STUDIA, ROZPRAWY, MONOGRAFIE 185

Transkrypt

1 INSTYTUT GOSPODARKI SUROWCAMI MINERALNYMI I ENERGI P O L S K I E J A K A D E M I I N A U K K R A K Ó W STUDIA, ROZPRAWY, MONOGRAFIE 185 Rados³aw Tarkowski, Lidia Dziewiñska, Sylwester Marek THE CHARACTERISTICS OF SELECTED POTENTIAL GEOLOGICAL STRUCTURES FOR CO2 UNDERGROUND STORAGE IN MESOZOIC DEPOSITS OF THE SZCZECIN MOGILNO UNIEJÓW TROUGH WYDAWNICTWO INSTYTUTU GOSPODARKI SUROWCAMI MINERALNYMI I ENERGI PAN KRAKÓW 2014

2 KOMITET REDAKCYJNY prof. dr hab. in. Eugeniusz Mokrzycki (redaktor naczelny serii) dr hab. in. Lidia Gawlik (sekretarz redakcji), prof. IGSMiE PAN dr hab. in. Zenon Pilecki, prof. IGSMiE PAN dr hab. in. Wojciech Suwa³a, prof. IGSMiE PAN dr hab. in. Alicja Uliasz-Bocheñczyk, prof. AGH RECENZENCI prof. dr hab. in. Aleksander Garlicki dr hab. in. Piotr Karnkowski Praca zrealizowana w ramach badañ statutowych Instytutu Gospodarki Surowcami Mineralnymi i Energi¹ PAN ADRES REDAKCJI Kraków, ul. Józefa Wybickiego 7 tel , fax OPRACOWANIE EDYTORSKIE: mgr Danuta Nikiel-Wroczyñska, Beata Stankiewicz Copyright by Autorzy Copyright by Instytut Gospodarki Surowcami Mineralnymi i Energi¹ PAN Printed in Poland Kraków 2014 ISSN ISBN IGSMiE PAN Wydawnictwo, Kraków 2014 Nak³ad 150 egz. Objêtoœæ ark. wyd. 9,27; ark. druk. 13,00 Druk i oprawa: Agencja Reklamowo-Wydawnicza Ostoja Maciej Hubert Krzemieñ, Cianowice, ul. Nieby³a 17, Ska³a

3 Contents Introduction Outline of tectonic setting of the Zechstein-Mesozoic complex in the Szczecin Mogilno Uniejów Trough Geological and geophysical exploration Geological setting Potential geological structures for underground CO 2 storage in Mesozoic formations of the Szczecin Mogilno Uniejów Trough Degree of geological exploration and criteria for selection Potential reservoirs for underground CO 2 storage Chabowo Anticline Geological setting Reservoir horizons Stratigraphy and lithology Marianowo Anticline Geological setting Reservoir horizons Stratigraphy and lithology Oœwino Anticline Geological setting Reservoir horizons Stratigraphy and lithology Strzelno Anticline Geological setting Reservoir horizons Stratigraphy and lithology Turek Anticline Geological setting Reservoir horizons Stratigraphy and lithology Tuszyn Anticline Geological setting Reservoir horizons Stratigraphy and lithology References... 80

4 4 The characteristics of selected potential geological structures for CO 2 underground storage in Mesozoic deposits of the Szczecin Mogilno Uniejów Trough Abstract Charakterystyka wybranych potencjalnych struktur geologicznych do podziemnego sk³adowania CO 2 w utworach mezozoiku niecki szczeciñsko-mogileñsko-uniejowskiej Streszczenie... 90

5 Introduction Poland has favourable conditions for underground storage of carbon dioxide due to the occurrence of a thick (several kilometres) complex of Permo-Mesozoic sedimentary rocks in the Polish Lowlands. Geological structure of this complex shows a number of anticlines, and salt pillows and ridges related to salt tectonics. They may be important (in the future) for large CO 2 emitters interested in reducing emissions of this gas by underground storage. Carbon dioxide capture and storage (CCS) in the subsurface requires recognition of relevant geological structures that will be able to hold safely an adequate amount of gas and will ensure its permanent entrapment. Directive 2009/31/EC of the European Parliament and of the Council of 23 April 2009 on the geological storage of carbon dioxide provides indications for the selection of storage sites. The adequacy of a geological structure to be used for CO 2 storage is determined by the characterisation and assessment of the potential storage complex and of the surrounding rock volume. The selected storage site should be represented by a geological formation in which gas storage carries neither significant risk of leakage nor any hazard to the environment and human health. Among the most important tasks in this field is to select appropriate structures, and then to characterise them thoroughly based on available geological, geophysical and other data, as well as reservoir parameters. The issue related to CO 2 storage in geological formations has been booming around the world since the early 1990s, and in Poland since the beginning of the twenty-first century. There is an extensive literature on these problems, and the number of publications is increasing rapidly. The authors wish to draw attention to some important reports in this field: Best practise 2006; CO 2 Capture and Geological Storage 2005; IPCC 2005; Rackley 2010; Tarkowski 2005, as well as reports on the implementation of 6FP EU projects concerning the geological storage of CO 2 (CO2ReMoVe, CO2SINK, EU GeoCapacity) or a national program entitled: Rozpoznanie formacji i struktur do bezpiecznego geologicznego sk³adowania CO 2 wraz z ich programem monitorowania (Assessment of formations and structures suitable for safe CO 2 geological storage including monitoring plans). A team of geologists and geophysicists from the MEERI PAS undertook a challenge to develop a preliminary characterisation of potential geological structures for CO 2 storage in Mesozoic deposits of the Polish Lowlands, which is presented in a monographic study published in 2010 and titled: Potencjalne struktury geologiczne do sk³adowania CO 2 w utworach mezozoiku Ni u Polskiego (charakterystyka oraz ranking) (Potential geological structures to CO 2 storage in the Mesozoic Polish Lowlands) (characteristics and ranking))

6 6 (Tarkowski, ed. 2010). Following this issue, the Division of Geotechnology of MEERI PAS started developing a detailed study of pre-selected geological structures within the framework of statutory research. The characteristics of some geological structures were already presented in several separate publications (Marek, Dziewiñska, Tarkowski 2011a, b, c; Marek, Dziewiñska, Tarkowski 2013). This paper provides a detailed description of six potential structures from the Szczecin Mogilno Uniejów Trough (Chabowo, Marianowo, Oœwino, Strzelno, Tuszyn and Turek anticlines). The two other structures suitable for CO 2 storage in this area the Choszczno and Suliszewo anticlines have been recently presented in Marek, Dziewiñska and Tarkowski (2013). Selection of these structures was based on their location within the Szczecin Mogilno Uniejów Trough, availability of detailed geological and reservoir data, as well as their position in the ranking of potential sites for geological storage of CO 2 in the Mesozoic saline formations of the Polish Lowlands (Uliasz-Misiak, Tarkowski 2010). It should be noted that each structure is unique and requires individual characterisation and assessment in terms of underground storage of carbon dioxide. Detailed characterisation of the potential sites for CO 2 underground storage in the Mesozoic formations of the Szczecin-Mogilno-Uniejów Trough was preceded by a description of the main features of geological and tectonic settings of the area (geological and geophysical surveys) and by a presentation of the state-of-the-art of the knowledge on the structures, including a presentation of potential reservoirs for carbon dioxide storage. In the literature, there are no detailed instructions regarding the description and characterisation of geological structures for underground CO 2 storage. The description mode presented in this monograph is the author s own version. Some indications are provided in a report of the Australian Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC) (2008). It presents a methodology that allows the estimation and classification of geological storage sites. It provides the procedure of selection of carbon dioxide storage sites at different levels, from a national scale to a storage-site scale. For individual storage sites, their detailed geological, engineering and economic characteristics are used to be developed, and, finally, a decision is to be made about the construction of storage facilities (CO2CRC, 2008; see: Uliasz-Misiak, Tarkowski 2010). Some notes on the description of geological structures suitable for CO 2 storage can also be found in Best Practice... (2006). However, they refer to the criteria of storage site selection rather than to the description of geological structures. Since 2008, Directive of the European Parliament and of the Council on the geological storage of carbon dioxide has been in force in the European Union, which regulates most of the issues in this field. Annex I to the Directive provides the criteria for description and assessment of storage sites (Directive 2009/31/EC). Such a description and assessment is carried out in three steps: 1. Data collection; 2. Building the three-dimensional static geological earth model; 3. Characterisation of the storage dynamic behaviour, sensitivity characterisation, risk assessment. The criteria specified in the Directive show how the storage sites should be described and assessed. With respect to the presented description, they refer to the first step.

