scholarly journals Features of the geological structure, tectonic development and oil and gas potential of the Chezhen depression (Bohai bay basin)

Author(s):  
Sh. Qiu ◽  
N. A. Kasyanova

Background. In terms of oil and gas, the territory of the Chezhen depression has been studied insufficiently compared to the neighbouring same-range depressions. These depressions complicate the first-order Jiyang depression, geographically coinciding with the largest Shengli hydrocarbon field. In recent years, much geological and geophysical information about the oil geologyof the Chezhen depression has been accumulated, which allows its prospecting oil and gas potential to be assessed.Aim. To reveal regular features of the geological structure and location of oil deposits in the Chezhen depression in order to support the prospecting and exploration work within the Chezhen block of the Shengli field.Materials and methods. A comprehensive analysis of literature data and collected materials was conducted. A historical and geodynamic study of the evolution of the studied area according to literature data was carried out, along with an analysis of the most recent geological and geophysical information and exploration data based on the materials of the “Shengli AKOO Sinopek” oil company. The analysis was based on the data from 52 drilling wells and the results of seismic surveys performed in the central part of the Chezhen depression.Results. Specific features of the block geological structure of the area under study were established, which formed under the repeated influence of large-scale horizontal tectonic movements occurring at different periods of geological history. The role of the most recent fault system in the modern spatial distribution of oil deposits was determined.Conclusions. Our studies demonstrate a great prospecting potential of the Chezhen depression territory, where the discovery of new industrial oil deposits can be expected.

Author(s):  
Anatoly M. NIKASHKIN ◽  
Alexey A. KLIMOV

One of the primary and significant tasks in the construction of geological models of oil and gas reservoirs and development facilities is the problem of correlation of productive layers. This task, as a rule, is reduced to the identification and areal tracing of presumably even-aged oil and gas strata, horizons, and layers characterized by clear boundaries between sand strata and clay layers overlapping them. The practice of work related to modeling the structure of oil and gas horizons, layers and strata indicates that the correlation is not always unambiguous. The ambiguity is especially noticeable when correlating strata characterized by a clinoform structure, one of the examples is the Achimov strata. The most reliable basis for well correlation is GIS materials and lithological features of the interlayers forming individual layers. Clay interlayers and clay strata separating productive deposits provide valuable information when choosing a correlation model in sedimentary sections. These interlayers are characterized by the greatest consistency in area and are most clearly displayed on geophysical diagrams by the nature of the drawings of GIS curves. However, even in this case, i. e. when using the entire accumulated volume of the most diverse lithological and field-geophysical information, the correlation models of the sections turn out to be different and often even opposite. In this paper, the authors had to face a similar situation when correlating the horizon AS11 of the Zapadno-Kamynskoye field. The paper describes a method for clarifying the position of the chops of the productive horizon of oil and gas deposits using a multidimensional deterministic-statistical numerical model of the correlation of sedimentary strata. The proposed approach allows us to uniquely determine the positions of the chops in the conditions of a complex geological structure of the object, high thin-layered heterogeneity. A concrete example shows the advantages of the proposed approach in comparison with the traditional one.


2020 ◽  
Vol 1 (2) ◽  
pp. 7-19
Author(s):  
Vladimir Sergeevich PONOMAREV ◽  
◽  
Kirill Svyatoslavich IVANOV ◽  
Yuriy Viktorovich EROKHIN ◽  
◽  
...  

