A modern seismic interpretation of coastal-continental deposits in the Jurassic complex of one of the fields in the north of the West Siberian Oil and Gas Province, including simultaneous stochastic inversion of seismic data was performed. The main object of the study was the interval of the group of J2 reservoirs. Petro-elastic modeling was carried out on the project. Modelling includes six wells with geophysical well logs. Feasibility study shows possibility of predicting lithology by stochastic inversion. In addition, optimal parametrization of elastic properties was determined to separate water-saturated and gas-saturated reservoirs from clay deposits. Interpretation of well and seismic data, as well as the results of stochastic inversion, made it possible to identify play zones in target interval. Probability cubes of gas-saturated reservoirs, made it possible to map the lenticular structure of the reservoirs and substantiate hydrodynamic barriers between individual gas plays.
{"title":"Reservoir characterization in coastal-continental environment of the Jurassic complex based on seismic data inversion","authors":"M.Yu. Shapovalov, I.M. Khamitullin, R.R. Shakirov, K.E. Filippova, A.A. Bregida","doi":"10.18599/grs.2023.3.7","DOIUrl":"https://doi.org/10.18599/grs.2023.3.7","url":null,"abstract":"A modern seismic interpretation of coastal-continental deposits in the Jurassic complex of one of the fields in the north of the West Siberian Oil and Gas Province, including simultaneous stochastic inversion of seismic data was performed. The main object of the study was the interval of the group of J2 reservoirs. Petro-elastic modeling was carried out on the project. Modelling includes six wells with geophysical well logs. Feasibility study shows possibility of predicting lithology by stochastic inversion. In addition, optimal parametrization of elastic properties was determined to separate water-saturated and gas-saturated reservoirs from clay deposits. Interpretation of well and seismic data, as well as the results of stochastic inversion, made it possible to identify play zones in target interval. Probability cubes of gas-saturated reservoirs, made it possible to map the lenticular structure of the reservoirs and substantiate hydrodynamic barriers between individual gas plays.","PeriodicalId":43752,"journal":{"name":"Georesursy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136248341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alexander B. Makeyev, Sergey G. Skublov, Olga L. Galankina, Evgeny A. Vasiliev, Anna O. Krasotkina
The two largest deposits of Russia – Yaregskoye and Pizhemskoye belong to the same genetic type; hydrothermal-metamorphic indigenous deposits. They are located in the same Timan structure at a distance of no more than 230 km from each other. According to the total approved reserves and forecast resources of titanium dioxide, they are approaching 60% of the all-Russian and will form the basis of industrial titanium raw materials used in Russia in the near future. In the interests of technological mineralogy, morphological features, internal structure, chemical composition of grains of the two main titanium mineral phases ‒ leucoxene and pseudorutile, TiO2 polymorphs, as well as the composition of mineral microinclusions in these phases have been studied in detail. The compositions of all mineral phases in polished preparations of leucoxene and pseudorutile were analyzed by SEM-EDS method at the Institute of Geology and Geochronology of the Precambrian of the RAS, 147 chemical analyses were obtained at the point (3 µk) and many images of polished grains of anatase, leucoxene and pseudorutile were scanned over the area (20×20 µk). In the leucoxene grains themselves, 12 mineral phases were diagnosed and characterized in the form of inclusions: pseudorutile, rutile, anatase, quartz, hydromuscovite-illite, kaolinite, siderite, zircon, xenotime, pyrite, florencite, monazite and kularite. TiO2 polymorphs are verified by Raman spectroscopy and X-ray diffraction analysis. New evidence has been obtained that the transformation of ilmenite into leucoxene occurs hydrothermally through intermediate phases ‒ Fe-rutile and pseudorutile; the enlargement of rutile crystals in the leucoxene grain itself is shown; the presence of secondary crystals of siderite, florencite and others inside the studied grains.
