Regional Trough Research Articles

THE NATURE OF DARK COLORATION OF DEVONIAN CARBONATE ROCKS (POTENTIALLY PETROLEUM-BEARING WITHIN THE YENISEI-KHATANGA REGIONAL TROUGH) IN THE AMBARDAKH AREA (EASTERN SIBERIA)

Lithological studies of sedimentary rocks are often challenged by manifestations of the superimposed processes which are related neither to the stages of lithogenesis, nor to its zonality/direction. This can be exemplified by skarns in the carbonate-terrigenous sections of the unified Yukta and Nakohoz-Kalargon formations of Devonian age which were studied in the area of Lake Baselak and the Ambardakh River basin during the expedition works. Since the latter contain potentially oil and gas-bearing strata in the area of the Yenisei-Khatanga regional trough, special attention was paid to the dark-colored lithotypes during the research. It was revealed that among the studied samples, the dark color of some of them was of mineral nature, rather than due to the presence of OM. In these samples, the mineral composition was studied in detail, with determination of the association of newly formed minerals, which allowed us to propose hypothesized mechanism and stages of their formation. The dark color of sedimentary rocks has been shown to be not a sufficient criterion for searches for oil and gas accumulation. New results of the field studies of Pre-Triassic sedimentary complexes in the northern part of Kureyka syneclise are also presented.

Prospects for increasing oil resources and reserves in the Yenisei-Khatanga regional trough

The capabilities of discovering large oil fields in the central part of the Yenisei-Khatanga regional trough were considered. Processing and integrated interpretation of geological, geophysical and geochemical information provided the basis for the identification of four promising oil accumulation zones (an area of 58 thousand km2). For the multi-deposit Payakha oil field, three more zones located at depths of 3.2– 3.5 km were identified at the base of the clinoform complex. This made it possible to ensure the increment of localized recoverable oil resources of D1l category.

Volgian and Ryazanian Stages in the Novoyakimovskaya-1 Well (Western Yenisei-Khatanga Regional Trough, Siberia). Article 1. General Characteristics of the Yanov Stan Formation and Its Molluscan Biostratigraphy

Volgian and Ryazanian Stages in the Novoyakimovskaya-1 Well (Western Yenisei-Khatanga Regional Trough, Siberia). Article 1. General Characteristics of the Yanov Stan Formation and Its Molluscan Biostratigraphy

The Volgian and Ryazanian in the Novoyakimovskaya-1 Well (Western Yenisei-Khatanga Regional Trough, Siberia). Article 1. The General Characteristics of the Yanov Stan Formation and Its Molluscan Biostratigraphy

The Volgian and Ryazanian in the Novoyakimovskaya-1 Well (Western Yenisei-Khatanga Regional Trough, Siberia). Article 1. The General Characteristics of the Yanov Stan Formation and Its Molluscan Biostratigraphy

Geological structure and oil and gas potential of the Yenisei–Khatanga regional trough

A model of the geological structure was constructed and the oil and gas potential prospects of the Yenisei-Khatanga regional trough were assessed. Construction of seismogeological sections, structural and tectonic maps, structural and tectonic analysis was carried out. It was concluded that the Neocomian clinoform complex, which contains about 90 % of oil, gas and condensate reserves in this region, is of the greatest interest in the study area in terms of searching for large oil accumulations. It should be expected that significant oil reservoirs localized in the Berriasian–Valanginian sand formations will be controlled by complex structural-lithological and lithological non-anticlinal traps.

Prospects for Increasing Oil Resources and Reserves in the Yenisei–Khatanga Regional Trough

Prospects for Increasing Oil Resources and Reserves in the Yenisei–Khatanga Regional Trough

CHANGES IN GEODYNAMIC SITUATION MANIFESTED IN SOIL RADON AND TEMPERATURE VARIATIONS AND ABNORMAL NATURAL PHENOMENA IN THE ZONE OF KATAV-IVANOVSK EARTHQUAKE (05.09.2018), THE SOUTHERN URALS

The strongest earthquake in the Urals registered during the period of instrumental observations, with a magnitude of ML-5.4 occurred in the area of Katav-Ivanovsk city, Chelyabinsk region, on 05.09.2018. In October 2018, Institute of Geophysics, the Ural Branch RAS organized temperature and radon observations. The conducted studies have shown that the behavior patterns of the volume radon activity (VRA) established for the tectonic event preparation in the subduction zone (Southern Kuriles), are also true for the South Ural region. The natural phenomena caused by the earthquake 2018 preparation are analyzed. During the observation period from 28.11.2018 to 23.05.2019, there was an increase in temperature with a gradient of 0.02°C per month. The observed patterns of VRA abnormal behavior before aftershocks in the Katav-Ivanovsk area are typical for the compression zone in the radon monitoring area. It is noted that the assumed compression deformations were manifested in the hydrogeodynamic field at least 10 years before the event proper. The proximity of earthquake foci to the identified aseismic zone within the boundaries of the East European Platform, the Pre-Ural Regional Trough, and the Bashkir anticlinorium indicates the most likely places of seismic events. The arranged temperature and radon monitoring network in the epicentral zone by observing aftershocks has shown the possibility of tracking the earthquake preparation process.

