Features of the composition of gas sorbed in the rocks of the upper part of the sedimentary cover section

2021 ◽  
pp. 23-35
Author(s):  
M. D. Zavatsky ◽  
A. A. Nezhdanov ◽  
A. N. Kurchatova

The topicality of the article is determined by the insufficient reliability of geochemical oil and gas exploration data for the localization of petroliferous geological objects. Geochemical surveys are carried out to mapping hydrocarbon anomalies caused by vertical migration of fluid from hydrocarbon deposits. Practice shows that not all anomalies in the content of hydrocarbons in the near-surface environment are related to the oil-bearing capacity of a given subsoil area. Therefore, when interpreting the data of geochemical oil and gas prospecting surveys, it is necessary to take into account not only quantitative indicators (namely, content of hydrocarbon gases on the surface), but also the composition of the gas sorbed by the near-surface substrate. The purpose of the article is to determine the composition of the dissipated gases in the rocks of the upper part of the section, to reveal the inter-component relationships, and, on this basis, to determine the genesis of each gas component sorbed by the rocks of the upper part of the section. To solve this problem, statistical processing of data on the component content of gas from core degassing of shallow (up to 30 m) wells drilled in the petroliferous territory of the north of Western Siberia was carried out. The obtained results confirmed the genetic heterogeneity of dissipated hydrocarbons and inorganic gases in the upper part of the sedimentary cover.

Author(s):  
А.Г. Шемпелев ◽  
С.У. Кухмазов ◽  
М.А. Компаниец ◽  
К.С. Харебов ◽  
Х.О. Чотчаев ◽  
...  

Несколькими организациями в последние десятилетия были выполнены региональные геофизические исследования различными методами в пределах Северного Кавказа. Вдоль Чегемского профиля (перевал Китлод – г. Буденновск) впервые к северу от зоны сочленения структур Большого Кавказа со Скифской плитой получены две чёткие субгоризонтальные сейсмические границы, разделяющие, вероятно, платформенный чехол, переходный комплекс и консолидированный фундамент. Платформенный чехол, представленный палеозойскими отложениями большой мощности, по аналогии со многими территориями мира, где уже обнаружены и разведаны уникальные месторождения нефти, включая шесть залежей углеводородов, в числе которых и газоконденсатное Кармалиновское месторождение в зоне Передового хребта, может оказаться перспективным на нефтегазовые структуры. Результаты глубинных геофизических работ последних лет могут скорректировать направление поисков углеводородов в регионе. Известные в этом районе Предкавказья восточнее Чегемского профиля нефтегазоносные структуры осадочного чехла приурочены к выделяемым по геофизике поднятиям в консолидированной коре или к их краевым частям. Это даёт основание ожидать наличие углеводородов, вероятно, в материнских палеозойских образованиях Чернолесской впадины, а также соответственно новые перспективные участки и в осадочном чехле по её обрамлению. Several organizations in recent decades have carried out regional geophysical studies by various methods within the North Caucasus. Along the Chegem profile (the Kitlod Pass – town of Budennovsk), for the first time to the north of the junction zone of the Greater Caucasus structures with the Scythian plate, two distinct subhorizontal seismic boundaries, probably sharing a platform cover, a transitional complex and a consolidated foundation have been obtained. The platform cover, represented by large Paleozoic deposits, by analogy with many areas of the world where unique oil deposits, including six hydrocarbon deposits, and the gas condensate Karmalinovskoye deposit in the zone of the Forward Ridge, have already been discovered and explored, may prove promising for oil and gas structures. The results of deep geophysical studies of recent years can correct the direction of hydrocarbon exploration in the region. The oil-and-gas-bearing structures of the sedimentary cover, known in this region of the Ciscaucasia to the east of the Chegem profile, are confined to uplifts in geophysics in the consolidated crust or to their marginal parts. This gives grounds to expect the presence of hydrocarbons, probably in the parent Paleozoic formations of the Chernoslavskaya depression, and also, respectively, new promising sites in the sedimentary cover along its framing.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Haitao Zhang ◽  
Guangquan Xu ◽  
Mancai Liu ◽  
Minhua Wang