{"title":"Pseudorutile-leucoxene-quartz ores of Timan ‒ a new genetic type of titanium raw materials: prospects for industrial development","authors":"Alexander B. Makeyev, Sergey G. Skublov, Olga L. Galankina, Evgeny A. Vasiliev, Anna O. Krasotkina","doi":"10.18599/grs.2023.3.10","DOIUrl":"https://doi.org/10.18599/grs.2023.3.10","url":null,"abstract":"The two largest deposits of Russia – Yaregskoye and Pizhemskoye belong to the same genetic type; hydrothermal-metamorphic indigenous deposits. They are located in the same Timan structure at a distance of no more than 230 km from each other. According to the total approved reserves and forecast resources of titanium dioxide, they are approaching 60% of the all-Russian and will form the basis of industrial titanium raw materials used in Russia in the near future. In the interests of technological mineralogy, morphological features, internal structure, chemical composition of grains of the two main titanium mineral phases ‒ leucoxene and pseudorutile, TiO2 polymorphs, as well as the composition of mineral microinclusions in these phases have been studied in detail. The compositions of all mineral phases in polished preparations of leucoxene and pseudorutile were analyzed by SEM-EDS method at the Institute of Geology and Geochronology of the Precambrian of the RAS, 147 chemical analyses were obtained at the point (3 µk) and many images of polished grains of anatase, leucoxene and pseudorutile were scanned over the area (20×20 µk). In the leucoxene grains themselves, 12 mineral phases were diagnosed and characterized in the form of inclusions: pseudorutile, rutile, anatase, quartz, hydromuscovite-illite, kaolinite, siderite, zircon, xenotime, pyrite, florencite, monazite and kularite. TiO2 polymorphs are verified by Raman spectroscopy and X-ray diffraction analysis. New evidence has been obtained that the transformation of ilmenite into leucoxene occurs hydrothermally through intermediate phases ‒ Fe-rutile and pseudorutile; the enlargement of rutile crystals in the leucoxene grain itself is shown; the presence of secondary crystals of siderite, florencite and others inside the studied grains.","PeriodicalId":43752,"journal":{"name":"Georesursy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135039287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Konstantin M. Fedorov, Ivan V. Vydysh, Alexander V. Kobyashev, Alexander S. Gavris’
Waterflooding of low-permeable reservoirs with high pressure is often accompanied by formation of induced fracture. The positive side of this process is an injectivity increase and oil production rise. However, when these fractures approach producing wells, an early water breakthrough occurs, and high productivity channels are formed between the injection and producing wells. The technology of fracture clogging, for example, by suspension composition injection into an injection well, allows reducing the length of the fracture. The paper considers the problem of the fracture size reducing process on the waterflood sweep efficiency. The example of a reverse five–point waterflood pattern was investigated. In the basic calculation run, fracture length was constant during all process. The run with transformable fracture length is compared with the basic one. The results of calculations showed that the process of waterflooding after fracture impact could be divided into the following stages. The first one, which follows immediately after the fracture clogging, demonstrates a water cut decrease and an oil production rate increase. The second, in which the oil production declines below the base variant. On the third stage, there is a low, but long-term increase in oil production due to increased waterflood sweep efficiency. The authors established that monitoring of induced fractures length is relevant, since timely fractures clogging allows to increase oil production after the well treatment and to incline the oil recovery coefficient through increasing waterflood sweep efficiency.
