Wyniki wyszukiwania - BazTech

1

Analiza mikrofacjalna dolomitu głównego (Ca2) we wschodniej części wielkopolskiej platformy węglanowej

Krzyżak Ewelina

Przegląd Geologiczny

|

2019

|

Vol. 67, nr 3

172--175

EN

Investigation of the Permian Basin in the western part of the Polish Lowland was initiated in 1961 when the Rybaki field was discovered - the first one outside the Carpathians in Poland. The Main Dolomite (Ca2) in the eastern part of the Wielkopolska Platform, located in western Poland, is characterized by a significant variety of microfacies, hence this research is aimed at better interpretation and understanding of depositional environments of current reservoir rocks as well as possibility of identification of facies distribution within the investigated carbonate platform. A detailed microfacies analysis of the Main Dolomite was conducted, which was supported by core logging. The author interpreted depositional environments and generated a 3D model of the top of the Main Dolomite using seismic reflection data. An attempt to correlate microfacies between the analyzed wells was also performed. Integrated analyses of thin sections and drill cores from 4 wells allowed me to interpret the depositional environments of the Main Dolomite. The generated 3D model of the top of the Main Dolomite provided a better insight into subsurface tectonics, paleogeography of the analyzed area and a better understanding of depositional lithofacies environments.

2

The siliciclastics/carbonates shift in the Jurassic of the Western Caucasus (central northern Neo-Tethys): reconsidering research over the last 50 years

Ruban Dmitry A.

Geologos

|

2019

|

Vol. 25, No. 2

153--162

EN

A chain of carbonate platforms evolved in the northern Neo-Tethys during the Late Jurassic, but current knowledge remains incomplete as long as data from several larger regions, such as the Western Caucasus, are not included. In order to fill this gap, it is here suggested to reconsider the information accumulated chiefly during Soviet times. Although these data are too general, they still matter with regard to some regional characteristics and tentative interpretations. Available data on the spatio-temporal distribution of Bajocian-Callovian sedimentary rocks are summarised in a novel way which permits documentation of depositional trends at six representative localities in the Western Caucasus. The extent of the carbonate platform increased at two localities since the Late Callovian and at a third since the Middle Oxfordian. Three additional sites were characterised either by non-deposition or deep-marine sedimentation. The onset of carbonate platform development marked a remarkable shift from chiefly siliciclastic to carbonate deposition, although this event was not sudden everywhere. The Bathonian pulse of tectonic activity, coupled with the eustatic sea level rise, allowed shelves to expand during the Callovian-Oxfordian, with a reduction in siliciclastic input from islands and seawater that became well oxygenated and warmer. These conditions were conducive to biogenic carbonate production, allowing the carbonate platform to expand subsequently.

3

The Racławka Valley – an example of an educational geosite related to the development of a Paleozoic carbonate platform

Szczurek S., Bąk M., Dulemba P.

Geotourism / Geoturystyka

|

2016

|

nr 1-2

45--56

EN

The location and most interesting geological features of the Upper Devonian through Lower Carboniferous limestones in the Racławka Valley were presented. The limestones outcropped almost continuously along the natural valley cutting. They comprise over 60 million years of continuous growth of the carbonate platform, which developed on the ancient terrane – the Upper Silesian Block. Geosites described herein may constitute a destination for geological trips for undergraduate students of Environmental Sciences, where they can actively discover the development of an ancient carbonate platform and accompanied post depositional structures.

PL

W dolinie Racławki znajdują się ważne geologicznie naturalne odsłonięcia wapieni (od późnego dewonu do wczesnego karbonu). Wapienie te obejmują okres ponad 60 milionów lat ciągłej sedymentacji węglanowej, która występowała na obszarze paleozoicznego kratonu – bloku górnośląskiego. Opisane stanowiska mogą być celem wycieczek geologicznych studentów pierwszego stopnia studiów przyrodniczych, w czasie których mogą oni w aktywny sposób śledzić rozwój kopalnej platformy węglanowej i struktur postdepozycyjnych.

4

Analiza statystyczna parametrów mikrofacji dolomitu głównego w granicznej strefie platformy węglanowej

Semyrka R., Jarzyna J. A., Krakowska P. I., Semyrka G.