7 The characteristics of each of the six geological structures consist of three parts. First part provides the characterisation of the geological structure taking into account elements such as location, degree of geological and geophysical exploration (information on drill holes and reflection seismic surveys). They have been supplemented by structural maps of reservoir horizons, with geological cross-section lines, seismic profiles and boreholes marked. Second part describes the reservoirs suitable for CO 2 storage, presenting their characteristics and basic geological and reservoir parameters that are important in terms of geological storage of carbon dioxide. This part was supplemented by a number of geological cross-sections and tables providing basic data on the geology and mineral resources (acreage of the structure, thickness, depth to the top and base, lithology of the reservoir horizon, CO 2 storage capacity, rectangular coordinates of the borehole, information on the overburden, faults and boreholes in the structure, etc.). Information on and investigations of cap rocks will be, in the future, one of the key factors to determine the quality of the structure, especially in the context of the absence of hydrocarbon accumulations in Mesozoic deposits of the Polish Lowlands, which would confirm the presence of a seal to the structural traps (a remark by P. Karnkowski). Third part of the description presents geological section (s) of deep boreholes located on the structure, with particular emphasis on reservoir horizons and cap rock series. 7

8 1. Outline of tectonic setting of the Zechstein-Mesozoic complex in the Szczecin Mogilno Uniejów Trough The selected geological structures that were analysed as potential underground storage sites of CO 2 in the Permian Mesozoic complex occur in the Szczecin Mogilno Uniejów Trough. The trough extends from the north-western extreme of Poland to the Be³chatów (Tomaszów Grójec) Graben in the SE, between the Pomeranian Kujawy Swell in the NE and the Sudetic Monocline in the SW (Dadlez, Marek 1974; Dadlez 1997; Dadlez ed. 1998; Dadlez 2008; Karnkowski 2008; Narkiewicz, Dadlez 2008; Po aryski 1974; Soko³owski 1967; elichowski 1983; elaÿniewicz et al. 2011). The area of the Szczecin Mogilno Uniejów Trough covers the south-western portion of the Pomeranian and Kujawy segment of the Mid-Polish Trough (Dadlez, Marek, Pokorski, eds. 1998; Narkiewicz ed. 1998) Geological and geophysical exploration Crucial role in identifying the main features of the geological and tectonic settings of the Zechstein Mesozoic complex and its basement in the Szczecin Mogilno Uniejów Trough was played by geological drilling and geophysical (mainly seismic and gravity) surveys. They were carried out mainly by the Polish Geological Institute and the Polish Oil and Gas Company to assess the prospects for exploration of oil and natural gas. The results of these studies are presented in a number of monographs, regional geology reports and mapping projects carried out in various research centres in Poland and abroad (Depowski ed ; Karnkowski 1993, 1999; Jaskowiak-Schoeneichowa ed. 1979; Marek ed. 1971). The degree of subsurface exploration of the Szczecin Mogilno Uniejów Trough by boreholes, reflection and refraction seismic surveys, and gravity surveys is very uneven. Deep boreholes piercing the Zechstein Mesozoic complex are concentrated in the Baltic Sea coastal area and in the south western part of the Szczecin Trough and Gorzów Block. In the Mogilno Uniejów segment, they are grouped in the south-western part of the Gniezno ask Block from the Szamotu³y and Wrzeœnia region (Mogilno segment) and the Zakrzyn and Kalisz region (Uniejów segment) to the erechowa, Gidle and Gomunice area near the boundary with the Nida Trough. Shallower boreholes piercing various Mesozoic sequences are generally located in small areas of local structures, and therefore they do not provide direct information on a regional scale.

9 Geophysical investigations were carried out using various geophysical methods, especially seismic reflection and refraction surveying, as well as gravimetric and magnetic methods. The most widely used method was reflection seismic surveying of regional near-surface imaging and a semi-detailed grid. Locally increased concentration of seismic work in some areas is related to the discovery of hydrocarbons in these zones. Since the introduction of digital technology, the focus has been on how to develop the data and use a wider and perfect range of processing. Seismic reflectors associated with the Cretaceous, Jurassic, Triassic and Zechstein horizons have been identified on almost all seismic sections. The image of seismic reflection boundaries allows the characterisation of the Permian Mesozoic succession and the separation of a number of geological units. The degree of seismic exploration and the location of boreholes determine reliability of the interpretation of geological structure of individual structures. The quality of seismic data is significantly lower in zones of stronger tectonic deformation related mainly to salt diapirs and major fault zones within synsedimentary grabens. The Z 1 boundary reflecting the structural surface of the base of the Upper Permian is the deepest boundary for which continuous seismic reflections are recorded on seismic sections across most of the Szczecin Mogilno Uniejów Trough. The major problem is the identification of sub-zechstein reflections. Therefore, important information is provided from refraction surveys that have allowed tracing the top of the consolidated basement of the Palaeozoic platform (M³ynarski 2002). In the area of the Szczecin Mogilno Uniejów Trough, there were also conducted regional and semi-detailed gravity and magnetic measurements. The summary and unification of the results of this work on a country-wide scale are presented in the form of Bouguer gravity anomalies in Gravimetric Atlas of Poland (Królikowski, Petecki 1995), as well as in Magnetic Map of Poland 1:500,000 (Petecki et al. 2004). Gravity and magnetic data, stored in a computer database, allows the development of new maps for a specific region in different variants based on digital data processing. Magnetic anomalies are poorly diverse and it is assumed that they are not only related to the sedimentary cover, but also to crystalline basement rocks. Essential information about the subsurface structure of the Zechstein-Mesozoic complex and its basement is derived from gravimetric studies. Most of the geological structures are reflected by the pattern of gravity anomalies. The origin of both positive and negative anomalies is associated in most cases with salt-cored structures strongly contrasting with respect to density against the surrounding areas. A very important factor that increases the reliability of geophysical and geological interpretations is its complexity that uses the relationship between physical parameters of the geological medium, such as seismic velocity, density and resistivity of rocks. Examples of regional seismic sections along selected profiles running across the Polish Lowlands are presented in Dziewiñska ([in] Marek, Pajchlowa 1997); M³ynarski ed. (1979, 1982). An important contribution to complementing the image of the geological structure in certain areas is a comprehensive surface interpretation of the results of both methods (Dziewiñska 1974, 1981; Skorupa, Dziewiñska 1976; Dziewiñska, Petecki 2004). 9