{"title":"Clogging of induced fracture to increase waterflood sweep efficiency","authors":"Konstantin M. Fedorov, Ivan V. Vydysh, Alexander V. Kobyashev, Alexander S. Gavris’","doi":"10.18599/grs.2023.3.18","DOIUrl":"https://doi.org/10.18599/grs.2023.3.18","url":null,"abstract":"Waterflooding of low-permeable reservoirs with high pressure is often accompanied by formation of induced fracture. The positive side of this process is an injectivity increase and oil production rise. However, when these fractures approach producing wells, an early water breakthrough occurs, and high productivity channels are formed between the injection and producing wells. The technology of fracture clogging, for example, by suspension composition injection into an injection well, allows reducing the length of the fracture. The paper considers the problem of the fracture size reducing process on the waterflood sweep efficiency. The example of a reverse five–point waterflood pattern was investigated. In the basic calculation run, fracture length was constant during all process. The run with transformable fracture length is compared with the basic one. The results of calculations showed that the process of waterflooding after fracture impact could be divided into the following stages. The first one, which follows immediately after the fracture clogging, demonstrates a water cut decrease and an oil production rate increase. The second, in which the oil production declines below the base variant. On the third stage, there is a low, but long-term increase in oil production due to increased waterflood sweep efficiency. The authors established that monitoring of induced fractures length is relevant, since timely fractures clogging allows to increase oil production after the well treatment and to incline the oil recovery coefficient through increasing waterflood sweep efficiency.","PeriodicalId":43752,"journal":{"name":"Georesursy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135039290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The question of the genesis of the anomalous Bazhen-Achimov zones remains to be one of the most controversial problems in Western Siberia. By now, about dozen hypotheses of the sedimentary environment of this specific formation have been proposed. However, none of these hypotheses is generally accepted. All hypotheses have been classified by genesis and their critical analysis is given in the article. The solution is closely related with experience of the geological exploration works, since the prospects of oil and gas are associated with these deposits. The article highlights the key features of the structure of the anomalous section’s zones based on drilling and seismic data. The classification of the hypotheses is given and the features of sedimentation in the Bazhenov and Achimov times are highlighted. An accumulated data has allowed us to substantiate the olistostromous genesis of the anomalous section. Based on a set of data, including paleogeographic, sedimentological, paleotectonic reconstructions, a principal detailed model of the sedimentary environment of olistostromes is proposed for the first time. The proposed model seems to be the most logical, supported by the actual data known to date, is the most universal and fits into the paleogeographic situation and tectonic regime that prevailed in the Achimov time.
{"title":"Structure and genesis of the Achimov olistostromic strata of Western Siberia","authors":"Vadim F. Sharafutdinov","doi":"10.18599/grs.2023.3.13","DOIUrl":"https://doi.org/10.18599/grs.2023.3.13","url":null,"abstract":"The question of the genesis of the anomalous Bazhen-Achimov zones remains to be one of the most controversial problems in Western Siberia. By now, about dozen hypotheses of the sedimentary environment of this specific formation have been proposed. However, none of these hypotheses is generally accepted. All hypotheses have been classified by genesis and their critical analysis is given in the article. The solution is closely related with experience of the geological exploration works, since the prospects of oil and gas are associated with these deposits. The article highlights the key features of the structure of the anomalous section’s zones based on drilling and seismic data. The classification of the hypotheses is given and the features of sedimentation in the Bazhenov and Achimov times are highlighted. An accumulated data has allowed us to substantiate the olistostromous genesis of the anomalous section. Based on a set of data, including paleogeographic, sedimentological, paleotectonic reconstructions, a principal detailed model of the sedimentary environment of olistostromes is proposed for the first time. The proposed model seems to be the most logical, supported by the actual data known to date, is the most universal and fits into the paleogeographic situation and tectonic regime that prevailed in the Achimov time.","PeriodicalId":43752,"journal":{"name":"Georesursy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135039886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Andrey V. Chernov, Andrey G. Koshcheev, Elena A. Potapova, Artem Y. Smirnov, Aleksey A. Pashinskiy, Anatoliy A. Rasskazov
In order to clarify the structure of promising oil and gas objects in the South Tambey field (Western Siberia), an integrated approach to the study of Achimov deposits has been developed. The oil and gas potential level includes layers from PK1 to Yu9 at depths from 1000 to 4000 meters. Despite the fifty-year history of drilling wells in the area, the Achimov objects are currently poorly explored in the study area and may have significant potential for development. The purpose of this work was to clarify the geological structure of the Achimov deposits, which became possible thanks to the acquisition of new geological exploration data during the study of the underlying Jurassic complex. CDP 3D seismic exploration work was completed using a modern full-azimuth observation system, and active drilling of exploration wells for Jurassic deposits in the slope parts of the main structures began. The objectives of the study were the interpretation of a 3D seismic cube covering most of the area of the site, seismic geological linking of data from the Achimov interval of the field with neighboring areas, including using the sequence stratigraphy method, accounting for the results of drilling wells for the pilot development of the Jurassic complex and the transit fund of prospecting and exploration wells, as well as the inclusion of the results of a petrophysical model in a first approximation for the Achimov reservoir interval of the South Tambey field. The results of full-azimuth CDP 3D seismic surveys made it possible to obtain reliable correlations between well data and seismic data, including analysis of AVO attributes (Amplitude Variation with Offset). Based on sequence stratigraphic analysis, the stratification of the section was clarified, correlation with neighboring territories was made, and a conceptual model of the clinoform complex was created. For each layer, system tracts within the sequences were determined. There is strong relationship existing between the formation conditions, geometry of objects and reservoir properties.