AbstractWith the reduction of oil and gas reserves and the increase of mining difficulty in Northern China, the carbonate rocks in Southern North China Basin are becoming a significant exploration target for carbonate reservoirs. However, the development characteristics, formation stages, formation environments and mechanisms of the carbonate reservoirs in Southern North China Basin are still unclear, which caused the failures of many oil and gas exploration wells. This study focused on addressing this unsolved issue from the Ordovician carbonate paleokarst in the Huai-Fu Basin, which is located in the southeast of Southern North China Basin and one of the key areas for oil and gas exploration. Based on petrology, mineralogy and geochemical data, pore types, distribution characteristics, and formation stages of the Ordovician paleokarst were analyzed. Then, in attempt to define the origins of porosity development, the formation environments and mechanisms were illustrated. The results of this study showed that pore types of the Ordovician carbonates in the Huai-Fu Basin are mainly composed of intragranular pores, intercrystalline (intergranular) pores, dissolution pores (vugs), fractures, channels, and caves, which are usually in fault and fold zones and paleoweathering crust. Furthermore, five stages and five formation environments of the Ordovician paleokarst were identified. Syngenetic karst, eogenetic karst, and paleoweathering crust karst were all developed in a relatively open near-surface environment, and their formations are mainly related to meteoric water dissolution. Mesogenetic karst was developed in a closed buried environment, and its formation is mainly related to the diagenesis of organic matters and thermochemical sulfate reduction in the Permian-Carboniferous strata. Hydrothermal (water) karst was developed in a deep-buried and high-temperature environment, where hydrothermal fluids (waters) migrated upward through structures such as faults and fractures to dissolve carbonate rocks and simultaneously deposited hydrothermal minerals and calcites. Lastly, a paleokarst evolution model, combined with the related porosity evolution processes, nicely revealed the Ordovician carbonate reservoir development. This study provides insights and guidance for further oil and gas exploration in the Southern North China Basin, and also advances our understanding of the genesis of carbonate paleokarst around the world.


2021 ◽  
pp. 23-31
Author(s):  
Y. I. Gladysheva

Nadym-Pursk oil and gas region has been one of the main areas for the production of hydrocarbon raw materials since the sixties of the last century. A significant part of hydrocarbon deposits is at the final stage of field development. An increase in gas and oil production is possible subject to the discovery of new fields. The search for new hydrocarbon deposits must be carried out taking into account an integrated research approach, primarily the interpretation of seismic exploration, the creation of geological models of sedimentary basins, the study of geodynamic processes and thermobaric parameters. Statistical analysis of geological parameters of oil and gas bearing complexes revealed that the most promising direction of search are active zones — blocks with the maximum sedimentary section and accumulation rate. In these zones abnormal reservoir pressures and high reservoir temperatures are recorded. The Cretaceous oil and gas megacomplex is one of the main prospecting targets. New discovery of hydrocarbon deposits are associated with both additional exploration of old fields and the search for new prospects on the shelf of the north. An important area of geological exploration is the productive layer of the Lower-Berezovskaya subformation, in which gas deposits were discovered in unconventional reservoirs.


2019 ◽  
pp. 3-11
Author(s):  
E. A. Rogozhin ◽  
A. V. Gorbatikov ◽  
Yu. V. Kharazova ◽  
M. Yu. Stepanova ◽  
J. Chen ◽  
...  

In the period from 2007 to 2017 complex geological and geophysical studies were carried out in the three largest flexural-rupture fault zones in the North-West Caucasus (Anapa, Akhtyrka and Moldavan). The micro-seismic sounding (MSM) was used as the main geophysical method. Studies with the help of MSM allowed us to identify the features of the deep structure of the earth’s crust in the study area and to associate them with specific tectonic structures on the surface.The binding was carried out by harmonizing the results of the MSM and the parameters of the section of the sedimentary cover and crustal boundaries according to the drilling data and the work previously performed by the reflected wave method (MOVZ). It was found that the Anapa flexure and longitudinal tectonic zones have clear deep roots, and also separate the pericline of the North-Western Caucasus from the Taman Peninsula and from the lowered blocks of the Northern slope of the folded system.Faults in the study area are divided into: (1) deep faults of the Caucasian stretch, penetrating into the lower crust and even to the upper mantle, and (2) near-surface faults, do not extend to the depths beyond the thickness of the sedimentary cover. The seismogenic role of these tectonic disturbances in the studied seismically active region has been determined.


Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3802
Author(s):  
Jun Li ◽  
Xiaoying Zhang ◽  
Bin Lu ◽  
Raheel Ahmed ◽  
Qian Zhang

Geological modelling is an important topic of oil and gas exploration and production. A new knowledge driven methodology of geological modelling is proposed to address the problem of “hard data” limitation and modelling efficiency of the conventional data driven methodology. Accordingly, a new geological modelling software (DMatlas) (V1.0, Dimue, Wuhan, China) has been developed adopting a grid-free, object-based methodology. Conceptual facies models can be created for various depositional environments (such as fluvial, delta and carbonates). The models can be built largely based on geologists’ understandings with “soft data” such as outcrops analysis and geological maps from public literatures. Basic structures (fault, folds, and discrete fracture network) can be easily constructed according to their main features. In this methodology, models can be shared and re-used by other modelers or projects. Large number of model templates help to improve the modelling work efficiency. To demonstrate the tool, two case studies of geological modelling with knowledge driven methodology are introduced: (1) Suizhong 36-1 field which is a delta depositional environment in Bohai basin, China; (2) a site of the north Oman fracture system. The case studies show the efficiency and reliability within the new methodology.


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.


Author(s):  
D. D. Ismailov ◽  
S. G. Serov ◽  
R. N. Mustaev ◽  
A. V. Petrov

The results of studies of hydrocarbon systems of the Eastern and Central Ciscaucasia are shown. The research area covers part of the Scythian platform, namely, the northern side of the Terek-Caspian foredeep, the north-eastern part of the East Kuban depression, the Tersko-Kum depression and the Stavropol arch. Based on the results of the work and basin modelling of hydrocarbons generation, emigration and accumulation processes, the reconstruction of the history of oil and gas formation and oil and gas accumulation in the sedimentary cover of the region was completed. The basin modelling of hydrocarbon formation processes in Central and Eastern Ciscaucasia was carried out using the PetroMod (Schlumberger) program complex. The obtained results made it possible to determine the dynamics of organic substance transformation processes, evolution of oil and gas formation zones, time and expected paths of hydrocarbon migration and phase composition and degree of hydrocarbon saturation of the section. The model reliability was corrected by comparing the values of benchmarks (modern reservoir temperatures measured in wells, with their calculated values obtained as a result of modelling). The location of possible foci of hydrocarbon generation in the sedimentary cover, the migration paths, the phase composition of hydrocarbons, the intensity of hydrocarbon saturation within individual tectonic zones and structures were determined. It has been established that the main foci of hydrocarbon generation in the southern part of the studied region are located in the Chechen depression (Tersko-Caspian deep), on the platform part–in the zone of the Manych deep and Nogai stage.


2021 ◽  
Author(s):  
Ayrat Bashirov ◽  
Ilya Galas ◽  
Marat Nazyrov ◽  
Dmitry Kuznetsov ◽  
Azamat Akkuzhin

Abstract In many oil and gas provinces not only in Russia, but throughout the world, carbonate strata make up a significant portion of the sedimentary cover, and large accumulations of hydrocarbons are associated with them. However, the purposeful study of them as reservoirs for hydrocarbons in our country practically began only in the post-war years. In the special petrography laboratory carbonate rocks composing various stratigraphic complexes of almost all oil and gas provinces of the Soviet Union were studied, and in particular, Paleozoic carbonate strata of the Timan-Pechora province, Ural-Volga region, Belarus, Kazakhstan, ancient Riphean-Cambrian formations of Yakutia and relatively young strata of the Late Cretaceous of the northeastern Ciscaucasia. Carbonates are widespread sedimentary rocks. A very significant part of them was formed in the conditions of vast shallow-water marine epicontinental basins. A large number of works are devoted to the study of such deposits. However, issues related to the conditions of formation of carbonate sediments and their postsedimentary changes cannot be considered resolved, as well as the classification of the rocks themselves. The analyzed field is the Osvanyurskoye one. It was discovered in 2007. The field is located in the north-east of the European part of the Russian Federation, 2 km from Usinsk in the Komi Republic. The field is a part of the Timano-Pechora oil and gas province and it is a mature field (fig. 1). The objective was a 2.5m thick layer of the Serpukhov horizon.


2013 ◽  
Vol 448-453 ◽  
pp. 3723-3727 ◽  
Author(s):  
Yun Pan ◽  
Zong Xiu Wang ◽  
Mao Pan

There are a lot of Permian volcanic rocks which are widely distributed in Tarim Basin. Because of the shielding effect of the volcanic rocks to the underlying structure, the distribution of the volcanic rocks in Tarim Basin is very important to the deep oil and gas exploration. However, with the progress of oil exploration in Tarim oil field in recent years, much more logging and seismic data is available. Based on the model of logging-seismic integrated identification, the distribution of the Permian volcanic rocks is revised by using the drilling, logging and seismic data. It shows that the rhyolite is mainly distributed in the north basin, and the basalt is widely distributed in the basin. Moreover, the basalt has larger area than which delineated by other people.


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