10 10 In parallel with near-surface surveys, geophysical measurements were also performed in deep boreholes from the study area (Szewczyk 1994, 2000a, b). Since 1992, these measurements have been carried out using high-quality digital equipment from Halliburton. Earlier measurements provided valuable results, but of quality importance. Seismometric measurements in boreholes, including average velocity, acoustic profiling and vertical seismic profiling studies, provided data for determination of velocity distributions necessary to provide a depth-related version of structural images Geological setting The Szczecin Mogilno Uniejów Trough developed as a result of Late Cretaceous regional inversion of the axial part of the Mid-Polish Trough, and formed on its SW side along the Pomeranian Kujawy Swell (Dadlez, Dembowska 1965; Raczyñska ed. 1987; Marek ed. 1977). The first phases of Cretaceous inversion of the Mid-Polish Trough occurred probably in Santonianian and Campanian times, however, the last deformation processes took place after the Maastrichtian and Paleocene and before the Middle Eocene, when it came to the final inversion the Mid-Polish Trough (Dadlez 1989; Dadlez, Marek 1977; Jaskowiak- -Schoeneichowa 1981; Krassowska 1997; Leszczyñski 1997, 2002a, b; Leszczyñski, Dadlez 1999; Leszczyñski, Waksmundzka 2013; Krzywiec 2000, 2006, 2009; Marek, Znosko 1972a and b; Znosko 1969). Some researchers express the opinion that there is no evidence of inversion processes before the Maastrichtian (Œwidrowska, Hakenberg 1999; Kutek, G³azek 1972). In the Szczecin Mogilno Uniejów Trough, tectonic and palaeogeographic evolution of the Zechstein-Mesozoic complex was controlled by varying mobility of tectonic blocks of the sub-zechstein Variscan basement cut by major fault zones visible not only in the sedimentary cover but also in the deeper parts of the Earth s crust (Dadlez 2001; Dadlez ed. 1998; Dadlez, Marek 1974; Dziewiñska 1974; Dziewiñska, Marek JóŸwiak 2001; Dadlez, Narkiewicz, Pokorski, Wagner 1998; Guterch, Grad, Materzok, Perchuæ 1986; Jaskowiak- -Schoeneichowa ed. 1979; Królikowski, Petecki, Dadlez 1996; Marek, Znosko 1972a, b; Marek ed. 1977; Marek, Pajchlowa eds. 1997; M³ynarski ed. 1979; M³ynarski 2002; Znosko ed. 1968, 1998). In the north-eastern zone of the Szczecin-Mogilno-Uniejów Trough, which extends along the Pomeranian-Kujawy Swell, there are major fault zones of Grzêzno Drawno Cz³opa Szamotu³y (Szczecin Trough), Wapno Damas³awek and Mogilno Strzelno (Mogilno Uniejów Trough), and Gop³o Ponêtów Wartkowice Pabianice (Uniejów Trough), deeply rooted in the basement of the Zechstein-Mesozoic complex. These fault zones are manifested by strings of salt-cored structures, in which salt has pierced partially or completely through the Mesozoic overburden. The salt structures are accompanied by synsedimentary grabens that were active especially in Early Jurassic, early Middle Jurassic and earliest Cretaceous times (Dadlez, Franczyk 1976; Marek ed. 1977; Feldman-Olszewska 1997; Leszczyñski 2002b).

11 The Grzêzno Drawno Cz³opa Szamotu³y, Wapno Damas³awek, Mogilno Strzelno and Gop³o Ponêtów Wartkowice Pabianice fault zones are the edge of the south-western slope of the very labile central part of the Pomeranian-Kujawy Swell. Significant thickness changes of individual formations are observed across these zones. Deeply rooted major fault zones also occur in the south-western part of the Szczecin Mogilno Uniejów Trough and on its outskirts. These are the Goleniów Krzy and Krzy Szamotu³y fault zones in the Szczecin segment, the Pyrzyce Krzy and Krzy Szamotu³y fault zones at the Szczecin Trough/Gorzów Block boundary, and the Lower Warta Fault bounding the Gorzów Block to the south (Jaskowiak-Schoeneichowa ed. 1979; Dadlez 1979). Major fault zones, deeply rooted in the basement, were also found on the extension of the Grzêzno Drawno Szamotuly Fault Zone at the Fore-SudeticMonocline/Mogilno Uniejów Trough boundary between Poznañ and Wieluñ. In the Zechstein Mesozoic complex, they are manifested as the Mesozoic Tertiary synsedimentary grabens of Siekierki, Klêki and Kliczków, active mainly in the Late Triassic and Early Jurassic (Deczkowski, Gajewska 1980; Kwolek 2000). Those areas of the Mogilno Uniejów Trough, which adjoin the Wapno Damas³awek, Mogilno Strzelno and Gop³o Ponêtów Wartkowice Pabianice fault zone to the west and southwest, are distinguished as the Gniezno ask Block and show a great similarity in the tectonic style to the Gorzów Block and Szczecin Trough. A paleomorphological feature, called the Wielkopolska Ridge, developed periodically in the central and north-eastern part of the Gniezno ask Block. It was tectonically active particularly in Early-Middle Jurassic and earliest Cretaceous times (Dadlez, Franczyk 1976; Dadlez, Marek 1977; Marek ed. 1977; Leszczynski 2002b). 11

12 2. Potential geological structures for underground CO 2 storage in Mesozoic formations of the Szczecin Mogilno Uniejów Trough 2.1. Degree of geological exploration and criteria for selection A preliminary characterisation of potential geological structures for CO 2 storage in Poland and previous studies in this area have been discussed (as of 2010) in a monograph entitled: Potencjalne struktury geologiczne do sk³adowania CO 2 w utworach mezozoiku Ni u Polskiego (charakterystyka oraz ranking) (Potential geological structures for CO 2 storage in the Mesozoic Polish Lowlands)(characteristics and ranking)) (Tarkowski, ed. 2010). Therefore, in this report, the authors refer mainly to the recent studies on these topics. A geological structure for CO 2 storage in a saline reservoir horizon is understood as an anticlinal form (anticline, salt-cored pillow, salt stock) comprising one or more reservoir horizons (Tarkowski ed. 2010, p.18). The aforementioned monograph presented the characteristics of 36 potential geological structures for CO 2 storage in deeply seated Lower Cretaceous, Lower Jurassic, and Upper, Middle and Lower Triassic aquifers in the Polish Lowlands (cf. Fig. 2.1). Fifteen of them are located in the Szczecin Mogilno Uniejów Trough: these are the Chabowo, Choszczno, Huta Szklana, Janowiec, Lutomiersk, Marianowo, Oœwino, Ponêtów, Strzelno, Suliszewo, Trzebie, Trzeœniew, Turek, Tuszyn and Wartkowice anticlines. For nine sites, a single aquifer for CO 2 storage has been indicated, and for six sites two aquifers have been proposed. The selection of structures was dictated primarily by a depth criterion, tectonic form of the structure, and significant thickness of the reservoir horizon overlain by poorly permeable layers. Those structures have been taken into consideration, which were penetrated by at least one borehole (Marek, Tarkowski, Dziewiñska 2010). The area of the structure in combination with the reservoir horizon thickness was to provide sufficient CO 2 storage capacity (tens of millions of tons or more). Description of each structure consists of three parts. The first part briefly characterizes the location, degree of geological and geophysical exploration, remarks on the history of their development, size and acreage with respect to the top of the reservoir horizon, information about faults and the overburden, and a generalized geological cross-section. The second part presents a description of the borehole that pierced the structure. The third part provides a tabular summary of the basic geological and reservoir data characterising the reservoir horizon and the cap rocks. The selected and preliminarily characterised structures were the basis for selecting the best and most appropriate ones to