{"title":"An integrated approach to the study of Achimov deposits within the South Tambey field (Western Siberia)","authors":"Andrey V. Chernov, Andrey G. Koshcheev, Elena A. Potapova, Artem Y. Smirnov, Aleksey A. Pashinskiy, Anatoliy A. Rasskazov","doi":"10.18599/grs.2023.3.6","DOIUrl":"https://doi.org/10.18599/grs.2023.3.6","url":null,"abstract":"In order to clarify the structure of promising oil and gas objects in the South Tambey field (Western Siberia), an integrated approach to the study of Achimov deposits has been developed. The oil and gas potential level includes layers from PK1 to Yu9 at depths from 1000 to 4000 meters. Despite the fifty-year history of drilling wells in the area, the Achimov objects are currently poorly explored in the study area and may have significant potential for development. The purpose of this work was to clarify the geological structure of the Achimov deposits, which became possible thanks to the acquisition of new geological exploration data during the study of the underlying Jurassic complex. CDP 3D seismic exploration work was completed using a modern full-azimuth observation system, and active drilling of exploration wells for Jurassic deposits in the slope parts of the main structures began. The objectives of the study were the interpretation of a 3D seismic cube covering most of the area of the site, seismic geological linking of data from the Achimov interval of the field with neighboring areas, including using the sequence stratigraphy method, accounting for the results of drilling wells for the pilot development of the Jurassic complex and the transit fund of prospecting and exploration wells, as well as the inclusion of the results of a petrophysical model in a first approximation for the Achimov reservoir interval of the South Tambey field. The results of full-azimuth CDP 3D seismic surveys made it possible to obtain reliable correlations between well data and seismic data, including analysis of AVO attributes (Amplitude Variation with Offset). Based on sequence stratigraphic analysis, the stratification of the section was clarified, correlation with neighboring territories was made, and a conceptual model of the clinoform complex was created. For each layer, system tracts within the sequences were determined. There is strong relationship existing between the formation conditions, geometry of objects and reservoir properties.","PeriodicalId":43752,"journal":{"name":"Georesursy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135039913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the article, based on a relatively deep-water clinoform model of the Achimov strata structure based on the analysis of sedimentological processes and 3D seismic data, the characteristics of the morphological types of clinoform formations, structural features and sedimentation of the Lower Cretaceous deposits in the zone of counter clinoforms are given, a new type of hydrocarbon traps is identified within this area, their seismic images are presented. It is noted that in the zone of east-dip clinoforms (the Ural source of demolition), it is necessary to evaluate the prospects for oil and gas potential of the section based on the analysis of seismic and gravity survey and logging data, in order to predict fractured reservoirs.
