This paper examines the petroleum bearing potential of the northwestern Chardzhou Step of the Bukhara-Khiva region of the Republic of Uzbekistan, encompassing the Gugurtli-Uchkyr and Kandym uplifts, and the opportunity for expanding the hydrocarbon resource base. The relevance of this study is determined by the leading role of the Bukhara-Khiva region in hydrocarbon production and reserve growth, as well as the high level of exploration of Jurassic carbonate strata, while exploration of terrigenous Jurassic, Cretaceous, and Paleozoic rocks on the Chardzhou Step remains insufficient. The aim of this study is to comprehensively analyze the geological and tectonical conditions, stratigraphic confinement, trap types, and resource base of hydrocarbon accumulations in the study area, assessing the prospects for their further development. Data on 34 discovered hydrocarbon fields is summarized, their classification is provided, and the conditions under accumulations formed in Jurassic and Cretaceous carbonate and terrigenous strata are characterized. Based on an analysis of the number of prospective and predicted hydrocarbon resources, an estimate is made of the potential increase in commercial reserves. It is concluded that the northwestern part of the Chardzhou steppe has high petroleum potential and that it is advisable to intensify exploration, primarily in the Cretaceous and terrigenous Jurassic strata, as well as in the Paleozoic.
A lithofacies modeling of Jurassic strata of the Kuanysh-Koskaly swell in the Ustyurt region was performed based on detailed laboratory core analysis and well geophysical survey data from the Western Barsakelmes field. Using V.S. Muromtsev's electrometric facies modeling method, continental formation conditions for the productive strata of the Middle Jurassic time were established. High-capacity reservoirs formed in channel zones of alluvial facies belts, while mudstones formed in lacustrine-marsh zones, and are of a local nature.
Assessing the reliability of seismic forecasts of reservoir filtration and capacity properties is a pressing problem of great practical importance, yet its theoretical foundations remain insufficiently developed. The objective of this research is to obtain an estimate based on a geostatistical approach to seismic data interpretation. The authors propose a new definition of the "degree of reliability of a seismic forecast" defined as the probability of the actual value of a geological parameter falling within a predetermined forecast corridor. Using the geostatistical approach, a probability density function with a mathematical expectation is derived for each point in the study area. The obtained results are experimentally verifiable, allowing for the construction of a probability function for the number of successful test wells and the determination of its quantiles, such as P90, P50, and P10. If the actual number of successful test wells falls within the P90-P10 range, the reliability assessment is considered correct. The methodology is discussed using the example of forecasting the effective thickness of a productive units at a well-studied field in Western Siberia.
The Laptev Sea shelf is considered a promising region with significant hydrocarbon potential. Study and exploration of its resources are hampered by its complex geological structure and the harsh climatic conditions. The southern part of the Laptev Sea shelf, whose geological structure remains poorly understood, is however considered a promising area for the effective development of natural resources. This paper presents the results of a comprehensive analysis of geological and geophysical data aimed at updating the geological model of the junction zone study the Siberian Platform, the Verkhoyansk-Kolyma folded region, and the Laptev Sea Plate. This recherche is based on the results of reinterpretation of 2D CMP seismic data in the southwestern and southern parts of the Laptev Sea shelf, as well as the analysis of geological survey data, paleotectonic reconstructions, and low-temperature thermochronology on adjacent land area.
This article examines current issues in the study of the pre-Jurassic volcanoclastic strata, using the example of a developing field located in the West Siberian petroleum basin. The focus is on methods for determining petrophysical parameters involved in assessing hydrocarbon resource potential and forecasting development. Methods for calculating the capacitive properties of volcanic rocks and substantiating reservoir boundary values using statistical criteria are proposed. Particular emphasis is placed on finding a solution to the problem of quantitatively assessing oil saturation in the absence of stable relationships between the nature of rock saturation and its electrical resistivity, due to the structural features of the void space.
