Articles

Geology

Justification of the oil-saturated volume of the deposit when calculating reserves in reservoirs with low FCP

Galimov A.A., Kotenev Yu.A., Voloshina A.A., Tokareva A.V.

DOI: 10.24412/2076-6785-2024-3-20-25

Abstract
This paper presents the results of research on the substantiation of the oil-saturated volume of the deposit, represented by low-permeability reservoirs, of the oil-saturated reservoir of the US2 Tyumen formation, using the example of a field within the Salymsky district of the Sredneobskaya oil and gas region. One of the main parameters characterizing the area and volume of the deposit is the calculation level. The reference level is the contact separating the water-saturated section from the productive one, which characterizes the entire oil-saturated volume of the pore space of the rock.
In deposits with low-permeability reservoirs, it is often problematic to reliably determine the oil-saturated volume of rocks, due to the presence of only oil-saturated tributaries in such facilities during testing and operation, both in the arch and in the slope part of the deposit, without a single-phase inflow of reservoir water. In this regard, to perform the calculation of reserves in such facilities, a conditional calculation level (CCL) is taken according to the lowest established mark of the sole of the oil-saturated reservoir, or according to the sole of the perforation interval. At the same time, the volume of the pore space below the received contact is not included in the calculation of reserves, even if there is no single-phase inflow of reservoir water.
During the analysis of geological, geophysical, petrophysical and operational data, results were obtained showing that deposits composed
of low-permeability reservoirs represent a mixed hydrodynamic oil-water system, without oil-water contact.

Materials and methods
Data on the geological structure of the formation, including the sedimentation model, intra-stratum correlation and distribution of filtration and reservoir properties by area and section. Data on the operation of producing wells. Detailing the geological structure, determining the characteristic features of the formation section.

Keywords
reserves calculation, tyumen formation, achimov formation,
low-permeability reservoirs, counting level, CCL, geophysical studies of wells, oil and water contact

Geochemical features of hydrocarbon accumulations in the northern region of Western Siberia

Punanova S.A.

DOI: 10.24412/2076-6785-2024-3-13-18

Abstract
The article is devoted to the study of the correlation between a complex of Trace Elements (TEs) identified in oils of large fields of the Khanty-Mansi Autonomous Region (KMAO) of the West Siberian oil and gas basin (OGB), with the composition of the earths crust at different levels - upper, lower and middle. Based on the results of the study, additional possible indicators for predicting sources of oil and gas in the deep horizons of the sedimentary cover were identified, which could help increase the predicted resources.

Materials and methods
A quantitative comparison of the contributions of different components of the earths crust - lower, middle and upper, as well as biota to the trace elements of oils was carried out based on correlation analysis. For a similar project, the author used analytical materials from many researchers obtained by inductively coupled plasma mass spectrometry (ICP-MS) (R.P. Gottikh, B.I. Pisotsky et al., Yu.N. Fedorov, K.S. Ivanov, Yu.V. Erokhin, A.V. Maslov, Yu.L. Ronkin, etc.).

Keywords
large deposits, trace element composition of oils, correlation coefficients, continental crust, biota, Western Siberia

Geologist-geochemical factors for forecasting large accumulations of oil and gas confined to megareservoirs

Shuster V.L.

DOI: 10.24412/2076-6785-2024-3-10-13

Abstract
The article supplements and systematizes the main geological and geophysical factors affecting the formation of large accumulations of oil and gas. Based on a critical analysis of the published material by Russian and foreign authors and a generalization of factual material on 26 of the worlds largest deposits, the relationship between the size of reserves and the geological parameters of the deposit is investigated.
Quantitative and qualitative estimates of predictive geological and geochemical factors have been determined.

Materials and methods
Materials on 26 largest oil and gas fields in the world were used. The quantitative and qualitative relationships of the size of oil and gas reserves with geological and geochemical characteristics (field area, filtration and reservoir properties of reservoir rocks, composition and thickness of fluid seals, oil and gas generation potential, etc.) are analyzed.

Keywords
oil, gas, large accumulations, reserves, resources, megareservar, favorable factors, forecast criteria

Allocation of improved filtration and reservoir properties zones using the example of an oil field in the Timan-Pechora oil and gas province

Shaburova M.E., Orlov N.N.