{"title":"Characteristics of morphotypes of Neocomian clinoform formations in the north of the West Siberian lowland in connection with the peculiarities of sedimentation processes","authors":"Vladimir N. Borodkin, Oleg A. Smirnov","doi":"10.18599/grs.2023.3.2","DOIUrl":"https://doi.org/10.18599/grs.2023.3.2","url":null,"abstract":"In the article, based on a relatively deep-water clinoform model of the Achimov strata structure based on the analysis of sedimentological processes and 3D seismic data, the characteristics of the morphological types of clinoform formations, structural features and sedimentation of the Lower Cretaceous deposits in the zone of counter clinoforms are given, a new type of hydrocarbon traps is identified within this area, their seismic images are presented. It is noted that in the zone of east-dip clinoforms (the Ural source of demolition), it is necessary to evaluate the prospects for oil and gas potential of the section based on the analysis of seismic and gravity survey and logging data, in order to predict fractured reservoirs.","PeriodicalId":43752,"journal":{"name":"Georesursy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135040044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kirill V. Dolzhenko, Lyubov S. Borisova, Alexander N. Fomin, Irina D. Popova
The evolution of the elemental composition of dispersed organic matter (DOM) heterocyclic components during catagenesis was traced via studying samples from the Tyumen (SG-6) and Srednevylyuy-27 (SV-27) super-deep wells of Siberia. During mesocatagenesis, the composition of terrigenous DOM asphaltenes and resins undergoes directed changes: a decrease in hydrogen and oxygen content, enrichment with carbon, and graphitization of the structure. During apocatagenesis, due to high-temperature destruction, on the one hand, there is a condensation of individual blocks of asphaltenes and their transition to an insoluble form (formation of epiasphaltenic kerogens – EPAK). On the other hand, the lighter part of the asphaltenes goes into the formation of hydrocarbons and gas formation – a relative increase in the concentration of the former in % by mass of residual bitumoids is noted, as well as structural redistributions within benzene and spirit-benzene resins. In all studied parameters of the elemental composition, a symmetrical (unidirectional) transformation of resinous and asphaltene components of bitumoids from the SG-6 and SV-27 wells under harsh thermobaric conditions is noted. The obtained results should be taken into account when predicting new oil and gas accumulation zones in deep-laid horizons.
{"title":"Composition transformation of terrigenous organic matter resinous-asphaltene components in super-deep wells in Siberia during meso- and apocatagenesis","authors":"Kirill V. Dolzhenko, Lyubov S. Borisova, Alexander N. Fomin, Irina D. Popova","doi":"10.18599/grs.2023.3.15","DOIUrl":"https://doi.org/10.18599/grs.2023.3.15","url":null,"abstract":"The evolution of the elemental composition of dispersed organic matter (DOM) heterocyclic components during catagenesis was traced via studying samples from the Tyumen (SG-6) and Srednevylyuy-27 (SV-27) super-deep wells of Siberia. During mesocatagenesis, the composition of terrigenous DOM asphaltenes and resins undergoes directed changes: a decrease in hydrogen and oxygen content, enrichment with carbon, and graphitization of the structure. During apocatagenesis, due to high-temperature destruction, on the one hand, there is a condensation of individual blocks of asphaltenes and their transition to an insoluble form (formation of epiasphaltenic kerogens – EPAK). On the other hand, the lighter part of the asphaltenes goes into the formation of hydrocarbons and gas formation – a relative increase in the concentration of the former in % by mass of residual bitumoids is noted, as well as structural redistributions within benzene and spirit-benzene resins. In all studied parameters of the elemental composition, a symmetrical (unidirectional) transformation of resinous and asphaltene components of bitumoids from the SG-6 and SV-27 wells under harsh thermobaric conditions is noted. The obtained results should be taken into account when predicting new oil and gas accumulation zones in deep-laid horizons.","PeriodicalId":43752,"journal":{"name":"Georesursy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135039888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In Western Siberia, the zone of abnormally high reservoir pressures (AHRP) covers an area of more than 500 thousand km2 in the north of the basin. It begins with a clay layer above the Achimov formation of Neocomian sandy-silty formation, covers the Achimov formation, Upper–Lower Jurassic, Triassic and partially Paleozoic and is subject to tectonic control, which indicates the deep origin of this phenomenon. Gas-pressure, or gas-dynamic, theory of AHRP, proposed by K.A. Anikiev in the 70s of the 20th century, allows us to assess the prospects for oil and gas content of the AHRP zone higher than it is commonly-accepted. Analysis of the results of previously completed geological exploration work on the deep horizons of the Yamalo-Nenets Autonomous Okrug indicates that their relatively low efficiency (50–60%) is associated with the insufficiently high quality of well operations, primarily cementing, which is also due to the influence of AHRP. In all wells drilled to deep horizons, direct signs of oil and gas potential were obtained and cementing defects were identified. It is concluded that deep fluid-dynamic processes (active, pressure degassing of the Earth’s interior) are responsible both for the saturation of reservoir rocks with hydrocarbons and for the dynamics of their filling (ultra-high pressures and velocities), which determine the main characteristics of reservoir rocks. Recognition of a deep source of hydrocarbons will not only make it possible to fundamentally increase the resource base of the AHRP zone, but will also require a revision of ideas about the formation and structure of hydrocarbon deposits in this zone and the petrophysical substantiation of their models. However, to realize the unique hydrocarbon potential of the AHRP zone, it is necessary, first of all, to improve the quality of deep wells construction and appropriate information content.