The use of INTEGRO GIS in the integrated geophysical study
 of the deep structure of oil and gas prospective regions (part 2)

This article continues a description of the methodological and technological aspects of the constructing physical-geological models of oil and gas promising regions with a help of the INTEGRO GIS tools. The methods are described on the materials of studying the deep structure of the Yenisei-Khatanga regional trough (YKRT).
 The first part of the article covered the stages of analysis of the spatial distributions of potential fields and integrated regional profile geophysical data. The present, second, part of the paper describes the process of the YKRT three-dimensional density model construction, which is based on the results of the previous analysis.

Priority oil and gas exploration facilities in the north-east of the Predpatomsky trough

The article discusses the geological structure and prospects of oil and gas potential of the north-eastern part of the Predpatomsky regional trough. The features of the ratio of the structural plans of the upper and lower parts of the geological section due to thrust dislocations are indicated. It is assumed that deep drilling in the area of the Ulugur structure has not reached the target productive horizons in the autochthonous part of the section. Here, after clarifying the scope of seismic work, it is proposed to lay a exploratory well of greater depth. As another priority object for oil and gas, a potential zone of wedging of terrigenous deposits of the Vendian on the southwestern slope of the Suntar uplift is designated. The high prospects of the gas content of the upper part of the section, where gas deposits were established in newly discovered fields, were also noted. The results of direct geochemical testing of the Ulugur and Ergedzheysky license areas are presented, which allow localizing promising zones and areas of the studied territory.

Influence of reservoir characteristics on size of hydrocarbon reserves in natural reservoirs

The article discusses some of the main criteria that determine the size of reserves in hydrocarbon fields. It is noted that large-scale oil and gas accumulation is possible in natural reservoirs that meet certain conditions. Reservoirs with good characteristics, in the presence of a powerful source of replenishment of hydrocarbons, can form larger deposits with sufficient trap volumes in the natural reservoir. With a homogeneous reservoir with high characteristics, the distribution area of hydrocarbon accumulation can be more concentrated. Heterogeneous reservoirs more often generate hydrocarbon accumulations scattered over the area. Using the example of unique and large deposits in the junction zone of the Yenisei- Khatanga regional trough with the West Siberian depression, a dependence with a high correlation coefficient between the value of hydrocarbon deposits and the effective volume of the trap, which is determined by the effective thickness of the reservoir and the area of distribution of the trap in the natural reservoir, was obtained. In the area of the Vankorskoye , Tagulskoye and Vostochno-Messoyakhskoye fields, the collectors of the Yakovlevskaya and Nizhnekhetskaya formations with the highest oil and gas saturation have the maximum effective capacity and distribution area. Keywords: collector; trap; effective volume; natural reservoirs; large-scale oil and gas accumulation; hydrocarbon reserves.

The Clinoform Complex of the Yenisei–Khatanga Regional Trough: The Structure and Oil Potential

Abstract —From the viewpoint of modern knowledge, the geological structure of the Upper Jurassic–Neocomian clinoform complex, its regional seismogeological model has been constructed, and the criteria to locate oil accumulation zones (OAZ) and specific oil-promising prospects have been identified. All these factors made it possible to provide a significant increase in oil resources.

Geoelectrical Model of the Deep Structure of the Yenisei–Khatanga Regional Trough

Geoelectrical Model of the Deep Structure of the Yenisei–Khatanga Regional Trough

Kerogen of the Upper Jurassic Source Rocks in the Western Part of the Yenisei–Khatanga Regional Trough

Kerogen of the Upper Jurassic Source Rocks in the Western Part of the Yenisei–Khatanga Regional Trough

New data on the stratigraphy and depositional environment of the Jurassic-Cretaceous boundary sediments of the northwestern part of the Yenisei-Khatanga trough

Research subject. Boundary Jurassic-Cretaceous sediments of the western part of the Yenisei-Khatanga Regional Trough. Materials and methods. The main correlation tools were seismostratigraphic, logging, and biostratigraphic methods. Litho- and biofacies methods were used to reconstruct the development conditions of the Yanovstan Formation and the NKh group of the Ryazanian Stage reservoirs. Results. The composition of macro- and microfauna complexes was defined, analogues of the ammonite and foraminiferal zones of the Upper Volgian substage and the Ryazanian stage of Siberia were established. The structure of the Upper Jurassic and Ryazanian complexes of the western part of the Yenisei-Khatanga Regional Trough was detailed. Conclusions were made about the formation conditions of the Volgian and Ryazanian deposits. Conclusions. The sediments were found to have been formed in a sea basin with stable salinity and low water energy, in relatively deep-water conditions. Mixed turbidite systems with multipoint supply sources were identified, in which the terrigenous material was supplied from southeast to northwest.