DOI: 10.24412/2076-6785-2024-4-16-21

Abstract
Carbonate reservoirs, as a rule, are characterized by heterogeneity of structure and filtration and reservoir properties. In this case, the zones with the improved filtration and reservoir characteristics are primarily involved in exploitation. In this regard, during the development process there is a need to replenish the resource base of the field and maintain production levels.
The article presents the results of developing a solution to this problem using the example of an oil field in the Lower Permian carbonate reservoirs of the northeastern part of the Timan-Pechora oil and gas province. Firstly, improved filtration and reservoir properties zone was identified within the parts of the field not involved in exploitation. Secondly, objects for additional exploration in complexes that are productive in the area of the studied have been substantiated. In addition, the article provides a brief geological overview of the study area and productive oil and gas complexes, and also substantiates the heterogeneity of the structure and properties of reservoirs.

Materials and methods
The basis for the study was the results of analysis of core and thin sections, interpretation of geophysical wells logging, wells testing, as well as interpretation of seismic survey materials. Using this data in specialized software, a three-dimensional geological model was built, on the basis of which promising improved filtration and reservoir properties zones were identified.

Keywords
carbonate reservoirs, reservoir properties, Dunham classification, fractures, organogenic buildings, additional exploration,
Timan-Pechora oil and gas province

Paleogeological features of the distribution of oil and gas accumulations confined to megareservaries of the sedimentary cover

Samoilova A.V.

DOI: 10.24412/2076-6785-2024-4-12-15

Abstract
In the article, by summarizing the data and their critical analysis, the typification of the processes of formation of mega-reservoirs of oil
and gas in the sedimentary cover of oil and gas basins in both traditional and unconventional reservoirs, including low-pore shale formations, accumulations with hard-to-recover reserves, reservoirs of decompacted basement ledges and other types of geological structures.

Materials and methods
Analytical and scientific data base on the geological features of hydrocarbon accumulations with gigantic and unique reserves in various oil and gas basins of the world. Analysis and comparative assessment of the qualitative features of the confinement of large-scale accumulations of hydrocarbons to certain natural objects.

Keywords
mega-reservoirs, oil and gas fields, scale of accumulations, reservoirs, shale formations

Analyzing confirmation of productivity criteria of the pre-jurassic complex by operational drilling results as a means of unlocking the target potential

Lapshina Ya.A., Ermakov P.V., Khazipov R.L., Patrakov D.P., Zharkov A.V.2, Nabokin I.R., Nabokin I.R.

DOI: 10.24412/2076-6785-2022-8-44-47

Abstract
RN-Nyaganneftegaz JSC is developing two license blocks within Krasnoleninskoye oil and gas condensate field with unique reserves:
Em-Egovsky + Palyanovsky and Kamenny (Western part) blocks.
The study and development of the pre-jurassic complex is associated with a number of complications:
    low coverage by core studies;
    the lack of unambiguous methods for interpreting net-reservoirs within the complex based on well logging data;
    low correlation between well productivities and oil net pays, taking into account fracturing, which complicates the estimation of start-up flow rates;
    high variability in the startup performance of wells drilled at a short distance at similar geological conditions.

Materials and methods
One of the development targets is the pre-jurassic complex which
is being developed within the Kamenny (Western part) license block. Despite the insignificant initial recoverable reserves of the target,
0,6 % of the total Kamenny block reserves, the startup flow rates
of up to 80 t/day (the average startup rates for directional wells are about 2025 t/day) produced by some directional wells indicate a significant development potential of this target.

Keywords
kamenny license block, pre-jurassic complex, fracturing, BH acid treatment, seismic attributes

Application of petrotyping to assess the permeability of rocks of the aptian-albian-cenomanian gas-bearing complex

Pokazaniev I.A., Zarai E.A., Ovchinnikova D.G., RodivilovD.B.

DOI: 10.24412/2076-6785-2022-8-40-43

Abstract
The main goal of the work is to develop a petrophysical model of the permeability of terrigenous rocks of the aptian-albian-cenomanian
gas-bearing complex. Reservoir rocks are represented by numerous lithological varieties from clayey siltstones to pure coarse-grained sandstones. The aptian-albian and cenomanian rocks differ in the degree of cementation. Due to weak consolidation, the core of the Cenomanian deposits has not been studied enough, which does not allow the development of an individual model, in particular, a permeability model. At the same time, the aptian-albian and cenomanian rocks have similar lithological and petrophysical characteristics within the framework of lithotypes substantiated by the lithological description of core samples. This factor makes it possible to identify unified petrotypes for the entire aptian-albian-cenomanian complex, to identify individual relationships for assessing permeability, and to level the lack of information from laboratory studies of cenomanian rocks.

