scholarly journals Western part of the Terek-Caspian trough as a zone of unloading of deep fluid systems

Author(s):  
A.A. Daukaev

The article describes the mechanisms of formation of the Terek and Sunzha anticlinoria as the main zones of oil and gas accumulation. An assumption is made about the formation of high-amplitude anticlinal folds in the Upper Cretaceous deposits as a result of vertical migration of high-pressure fluids along deep faults with a breakthrough of their upper horizons of the sedimentary cover into the late orogenic phases of folding. The main prerequisites for the deep genesis of oil and gas are listed – a pronounced unevenness in the distribution of hydrocarbon accumulations, abnormal pressure, hydrochemical anomalies.

GEODYNAMICS ◽  
2021 ◽  
Vol 2(31)2021 (2(31)) ◽  
pp. 66-83
Author(s):  
Sergiy Anikeyev ◽  
◽  
Svitlana Rozlovska ◽  

The aim of the research presented in this article is to analyze the properties and geological informative value of the anisotropic transformations of gravitational and magnetic fields, which use averaging procedures, including analysis of Andreev-Klushin's method. Anisotropic transformations of potential fields are designed to detect and track elongated anomalies or their chains, caused by deep linear dislocations in the geological section. The study of the anisotropic transformations properties is based on the analysis of their depth characteristics, as well as theoretical and practical experiments. The study applies the analysis method of fault tectonics reflection features in anisotropic anomalies of gravimagnetic fields, in particular, on the example of the South-East of the Ukrainian Carpathians. It is based on the search of morphological signs of manifestation of deep faults and other long structural-tectonic dislocations in gravitational and magnetic anisotropic anomalies. The method also suggests tracing these elements, relying on the comparison of morphology, intensity, size and direction of anisotropic anomalies with published regional tectonic and geological maps. Results. The paper presents definitions and algorithms of such anisotropic transformations as Andreev-Klushin's methods of anticlinal and terrace types, anisotropic averaging and anisotropic difference averaging. The research allowed us to perform study of the geological informative value of anisotropic transformations of potential fields on theoretical and practical examples. It is shown that in the morphology of anisotropic gravitational and magnetic anomalous fields in the south-east of the Ukrainian Carpathians long local anomalies are traced. They are caused by fault tectonics, in particular deep longitudinal and transverse faults, as well as linear complications into sedimentary cover. The analysis of anisotropic anomalous fields reveals a number of characteristic features of large tectonic zones reflecting regional behavior of the foundation surface and deep faults; on its basis fault tectonics schemes of the South-Eastern region of the Ukrainian Carpathians can be constructed. The study traced a significant extension of the foundation of the Eastern European platform from the Maidan's ledge and the Pokutsko-Bukovynian Carpathians under the Folded Carpathians. The definition of a number of anisotropic transformations is given and their properties are considered. The work substantiated geological informative value of the anisotropic transformations morphology of potential fields in the study of the Ukrainian Carpathians and adjacent depressions fault tectonics. The use of anisotropic transformations of potential fields will increase the reliability and detail of tracing deep faults, as well as other linear dislocations both in the foundation and in the sedimentary cover. The study of fault tectonics is an important factor in the successful solution of problems in the search and exploration of areas which are promising for oil and gas deposits.


2020 ◽  
pp. 8-19
Author(s):  
E. S. Milei ◽  
S. R. Bembel

The article is devoted to a comprehensive analysis of the geological structure of a complex oil reservoir located in the southeastern part of the Pannonian basin. The concept of the hydrocarbon traps formation is based on the connection with the deep processes of oil and gas formation and phenomena, which lead to the formation of cracks, faults, local positive structures in the interval from the foundation to the upper part of the sedimentary cover. The article shows the significance of deep faults in the basement during the formation of sedimentary cover structures. These processes result in a wide range of oil and gas potential of the Pannonian basin deposits. In studying the specifics of tectonic movements and the features of gravitational deposits (conglobreccia), a tectono-sedimentary approach has been developed that can reduce a number of methodological difficulties in creating geological models and concepts. Recommendations are given on the additional study of adjacent structures in order to detect hydrocarbon deposits on the slopes with protrusions of the crystalline basement. Characteristic features of the geological structure are the local volume of the identified oil and gas deposits, small foci of increased productivity and improved filtration properties of reservoirs. Such features of the uneven distribution of sites of different productivity have a significant impact on the success of prospecting and exploration, the effectiveness of development of oil and gas deposits.


