in the north-west direction. Within the study area, mapped three large landslide bodies in the Bazhenov formation interval, each of which was formed an internal zonality and because of the introduction of rocks from the overlying interval.

The effective usage of APG surplus for oil-gas field on the example of carbon black production technology

Background. The present work is devoted to 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. One of the eco-friendly ways of processing natural and associated gas is the production of carbon black (soot) from it. This method is also included in the list of best available technology (BAT). Nowadays, soot is a raw material for massive scale production of rubber products, which accounts for a large share of the manufacture of tyres, besides, carbon black is a valuable component in the paint-and-varnish and petrochemical industry (inks, plastics and many other things). The aim of the project is to assess the applicability of technologies for processing the surplus of associated petroleum gas (APG) into carbon black (CB). Materials and methods. The technology is based on the pyrolysis of hydrocarbons under the influence of high temperature with a lack of air. In the work, the following tasks were performed: CB market was studied; the analysis and choice of the optimal method for obtaining soot from APG for the N field, technological calculation, and selection of equipment and economic evaluation of the technology were performed. Results. Calculations have shown that the use of this method of APG utilization is cost-effective. The PI of the project is more than 2. Conclusion. The main advantages of this technology are: relatively low capital outlays, efficient gas utilization, reduction of carbon dioxide emissions into the atmosphere, additional income from the sale of a new product in high demand. The main disadvantage of this method of gas utilization is the lack of experience and practice of oil companies in the possibilities and methods of carbon black from APG.

Refinement of the petrophysical model of the Achimov formation based on facial analysis of sedimentation conditions

Aim. Due to the depletion of reserves of the main oil and gas complexes, the greatest interest is attributed to hard-to-recover reserves, complex-built objects of the sedimentary cover, the development of which was unprofitable until recently. One of these is the oil-bearing complex of the Achimov deposits of the Malobalykskoye field in Western Siberia. This article is devoted to the facies analysis and typification of reservoir rocks of the Achimov deposits in order to increase the reliability of determining the boundaries of the reservoirs, their interpretation and assessment of the petrophysical properties of the reservoirs. At the same time, special attention is paid to the facies analysis, which determines the characteristics of the reservoir. The Achimov deposits are a promising source of increasing resources and maintaining production at a high level. With their increasing importance, there are problems that complicate the search and assessment of deposits. Such problems include a high degree of reservoir compartmentalization, sharp facies variability, complex pore space structure, high clay content, low permeability values, etc. Materials and methods. The work is based on a comprehensive interpretation of the data of the lithological description of the core, the results of laboratory studies of the core and well logging data analysis of the Achimov deposits of the Malobalykskoye field. The methods used in the interpretation of GIS data, statistical analysis, comparison. Due to the fact that the reservoir properties of sand bodies are determined by the peculiarities of their formation in different conditions of sedimentation, it is necessary to establish a relationship between the petrophysical characteristics of rocks and their facies nature by substantiating petrofacies models. The use of the latter in geological modeling makes it possible to more effectively predict the reservoir properties (reservoir properties) of various facies lithotypes. Results. The paper presents the results of facies analysis and typification of the reservoirs of the Achimov deposits of the Malobalykskoye field, on the basis of which the boundaries of the reservoirs and the effective oilsaturated thicknesses were refined. Conclusions. Based on the results of the study, it can be concluded that it is necessary to develop refined petrophysical models for reservoirs with complex geological structure that take into account the facies features of rocks.

Forecasting the operation of wells in the Bazhenov formation based on a modified dynamic material balance model

Background. Predicting the dynamics of the Bazhenov formation is an important task. Traditionally, it is carried out using geological and hydrodynamic modeling, i. e., solving the direct problem of hydrodynamics. However, for shale reservoirs, this approach is not possible, oil production is a derivative of geology to a lesser extent than technology. Industrial net production rates can be obtained from non-reservoirs in the usual sense. The system of technogenic fractures forms a reservoir associated with oil-saturated rock and the properties of such a system are described by too many parameters with high uncertainty and a number of assumptions [3–7]. On the other hand, there are forecasting methods based on solving the inverse problem of hydrodynamics. Having a sufficient amount of development data, it is possible to predict the dynamics of work based on statistical dependencies [9] or proxy material balance models. The purpose of this work. The purpose of this work was to create a convenient methodology for calculating oil production from the reservoirs of the Bazhenov formation. Methodology. The paper proposes and tests a method for predicting the dynamics of oil, liquid and gas production for wells in the Bazhenov formation based on a modification of the CRM dynamic material balance model (Capacity-Resistive Models — volume-resistive model). Results. The method was tested when calculating the technological indicators of development for the object of one of the fields located in the KhMAO and showed its efficiency, which allows us to recommend it as a basis for drawing up project documents as an alternative to building a hydrodynamic model (GDM).