Materials and methods
The analysis of the results of the study of core material and conducted geophysical studies is carried out. The principle of petrotype separation is based on the relationship between lithological characteristics, filtration-capacitance properties, capillary characteristics of the pore space and grain dimension.

Keywords
permeability, petrotypes, core, logging, petrophysical model, terrigenous rocks, reservoir

Comparative analysis of the application of 2D/3D segmentation models in the task of identifying seismic horizons

Kanonirov A.P.

DOI: 10.24412/2076-6785-2022-8-36-39

Abstract
In this paper, two approaches to solving the problem of identifying seismic horizons by partially specified positions of horizons in a cube of seismic amplitudes are compared. The first approach is to train a neural network of the U-Net architecture for two-dimensional data on longitudinal and transverse sections of the cube. The second approach is to transform the standard U-Net architecture into a three-dimensional one and train it on 3D cubes of seismic data. Both approaches have been tested on publicly available data on the F3 Netherlands field. A three-dimensional model gives a more accurate forecast, and a two-dimensional model learns much faster and requires fewer computing resources.

Materials and methods
A comparative analysis of the quality of solving the problem of seismic horizons allocation for 2D and 3D architectures of the segmentation convolutional neural network U-Net is performed. The advantages and disadvantages of each of the approaches are determined. Practical recommendations for evaluating and training models on new data are given.

Keywords
seismic exploration, reflected wave method, geology, segmentation, computer vision, U-Net, seismic horizons, neural networks

Results of facies modeling and productive formations cross-well prediction problems in the cretaceous and jurassic oil and gas reservoirs of Western Siberia

Grishchenko M.A.

DOI: 10.24412/2076-6785-2022-8-30-35

Abstract
This article continues the cycle of scientific publications of NK Rosneft PJSC devoted to the development of the scientific direction in the field of facies modeling of complex geological objects of oil and gas fields within the Russian Federation. The article presents the results of work on the creation of facies models in different stratigraphic complexes of Western Siberia, which served as the basis for localization of the most productive zones and justification for optimizing systems for the development of hard-to-recover reserves. Present the current status of problems in the field of facies modeling and forecasting of inter-well space.

Materials and methods
Materials: data on various types of geological, geophysical and field information studies, including laboratory core studies, petrophysical core interpretation, logging, seismic studies (including results
of inversion transformations and attribute analysis).
Methods: to create a digital facies model, methods of combining core data, logging, seismic studies and various stochastic algorithms
of 3D modeling were used.

Keywords
sedimentological analysis, conceptual model, seismic facies analysis, facies model

Algorithm for operation and creation of 1D facies model based on core data and well logs of productive formations in the cretaceous and jurassic oil and gas reservoirs of Western Siberia

Grishchenko M.A.

DOI: 10.24412/2076-6785-2022-8-22-28

Abstract
This article continues the cycle of scientific publications of NK Rosneft PJSC devoted to the development of the scientific direction in the field of facies modeling of complex geological objects of oil and gas fields within the Russian Federation. The article presents the history of facies modeling in the Tyumen petroleum research center and the results of the generalization of experience in creating facies models in different stratigraphic complexes of Western Siberia. Described is an algorithm for facies modeling, which includes three main stages and the formation of models of 1D, 2D, and 3D level. This article discusses the features of creating 1D models for integrated core and log studies.

Materials and methods
Materials: a set of various-scale data of geological and geophysical information obtained as a result of sedimentological analysis and laboratory studies of the core, cyclostratigraphic and sequence-stratigraphic analysis for the complex of this core and log.
Methods: to create a facies model, an algorithm has been developed that includes three main stages and the formation of models of 1D, 2D and 3D levels. Core and log data integration techniques were used.