Relevance of the work. The Western Siberian megabasin is the main source of oil and gas in Russia. Therefore, the study of geological structure and evolution of the development of sedimentary cover rock complexes and the basement of the region is important for estimating the oil and gas potential of this vast territory. The object of this paperis the mineralogical and petro-geochemical study of volcanites from the pre-Jurassic basement of the Lakyuganskaya area (well no. 101) of the Longyugansk exploration acreage within the territory of the Nadym megadepression of the Western Siberian megabasin. Scope of work. This work can be useful when constructing geological maps of the basement of the northern part of the Western Siberian Plate. Results and conclusions. We have studied and described the mineralogy of strongly altered volcanites from the pre-Jurassic basement of the Lakyugansk area (well no. 101) of the Western Siberian Plate. According to chemical composition, the studied volcanites are classified as moderate and high potassic basalts, andesite-basalts and andesites. The rocks were subjected to significant secondary changes in the mineral composition, such as greenschist metamorphism and propylitization. Only titanomagnetite has been preserved from primary minerals in volcanites; all other minerals were subjected to changes. In general, we have determined the following minerals – albite, clinochlore, titanite, calcite, goethite, titanomagnetite (magnetite, ulvospinel), fluorapatite, and rutile. For the first time, ferroaluminoceladonite (dioctahedral mica) and three relatively rare secondary copper sulfides – spionkopite, yarrowite, and geerite – were identified and described in basalts from the basement of Western Siberia. Sulfide coppery mineralization in the studied basalts was due to overlapped propylization processes. The rocks have features of volcanites of island arcs, as well as evidence of calc-alkali and intraplate basalts. The petrological and geochemical characteristics of the studied volcanites are similar to basalts composing the Koltogorsko-Urengoysky rift of the Western Siberian Plate.


2021 ◽  
Vol 82 (3) ◽  
pp. 19-26
Author(s):  
POPKOV VASILY I. ◽  

The surface of the folded base of the platforms is an important geological boundary separating rock complexes formed in different geodynamic settings and characterized by different physical properties, which largely determine the patterns of formation of minerals in them. Therefore, determining the depth of its occurrence and morphology is not only theoretical, but also practical. Despite many years of studying the foundation of the west of the Turan Platform, there is no unity among geologists and geophysicists in their ideas about its structure, depth of occurrence and surface structure. In this regard, the aim of the work is to build a structural map of the surface of the foundation of the west of the Turan plate, to identify the main tectonic structures and their morphology. The construction is based on a comprehensive analysis of drilling materials and geophysical data. When drawing up the structural map, all the currently available geological and geophysical material was used, including data from drilling, gravity and magnetic surveys, and seismic surveys of various modifications, which made it possible to perform fairly detailed and reliable constructions. The article provides a detailed description of the surface structure of the folded base of the west Turan platform. The obtained results can be used in solving the issues of oil and gas potential of the studied territory. The folded base of the western Turan plate is a heterogeneous and heterochronous formation, differentiated by the depth of occurrence, which allows for morphostructural zoning of its surface.


2020 ◽  
Author(s):  
Meng Zhang ◽  
Zhiping Wu ◽  
Shiyong Yan

<p>Buried-hills, paleotopographic highs covered by younger sediments, become the focused area of exploration in China in pace with the reduction of hydrocarbon resources in the shallow strata. A number of buried-hill fields have been discovered in Tanhai area located in the northeast of Jiyang Depression within Bohai Bay Basin, which provides an excellent case study for better understanding the structural evolution and formation mechanism of buried-hills. High-quality 3-D seismic data calibrated by well data makes it possible to research deeply buried erosional remnants. In this study, 3-D visualization of key interfaces, seismic cross-sections, fault polygons maps and thickness isopach maps are shown to manifest structural characteristics of buried-hills. Balanced cross-sections and fault growth rates are exhibited to demonstrate the forming process of buried-hills. The initiation and development of buried-hills are under the control of fault system. According to strike variance, main faults are grouped into NW-, NNE- and near E-trending faults. NW-trending main faults directly dominate the whole mountain range, while NNE- and near E-trending main faults have an effect on dissecting mountain range and controlling the single hill. In addition, secondary faults with different nature complicate internal structure of buried-hills. During Late Triassic, NW-trending thrust faults formed in response to regional compressional stress field, preliminarily building the fundamental NW-trending structural framework. Until Late Jurassic-Early Cretaceous, rolling-back subduction of Pacific Plate and sinistral movement of Tan-Lu Fault Zone (TLFZ) integrally converted NW-trending thrust faults into normal faults. The footwall of NW-trending faults quickly rose and became a large-scale NW-trending mountain range. The intense movement of TLFZ simultaneously induced a series of secondary NNE-trending strike-slip faults, among which large-scale ones divided the mountain range into northern, middle and southern section. After entry into Cenozoic, especially Middle Eocene, the change of subduction direction of Pacific Plate induced the transition of regional stress field. Near E-trending basin-controlling faults developed and dissected previous tectonic framework. The middle section of mountain range was further separated into three different single hill. Subsequently, the mountain range was gradually submerged and buried by overlying sediments, due to regional thermal subsidence. Through multiphase structural evolution, the present-day geometry of buried-hills is eventually taken shape.</p>


