Geologia
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ISSN 0138-0974
e-ISSN: 2353-0782
Issue Date
2008
Volume
T. 34
Number
Nr 3
Description
Journal Volume
Geologia
T. 34 (2008)
Projects
Pages
Articles
Wgłębna budowa Karpat w strefie sigmoidy przemyskiej: interpretacja profili sejsmicznych i ocena prognoz naftowych
(Wydawnictwa AGH, 2008) Kuśmierek, Jan; Baran, Urszula
The authors expose some new aspects of interpretation of the subsurface tectonics of flysch and molasse covers and their autochthonous basement in connection with assessment of prospects for hydrocarbon discoveries in the zone of the Przemyśl Sigmoid (PS). They are based on drilling results and geological interpretation of seismic sections which were reprocessed with application of a methodology presented in another publication. Interpretation results incline towards an opinion that the northern depositional extent of flysch sediments was oblique to overthrusts of the Marginal Group units. In this context, it can be accepted that before the deposition of the molasses that build up the Stebnik Nappe the flysch deposits had filled longitudinal depressions of the platform slope and the post-erosional patches had been detached and thrust together with Miocene sediments. Such a solution corresponds with views on pinching-out of deep-seated folds of the Boryslav-Pokutya Unit along PS. In the light of these results and insignificant thermal transformation of organic matter, prospects for hydrocarbon discoveries in the NE Polish Carpathians are not optimistic. Potential structural traps were preserved only in the autochthonous Miocene series overlain by the sealing overburden of the allochthonous covers. Discovery of new gas fields in the traps will depend mostly on favourable reservoir properties, particularly in zones of pinching-out of sandy horizons of the autochthonous series against the basement highs or in zones of their screening by thrust planes.
Wpływ zeszczelinowania na ropogazonośność mikroporowych piaskowców fliszowych
(Wydawnictwa AGH, 2008) Machowski, Grzegorz; Kuśmierek, Jan
For tens of years the influence of fracturing of oil- and gas-bearing Carpathian flysch lithofacies on their permeability and porosity has been studied on drill cores and in outcrops. The analyses of cores from the reservoir series of the Krosno-Grybów Beds in the Słopnice near Limanowa oil and gas field, and particularly of the whole section of the Kuźmina-1 deep well, have proved strong influence of solidity of the studied series on their fracturing intensity. During the last decade the fracturing studies have been focused on the Oligocene Krosno Sandstones and Cretaceous-Paleocene Inoceramian Sandstones in the Eastern Polish Carpathians. The investigations have been carried out in measurement fields located within outcrops of oil- and gas-bearing folds. Analysis of a large set of data processed into averaged reservoir parameters has proved that the effective fracture porosity for the whole population of macrofractures is low and only rarely exceeds 1%. Total fracture permeability varies widely, from fractions of millidarcy to several hundred millidarcy (mD). It is characteristic that results of laboratory measurements of rock samples from the studied sandstone series have documented, in general, their insignificant intergranular permeability (usually less than 0.1 mD), related to predominant contribution of micropores.
Produktywność karpackich skał zbiornikowych w świetle historii wydobycia węglowodorów
(Wydawnictwa AGH, 2008) Marcinkowski, Artur; Szewczyk, Elżbieta
The paper intends to characterize productivity of oil- and gas-bearing Carpathian sandstones in the area situated to the east of the Wisłok river valley where prospects for new hydrocarbon discoveries are best. It was based on materials from the POGC's files, which contain full documentation of oil, gas and reservoir water production from particular fields and wells. Graphs of the media production, constructed for the Silesian and Skole units, illustrate trends of the production decline in the years 1955-2007. The most fundamental premises for assessment of prospects for new oil-field discoveries result from diagrams that document the productivity of individual oil- and gas-bearing horizons, as well as depth intervals of occurrence of hydrocarbon inflows, shows and traces. Interpretation of the presented data indicates that in the Silesian Unit the greatest oil production was achieved from the Lgota and Krosno sandstones, whereas gas production - from the Istebna Sandstones. In the Silesian Unit, the Kliwa Sandstones of the Menilite Beds represent a predominating productive series, the sandstones are characterized by the best reservoir properties over the whole analyzed area.
Nowe spojrzenie na właściwości zbiornikowe i filtracyjne piaskowców karpackich
(Wydawnictwa AGH, 2008) Such, Piotr; Leśniak, Grzegorz
On the base of 388 samples of the Carpathian sandstones analyses of intergranular and fracture permeability and porosity were performed, as well as granulometric analyses and investigations of diagenesis processes. Pore space of these sandstones was created by diagenetic processes. Mechanical compaction and cementation dominates but dissolution played role in creating of secondary porosity. Conducted investigations thrown a new light on filtration properties of moderate porosity sandstones. Intergranular permeability are very low but fracture porosity can reach relatively high values (up to 50 mD) in great part of investigated sandstones. This fact opens new opportunities in exploration of such type of sandstones in the Carpathian flysch.
Zmienność parametrów petrofizycznych subfacji dolomitu głównego zachodniej strefy półwyspu Grotowa w świetle badań porozymetrycznych
(Wydawnictwa AGH, 2008) Semyrka, Roman; Semyrka, Grażyna; Zych, Izabela
The microfacial analysis, together with detailed sedimentological analysis, enabled the authors to distinguish depositional environments of the Main Dolomite succession in the study area. The Main Dolomite is characterized by diversity in thickness, lithology and facial development of the following zones: foot of the carbonate platform, barrier and platform plain. Three principal sub-facies were distinguished there: grainstones, mudstones and boundstones (the microbial sub-facies). These sub-facies reveal diversified petrophysical paramaters. The analysis is based on results of porosimetric measurements which enable assessment and qualification of this horizon from the point of view of its hydrocarbon reservoir capacity and pore space character. Principles of porous rock qualification in terms of hydrocarbon reservoirs include mainly assessment of: effective and dynamic porosities for oil and gas, bulk and framework densities, and pore space geometry (distribution of predominating pore diameters and specific surface of the pore space). This assessment refers to the pore space in which processes of migration and accumulation of reservoir fluids occur. Statistical analysis of the petrophysical parameters revealed their relationships within the distinguished lithofacial zones, which represent also an important solution.