Approaches to forecast oil field performance at the well pads level and beta testing on oilfields of RN-Nyaganneftegaz (ROSNEFT)

Background. The study performed by Rosneft employees shown in this paper demonstrates approach and analytical methods that allows to forecast oil production at the level of minimal infrastructure units. These approaches are used to forecast long-term oil production and predict infrastructure blockage. The approach was partially automated by the authors. This made it possible to testing at giant Krasnoleninskoye oilfield. Aim. The study was performed in order to develop and test an approaches to forecast oil production of large oil fields with high detail levels. Materials and methods. Common methods of decline curve analysis and water-into-oil curve analysis were used in this work to analyze the precondition. The main feature of the approach is the analysis of precondition at the level of large well clusters and transfer it to the level of wells. Some of the actions were automated by new proprietary software and were tested at the giant brown field. The software was integrated with the corporate database. Results. An author’s approach has been developed. The approach allows to forecast oil production at the level of infrastructure units using analytical methods. Oil production of the giant brown field with high detail levels were forecasted using the proposed approaches and developed software. Conclusions. The results show that the developed approaches and software can be used to forecast mediumand long-term performance of producing oil fields in the conditions of existing external and infrastructural constraints.

The data-driving management in oil and gas industry: examples and opportunities

Background. Decision-making process in the oil and gas industry, traditionally extremely expensive, should be based on the point of maximizing the business value. Forecasting the effectiveness of investments of any business unit in oil and gas should be based on a data-driven management approach. The purpose of this article — to study methods and best practices of applying a data — driven approach to decision-making and analyze the possibility of scaling methods of best practices in the processes in oil and gas company. Materials and methods. Research a various case with data-driven management shows that using data-driven approach allows solving several tasks at once: to make a fast and quality decisions based on data that can always be checked, and the result can be analyzed; to reduce the costs by eliminating inefficient steps and increase the flexibility of the process; to form the correct attitude to data (data culture) and prepare for the implementation of the technologies of Industry 4.0. Analyze cases revealed two common and important things: engineering of business processes from the key performance indicators and the technological development. Results. In article discusses the topic of applying a data-driven decision-making approach in oil and gas companies using several examples of Gazprom Neft. These examples shows that better effect from the using of data-driven management is achieved by consistently modeling business processes for achieving maximum values; highlighting and fixing key business performance indicators and creating a digital monitoring of these indicators, which allows you to the achievement of goals. Conclusions. In the conclusion of the article there are recommendation about using data-driven management approach for various processes of an oil and gas company.

Quantitative assessment of areal geological complexity

Background. The article presents a new approach to assessing the geological complexity — quantitative assessment of areal complexity, as well as an alternative methodology for assessing complexity in 1D. Aim. Developing a numerical metric for assessing the geological complexity and creating an algorithm for complexity maps construction. Materials and methods. Generally, complexity describe the reservoir in one number, that often underestimates the real complexity of the deposit. Geological complexity, presented in the article consists of 5 groups: structuraltectonic, facies-lithological, permeability and porosity, secondary alteration and fluid properties, 13 characteristics describe the complexity space of these groups. Each of these characteristics could be presented not only in 1D but also in 2D. The proposed methodology was tested on the company’s assets. Results. The presented examples of complexity maps for several fields show the advantage of 2D complexity estimation in comparison with 1D. The analysis of decomposed complexity estimation (for individual groups) on the company’s assets showed that the key groups of complexity are structural-tectonic, facies-lithological characteristics. Therefore, characteristics that describe these groups should be taken into account during the decision-making process and assets ranking. Conclusion. A methodology of quantitative assessment of areal geological complexity has been developed. This areal assessment allows identify the most “problematic” areas, analyzing existing sources of uncertainty, and also ranking and screening company assets when making strategic decisions.

Carbonate reservoir rock typing algorithm based on integrated approach (IRT)

The goal of carbonate rock typing is a realistic distribution of well data in a 3D model and the distribution of the corresponding rock types, on which the volume of hydrocarbon reserves and the dynamic characteristics of the flow will depend. Common rock typing approaches for carbonate rocks are based on texture, pore classification, electrofacies, or flow unit localization (FZI) and are often misleading because they based on sedimentation processes or mathematical justification. As a result, the identified rock types may poorly reflect the real distribution of reservoir rock characteristics. Materials and methods. The approach described in the work allows to eliminate such effects by identifying integrated rock types that control the static properties and dynamic behavior of the reservoir, while optimally linking with geological characteristics (diagenetic transformations, sedimentation features, as well as their union effect) and petrophysical characteristics (reservoir properties, relationship between the porosity and permeability, water saturation, radius of pore channels and others). The integrated algorithm consists of 8 steps, allowing the output to obtain rock-types in the maximum possible way connecting together all the characteristics of the rock, available initial information. The first test in the Middle East field confirmed the applicability of this technique. Results. The result of the work was the creation of a software product (certificate of state registration of the computer program “Lucia”, registration number 2021612075 dated 02/11/2021), which allows automating the process of identifying rock types in order to quickly select the most optimal method, as well as the possibility of their integration. As part of the product, machine learning technologies were introduced to predict rock types based on well logs in intervals not covered by coring studies, as well as in wells in which there is no coring.