Keywords
sedimentological analysis, cyclostratigraphic analysis, microfacia, macrofacia, conceptual model, facies model

Approaches to the extraction of residual oil reserves at a late stage of development in conditions of a complex geological structure using the example of the North Salym field

Andreeva S.V., Suleymanov E.D., Kulbaeva D.R., Trofimchuk A.S., Khabibullin G.I., Grishchenko V.A.

DOI: 10.24412/2076-6785-2024-2-15-21

Abstract
The study considers the issue of depleting reserves of a development object is at the final stage of development and is characterized by a decrease in the efficiency of the oil extraction process due to the gradual deterioration of the structure of residual mobile oil reserves. Based on the detailing of the geological structure of the object, which has a clinoform structure and includes three terrigenous layers, analysis of field studies and geological and hydrodynamic modeling, it was established that the areas of localization of reserves are confined to the bottom parts, which are characterized by deterioration of filtration parameters and increased dissection. Based on the results of the analysis, a strategy for extracting reserves was developed, which included hydraulic fracturing in high-thickness zones of the dissected part of the reservoir, the further implementation of which showed high success.

Materials and methods
Data on the geological structure, including the sedimentation model, intrastratal correlation and distribution of filtration and reservoir properties over the area and section. Indicators of operation of production and injection wells, results of field geophysical studies, results of inflow stimulation methods.

Keywords
oil field development, geological structure, reserve development, hydraulic fracturing, late stage of development, hydrodynamic model

Complex interpretation well logging, marker test and seismic data for correct segmentation of horizontal wells in carbonate fractured reservoir

Gerasimov R.V., Surikova E.S., Muslimov B.Sh., Islamov R.R.

DOI: 10.24412/2076-6785-2024-1-24-29

Abstract
When developing oil rims, horizontal wells with an intelligent completion system are widely used, including wellbore segmentation and installation of automatic inflow control devices. When segmenting, a uniform arrangement of casing packers along the wellbore is often used, the main disadvantage of which is the high risk of loss of tightness when installing the packer into the fractured zone of the reservoir. The paper presents an approach based on the complex interpretation of well and seismic data for predicting zones of increased open fracturing along of design horizontal wells in a carbonate cavernous-fractured reservoir for the purpose of their correct segmentation. This will exclude the risks of leaky planting of casing packers, prevent breakthrough of an undesirable phase (gas, water) to the wellbore during its production and to increase the efficiency of selective stimulation of highly fractured. Dynamic modeling confirmed the effectiveness of the proposed approach.

Materials and methods
The analysis of well logging, marker test made it possible to identify fractured zones along the horizontal hole wells and prove the conductivity of these zones. Attribute analysis of seismic data allows to determine fracture zones, but does not provide information about their conductivity. A complex analysis of well logging with seismic data allows to select attributes for forecasting possible areas of increased fracturing along planned horizontal hole in order to effectively segment design wells with automatic inflow control devices.

Keywords
segmentation of horizontal wells, fracturing, inflow control devices, attribute analysis, UBI microimager, marker test, casing packer

Clarification of the geological structure of the achimov deposits in the southern part of the Frolovskaya mega deflection with the purpose of identifying promising objects

Valitov Sh.K. , Dushin A.S. , Vasiliev V.E.

DOI: 10.24412/2076-6785-2024-1-17-23

Abstract
The study examines the facies and depositional settings for deep marine fans of the Lower Cretaceous (Neocomian) clinoforms in the southern part of the Frolov zone of Western Siberian basin. These strata demonstrate a complex geological structure in the study area: high heterogeneity of the facies, small size of sand bodies and uneven oil saturation, which affects the forecast and quality of reservoirs. Integrating methods seismic stratigraphy and seismic facies analysis helped solve one of the main problems, namely, to carry out facies typification of the Achimov deposits.

Materials and methods
In the article, based on the results of the analysis of wells (logging curves, core material, sampling) and seismic data, the geological models of the Achimov deposits were refined. The use of seismic stratigraphy, facies analysis and seismic facies analysis made it possible to identify promising objects.

Keywords
neocomian oil and gas complex, facies analysis, seismic facies analysis, underwater fans, conceptual model

On the significance of sedimentation-tectonic processes for the structure of large objects in space and time

Andreeva E.E., Baranova A.G., Khaziev R.R., Valeeva S.E., Anisimova L.Z., Valeeva A.V., Khairtdinov R.K.