13 13 Koszalin Gdañsk Rokita Wierzchowo Trzebie Oœwino Debrzno Orze³ek Bys³aw Marianowo Koronowo Che³m a-kijewo Chabowo Suliszewo Choszczno Lipno Huta Szkana Janowiec Konary Sierpc Brzeœæ Strzelno Kujawski Bielsk-Bodzanów Kamionki Dzier anowo Poznañ Gostynin Wyszogród Trzeœniew Ponêtów Wartkowice Sochaczew WARSZAWA Turek Je ów Lutomiersk yrów-czachówek Zaosie Tuszyn POLISH LOWLANDS Wroc³aw SUDETES Kraków CARPATHIAN FOREDEEP km CARPATHIANS Fig Location of potential geological structures for CO 2 storage in Mesozoic deposits of the Polish Lowlands Rys Lokalizacja potencjalnych struktur do sk³adowania CO 2 w utworach mezozoiku Ni u Polskiego recognize the possibility of underground storage of carbon dioxide for the large CO 2 emitters in Poland (Uliasz-Misiak, Tarkowski 2010). In order to meet the needs of the Directive and existing demands, a team of geologists and geophysicists from the MEERI PAS took a more detailed analysis of the previously selected and pre-characterised potential structures for CO 2 storage in geological formations of the Polish Lowlands. So far, detailed analyses are available for the following structures: Kamionki (Marek, Dziewiñska, Tarkowski 2011a), Dzier anowo, Wyszogród (Marginal Trough) (Marek, Dziewiñska, Tarkowski 2011b), Zaosie (Pomeranian Kujawy Swell) (Marek, Dziewiñska, Tarkowski 2011c), Choszczno and Suliszewo (Szczecin ódÿ Trough, Marek, Dziewiñska, Tarkowski 2013). In the next stage, detailed characteristics were prepared for selected six structures from NW Poland, for which development of the pre-

14 14 liminary recognition of possible geological storage of CO 2 is presented in this monograph. Detailed description of the structures includes: characterisation of the geological structures against the background of the geological setting of the region, detailed geological setting, characterisation of potential reservoirs suitable for underground storage of carbon dioxide along with an assessment of their usefulness (mostly interpreted by the authors). For the analysis of geological and reservoir data, we have used information derived from regional studies and those presented on the website of the project completed in 2012 and titled: Rozpoznanie formacji i struktur do bezpiecznego geologicznego sk³adowania CO 2 wraz z ich programem monitorowania (Assessment of formations and structures suitable for safe CO 2 geological storage including monitoring plans) ( pl/twiki/bin/view/co2/webhome, available March 19, 2013). It has allowed presenting the problem on a regional scale. A similar procedure is implemented in geological and geophysical works carried out within the framework of the national program, concerning determinations of reservoir parameters in selected boreholes of the Szczecin Trough. They confirm good reservoir properties of rocks composing the selected sandstone horizons ( available March 19, 2013) Potential reservoirs for underground CO 2 storage In terms of the possibility of underground storage of CO 2 from industrial gases in the Mesozoic formations of the Szczecin Trough, the forefront reservoir is the Upper Triassic series of the Middle Keuper Reed Sandstone characterised by very good reservoir properties, overlain by claystones of the Upper Gypsum Beds representing the Upper Keuper, Carnian and Rhaetian. Shallower-seated Lower Jurassic reservoirs are represented by the Kamieñ and Komorowo Beds overlain by a sealing series of the Gryfice Beds, and the Radowo and Mechowo beds sealed by the obez Beds. Especially favourable properties for CO 2 storage have been found for the Upper Pliensbachian (Domerian) Komorowo Beds reservoir. The above-mentioned reservoirs are presented based on the Marianowo and Chabowo anticlines located in the SW part of the Szczecin Trough, surveyed by a semi-detailed seismic survey and, each of them, by three deep boreholes. In the NE part of the Szczecin Trough, the Oœwino Anticline (salt stock) was selected to study, documented by a semi-detailed seismic survey and by the Oœwino IG 1 borehole. For the purpose of CO 2 storage, two reservoir formations are important in the Mesozoic of this area: the Mogilno Formation (Barremian-Middle Albian) and the Borucice Formation (Upper Toarcian). The sealing series are represented by, respectively: Upper Cretaceous limestones, marls and opoka (siliceous marls), and Middle Jurassic clay-muddy rocks. Throughout the Uniejów Trough, as in the case of the Oœwino Anticline, the best reservoir properties have been found for the Barremian Middle Albian deposits of the Mogilno Formation represented by three lower-order units: Kruszwica Member sand-

15 stones, Gop³o Member siltstones and sandstones, and Pagórki Member sandstones. Cap rocks are represented here by Upper Cretaceous (Upper Albian Maastrichtian) carbonates and carbonate-siliceous rocks (opoka). This situation occurs in the Strzelno Anticline explored by three boreholes and semi-detailed reflection seismic surveying. The anticline is situated in the NE part of the Uniejów Trough at the boundary with the Mogilno Trough, within the Wielkopolska Ridge. The Turek Anticline, covered with a semi-detailed seismic survey and explored by two boreholes, is located in the Gniezno ask Block constituting the central and western parts of the Uniejów Trough. The main potential reservoir of this area is the Kruszwica Member of the Mogilno Formation (Lower and Middle Albian). The second potential reservoir for underground CO 2 storage is the Upper Pliensbachian (Domerian) Komorowo Formation sealed by Upper Bajocian, Bathonian and Callovian (Middle Jurassic) alternating claystones, mudstones and sandstone. Another structure, confirming the favourable reservoir properties of the Mogilno Formation is the Tuszyn Anticline, explored by both regional seismic surveying and five boreholes. It is situated in the south-eastern part of the Uniejów Trough within the Gniezno ask Block covering the area of the Wielkopolska Ridge. The deeper-seated Lower Jurassic reservoir is represented by the sandy Drzewica Formation (Upper Pliensbachian, Domerian) which is the age equivalent of the Komorowo Formation (Szczecin Trough). This reservoir is sealed by the Lower Toarcian Ciechocinek Formation composed of alternating claystone-mudstone-sandstone deposits. 15