Author(s):  
H.O. Zhuchenko ◽  
I.R. Mykhailiv ◽  
N.V. Hoptariova ◽  
H.D. Horvanko

The topicality of the research is determined by the detailed study of the peculiarities of the geological structure of Boryslav-Pokuttia zone of the Precarpathian deflection, in particular of local structural forms as probable traps for oil and gas, for reliable prediction of the oil and gas potential of the subsoil. Boryslav-Pokuttia zone of the Precarpathian deflection refers to one of the oldest oil and gas producing regions in Ukraine. Its hydrocarbon potential is far from being exhausted. The complex block structure of Boryslav-Pokuttia zone requires the development of specific methods for conducting oil and gas prospecting. In this regard, determining the distribution nature of the local structures and specifying the peculiarities of their morphological forms in the area under investigation are of great importance. The issue of tracing tectonic disturbances and determining their screening ability which determines the possible existence of hydrocarbon deposits remains to be an urgent matter. Solving these issues will significantly improve the geological efficiency of prospecting and exploration in the areas of Boryslav-Pokuttia zone. At the modern stage of the Earth sciences development computer processing of geological data is widely used.Therefore, along with the traditional approach to describing structures as potential traps for oil and gas, it isnecessary to analyze their quantitative (numerical) parameters. It gives a possibility to confirm the stablished regularities more reasonably. Handling large array of quantitative indicators of local structures and the dependencies established among them makes it possible to simulate the processes that formed them and to determine the regularities of their distribution. The most important scientific and practical results include: the quantitative indicators ranking of the local structures of Boryslav-Pokuttia zone (the ranking contains four groups of structures classified according to their morphological texture); the investigated conditions for the formation of morphological varieties of local structures and the character of the distribution of tectonic deformations in them. The results of geological and mathematical simulation according to a complex of quantitative indicators help to state that local structures with certain morphological features, which are revealed to various extent in their deformations, are formed by tectonic movements of different magnitude and direction and are described by the numerical parameters peculiar only to them. Investigating the distribution of tectonic stresses and deformations, which can be estimated in quantitative indicators, will contribute to a more reliable prediction of the oil and gas potential of the subsoil. In its turn, it will improve significantly the geological performance of oil and gas prospecting in the areas of BoryslavPokuttia zone of the Precarpathian deflection.


2017 ◽  
pp. 25-34
Author(s):  
G. .. Mukher ◽  
S. F. Kulagina ◽  
A. V. Goryachev ◽  
E. A. Pakhomova ◽  
A. A. Gladyshev

The features of the geological structure and oil and gas potential of the Bazhenov-Abalak oil and gas complex are discussed. Based on new geological and seismic data, using an integrated approach, the zones of distribution and the boundaries of thinning out of silty sand reservoir rocks of Vogulkinskaya strata were mapped, four traps and two zones (Ourinskaya, Eastern Tolumskaya), which are perspective for hydrocarbon deposits search, were distinguished. In Bazhenov horizon, the zones of development of anomalous sections and bituminous sediments were mapped, laying above Bazhenov formation, which are perspective for hydrocarbon deposits search. Recommendations for further exploration are given.


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