{"title":"Prospects for the oil and gas potential of the zone of abnormally high reservoir pressures in the Yamalo-Nenets Autonomous Okrug assuming deep fluid dynamics","authors":"Alexey A. Nezhdanov, Valeriy V. Ogibenin","doi":"10.18599/grs.2023.3.3","DOIUrl":"https://doi.org/10.18599/grs.2023.3.3","url":null,"abstract":"In Western Siberia, the zone of abnormally high reservoir pressures (AHRP) covers an area of more than 500 thousand km2 in the north of the basin. It begins with a clay layer above the Achimov formation of Neocomian sandy-silty formation, covers the Achimov formation, Upper–Lower Jurassic, Triassic and partially Paleozoic and is subject to tectonic control, which indicates the deep origin of this phenomenon. Gas-pressure, or gas-dynamic, theory of AHRP, proposed by K.A. Anikiev in the 70s of the 20th century, allows us to assess the prospects for oil and gas content of the AHRP zone higher than it is commonly-accepted. Analysis of the results of previously completed geological exploration work on the deep horizons of the Yamalo-Nenets Autonomous Okrug indicates that their relatively low efficiency (50–60%) is associated with the insufficiently high quality of well operations, primarily cementing, which is also due to the influence of AHRP. In all wells drilled to deep horizons, direct signs of oil and gas potential were obtained and cementing defects were identified. It is concluded that deep fluid-dynamic processes (active, pressure degassing of the Earth’s interior) are responsible both for the saturation of reservoir rocks with hydrocarbons and for the dynamics of their filling (ultra-high pressures and velocities), which determine the main characteristics of reservoir rocks. Recognition of a deep source of hydrocarbons will not only make it possible to fundamentally increase the resource base of the AHRP zone, but will also require a revision of ideas about the formation and structure of hydrocarbon deposits in this zone and the petrophysical substantiation of their models. However, to realize the unique hydrocarbon potential of the AHRP zone, it is necessary, first of all, to improve the quality of deep wells construction and appropriate information content.","PeriodicalId":43752,"journal":{"name":"Georesursy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135039895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The sequence stratigraphic models for the clinoform part of the section in the territory studied by production drilling within the Nadym-Pur oil and gas region of Western Siberia are constructed. The purpose of study was to identify patterns in the distribution of reservoir properties of the Achimov objects and substantiate a systematic approach to the correlation of reflecting horizons. The main task is to identify the characteristic features of systemic tracts based on core data from a well-studied field. To solve the problem, a classification of sediments studied by core in wells was carried out within the framework of a sequence model. To confirm theoretical concepts about the formation of improved reservoir zones in system tracts, an analysis of filtration and capacitance parameters (porosity, permeability) was performed. There is the relationship between the reservoir properties and the type of system tract in which the deposits were formed. The seismic section requires the interpretation according to the principles of sequence stratigraphy, and criteria for tracing reflecting horizons. An algorithm for constructing a model is proposed that provides a forecast of zones with improved reservoir properties. A number of advantages for the unsystematic approach to correlating reflecting horizons are given.