16 3. Chabowo Anticline 3.1. Geological setting The Chabowo Anticline is located approximately 15 km ESE of Gryfino, being one of the culminations that have formed in the Gryfino Chabowo Choszczno salt-cored ridge. It was explored by three boreholes: Chabowo 1, Chabowo 2 and Chabowo 3, and by semi-detailed reflection seismic surveying. The subsurface geological structure of this area is illustrated by structural maps of the top of the Komorowo Formation (Fig. 3.1) and the Reed Sandstone (Fig. 3.2), and of the base of the Upper Cretaceous (Jaskowiak-Schoeneichowa ed. 1979), supported by a number of geological cross-sections (Fig ). In all the structural maps, the Chabowo Anticline shows a marked asymmetry with the gently sloping SW flank and steeper dips in the NE flank. The NE flank drops by about 1200 m while the SW flank drops by about 500 m. Assuming that the outlines of the anticline are delimited by closed contour lines on the maps of structural surfaces, the Chabowo Anticline is km long and 5 7 km wide, and its amplitude is up to m. As is apparent from detailed analysis of drilling and seismic materials, the Chabowo salt pillow was most active at the Late Cretaceous/Tertiary transition. It was also active in earlier periods. The Chabowo 1 borehole is located in the centre of the anticline, whereas the Chabowo 2 and 3 boreholes on its north-eastern and south-western flanks, respectively (Fig. 3.1, Fig. 3.2). The Chabowo 1 borehole, the deepest one attaining a depth of 2708 m, was completed in Zechstein deposits of the cyclothem PZ4, while the Chabowo 2 borehole, 1760 m deep, and the Chabowo 3 borehole, 2090 m deep, reached upper Muschelkalk deposits (Fig. 3.3) Reservoir horizons Among the most significant Triassic reservoirs of good porosity and permeability properties is the Middle Keuper Reed Sandstone. This reservoir is sealed on the top by claystones of the Upper Gypsum Beds. In the Jurassic section, the particularly interesting rocks for CO 2 storage are Lower Jurassic deposits attaining a thickness of more than 400 m, composed of interbedding sandstones, mudstones and claystones. They consist of four saline aquifers of good reservoir properties: in the Mechowo Beds, Radowo Beds, Komorowo Beds and Kamieñ Beds, sealed by the obez Beds and Gryfice Beds (Tab. 3.1).

17 XI III XI XI ,5 CHABOWO 2 813,5 CHABOWO I-90W XI-72 7-I-90W , CHABOWO ,0 1-I-90W XI XI Fig I-90W Boreholes Elevation of the top of the Komorowo Beds in borehole, in metres (b.s.l.) Contour lines of the top of the Komorowo Beds, in metres (b.s.l.) Geological cross-sections 1300 Reflection seismic profiles 5 km 12-XI-72 Fig Structural map of the top of the Komorowo Beds (Lower Jurassic) in the Chabowo region Rys Mapa strukturalna stropu warstw komorowskich (dolnej jury) w rejonie Chabowa Fig. 3.4 Fig. 3.3, 3.5

18 XI III XI Fig XI-72 CHABOWO , ,0 CHABOWO I-90W XI-72 7-I-90W ,0 CHABOWO I-90W I-90W 2-XI , XI Fig. 3.4 Boreholes Elevation of the top of the Reed Sandstone in borehole, in metres (b.s.l.) Contour lines of the top of the Reed Sandstone, in metres (b.s.l.) Geological cross-sections 12-XI I-90W Reflection seismic profiles 5 km Fig. 3.3, 3.6 Fig Structural map of the top of the Reed Sandstone (Upper Triassic) in the Chabowo region (after Birg et al. 1990, modified by the authors) Rys Mapa strukturalna stropu warstw piaskowca trzcinowego (górnego triasu) w rejonie Chabowa (na podstawie Birga i in z uzupe³nieniami autorów)

19 Chabowo 3 Chabowo 1 Chabowo 2 SW NE 52,0 31,6 32,5 Cenozoic 159,0 92,5 101, K J2-J3 J1 T3 T2 T1 Upper and Lower Cretaceous Jurassic Upper and Middle Lower Jurassic 1024,0 1098,0 1511,5 K J2-J3 J1 T3 Upper Triassic: Middle-Upper Keuper and Rhaetian ,5 2090,0 678,5 714,5 750,0 796,5 1163,0 1589,0 2073,0 T2 Middle Triassic: Röt-Muschelkalk-Lower Keuper ,0 2708,0 1218,5 1658,0 1760,0 T Lower Triassic: Lower and Middle Buntsandstein Zechstein P2 P P1 Rotliegend P1 m b.s.l. m b.s.l km 4000 Fig Geological cross-section of the Chabowo Anticline, trending SW-NE along the line connecting the boreholes of Chabowo 3, Chabowo 1 and Chabowo 2 Rys Przekrój geologiczny antykliny Chabowa SW-NE, wzd³u linii z otworami Chabowo 3, Chabowo 1, Chabowo 2

20 Chabowo 1 WNW ESE 31,6 Cenozoic Upper and Lower Cretaceous 92,5 0 K Jurassic 800 Upper and Middle 678,5 750,0 J2-J ,0 Lower Jurassic J T3 Upper Triassic: Middle-Upper Keuper and Rhaetian ,0 Middle Triassic: Röt-Muschelkalk- Lower Keuper ,0 T2 Lower Triassic: Lower and Middle Buntsandstein ,0 2708,0 T P2 Zechstein Rotliegend 4000 P1 m b.s.l. m b.s.l km Fig Geological cross-section of the Chabowo Anticline, trending WNW-ESE along the axis line crossing the Chabowo 1 borehole Rys Przekrój geologiczny antykliny Chabowa WNW-ESE, wzd³u linii osiowej z otworem Chabowo 1

21 21 Chabowo 3 Chabowo 1 Chabowo 2 SW NE 1110,5 794, , ,0 Gryfice Beds (seal) 920,0 1224, Komorowo Beds (reservoir) 985,5 1031,5 1347,0 obez Beds m m km Fig The Komorowo Beds reservoir in the Chabowo Anticline Fig The Komorowo Beds reservoir in the Chabowo Anticline Rys Poziom zbiornikowy warstw komorowskich w antyklinie Chabowa

22 22 0 Chabowo 3 Chabowo 1 Chabowo 2 SW NE 1511,5 1163,0 1218, Upper Gypsum Beds + Rheatian (seal) ,5 1466, ,0 1530,0 1777, , Read Sandstone Beds (reservoir) Lower Gypsum Beds km 550 m m Fig The Reed Sandstone reservoir in the Chabowo Anticline Fig The Reed Sandstone reservoir in the Chabowo Anticline Rys Poziom zbiornikowy warstw piaskowca trzcinowego w antyklinie Chabowa

23 23 Table 3.1 The Komorowo Beds and Gryfice Beds in the Chabowo region [in metres] Tabela 3.1 Warstwy komorowskie i warstwy gryfickie w rejonie Chabowa [w metrach] Borehole Depth to the top of Komorowo Beds Elevation of the Komorowo Beds Thickness of the Komorowo Beds Thickness of the Gryfice Beds cap rocks Chabowo Chabowo Chabowo Pyrzyce GT Pyrzyce GT Pyrzyce GT Pyrzyce GT Banie The Mechowo Beds reservoir is represented by sandstones and forms a very good aquifer with a maximum thickness of m in the Chabowo 1 borehole. The porosity of the sandstones is up to 30.36%, and the permeability attains / md. The discharge rate is 6.35 m 3 /h, and the brines contain 98.0 g/l TDS, representing chloride-calcium type I brines. The brine temperature within the reservoir formation was 46 o C. The sandstones are interbedded with mudstones showing an effective porosity of 8.83%, and a claystone layer at the top with a porosity of 8.35% to 10.41% and a thickness ranging from 2.0 m to 5.5 m, which separates the Mechowo Beds aquifer from the Radowo Beds aquifer. The Radowo Beds aquifer, with a thickness ranging from 34.0 m in the Chabowo 1 borehole to 54.0 m in Chabowo 2, is also composed of sandstones showing an effective porosity of 18.79%, and a permeability of 375/8.5 md. In the Chabowo 2 borehole, the discharge rate was 7.68 m 3 /h of brine containing 114 g/l TDS, representing a chloride- -calcium class I type with a temperature of 49 C. The overlying obez Beds, ranging in thickness from 19 m in the Chabowo 1 borehole to 24.5 m in Chabowo 3, consist of claystones and mudstones with sandstone interbeds. The effective porosity of the claystones and mudstones ranges from 7.66% to 13.67%, and the permeability is 0.66/0.18 md. The proportion of sandstones in the reservoir horizon is 35 55%, which reduces the sealing quality of these layers. The Komorowo Beds aquifer, ranging in thickness from m in the Chabowo 2 borehole to m in Chabowo 1, was encountered at depths of 845 m ( m) in the Chabowo 1 borehole, 920 m ( m) in Chabowo 2, and 1224 m ( 1189 m) in Chabowo 3. It is represented predominantly by sandstones with a few interbeds of claystones and

