The Ciezkowice Sandstone: Examples of Basin-floor Fan-stacking Patterns from the Main (Upper Paleocene to Eocene) Reservoir in the Polish Carpathians
Piotr S. Dziadzio, Mark A. Enfield, Matthew P. Watkinson, Szczepan J. Porębski, 2006. "The Ciezkowice Sandstone: Examples of Basin-floor Fan-stacking Patterns from the Main (Upper Paleocene to Eocene) Reservoir in the Polish Carpathians", The Carpathians and Their Foreland: Geology and Hydrocarbon Resources, Jan Golonka, Frank J. Picha
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The Ciezkowice Sandstone is a lithostratigraphic term used to define a sand-prone succession of late Paleocene–middle Eocene age and is one of the main producing petroleum reservoirs in the Silesian unit of the central and eastern Polish Outer Carpathians. The excellent reservoir potential of these sandstones and their widespread occurrence make them a key objective for future exploration. In this study, the Ciezkowice Sandstone was analyzed using geophysical logs and nearby exposures in the Silesian unit between the towns of Ciezkowice and Krosno.
The analysis presented in this chapter has identified as much as four laterally persistent, sand-prone units in the Ciezkowice Sandstone. The dominant lithology of these units is coarse-grained, thick-bedded sandstones interbedded with fine-grained turbidites. The thickness of individual sandstone bodies ranges from 20 to more than 50 m (66 to more than 160 ft) within a gross sand-prone interval of as much as 350 m (1100 ft), in which sand/shale ratios can be as much as 9:1. Sandstone beds are mostly massive to normally graded and commonly display shale clasts, horizontal planar stratification, and water escape structures. The thickest beds are commonly amalgamated and locally display very large-scale trough cross-bedding. These sandstones are interpreted as high-density turbidites.
The Ciezkowice Sandstone units are interbedded with pelagic mudstone-dominated tongues, lithostratigraphically termed the “Variegated shales.” Sedimentological features of the sandiest units in the Ciezkowice Sandstone indicate that they were deposited in basin-plain settings during lowstand phases of basin evolution.
Copyright ©2006. The American Association of Petroleum Geologists.
The Ciezkowice Sandstone represents a second-order lowstand sequence set (basin-floor fan equivalent). The Variegated shales were deposited during transgressive and highstand systems tracts, when sand supply to the basin was reduced significantly. Each Ciezkowice Sandstone–Variegated shale cycle is interpreted to represent a third-order depositional sequence in a lowstand sequence set of latest Paleocene to middle Eocene age. Several subunits of the Ciezkowice Sandstone provide good examples of basin-floor fan-stacking patterns characteristic for deposition in lowstand basin conditions.
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This volume of 30 chapters authored by 107 geologists and geophysicists from Austria, Czech Republic, Hungary, Poland, Romania, Slovakia, Ukraine, United Kingdom, and the USA provides a comprehensive and understandable account of geology and hydrocarbon resources of the entire Carpathian system from northeastern Austria to southern Romania, including the Neogene foredeep, the foreland platform both in front and beneath the thrust belt, the Carpathian thrust belt, and the late and post orogenic intermontane basins. Principal chapters on regional geology are supplemented by thematic contributions on geodynamic reconstructions, regional geophysical investigations, hydrocarbon systems, and case studies of major oil and gas fields. To date, close to 7 billion barrels of oil and more than 53 trillion cubic feet of natural gas have been produced from the entire Carpathian system. Additional new reserves may be found, especially at deeper structural levels below the Neogene foredeep and the thin-skinned Carpathian thrust belt. Seventeen chapters of Memoir 84 have been printed in full. The remaining chapters have been printed as abstracts only, with the full paper for all 30 chapters as .pdf files on the CD-ROM in the back of this publication. The publication is intended as a source of information to schools, governmental and private institutions, oil companies, and potential investors.