DOI: 10.24412/2076-6785-2024-1-10-14

Abstract
The paper discusses the results of paleotectonic analysis of a number of oil uplifts of a field located in the northern part of the Ulyanovsky ridge on the territory of Tatarstan Republic. To determine the history of the development of sedimentary strata, the method of the isopachic triangle was used. The method allows you to restore the general course of events and trace the objects of research at different points in geological time. A set of paleostructural maps constructed within the deposit is summarized in a general scheme that allows us to trace the tectonic rearrangements characteristic of the beginning of the Lower Carboniferous time. Acording to isopachic triangle of maps, we have obtained information about structural forms and paleotectonics at different time intervals of geological time within the field, but not large enough to draw conclusions about regional interruptions with which significant tectonic movements can be associated.

Materials and methods
The structural surfaces obtained from the Vereyan, Bashkirian, Tulian, Bobrikovsky and Tournaiyan surfaces were used in the work; as well as isopachite maps constructed between the studied surfaces.
All constructions are made according to the data obtained as a result of the interpretation of borehole geological and geophysical studies and the results of seismic surveys.

Keywords
isopachic triangle, structural maps, isopachite maps, paleostructural analysis

Structural characteristics, history of tectonic evolution and features of the development of the Severo-Komsomolskoye field. Part 1

Surikova E.S., Sobakar M.V., Gallyamov R.I., Zagorodniy A.V., Akhmadullin M.E.

DOI: 10.24412/2076-6785-2023-5-40-45

Abstract
The article analyzes the modern structure and history of tectonic evolution of the Severo-Komsomolskoye oil-and-gas field. Particular attention is paid to faults.

Materials and methods
Integrated interpretation of 3D seismic and well logging data made it possible to build a structural frame of the study area. For fault tracing we used sedimentary and horizontal slices, a set of attribute maps: Variance, Ant tracking, dip deviation, RMS amplitudes. Accurate results were obtained when faults were identified using the Geoplat package, which uses an algorithm based on machine learning and neural networks. The paleostructural and paleotectonic methods were used
to study the history of tectonic development.

Keywords
Western Siberia, Severo-Komsomolskoye oil-and-gas field, basement strike slip fault, Cenozoic tectonics, 3D seismic

Morphological features of sand bodies of the achimov deposits of the Tarasovskoye field. Part 1

Khlebnikov D.S., Dushin .S., Martyanova K.V., Khlebnikov M.S., Odintsova M.Yu., Gabdullina E.G., Zhernovkova T.V.

DOI: 10.24412/2076-6785-2023-5-34-38

Abstract
The use of the results of dynamic analysis and the application of the classification of underwater fans made it possible to identify the internal morphology of alluvial fans within one layer of the field. Alluvial fan data differ in the type of feed system, their porosity properties and different effective thicknesses. In the article, using the example of the Ach1 reservoir, the morphological features of sand bodies of alluvial fans within the same reservoir and their identification by seismic attributes during dynamic interpretation are shown.

Materials and methods
Cube slices were calculated by the envelope length attribute, spectral decomposition maps (RGB), obtained by mixing different frequencies. On all maps of seismic attributes (maps of seismic classes, slices by attributes, RGB maps), morphological objects are traced, identified as deep-water (achimov) alluvial fans and feeding channels. A spectral decomposition map of the Ach1 reservoir was built, which contains the most promising areas that are associated with underwater fans. The morphology of the formation of underwater fans associated with the conditions of sedimentation and types of source of power supply.

Keywords
typification of extension cones, achimov formation, attribute analysis, sand reservoir rocks

Methods for analyzing and correcting the deviation of amplitude attributes in the process of seismic data processing based on wavefield simulation

Vlasov S.V., Sharin S.V., Ovchinnikov K.R., Finikov D.B., Shalashnikov A.V.

DOI: 10.24412/2076-6785-2023-5-28-33

Abstract
The article reviews the approaches to using the solution of the direct seismic survey problem by integral methods as a means for:
    studying the wave fields to optimize planning and plotting of the seismic survey data processing flow graph under certain seismic and geological conditions;
    correction of dynamic distortions of the wave fields during processing of seismic data.
Based on the results of the studies, solid evidence was obtained on the need for widespread implementation of such procedures to obtain a correct dynamic picture of the wave field, as well as some conclusions about the actual efficiency of certain procedures, and the main reasons
for the dynamic distortions obtained by the processing results are described.