24 24 mudstones. The sandstones, from 1.0 m to 35.0 m in thickness, correlate in all three boreholes. Their effective porosity is 21.55% and permeability 800.0/540.0 md. Sampled intervals: two in the Chabowo 2 borehole, 10 m and 15 m thick, and one in the Chabowo 3 borehole, 3 m thick, have yielded similar results: discharge rates of 14.4 m 3 /h to m 3 /h of brines representing a chloride-calcium class I type containing 67 g/l to 87.5 g/l TDS, and the temperature ranging from 40 C to 46 o C. These sandstones have very good reservoir properties and occur between siltstones and claystones with the porosities varying from 10.3% to 18.6%, which cannot be a good seal. The percentage contribution of sandstones to the lithology of the Komorowo Beds ranges from 61% to 84%, and therefore the entire series of the Komorowo Beds has been considered as a reservoir horizon. The volumetric capacity of CO 2 storage in these layers (at the storage efficiency coefficient of 10%) is 78.9 million tons (Tab. 3.2). The Kamieñ Beds aquifer that occurs at the top of the Lower Jurassic section in the Chabowo Anticline is also composed of sandstones with a small proportion of claystones and mudstones. The thickness of these layers varies between 12.5 m in the Chabowo 3 borehole to 44.0 m in Chabowo 1. The sandstones show very good reservoir properties: effective porosity is 27.4%, and discharge rate is 3.89 m 3 /h of brine containing 70.6 g/l TDS, representing a chloride-calcium class I type. The Reed Sandstone aquifer was encountered at depths of m ( 1363 m) in the Chabowo 1 borehole in the centre of the anticline, at m ( 1,433.5 m) in Chabowo 2 on its NE flank, and at m ( 1725, 0 m) in Chabowo 3 in its SW flank. The thickness of these rocks is 85.5 m, 55 m and 64 m, respectively. Reed Sandstone layers are represented predominantly by sandstones showing very good reservoir properties, namely: effective porosity varies from 14.46% to 22.73%, permeability from 0.34 md to md; discharge rate of brine is 2.03 m3/h, its TDS content is g/l, and the temperature is 64 o C. The contribution of sandstones to the Reed Sandstone series is variable. At the crest of the anticline (Chabowo 1), the thickness of sandstones is 79 m, which is 92% of the total thickness of the layers, in the near NE slope (Chabowo 2) 47 m, which is 64%, and in the far SW slope of the anticline (Chabowo 3), the thickness is 14 m, which is only 25%. The estimated volumetric capacity of CO 2 storage in the Reed Sandstone layers (at the storage efficiency coefficient of 10%) is 32.8 million tons (Tab. 3.2). The Reed Sandstone is sealed by the overlying layers of the Keuper Upper Gypsum Beds attaining the following thicknesses: Chabowo m, Chabowo m, and Chabowo This is a complex of claystones, locally marly and dolomitic, with thin mudstone interbeds and anhydrite intercalations. Effective porosity of the claystone is quite varied and ranges from % in the Chabowo 3 borehole to % in Chabowo 2, and their permeabilityn (only sporadically measured) ranges from 0.93/0.34 md to 1.69 md. The cap rock series (sealing the Reed Sandstone reservoir) also includes Rhaetian deposits of the following thicknesses: 92.5 m (Chabowo 1), 99.5 m (Chabowo 2) and 116 m (Chabowo 3).

25 25 Table 3.2 Geological and reservoir data on the Chabowo Anticline Reservoir horizons: 1. Komorowo Beds (Upper Pliensbachian Domerian) 2. Reed Sandstone (Middle Keuper) Tabela 3.2 Dane geologiczne i z³o owe dotycz¹ce antykliny Chabowo Poziomy zbiornikowe: 1) warstwy komorowskie (pliensbach górny domer) 2) piaskowiec trzcinowy (kajper œrodkowy) Name Chabowo Anticline Anticline acreage 90 km 2 Reservoir horizon thickness CO 2 storage capacity of reservoir (CO 2 storage efficiency coefficient 10%) Depth to the top of reservoir Depth to the base of reservoir Formation temperature Percentage of sandstones in reservoir Lithology of reservoir Lithological studies Rectangular coordinates X Y m, average m m, average 67 m million tons million tons m (Chabowo 1) to m (Chabowo 3) m (Chabowo 1) to m (Chabowo 3) m (Chabowo 1) to m (Chabowo 3) m (Chabowo 1) to m (Chabowo 3) o C o C 1. 70% 2. 60% Mostly sandstones, subordinate claystones and mudstones Physico-chemical Chabowo Chabowo Chabowo Coordinate system Rectangular coordinate system 1942 Overburden Overburden lithology Faults 1. Gryfice Beds, average thickness ~ 110 m 2. Upper Gypsum Beds (Upper Keuper) + Rhaetian, average thickness ~ 248 m 1. Sandy claystones and mudstones 2. Claystones and mudstones with anhydrites None Number of boreholes 3. Chabowo 1, Chabowo 2, Chabowo 3 Depth of boreholes Chabowo m (central part), Chabowo m (SW flank), Chabowo m (NE flank)

26 26 The Rhaetian sediments are dominated by claystones, locally dolomitic, with thin mudstone interbeds on the flanks of the anticline. Effective porosity of the Rhaetian deposits is as follows: Chabowo %, Chabowo %. In summary of the above considerations, it must be stressed that within the Reed Sandstone reservoir of the Chabowo Anticline, sealed by cap rocks of the Upper Gypsum Beds and Rhaetian deposits, can be considered a potential underground reservoir for industrial gases. The Lower Jurassic formations are sealed by the Gryfice Beds that overlie the Komorowo Beds. The Gryfice Beds are a complex composed mostly of claystones with occasional interbeds of m thick sandy-muddy deposits. The percentage contribution of sandy deposits to the Gryfice Beds ranges from 18% to 26%. Effective porosity of the claystones is relatively high and ranges from 8.01% to 18.98%. Effective porosity of some sandstone interbeds is up to 22%, permeability up to 38.5/435 md, and discharge rate of 3.75 m 3 /h of brine that contains 76.5 g/l TDS and represents a chloride-calcium class I type. These parameters may suggest that the Gryfice Beds are not a good seal to the underlying Komorowo Beds reservoir. The above data indicate that the reservoir rocks of the Mechowo Beds, Radowo Beds and Komorowo Beds, and, to a lesser extent, of the Kamieñ Beds, show very good reservoir properties for brines, which, due to their considerable thicknesses, can be used as well for industrial or medicinal purposes. A uniform type of the brines found in all the reservoirs may indicate poor sealing properties of the cap rocks (claystones and mudstones) which, due to their high porosity, may allow mixing of the waters at different horizons Stratigraphy and lithology Borehole section Geological section of the Chabowo 1 borehole (31.6 m a.s.l.), year of drilling (92.5 m) Cenozoic (586.0 m) Upper Cretaceous, including Upper Albian (17.5 m) Upper Jurassic, Oxfordian (54.0 m) Middle Jurassic (413.0 m) Lower Jurassic, including: (44.0 m) Upper Toarcian Kamieñ Beds (reservoir horizon): sandstones with a small proportion of claystone-mudstone rocks (51.0 m) Lower Toarcian Gryfice Beds: sandy claystones and mudstones (cap rocks) (140.5 m) Upper Pliensbachian Domerian (Komorowo Beds) (reservoir horizon I): sandstones (70%), subordinate claystones and mudstones (19.0 m) Lower Pliensbachian Carixian obez Beds: claystones and mudstones with sandstone interbeds