Author(s):  
Mevlud Sharikadze ◽  
◽  
Irakli Tavdumadze ◽  
Zurab Suramelashvili ◽  
◽  
...  

Abnormal high formation pressure (AHFP) zones are widely spread in sedimentary cover of numerous oil and gas regions of the world and our fields are among them. A lot of money and time are spent on elimination of some drilling complications of relevant intervals and that makes well costs more expensive. Therefore, study of forecast abnormal pressure generation and distribution zones is one of the current problems of deep well drilling activities. According to the drilling, geological and geophysical data analyzes and references, the generation of abnormal pressure in the sedimentary cover of the studied territory is mainly caused by: the existence of long submerged sedimentary basin, wide distribution of thick plastic clayey formations enriched with bentonite, primate of submersion velocity against persistence of hardening of faeces, intense folding of formations and frequent network of fault dislocations. Stratigraphically AHFP zone corresponds mainly with Middle Sarmatian-Maikopian-Upper Eocene clayey-sandstone suit distribution intervals. Formation pressure maximum gradient within the region varies from 1.75-1.85 to 2.00-2.20, intervals of distribution AHFP zones - from 600-2200m to 3700-4500m, thicknesses - from 700-2100m to 2500-3000m. Indicators of the given parameters generally increase roughly from South-West to North-East towards the thicknesses of plastic clayey formations, their submersion depth and tectonic tense growth factor. Besides, geological characteristics of some particular areas cause some adjustments: AHFP zone is hypsometrically aroused in the hinge lines of fault anticlines and is sunk in syncline depressions, thickness and formation pressure gradients are less in anticlines than in synclines.


Author(s):  
N. Narimanov ◽  
G. Gahramanov ◽  
M. Babayev ◽  
S. Shpyrko ◽  
G. Nasibova ◽  
...  

Mud volcanoes are indicators of the oil and gas generation processes in the hydrocarbon basins and can show the hydrocarbon potential of local anticline structures where they arise. The quantitative study of the composition of gas ejecta from volcanoes and their age can reveal the generation zones in the sedimentary cover and help assess the hydrocarbon bearing potential of an area. Mud volcanoes are often spatially related to the disjunctive faults intersections, and, on the other hand, there is a clear correlation between the location of the major oil and gas deposits and deep faults. Therefore, ejecta of mud volcanoes present a tool for geochemical probing of potentially hydrocarbon bearing structures. We used a spatial analysis of the composition of gases in mud volcanoes in order to reveal the prospective hydrocarbon targets in Baku Archipelago, located in the western part of the South Caspian Basin. The results confirm the prognosis for the existence of major gas condensate and gas accumulations in its deep water part. The calculations for the ages of mud volcanoes show that they refer to Cretaceous and Miocene-Pliocene periods.


LITOSFERA ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 752-766
Author(s):  
V. B. Pisetski ◽  
K. S. Ivanov

Research subject. The idea of forecasting fluid-dynamical parameters is based on the views connecting the processes of sedimentation, tectonogenesis and fluid flows into an active fluid-dynamical model of the “sedimentary cover–basement” system. In such models, main fluid-dynamical parameters of oil and gas collectors, i.e. penetration and the vector of the fluid flow, are functionally connected with the components of the current state of the rock massif having a discrete (block) structure. These parameters can be calculated using DFM-interpretation technology developed by the authors in their previous works.Materials and methods. For the first time, DFM results are provided for the Yamal Novoportovsky oiland gas-condensing deposit. Here, the paleozoic basement stripped at a depth of 2700–3200 m is largely represented by metamorphic schists and marbled limestones. The basement has been covered by sediments and a platform cover since the early Jurassic age. The forecast of parameters describing modern geodynamical processes was performed on the basis of a comprehensive tectonophysical analysis of major geological and geophysical data.Results. The main axes of the neo-tectonic activity of the plate complex break the area under study into a quite regular block system that reflects a right-sided shift of fundamental blocks, that, in its turn predetermines the block shift in plate complex with the turn of the shift axis by 30 degrees. The most significant oil and gas holes in terms of influx demonstrate a connection with the described scheme of block activity. Thus, practically all high-debit boreholes were drilled in active axial zones.Conclusion. The proposed scheme of block activity satisfies the general principles of geodynamics. The developed model of abnormal pressure estimations by main productive intervals shows a good agreement with the distribution oiland gas boreholes in terms of productivity. Contact zones of active blocks present a particular interest from the standpoint of selecting the location of high-debit boreholes. These zones should be taken into account when developing new oil and gas deposits. 


