Conditions of the Formation Gas Deposits in the Epart of the Dnieper-Donets Basin: Integration of Basin Modeling Data with Consequences of Strike-Slip Faulting Effects

2021 ◽  
Author(s):  
Vitaliy Privalov ◽  
Valentyn Loktyev ◽  
David Misch ◽  
Reinhard Sachsenhofer ◽  
Ivan Karpenko ◽  
...  
Keyword(s):  
Fractured Reservoirs ◽  
Strike Slip ◽  
Naturally Fractured Reservoirs ◽  
Donets Basin ◽  
Lower Permian ◽  
Synthetic Approach ◽  
Basin Modeling ◽  
The North ◽  
Exploration And Production ◽  
Gaseous Hydrocarbons

Abstract Since 1950, when the megascale Shebelinka deposit was found in the north-eastern portion of the Dnieper-Donets basin (DDB) this district has been served as a heartland of the hydrocarbon extraction in Ukraine. Right now, this area is again facing a new wave of commercial interest. Most conventional hydrocarbon plays here contain natural gas and liquid gas accumulated in numerous clastic and fractured horizons throughout Carboniferous to Lower Permian successions. The numerical basin modelling in the Donbas segment indicated that organic-rich sediments are thermally mature in the deep levels of the basin. Our interpretation of the structural patterns within the study area suggests that the kinematic development of the fracture sets is consistent with the model of development of subsidiary structures within the dextral strike-slip zone. Nearly all gas and gas condensate fields in the eastern part of the DDB may be classified as naturally fractured reservoirs in fault-breached anticlinal traps associated with releasing jogs in strike-slip assemblages. Gaseous hydrocarbons generated in deep "gas window" compartments have escaped here via several fracture corridors forming "sweet spots " sites. The main objective of this contribution is to get an insight into the style and structural trends of formation structural traps of hydrocarbons which in concert with basin modeling technologies will ensure proper technical decisions for the efficient exploration and production of gas reservoirs. This research summarizes new insights into gas deposits formation in the eastern part of DDB based on a synthetic approach ascertaining a vital connection of basin modeling results with the spatial distribution of kinematically induced releasing jogs which facilitating magnified fluid-and-gas conductivity.

Modern Analogues of Sedimentation of Lower Permian Reservoirs in the Dnieper-Donets Depression

2021 ◽  
Author(s):  
Valentyn Loktyev ◽  
Sanzhar Zharkeshov ◽  
Oleg Gotsynets ◽  
Oleksandr Davydenko ◽  
Mikhailo Machuzhak ◽  
...  
Keyword(s):  
Donets Basin ◽  
Lower Permian ◽  
River Channels ◽  
Current Time ◽  
Meandering Channels ◽  
The North ◽  
Complex Picture ◽  
Middle Carboniferous ◽  
The Indian Ocean ◽  
Desert Dunes

Abstract The paper considers the problematics of identifying proper analogues for understanding carbonate and clastic reservoir distribution and prediction in the Lower Permian and Upper and Lower Carboniferous within the Dnieper-Donets basin. The focus of the exploration team was finding meandering rivers. This choice was proven good in mapping reservoirs and finding traps deeper in the Upper and Middle Carboniferous, although for Permian clastic section the approach was not helpful. The second option was desert dunes, but poor sorting of reservoirs suggests a more complex picture. Analogues such as desert environment is quite logical for describing Lower Permian as aridic climate, with red and brown shales and sands. Lower Permian reservoirs have a moon-like shape in the vertical sections that could be easily mistaken for river channels, but in such a dry climate, it is very likely water flow channels with sporadic hurricane-related activities. Core and logs shows chaotic grain sizes, but more with fine grains with almost no coarse grains. The source of sedimentary material could be mountains of Ukrainian Rock Shield from the South and Voronezh massif from the North. This conceptual model is proposing not to look for meandering channels, but more for braided channels with poorly sorted material. The current time analogue could be the Oman desert between the mountains and peninsula. From satellite images, braided channels are clearly visible in the direction towards the Indian Ocean. The channels’ internal structure is quite heterogeneous. This method suggests exploration targets with possible widths of the channels as big as hundreds of meters and their lengths under 10 and between 10-20 kilometres maximum.

scholarly journals A captorhinid-dominated assemblage from the palaeoequatorial Permian of Menorca (Balearic Islands, western Mediterranean)

2021 ◽  
pp. 1-21
Author(s):  
Rafel MATAMALES-ANDREU ◽  
Francesc X. ROIG-MUNAR ◽  
Oriol OMS ◽  
Àngel GALOBART ◽  
Josep FORTUNY
Keyword(s):  
Western Mediterranean ◽  
Balearic Islands ◽  
Distribution Area ◽  
Lower Permian ◽  
Incertae Sedis ◽  
The North ◽  
Low Latitudes ◽  
High Fibre ◽  
Successful Group ◽  
Neighbouring Island