27 (34.0 m) Upper Sinemurian Radowo Beds (reservoir horizon): sandstones ( claystone bed) (124.5 m) Lower Sinemurian Hettangian Mechowo Beds (reservoir horizon): sandstones with mudstone interbeds (231.5 m) (cap rocks), including: (92.5 m) Upper Triassic Rhaetian: claystones, occasionally dolomitic (139.0 m) Upper Triassic Norian Upper Gypsum Beds (Upper Keuper): claystones, occasionally marly and dolomitic, with thin mudstone interbeds and anhydrite intercalations, and mudstones with anhydrites (85.5 m) Upper Triassic, Carnian Reed Sandstone (Middle Keuper) (reservoir horizon II): sandstones (92%), subordinate claystones and mudstones (109.0 m) Middle Triassic Ladinian Lower Keuper (429.0 m) Middle Triassic Muschelkalk ( m) Middle and Lower Triassic Buntsandstein (98.0 m) Zechstein 27

28 4. Marianowo Anticline 4.1. Geological setting The Marianowo Anticline developed along the axis of the Szczecin Wielgowo Marianowo salt-cored ridge located approximately 45 km NE of Gryfino and about 10 km of Stargard Szczeciñski. It was penetrated by three deep boreholes: Marianowo 1 drilled at the crest of the anticline, Marianowo 2 drilled on its NE flank and Marianowo 3 located on the SW flank, as well as by semi-detailed seismic surveying (Fig ). The Marianowo Anticline, delimited by contour line of the top of the Komorowo Beds, is about km long and about 7 km wide, and its amplitude is m (Fig. 4.1). With respect to the 2250m contour line of the top surface of the Reed Sandstone, the anticline has a similar outline, but the amplitude increases to about 250 m (Fig. 4.2) Reservoir horizons Geological, geophysical and hydrogeological studies suggest that the Upper Pliensbachian (Domerian) Komorowo Beds and the Carnian (Middle Keuper) Reed Sandstone show the best reservoir properties for underground gas storage among all of the Triassic and Jurassic formations in the Marianowo Anticline (Fig. 4.3, Fig. 4.5, Fig. 4.6). In the Lower Jurassic section of the Marianowo Anticline, like in the Chabowo Anticline, the best reservoir properties have been found in the reservoir horizons of the Mechowo Beds, Radowo Beds and Komorowo Beds. The Mechowo Beds, attaining a thickness of 140 m in the centre of the anticline and 160 m on its NE flank (Marianowo 2), are composed mainly of sandstones whose porosity is up to 26.78% in the centre of the anticline. Slightly lower values have been measured on both flanks: from 6.97% to 22.32%. Permeability of the sandstone is also very high attaining 5000 md/5300 md in the Marianowo 1 borehole. The proportion of sandstones in the Mechowo Beds is 75% in Marianowo 1, 68% in Marianowo 2 and 84% in Marianowo 3. Effective porosity of the claystones and siltstones ranges from 4.91% to 10.76%, even attaining 16.04% in sandy mudstones. In testing the boreholes by means of an air-lift test, the average amount of brine taken out of the Mechowo Beds was 86.0m 3 /h. It contained g/l TDS and the brine was

29 III-73 16B-X-74 16A-X-74 7-X X X X X a-I-90W 32-III-86W 34a-III III-86W 3-I III-86W Fig a-II-80 MARIANOWO , III b-I-90W A-III III-85W , III III-73 Fig. 4.3, , A-III I-90W 4-III Boreholes STARGARD 1 5 km Elevation of the top of the Komorowo Beds in borehole, in metres (b.s.l.) 1376,0 MARIANOWO ,0 MARIANOWO 3 CHOCIWEL 3 12-III Contour lines of the top of the Komorowo Beds, in metres (b.s.l.) 7A-III III-86W 7-III d-III-88W 6-III-73 5-XI-72 Fig I-90W Geological cross-sections Reflection seismic profiles 14 Fig Structural map of the top of the Komorowo Beds (Lower Jurassic) in the Marianowo region Rys Mapa strukturalna stropu warstw komorowskich (dolnej jury) w rejonie Marianowa

30 a-I-90W B-X III-86W 20-III-86W 34a-III I A-X-74 Fig X III-86W a-II-80 5-III X b-I-90W X A-III III-85W 2788,5 STARGARD 1 MARIANOWO ,0 MARIANOWO ,5 CHOCIWEL III MARIANOWO III-73 Fig. 4.3, I-90W 4-III A-III-73 6-III ,0 12-III III-86W 7-III XI A-III d-III-88W 2850 Fig. 4.3 Boreholes 5 km Elevation of the top of the Reed Sandstone in borehole, in metres (b.s.l.) Contour lines of the to of the Reed Sandstone, in metres (b.s.l.) Geological cross-sections I-90W Reflection seismic profiles Fig Structural map of the top of the Reed Sandstone (Upper Triassic) in the Marianowo region (after Biernat et al. 1992, complemented by the authors) Rys Mapa strukturalna stropu warstw piaskowca trzcinowego (górnego triasu) w rejonie Marianowa (na podstawie Biernat i in., 1992 z uzupe³nieniami autorów)

31 Marianowo 3 Marianowo 1 Marianowo 2 SW NE Cenozoic 53,7 59,2 52,3 189,0 230,0 128, Upper and Middle Jurassic Upper Triassic: Middle-Upper Keuper and Rhaetian Lower Jurassic Middle Triassic: Röt-Muschelkalk-Lower Keuper Lower Triassic: Lower and Middle Buntsandstein K J2-J3 J1 T3 T2 T1 K Upper and Lower Cretaceous 1391,5 1554,0 1959,5 2045,0 1245,5 1390,0 1786,0 2241,0 2658,0 2917,0 1451,5 1605,0 1957,0 2100,0 J2-J3 J1 T3 T2 T1 P2 P Zechstein m b.s.l. m b.s.l. P km Fig Geological cross-section of the Marianowo Anticline, trending SW-NE along the line connecting the boreholes of Marianowo 3, Marianowo 1 and Marianowo 2 Rys Przekrój geologiczny antykliny Marianowa SW-NE, wzd³u linii z otworami Marianowo 3, Marianowo 1, Marianowo 2