Materials and methods
The set of synthetic data of seismic survey based on the composite seismic and geological model are used as the materials. The seismic and geological model was plotted layer by layer with the use of volumetric interpolation and geostatistical simulation methods. The wave fields were simulated with the method of field transfer by integral operators. The correction of dynamic distortions was performed by wide view calibration with control of the results by methods of studying amplitude variations depending on source-receiver distance.

Keywords
seismic survey data processing, wave fields simulation,
wave field dynamic performance, calibration

Typification of well testing processes during prospecting and exploration is a step towards reducing labor costs

Lyalin A.A., Vasiliev V.V., Kravchenko .N.

DOI: 10.24412/2076-6785-2023-5-24-27

Abstract
Improving labor efficiency by reducing labor costs for simple routine operations and freeing up time for processes that require a creative approach is an urgent task of labor organization, especially in the oil and gas industry. One of the approaches to solving this problem is the typification of the processes of work, as well as the formation of standard documentation. The article is devoted to the application of this approach to the testing processes of prospecting and exploration wells in cased and open holes. It is shown that in these processes it is possible to type: the process of planning tests, documentation for planning work on testing, the process of implementing tests, documentation for the implementation of tests, as well as reporting on the performance of work on testing. It is analyzed what exactly is typed in these processes and how it affects the labor costs of specialists and managers. The qualitative effects of unification and typification of well testing processes during prospecting and exploration drilling are shown. The conclusion about the indisputable benefits of the introduction of unification and typification in the processes related to the geology and development of oil and gas fields is substantiated.

Materials and methods
It is analyzed what can be typified in the testing processes of prospecting and exploration wells. It is shown how this typification will affect to labor costs and what qualitative effects it will lead to.

Keywords
prospecting and exploration work; well testing; cased hole; open hole; process typification; standard documentation; labor organization; labor efficiency; labor costs

Efficiency of reservoir pressure maintenance system and ways to improve it on carbonate sediments of the Arlanskoye oil field

Erokhin G.S., Nurov S.R., Vagizov A.M., Gareev A.T., Azarova T.P., Yakupov R.F.

DOI: 10.24412/2076-6785-2023-7-44-48

Abstract
More than a third of the recoverable reserves of the Arlanskoye oil field are contains in the middle carbon sediments, which develop with pressure maintenance system. This sediments are characterized low filtration properties, high heterogeneity and natural fractures. For improving development drilled horizontal wells with multi-stage fracturing. Low filtration properties, excess fracturing pressure during injection leads to the autofracturing effect, which be dagger-like water breakthroughs ahead high-conducting channels-cracks to producing wells. For improving the efficiency and increasing the coverage of injection in low-permeability carbonate reservoir are used horizontal wells.

Materials and methods
Research of fracturing pressure according to hydraulic fracturing reports, creating fracturing pressure map, identification of the relationship between autofracturing effect in injection wells and increasing water-phase in producing wells, comparison of injection conditions in horizontal and directional wells.

Keywords
Arlanskoye oil field, carbonate sediments, low- permeability reservoir, hydraulic fracturing, multistage hydraulic fracturing, horizontal wells, autofracturing effect, injection, high injection pressures

Operational construction of the facies scheme of the chimov deposits for the purposes of supporting production drilling

Arapov V.O., Geist I.V., Puharev V.A.

DOI: 10.24412/2076-6785-2023-7-38-43

Abstract
The paper considers the results of the operational construction of the facies scheme of the Achimov deposits in the south of the Tyumen region, accompanied by operational drilling, using the results of interpretation of seismic exploration and well data. In the process of the work, new promising areas for an additional well fund were identified and confirmed by pilot drilling.

Materials and methods
As part of the work, an analysis of the geological structure of the studied area was carried out, a detailed correlation of sediments was performed according to well and seismic data, facies features of the formation were determined with the allocation of electrofacies according to the Muromtsev V.S. method, dynamic and kinematic seismic attributes and slices were analyzed, followed by linking with well data. A facies scheme of the chimov deposits was constructed using the integration of well and seismic data.

Keywords
facies analysis, seismic attributes, geological model