Modern studies have made it possible to clarify and detail the overall picture of paleogeographic development and establish the basic patterns of the structure of Upper Ordovician-Lower Devonian sedimentary column in the Pechora-Barents Sea megabasin. The strata of the Upper Ordovician, Silurian and Lower Devonian are divided into 10 sedimentary sequences reflecting cycles of fluctuations in the level of the 3rd order of the World Ocean, lasting from 4 to 10 million years. The identified sequences made it possible to compare different facies in the sedimentation basin and confirm the conclusion about the existence of a single Pechora-Barents Sea megabasin in the Ordovician, Silurian and Early Devonian. Based on the analysis of facies maps, extensive and prolonged transgressions and the most pronounced regressive stages in the development of the basin have been identified.
The northern marginal part of the Siberian Platform exhibits direct signs of petroleum potential associated with source rocks of varying ages (from the Lower Riphean to the Mesozoic). Reconstructing paleotemperature conditions is important for assessing petroleum potential. Based on one-dimensional modeling, thermal evolution was reconstructed for the Ust-Olenek 2370 and Bur 3410 wells to determine the conditions for the onset of hydrocarbon generation. Modeling results revealed that Upper Proterozoic strata in the Bur area were exposed to temperature conditions favorable for oil and gas generation prior to pre-Vendian erosion, and by the beginning of the new sedimentation cycle, the source rocks may have largely exhausted their generation potential. Vendian-Lower Paleozoic strata entered optimal conditions for oil generation in the Late Permian. Upper Paleozoic strata, in turn, reached depths and, correspondingly, temperatures favorable for intense oil and gas generation processes within a limited area - the platform's foreland (Ust-Olenek 2370 well) - during the formation of the Verkhoyansk-Kolyma folded region.
In recent years, a number of large gas condensate fields (Shah Deniz, Absheron, and Umid-Babak) have been discovered in the deepwater South Caspian Basin. Gas condensate accumulations are also expected to be discovered in other promising structures. Therefore, the main objective of this article is to analyze the prospects for increasing underground gas storage capacity in Azerbaijan, both by expanding the capacity of existing underground gas storage facilities (Garadagh and Galmas) and by creating new storage facilities at new geological sites. This study utilizes geological and geophysical data (seismic exploration and well logging results) and field data (total well productivity and well dynamics), processed and graphically plotted using standard computer programs. As a result of these tasks, the following potential sites are proposed for underground gas storage: productive unit VI (Lower Pliocene) of the Galmas structure, which is in the depletion stage; productive unit VIII of the southern flank of the Garadagh structure; and the Nehram and Tumbul areas in the Nakhchivan Autonomous Republic, where additional studies using modern technologies are recommended to assess the feasibility of creating underground gas storage facilities in salt and presalt strata.
Oil depletion in late-life fields represents a significant challenge in petroleum geology, driving the search for more efficient methods to sustain production. This paper presents a study of a production enhancement program applied in a late-life field in Yugra (Khanty-Mansi Autonomous Okrug). The field is associated with the Lower Cretaceous reservoirs of the Savuy clinoform system, which are at a mature stage of development. This study employs retrospective analysis to assess the efficiency of implementing modern production enhancement technologies, such as sidetracking, near-wellbore stimulation, and hydraulic fracturing. Analysis of the 2013-2023 period indicates that 219 production enhancement well interventions (both full-scale and pilot-scale) yielded an incremental production of 159.3 thousand tons of oil. Sidetracking was the most effective measure, providing the largest share of the incremental oil production.