Gospodarka Surowcami Mineralnymi

|

2015

|

T. 31, z. 1

123--140

PL

Duża liczba wyników badań laboratoryjnych parametrów zbiornikowych dolomitu głównego na obszarze platformy węglanowej, w rejonie wschodniej części platformy Gorzowa, w zatoce Noteci wraz z mikroplatformą Krobielewka, na półwyspie Grotowa, oraz na fragmencie platformy wielkopolskiej, sięgającym rejonu Pniew umożliwiła wykonanie wiarygodnych analiz statystycznych. Standardowe badania na próbkach skał (gęstości objętościowej, porowatości efektywnej i przepuszczalności fizycznej) wzbogacone zostały o wyniki pomiarów porozymetrii rtęciowej. Wyniki badań laboratoryjnych, przede wszystkim porozymetrii rtęciowej, rozszerzyły znacznie informację o skale zbiornikowej (dolomicie głównym) i przyczyniły się do wydzielenia różnorodnych mikrofacji oraz stref paleogeograficznych. Na podstawie wyników przeprowadzonej analizy statystycznej porównano parametry petrofizyczne trzech mikrofacji i stwierdzono, że utwory ziarnozwięzłe charakteryzowały się najlepszymi właściwościami zbiornikowymi. Dla tych utworów stwierdzono wysoką średnią porowatość efektywną oraz wysoką średnią porowatość dynamiczną dla gazu i ropy. Utwory te charakteryzowały się także wysoką przepuszczalnością. [...]

EN

Reliable statistical analysis was carried out for the Main Dolomite reservoir parameters on the area of carbonate platform in the vicinity of the east part of Gorzów Platform, in the Noteć Bay, together with Krobielewko Microplatform, on the Grotów Peninsula and on the part of Wielkopolska Platform, reaching Pniewy region thanks to large number of laboratory measurements results. The standard measurements on the core samples (bulk density, effective porosity and absolute permeability) were enriched by mercury porosimetry results. Laboratory measurements results, especially mercury porosimetry, extended considerably information about the reservoir rock (the Main Dolomite) and contributed to the separation of diverse microfacies and paleogeographic zones. Petrophysical parameters of the three microfacies were compared based on the results of statistical analysis. It was found that grainstones were characterized by the best reservoir parameters. For these microfacies high average effective porosity and average dynamic porosity for oil and gas were discovered. Additionally, grainstones characterized by high permeability. [...]

5

Small-scale cyclic deposition in the Frasnian (Upper Devonian) of the Holy Cross Mountains, Poland

Vierek A.

Geologos

|

2014

|

Vol. 20, No. 4

239--258

EN

In sections exposing Frasnian limestones at five outcrops in the Holy Cross Mountains, five lithofacies (L1 to L5) that represent upper slope to basinal environments are identified. These lithofacies are characterised by dark-coloured micritic limestones–marly shale couplets with many light-coloured intercalations of fine- to coarse-grained limestones (= event beds). This lithofacies pattern characterises mostly low-energy domains punctuated by storm episodes. In addition, these upper-slope to basinal lithofacies are arranged into small-scale, coarsening-upward beds and cycles. The cycles are locally composed of fining/thinning-upward beds. The small-scale cycles have a calculated duration of 19 to 42 kyr. The differential thickness of beds and cycles within and between sections was probably caused by differential subsidence and local tectonics. Possible evidence of tectonic activity is also related to a difference in number of cycles recorded in the time-equivalent sections. The recognised cyclicity shows sea-level fluctuations and a few deepening episodes. Some of them are correlated with the Timan global eustatic events. However, local tectonics and episodic subsidence may have played a significant role in recording brief deepening pulses. Thus, low-amplitude sea-level changes were major factors in platform generation and evolution in the Frasnian of the Holy Cross Mountains modified by local, block-related subsidence.

6

The Steinplatte complex (Late Triassic, Northern Calcareous Alps, Austria) - subsidence-controlled development of a carbonate-platform-to-intrashelfbasin-transition

Kaufmann B.