Formation conditions and geological structure of the Yenisei-Khatanga regional through

A comprehensive analysis of geophysical data was carried out and a model of the deep structure of the Yenisei–Khatanga regional trough was constructed. A distinct platform appearance of the Neoproterozoic-Paleozoic sediments, the synchronous occurrence of ancient and Mesozoic sedimentary complexes in the axial most submerged part of the Yenisei–Khatanga linear depression. A wide territorial distribution of trap magmatism was revealed, which is not localized in the linear structure of the trough. It is concluded that the formation of the Yenisei-Khatanga regional trough is not associated with the Late Permian–Early Triassic rifting.

The oil and gas potential of the north of the Siberian platform and adjacent shelf

The objective of this article is an estimation of the oil and gas potential of the north of the Siberian platform and adjacent shelf. The Siberian platform is characterized by a large concentration of oil and gas resources in the southern and central parts of the platform. The main oil and gas province of the Siberian Platform is the Leno-Tungus oil and gas province. The oil- bearing strata in the Lena-Tungus oil and gas province are confined to the Riphean, Vendian, Lower-Middle Cambrian deposits, in which large oil and gas fields are discovered. In modern contours the Siberian platform in the north and north-west is fringed by the Yenisei-Khatanga regional trough. In the east, the Yenisei-Khatanga regional trough is connected with the Anabar- Lena trough, framing the north-eastern part of the Siberian platform. Analysis of the available geological and geophysical materials shows a fairly high potential of the Anabar-Lena and Yenisei-Khatanga troughs for the discovery of large hydrocarbon fields. The basic understanding of the geologic-tectonic structure and petroleum potential of the northern part of the Siberian Platform and the adjacent shelf of the Arctic zone are currently based on seismic data by the method of the common depth point (CDP), tied to the existing deep search and parametric wells. Representations of the deep structure and oil and gas potential of specific areas, the allocation of targeted promising oil and gas horizons can change dramatically as the depth of seismic acquisition of the method of the common depth point increases and the software for processing and interpreting seismic data is improved. The localized oil and gas resources of the north of the Siberian platform and adjacent shelf are 41017,3, subsequently, 27582,3 - onshore and offshore - 13435 MMT (million tons) of oil equivalent.

Oil-promising zones and local objects of clinoform sequence in the Yenisei-Khatanga regional trough

Oil-promising zones and local objects of clinoform sequence in the Yenisei-Khatanga regional trough

The Shirokoe Place as a reference section of the upper Visean substage in the Upper Pechora basin (Unya river, Northern Urals)

Research subject. Carbonate rocks in the “Shirokoe Place” section (Unya River, Northern Urals). Material and methods. The work was based on a study of the composition and structural peculiarities of rocks and species diversities of forami- nifera and calcareous algae in the most important section of Upper Visean sediments in the lower reaches of the Unya river.Results. The rocks in the section are represented by bioclastic limestones, dolomites and various transition differences. The section features a wide presence of green Koninckopora, red Epistacheoides and Ungdarella algae. Less common are Palaeoberesella, Anthracoporella, Kamaena and Stacheoides. Fasciella is extremely rare, and Calcifolium is virtually absent. Foraminifera complexes are representative, but there are no zonal species Eostaffella tenebrosa (Venevsky horizon), genera Valvulinella (Tula horizon), Bradyina and Howchinia (Mikhailovsky and Venevsky horizons). Endothyranopsis, Janischewskina and Cribrospira are rare.Conclusions. The study of the species diversity of foraminifera and calcareous algae allowed us to clarify the stratigraphic division of the upper Visean sediments in the “Shirokoe Place” section. The Tula, Aleksinsky, Mikhailovsky and Venevsky horizons of the Upper Visean were reliably identified. The studied section can be used as a reference when creating stratigraphic schemes of Later Visean deposits for the Western subzone of the Upper Pechora transverse sinking of the Western folded zone of the Urals and adjacent areas of the PreUrals regional trough.

Экологически безопасные методы оценки трещиноватости карбонатных пород на месторождениях Месопотамского краевого прогиба

Экологически безопасные методы оценки трещиноватости карбонатных пород на месторождениях Месопотамского краевого прогиба

ПРИМЕР ПОСТРОЕНИЯ И УТОЧНЕНИЯ ГЛУБИННО-СКОРОСТНОЙ МОДЕЛИ С ПРИМЕНЕНИЕМ МИГРАЦИОННЫХ И ТОМОГРАФИЧЕСКИХ ПРЕОБРАЗОВАНИЙ

The article is devoted to the overview of the main methods for constructing velocity-depth models (VDM), applied today and the effectiveness of their use in complicated seismic and geological conditions. In the present work, the method of integrated approach is considered along with well-known and generally accepted algorithms. The method of integrated approach is based on a combination of two model-building techniques for the VDM. The concerned approach allows researchers to combine positive aspects of combined methods while leveling their disadvantages. Using the example of real modern data obtained on the territory of East Siberia near fold-thrust dislocations of the Cis-Patom regional trough, the possibility of improving the quality of seismic image is demonstrated due to the use of the integrated approach and tomographic transformations for complexly constructed environments in the process of deep migration.