<abstract xmlns="http://www.w3.org/1999/xhtml">Our reconstruction of the pre-compactional thickness of the Main Dolomite strata from the so-called Grotów Peninsula (northwest Poland) was based on macroscopic observations of drill cores from three wells: Mokrzec-1, Sieraków-4 and Międzychód-5. These wells are located in various palaeogeographical zones of the Main Dolomite and cored rocks represent a range of microfacies. The amount of compactional reduction in thickness of the Main Dolomite was estimated by summing the total heights (Wst) of all stylolites encountered in logs of these wells. For calculations, a generalised model of a drill core was developed, which embraced all types of stylolite seams present in the Main Dolomite succession studied. Also the method of stylolite dimensioning was demonstrated. The number of stylolites in the drill cores studied varied from 511 in the Sieraków-4 well to 1,534 in the Międzychód-5 well. In all cores studied low-amplitude macrostylolites predominated, but the reduction of thickness was controlled mostly by the low- and medium-amplitude macrostylolites. The largest number of stylolites was found in the grainstone/packstone microfacies. The turnout of stylolites depends of microfacies. The highest density of stylolites was documented in mudstones/wackestones (24 stylolites per metre of rock thickness) and the lowest in boundstones (14 stylolites per metre of rock thickness). The low-amplitude stylolites appear most frequently in the mudstone/wackestone microfacies (15 stylolites per metre of rock thickness); in grainstones/packstones, rudstones/floatstones and boundstones middle-amplitude stylolites are rare (3 stylolites per metre of rock thickness). The degree of compaction of the Main Dolomite succession studied varied from 6 to 10%; hence, its calculated initial thickness also varied in the wells studied: from 41.3 m in the Sieraków-4 well to 56.9 m in the Mokrzec-1 well and to 97.1 m in the Międzychód-5 well. The volumes of reservoir fluids expelled during compaction of 1 m3 of Main Dolomite carbonates were estimated as 56 l in the Sieraków-4 well, 90 l in the Mokrzec-1 well and 97 l in the Międzychód-5 well.</abstract>

Our reconstruction of the pre-compactional thickness of the Main Dolomite strata from the so-called Grotów Peninsula (northwest Poland) was based on macroscopic observations of drill cores from three wells: Mokrzec-1, Sieraków-4 and Międzychód-5. These wells are located in various palaeogeographical zones of the Main Dolomite and cored rocks represent a range of microfacies. The amount of compactional reduction in thickness of the Main Dolomite was estimated by summing the total heights (Wst) of all stylolites encountered in logs of these wells. For calculations, a generalised model of a drill core was developed, which embraced all types of stylolite seams present in the Main Dolomite succession studied. Also the method of stylolite dimensioning was demonstrated. The number of stylolites in the drill cores studied varied from 511 in the Sieraków-4 well to 1,534 in the Międzychód-5 well. In all cores studied low-amplitude macrostylolites predominated, but the reduction of thickness was controlled mostly by the low- and medium-amplitude macrostylolites. The largest number of stylolites was found in the grainstone/packstone microfacies. The turnout of stylolites depends of microfacies. The highest density of stylolites was documented in mudstones/wackestones (24 stylolites per metre of rock thickness) and the lowest in boundstones (14 stylolites per metre of rock thickness). The low-amplitude stylolites appear most frequently in the mudstone/wackestone microfacies (15 stylolites per metre of rock thickness); in grainstones/packstones, rudstones/floatstones and boundstones middle-amplitude stylolites are rare (3 stylolites per metre of rock thickness). The degree of compaction of the Main Dolomite succession studied varied from 6 to 10%; hence, its calculated initial thickness also varied in the wells studied: from 41.3 m in the Sieraków-4 well to 56.9 m in the Mokrzec-1 well and to 97.1 m in the Międzychód-5 well. The volumes of reservoir fluids expelled during compaction of 1 m3 of Main Dolomite carbonates were estimated as 56 l in the Sieraków-4 well, 90 l in the Mokrzec-1 well and 97 l in the Międzychód-5 well.

Reconstruction of the pre-compactional thickness of the Zechstein Main Dolomite in northwest Poland

AGH University of Science and Technology, Faculty of Geology, Geophysics and Environment Protection, Department of Fossil Fuels, Mickiewicza 30, 30-059 Kraków, Poland

AGH University of Science and Technology, Faculty of Drilling, Oil and Gas, Department of Gas Engineering, Mickiewicza 30, 30-059 Kraków, Poland

Polish Oil and Gas Co. SA, Branch of Geology and Exploitation, Department of Projects in Piła, Staszica 9, 64-920 Piła, Poland

Geologos

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Our reconstruction of the pre-compactional thickness of the Main Dolomite strata from the so-called Grotów Peninsula (northwest Poland) was based on...

Reconstruction of the pre-compactional thickness of the Zechstein Main Dolomite in northwest Poland

Published Online: Jan 22, 2016

Page range: 303 - 314

Received: Mar 20, 2015

Accepted: Sep 15, 2015

DOI: https://doi.org/10.1515/logos-2015-0022

Keywords
compaction, solution seam, stylolitic seam, thickness reduction

© 2015 Grażyna Semyrka et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Reconstruction of the pre-compactional thickness of the Zechstein Main Dolomite in northwest Poland

Published Online: Jan 22, 2016

Page range: 303 - 314

Received: Mar 20, 2015

Accepted: Sep 15, 2015

DOI: https://doi.org/10.1515/logos-2015-0022

Keywordscompaction, solution seam, stylolitic seam, thickness reduction

© 2015 Grażyna Semyrka et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
compaction, solution seam, stylolitic seam, thickness reduction