2020 ◽  
Vol 42 (4) ◽  
pp. 33-49
Author(s):  
O.V. CHEPIZHKO ◽  
V.V. YANKO ◽  
V.M. KADURIN ◽  
I.M. NAUMKO ◽  
S.M. SHATALIN

For the first time the importance of mineralogical and lithological-petrographical ranks in the line of geological information ranks is substantiated for implementation of long-term forecasts, standard and non-standard approaches to research of physical and geochemical parameters as a basis of creation of complex system of forecast criteria and prospecting indicators of hydrocarbons within the sedimentary cover of Black sea based on the theory of global fluid-flows derivation. These criteria have different sensitivity to the object (hydrocarbon deposits) and are therefore ranked. The ranking determined the following parameters: 1) seismic data within the object, obtained by the method of deep seismic sounding, RWM SDP; 2) parameters of tectono-geodynamic structures; 3) the main characteristics of sedimentary cover and bedrock; 4) geochemical characteristics; 5) parameters of mineral complexes and fluid inclusions in mineral neoformations; 6) the value of the distribution of meiobenthos. Based on modern views of oil and gas geology, structural-tectonic and lithological-facies criteria are among the main ones. The study of the mineralogical component of sediments is made with using mineralogical, thermobarogeochemical and X-ray spectral methods. Fixation of anomalies of fluid flow at the bottom of the Black Sea as to the distribution of abiotic parameters in order to assess the prospects of oil and gas is determined by structural and tectonic features and high permeability of fluid flow; parameters of mineral complexes (minerals, facies) and genetic connections; heterogeneity of geochemical characteristics of bottom sediments; the presence of hydrocarbon inclusions in authigenic minerals of bottom sediments.


2017 ◽  
Vol 54 (4) ◽  
pp. 265-293 ◽  
Author(s):  
Roger Matson ◽  
Jack Magathan

The Hanna Basin is one of the world’s deeper intracratonic depressions. It contains exceptionally thick sequences of mature, hydrocarbon-rich Paleozoic through Eocene rocks and has the requisite structural and depositional history to be a significant petroleum province. The Tertiary Hanna and Ferris formations consist of up to 20,000 ft of organic-rich lacustrine shale, shaly mudstone, coal, and fluvial sandstone. The Upper Cretaceous Medicine Bow, Lewis, and Mesaverde formations consist of up to 10,000 ft of marine and nonmarine organic-rich shale enclosing multiple stacked beds of hydrocarbon-bearing sandstone. Significant shows of oil and gas in Upper Cretaceous and Paleocene rocks occur in the basin. Structural prospecting should be most fruitful around the edges where Laramide flank structures were created by out-of-the-basin thrust faults resulting from deformation of the basin’s unique 50-mile wide by 9-mile deep sediment package. Strata along the northern margin of the basin were compressed into conventional anticlinal folds by southward forces emanating from Emigrant Trail-Granite Mountains overthrusting. Oil and gas from Pennsylvanian to Upper Cretaceous aged rocks have been found in such structures near the Hanna Basin. Only seven wells have successfully probed the deeper part of the Hanna Basin (not including Anadarko’s #172 Durante lost hole, Sec. 17, T22N, R82W, lost in 2004, hopelessly stuck at 19,700 ft, unlogged and untested). Two of these wells tested gas at commercial rates from Upper Cretaceous rocks at depths of 10,000 to 12,000 ft. Sparse drilling along the Hanna Basin’s flanks has also revealed structures from 3,000 to 7,000 feet deep which yielded significant shows of oil and gas.


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