An essay in memory of Dr. Fabian Grigorievich Gurari, the first delegate from the SNIIGGiMS to the 22nd session of the International Geological Congress (Delhi, India, 1964), who informed the international community of the discovery of a new major oil and gas province in Western Siberia in the Soviet Union. This event significantly changed the situation on the international oil and gas market. It was preceded by decades of scientific discussions, calculations, and a gradual shift in scientific thinking, reflected in numerous multi-vector forecasts, searches for the best directions and methods for hydrocarbon exploration activity, and economic and operational decisions. Along the long, difficult path, scientists encountered a series of difficulties, non-random patterns, and, some times, misunderstandings from authorities, spiced with a fair share of interdepartmental conflicts of interest. Only later did this discovery led to major successes in the oil and gas industry and well-deserved awards. This essay is based on materials from open internet sources and a monograph by Dr. G.-M. Sciences (1962), professor (1967), Honored Geologist of the Russian Federation (1980) - F.G. Gurari.
The stratotypic and hypostratotypic sections of the Kykael Formation, Severolemyov Formation, Yagshor Formation, and Zapadnotebuk Formation of the Upper Ordovician Izhma-Pechora syneclise are described. The stratotype of the Kykael Formation was found in the Kykael 90 well, and the hypostratotype was found in the Sevenvozh 11 well. The stratotypes of the Severolemyev Formation, Yagshor Formation, and Zapadnotebuk formation are proposed in the context of the Vanyusk 55 well, the hypostratotypes of the Severolemyev Formation and Zapadnotebuk Formation in the Palyu 21 well, and the Yagshor Formationin the Yagshor 1 well.
The results of a palynological study of shallow stratigraphic cores drilled in the northern part of the Barents Sea are presented. Five palynoassociations and two levels with dinocysts are identified and described in detail. According to the composition of the main groups and individual taxa, the isolated palynostratons correlate well with associations from the Svalbard Archipelago, wells in the Russian and Norwegian sectors of the Barents Sea region. Based on this data, Ladinian, Early Carnian, Late Carnian, Norian, and Norian-Rhaetian(?) the age of the strata uncovered by shallow wells was established.
The study of Cambrian intersalt levels in the Angara-Lena petroleum region is currently of great importance. These strata are considered, on the one hand, as a return target for gas exploration, and on the other, as the main source of hydromineral raw materials. Under these circumstances, analysis of well testing data and well geological complications in the Angara-Lena petroleum region are necessary for understanding the fundamental patterns of the geological structure of Cambrian intersalt levels. Testing and various well complications were analyzed for over 400 wells. It is shown that the Osinsk level has been the most extensively tested. The maximum number of brine shows was observed during drilling in the Usol Formation, while the largest number of gas shows were recorded in the Angara Formation. The upper part of the Cambrian salt bearing structure (the Litvintsev Formation and Angara Formation) is characterized by intense mud losses. The results of these studies can be used in planning geological exploration in the Angara-Lena petroleum region of Eastern Siberia.
The objective of this study is to comprehensively assess the resource potential and oil and gas potential of the southeastern part of the Republic of Uzbekistan, taking into account its location within the Bukhara-Khiva, Southwest Gissar, and Surkhandarya regions, as well as to identify the factors controlling the formation and distribution of hydrocarbon accumulations in various structural and tectonic areas. The methodological basis of the study is an analysis of geological and geophysical data, a summary of drilling results, structural-stratigraphic constructions, and hydrocarbon reserve and resource assessment data, using comparative and systems approaches. As a result, patterns in the distribution of levels across stratigraphic structures were established, fundamental differences in the oil and gas potential of the regions under consideration were revealed, and the high potential of Lower-Middle Jurassic terrigenous strata (primarily the Bukhara-Khiva region) as a source and accumulation site for hydrocarbons, previously underutilized in exploration, was substantiated. A quantitative estimate of the projected increase in hydrocarbon reserves was obtained due to the involvement of new structures and the development of deep-seated levels during the planned geological exploration. The novelty of the study lies in the reson for the inclusion of Lower-Middle Jurassic and Cretaceous structures in exploration and the development of a scenario for the sustainable expansion of the hydrocarbon resource base over the long term.