{"title":"Sequence stratigraphic model as a modern tool for seismic data interpretation","authors":"Elena A. Potapova","doi":"10.18599/grs.2023.3.4","DOIUrl":"https://doi.org/10.18599/grs.2023.3.4","url":null,"abstract":"The sequence stratigraphic models for the clinoform part of the section in the territory studied by production drilling within the Nadym-Pur oil and gas region of Western Siberia are constructed. The purpose of study was to identify patterns in the distribution of reservoir properties of the Achimov objects and substantiate a systematic approach to the correlation of reflecting horizons. The main task is to identify the characteristic features of systemic tracts based on core data from a well-studied field. To solve the problem, a classification of sediments studied by core in wells was carried out within the framework of a sequence model. To confirm theoretical concepts about the formation of improved reservoir zones in system tracts, an analysis of filtration and capacitance parameters (porosity, permeability) was performed. There is the relationship between the reservoir properties and the type of system tract in which the deposits were formed. The seismic section requires the interpretation according to the principles of sequence stratigraphy, and criteria for tracing reflecting horizons. An algorithm for constructing a model is proposed that provides a forecast of zones with improved reservoir properties. A number of advantages for the unsystematic approach to correlating reflecting horizons are given.","PeriodicalId":43752,"journal":{"name":"Georesursy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135040045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The findings of platinum group metal mineralization (PGM) and the distribution of platinum group elements (PGE) in lherzolites of the Northern Kraka massif are described. The total contents of PGE are approximately two orders of magnitude lower than those in chondrite and are close to pyrolite, relative to which the studied lherzolites are enriched in Pd and depleted in Ru. In segregations of PGMs, the presence of all PGEs (except rhodium) in various proportions was established. All found grains are divided into three contrasting types: the refractory triad Os–Ir–Ru, essentially platinum with the participation of Pd, and Cu–Pd. Almost all found PGM grains are localized either in the peripheral parts of grains of altered sulfides (heazlewoodite, pentlandite) or in the silicate matrix in the immediate vicinity of sulfide segregations. Based on the mineral associations and PGE distribution, a probable genesis of segregations has been suggested. Associations of Cu–Pd and Pd–Pt(+Cu) composition most likely formed during the crystallization of sulfides from the extracted partial melts. This is indicated by their close association with clinopyroxenes and the presence of relatively fusible platinoids and copper. The associations of Pt–Ir and Os–Ir–Ru(+Pt) composition are most likely restitic, formed in place of primary mantle sulfides as a result of extraction of more fusible elements and further desulphurization. The isolation of platinoids as their own mineral phases is associated with the influence of superimposed low-temperature processes – subsolidus redistribution during cooling and subsequent serpentinization.
{"title":"Accessory mineralisations in lherzolites of Northern Kraka massif (South Urals)","authors":"Dmitry E. Saveliev, Ruslan A. Gataullin","doi":"10.18599/grs.2023.3.24","DOIUrl":"https://doi.org/10.18599/grs.2023.3.24","url":null,"abstract":"The findings of platinum group metal mineralization (PGM) and the distribution of platinum group elements (PGE) in lherzolites of the Northern Kraka massif are described. The total contents of PGE are approximately two orders of magnitude lower than those in chondrite and are close to pyrolite, relative to which the studied lherzolites are enriched in Pd and depleted in Ru. In segregations of PGMs, the presence of all PGEs (except rhodium) in various proportions was established. All found grains are divided into three contrasting types: the refractory triad Os–Ir–Ru, essentially platinum with the participation of Pd, and Cu–Pd. Almost all found PGM grains are localized either in the peripheral parts of grains of altered sulfides (heazlewoodite, pentlandite) or in the silicate matrix in the immediate vicinity of sulfide segregations. Based on the mineral associations and PGE distribution, a probable genesis of segregations has been suggested. Associations of Cu–Pd and Pd–Pt(+Cu) composition most likely formed during the crystallization of sulfides from the extracted partial melts. This is indicated by their close association with clinopyroxenes and the presence of relatively fusible platinoids and copper. The associations of Pt–Ir and Os–Ir–Ru(+Pt) composition are most likely restitic, formed in place of primary mantle sulfides as a result of extraction of more fusible elements and further desulphurization. The isolation of platinoids as their own mineral phases is associated with the influence of superimposed low-temperature processes – subsolidus redistribution during cooling and subsequent serpentinization.","PeriodicalId":43752,"journal":{"name":"Georesursy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135039288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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