ABSTRACT Moradisaurine captorhinid eureptiles were a successful group of high-fibre herbivores that lived in the arid low latitudes of Pangaea during the Permian. Here we describe a palaeoassemblage from the Permian of Menorca (Balearic Islands, western Mediterranean), consisting of ichnites of small captorhinomorph eureptiles, probably moradisaurines (Hyloidichnus), and parareptiles (cf. Erpetopus), and bones of two different taxa of moradisaurines. The smallest of the two is not diagnostic beyond Moradisaurinae incertae sedis. The largest one, on the other hand, shows characters that are not present in any other known species of moradisaurine (densely ornamented maxillar teeth), and it is therefore described as Balearosaurus bombardensis gen. et sp. nov. Other remains found in the same outcrop are identified as cf. Balearosaurus bombardensis gen. et sp. nov., as they could also belong to the newly described taxon. This species is sister to the moradisaurine from the lower Permian of the neighbouring island of Mallorca, and is also closely related to the North American genus Rothianiscus. This makes it possible to suggest the hypothesis that the Variscan mountains, which separated North America from southern Europe during the Permian, were not a very important palaeobiogeographical barrier to the dispersion of moradisaurines. In fact, mapping all moradisaurine occurrences known so far, it is shown that their distribution area encompassed both sides of the Variscan mountains, essentially being restricted to the arid belt of palaeoequatorial Pangaea, where they probably outcompeted other herbivorous clades until they died out in the late Permian.

The 25 October, 2018 Zakynthos (Greece) earthquake: seismic activity at the transition between a transform fault and a subduction zone.

2020 ◽  
Author(s):  
P Papadimitriou ◽  
V Kapetanidis ◽  
A Karakonstantis ◽  
I Spingos ◽  
K Pavlou ◽  
...  
Keyword(s):  
Spatial Clustering ◽  
Accretionary Prism ◽  
Velocity Model ◽  
Strike Slip ◽  
Double Difference ◽  
Strain Partitioning ◽  
Transform Fault ◽  
Fault Plane Solutions ◽  
The North ◽  
Waveform Modelling

Summary The properties of the Mw = 6.7 earthquake that took place on 25 October 2018, 22:54:51 UTC, ∼50 km SW of the Zakynthos Island, Greece, are thoroughly examined. The main rupture occurred on a dextral strike-slip, low-angle, east-dipping fault at a depth of 12 km, as determined by teleseismic waveform modelling. Over 4000 aftershocks were manually analysed for a period of 158 days. The events were initially located with an optimal 1D velocity model and then relocated with the double-difference method to reveal details of their spatial distribution. The latter spreads in an area spanning 80 km NNW-SSE and ∼55 km WSW-ENE. Certain parts of the aftershock zone present strong spatial clustering, mainly to the north, close to Zakynthos Island, and at the southernmost edge of the sequence. Focal mechanisms were determined for 61 significant aftershocks using regional waveform modelling. The results revealed characteristics similar to the mainshock, with few aftershocks exhibiting strike-slip faulting at steeper dip angles, possibly related to splay faults on the accretionary prism. The slip vectors that correspond to the east-dipping planes are compatible with the long-term plate convergence and with the direction of coseismic displacement on the Zakynthos Island. Fault-plane solutions in the broader study area were inverted for the determination of the regional stress-field. The results revealed a nearly horizontal, SW-NE to E-W-trending S1 and a more variable S3 axis, favouring transpressional tectonics. Spatial clusters at the northern and southern ends of the aftershock zone coincide with the SW extension of sub-vertical along-dip faults of the segmented subducting slab. The mainshock occurred in an area where strike-slip tectonics, related to the Cephalonia Transform Fault and the NW Peloponnese region, gradually converts into reverse faulting at the western edge of the Hellenic subduction. Plausible scenarios for the 2018 Zakynthos earthquake sequence include a rupture on the subduction interface, provided the slab is tilted eastwards in that area, or the reactivation of an older east-dipping thrust as a low-angle strike-slip fault that contributes to strain partitioning.

scholarly journals The nucleation of the Izmit and Düzce earthquakes: Some mechanical logic on where and how ruptures began

2021 ◽  
Author(s):  
Michel Bouchon ◽  
Hayrullah Karabulut ◽  
Mustafa Aktar ◽  
Serdar Özalaybey ◽  
Jean Schmittbuhl ◽  
...  
Keyword(s):  
Strike Slip ◽  
Seismic Events ◽  
Fault Geometry ◽  
Brittle Transition ◽  
The North ◽  
Impending Rupture ◽  
Natural Tendency ◽  
Ductile To Brittle Transition ◽  
Mechanical Logic ◽  
Rupture Speed

Summary In spite of growing evidence that many earthquakes are preceded by increased seismic activity, the nature of this activity is still poorly understood. Is it the result of a mostly random process related to the natural tendency of seismic events to cluster in time and space, in which case there is little hope to ever predict earthquakes? Or is it the sign that a physical process that will lead to the impending rupture has begun, in which case we should attempt to identify this process. With this aim we take a further look at the nucleation of two of the best recorded and documented strike-slip earthquakes to date, the 1999 Izmit and Düzce earthquakes which ruptured the North Anatolian Fault over ∼200 km. We show the existence of a remarkable mechanical logic linking together nucleation characteristics, stress loading, fault geometry and rupture speed. In both earthquakes the observations point to slow aseismic slip occurring near the ductile-to-brittle transition zone as the motor of their nucleation.

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