This article examines current issues related to follow-up exploration and refinement of the geological structure of the Uchkyr oil and gas condensate field, located in the Bukhara-Khiva petroleum bearing region of the Republic of Uzbekistan. Despite the high degree of development of its initial hydrocarbon reserves, the field retains significant potential for reserve growth by re-commissioning wells from abandoned well stock. An analysis of geological and geophysical data, well testing results, and core studies. It was established that during the 1965 reserve estimation, low core coverage of productive units was observed, which affected the reliability of porosity, permeability, oil and gas saturation, and effective capacity determinations. Based on the created 3D geological model and the constructed structural maps for the main levels and geological profiles, the selection of abandoned well candidates for deepening was substantiated to penetrate the XV-1, XV-2, and XVI units, conduct a full range of well geophysical surveys, and perform mandatory core sampling. If repairs are technically impossible, drilling two appraisal and production wells is proposed. Implementation of these recommendations will refine the reservoir properties, refine the calculation parameters, increase the reliability of the geological model, and ensure an increase in hydrocarbon reserves in the late stage of field development.
For the first time, remains of the stromatoporoids Stylostroma absurdа Antropova and Anostylostroma sp. have been found in strata of the Over-Volga level of the Upper Famennian. Stromatoporoid coenosteums are associated with gray, microbial, lumpy limestones, which include thin interbeds of dark gray rocks with a high organic matter content. Co-occurrence of stromatoporoids with microbial formations can be considered symbiotic and are indicators of shallow-water environments, ranging in depth from meters to a few tens of meters. This suggests that the limestones and interbedded interbeds with high organic matter content may have formed in shallow water.
This paper presents the main changes in subsoil legislation and the state regulation of subsoil use. It analyzes the main changes in the subsoil plots licensing system and provides statistical data on the current hydrocarbon licenses in the North-Western federal district of the Russian Federation.
This paper presents a study of conodont assemblages from the Vorgashor Formation exposed along the Haruta River (Polar Urals). The material includes subautochthonous conodont associations recovered from hemipelagic deposits and calciturbidites in the lower part of the formation. The taxonomic composition, represented by Gnathodus bilineatus, G. remus, G. praebilineatus, Lochriea commutata, Pseudognathodus homopunctatus, Kladognathus, and Idioprioniodus, indicates a late Viséan-Serpukhovian age. Paleoecological analysis suggests that most taxa were epipelagic and not restricted to particular depositional depths. The obtained data allow for interfacial correlation between sections from different facies belts and refine the applicability of standard conodont zonation within the Upper Viséan-Serpukhovian interval. The first appearance levels of Gnathodus bilineatus and G. bollandensis are proposed as reliable interfacial correlation markers corresponding approximately to the bases of the upper Viséan and upper Serpukhovian substages, respectively.
The results of studies of the form of precipitation, distribution, and formation conditions of microbialites in limestone deposition types of the Visean-Serpukhovian, which are widespread in the southeastern boundary of the Timan-Pechora petroleum basin (Unya Cave section, Unya River, Northern Urals) are presented. It has been established that microbialites the Unya Cave section is divided into separate forms (microclots, bacterial biofilms, colonies of cyanobacteria), ooliths, oncoliths, stromatoliths, thromboliths, and dendroliths. Their composition and quantity change from base to top of section. The relatively deep-water Visean limestones contain only isolated microbial forms in small quantities. The shallow-water rocks of the upper part of the Kosogor level of the Serpukhovian section contain columnar and layered stromatolites. The extremely shallow deposits of the Protvian level of the Serpukhovian section contain ooids, stromatolites, thrombolites, and dendrolites. It is assumed that by the beginning of the Protvian time, a shallow-water zone had been formed in the area of the Unya Cave section.
When forecasting oil and gas potential in Western Siberia, priority has traditionally been given to identifying reservoir rock development zones in terrigenous formations. Currently, the need to identify effective seal zones and to develop detailed sedimentation models of seal formations is increasing. Methods for identifying seal zones based on wellbore geophysical data and predicting them using facies analysis are discussed.