Acta Geologica Polonica

|

2009

|

Vol. 59, no. 3

341-357

EN

In Rhaetian (Late Triassic) times, the Hauptdolomit/Dachstein carbonate shelf situated at the passive continental margin of the northwestern Tethys was characterized by an extensional tectonic regime. Rifting and spreading movements fragmented this shelf into a loosely fitted mosaic of fault-bounded blocks characterized by a differential subsidence pattern. This is expressed in significant thickness variations of platform carbonates and in the formation of the intrashelf Kossen Basin. In this study, it can be demonstrated that tectonic subsidence triggered the development of a carbonate platform margin and that the influence of eustatic sea-level changes was negligible. The Steinplatte complex developed at the transition of the Kossen Basin to the Dachstein Carbonate Platform. Small-scale isolated carbonate mounds situated on a smoothly inclined homoclinal ramp characterized the initial phase and acted as nuclei of further carbonate buildup growth. However, only the ideal palaeogeographic position far enough away from the carbonate-suppressive terrigenous influence of the Kossen Beds, combined with vigorous carbonate production stimulated by rapid subsidence-caused sea-level rise, favoured continuous mound growth. Once established, the carbonate buildup was characterized by rapid aggradational growth, developing a palaeogeographic high with a steep slope and a depression with decreased sedimentation behind, several kilometres distant from the Dachstein Carbonate Platform. Contemporaneously, isostatic adjustment caused an accommodation minimum on the nearby margin of the Dachstein Carbonate Platform leading to its westward progradation. Fading out of subsidence caused filling of the former depression in the back of the buildup by prograding shallow-water Dachstein Limestones. Thus, a new platform margin was established in the Steinplatte area, elevated almost 200 m above the adjacent Kossen Basin. At the Triassic-Jurassic boundary, the Steinplatte complex was subjected to subaerial exposure by a sudden tectonic uplift followed by a rapid isostatic drop. Emergence is indicated by levels of karstified limestones directly underlying supposed exposure surfaces. Final drowning of the Steinplatte complex as well as of the whole Dachstein Carbonate Platform is indicated by the cover of Early Jurassic (Sinemurian) deeper water, ammonitebearing limestones (Adnet Formation).

7

Układ faz węglowodorowych w obszarze złożowym Lubiatów - Międzychód - Grotów (LMG)

Słupczyński K., Machowski G., Papiernik B., Semyrka R.

Geologia / Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie

|

2008

|

T. 34, z. 3

469-487

PL

Dla strefy złożowej Lubiatów - Sowia Góra - Międzychód - Grotów (LMG), umiejscowionej w obszarze platformy węglanowej i na jej przedpolu, w poziomie dolomitu głównego Ca2, kryteriami równowagi statycznej zachodzącej w ośrodkach porowo-szczelinowych wypełnionych oddzielnymi fazami węglowodorowymi, wyznaczono fazowe powierzchnie rozdziału kondensatowego gazu ziemnego od nasyconej gazem ropy naftowej. Udowodniono łączność hydrauliczną pomiędzy poszczególnymi komercyjnymi polami zasobów reprezentującymi oddzielne złoża węglowodorów. Wykazano, że wąskie strefy o miąższości poniżej 15 m, o różnej hipsometrii, spełniają tylko rolę semiprzepuszczalnych ograniczeń komercyjnych pól zasobowych. Wyznaczone powierzchnie rozdziału gazu ziemnego i ropy naftowej znacznie rozszerzają powierzchnię akumulacyjną w obszarze występowania platformy węglanowej i jej przedpola.

EN

For the Lubiatów - Sowia Góra - Międzychód - Grotów (LMG) hydrocarbon reservoir zone, situated within the area of the Main Dolomite carbonate platform and its foreland, interfacial surfaces between natural condensate gas and gas-saturated oil was determined applying the criterion of stable equilibrium in porous-fractured media filled with separate hydrocarbon phases. Hydraulic connection between individual hydrocarbon accumulations was proved. It was evidenced that narrow zones with Main Dolomite thickness less than 15 m and different hypsometric positions play the role of semi-permeable boundaries only. The determined surfaces between natural gas and crude oil considerably extend the accumulation zone in the area of the carbonate platform and its foreland.