32 Marianowo 1 NW SE Cenozoic 59,2 230, K Upper and Lower Cretaceous K Upper and Middle Jurassic Lower Jurassic Upper Triassic: Middle-Upper Keuper and Rhaetian Middle Triassic: Röt-Muschelkalk-Lower Keuper Lower Triassic: Lower and Middle Buntsandstein J2-J3 J1 T3 T2 T1 1245,5 1390,0 1786,0 2241,0 2658,0 2917,0 J2-J3 J1 T3 T2 T Zechstein P2 P m b.s.l km m b.s.l. Fig Geological cross-section of the Marianowo Anticline, trending NW-SE along the line crossing the Marianowo 1 borehole Rys Przekrój geologiczny antykliny Marianowa NW-SE, wzd³u linii osiowej z otworem Marianowo 1

33 33 Marianowo 3 Marianowo 1 Marianowo 2 SW NE ,0 1390,0 1605,0 0 Gryfice Beds (seal) ,0 1435,0 1652,0 50 Komorowo Beds (reservoir) ,0 1733, ,5 1573,5 1752, , obez Beds m km m Fig The Komorowo Beds reservoir in the Marianowo Anticline Rys Poziom zbiornikowy warstw komorowskich w antyklinie Marianowa

34 34 Marianowo 3 Marianowo 1 Marianowo 2 SW NE 1959,5 1786,0 1957, ,0 Upper Gypsum Beds + Rheatian (seal) , Reed Sandstone Beds (reservoir) 2132,0 Lower Gypsum Beds m m km Fig The Reed Sandstone reservoir in the Marianowo Anticline Fig The Reed Sandstone reservoir in the Marianowo Anticline Rys Poziom zbiornikowy warstw piaskowca trzcinowego w antyklinie Marianowa

35 represented by a chloride-calcium class I type with an outlet temperature of 65.5 o C. The Mechowo Beds reservoir is topped by a thin (1.5 to 3.0 m) claystone-mudstone bed, which correlates well between all the three boreholes. The Radowo Beds overlie the Mechowo Beds and are composed mainly of sandstones, occasionally with claystone and mudstone interbeds. Their thickness varies from m in the Marianowo 1 and 2boreholes to 93 m in Marianowo 3. Effective porosity of the sandstones ranges from 13.08% to 26.78%; their permeability parallel to layers varies from 104 md to 1,750 md, and the permeability perpendicular to layers ranges between 13 md and 1500 md. As with the Mechowo Beds, the average discharge rate of chloride-calcium class I brine was 86.0 m 3 /h, its TDS was g/l, and the outlet temperature 65.5 C. The overlying obez Beds, 18.5 m to 32.5 m thick, are represented by a claystone-mudstone complex with sandstone interbeds exhibiting good reservoir properties: porosity of 21.7% to 22.66% (decreasing to 14.86% in mudstones) and permeability at a maximum of 320mD/38mD. Due to the lack of data on clay rocks, it is impossible to define clearly their sealing properties. The Komorowo Beds consist mainly of sandstones with occasional interbeds of claystones and mudstones. The thickness of the Komorowo Beds ranges from about 80 m on the flanks of the anticline to m in its central part. The sandstones are characterised by very high effective porosity values reaching a maximum of 30.1%. Permeability of the sandstones is up to 3200 md. Effective porosity of the mudstones and claystones varies from 6.45% to 15.06%. Their permeability has not been determined and no formation tests have been performed in the boreholes. However, the results of geophysical surveys and a comparison to the same reservoir in the Chabowo Anticline indicate that this reservoir horizon shows favourable reservoir properties. The estimated volumetric capacity of CO 2 storage in the Komorowo Beds (at the CO 2 storage efficiency coefficient of 10%) is million tons (Tab. 4.1). The Gryfice Beds that occur at the top of the Lower Jurassic section in the Marianowo Anticline are considered cap rocks to the Komorowo Beds reservoir. They are composed mainly of claystones and mudstones with silty sandstone interbeds especially numerous at the top. Effective porosity of the sandstone reaches a maximum of 25.19%, and their permeability is 970mD/500mD. Effective porosity of the sandy mudstones is high, ranging from 14.91% to 24.29%. Permeability of the claystones and mudstones has not been specified, and therefore it is currently impossible to determine exactly their sealing properties. It is worth mentioning that the Gryfice Beds of the Marianowo Anticline underwent profound erosion in the Middle Jurassic. As evidenced by a comparison with the corresponding section of the Chabowo Anticline, at least half of the original thickness of the Gryfice Beds was removed in the Marianowo Anticline. The present-day thickness pattern is as follows: 45.0 m in the Marianowo 1 borehole (central part of the anticline), 47.0 m in Marianowo 2 (NE flank) and 46.0 m in Marianowo 3 (SW flank). The above-presented considerations show that the reservoirs of the Mechowo Beds, Radowo Beds and Komorowo Beds are characterised by very good reservoir parameters. 35

36 36 Table 4.1 Geological and reservoir data on the Marianowo Anticline Reservoir horizons: 1. Komorowo Beds (Upper Pliensbachian Domerian) 2. Reed Sandstone (Middle Keuper) Tabela 4.1 Dane geologiczne i z³o owe dotycz¹ce antykliny Marianowo Poziomy zbiornikowe: 1) warstwy komorowskie (pliensbach górny domer) 2) piaskowiec trzcinowy (kajper œrodkowy) Name Anticline acreage km 2 Reservoir horizon thickness CO 2 storage capacity of reservoir (CO 2 storage efficiency coefficient 10%) Depth to the top of reservoir Depth to the base of reservoir Formation temperature Percentage of sandstones in reservoir Lithology of reservoir Lithological studies Rectangular coordinates X Y m m million tons million tons Marianowo Anticline m (Marianowo 1) to m (Marianowo 2) m (Marianowo 1) m (Marianowo 1) to m (Marianowo 2) m (Marianowo 1) o C C 1. 80% = (~80 m) 2. 57% = (~47 m) 1. Sandstones, locally with claystone and mudstone interbeds 2. Sandstones with claystone and mudstone interbeds Microscopic and physico-chemical investigations Marianowo 1: Marianowo 2: Marianowo 3: Coordinate system Rectangular coordinate system 1942 Overburden Overburden lithology Faults 1. Gryfice Beds (Lower Toarcian) 2. Upper Gypsum Beds (Upper Keuper) + Rhaetian 1. Claystones and mudstones with sandstone interbeds with total thickness of m 2. Claystones and mudstones with anhydrites wih total thickness of 264 m Faults observed in the Zechstein and Triassic Number of boreholes Three boreholes: Marianowo 1, Marianowo 2, Marianowo 3 Depth of boreholes Marianowo 1: Marianowo 2: m m Marianowo 3: m

37 37 Like in the case of the Chabowo Anticline, the rocks contain the same brine type defined as chloride-calcium class I. It may indicate that the sealing properties of the clay-muddy cap rocks occurring within the reservoirs as well as within the obez Beds, defined as a sealing horizon, are poor. It can also be the case with the Gryfice Beds, which are the seal to the Komorowo Beds reservoir that probably remains in a hydrological connection with the Radowo Beds and Mechowo Beds. Reed Sandstone. Reed Sandstone deposits of the Marianowo Anticline have been examined only in its central part in the Marianowo 3 borehole at a depth of m (82.0 m thick). Sandy beds in the Reed Sandstone series predominate in the middle and bottom parts of the section, and their total thickness is 47.0 m, which accounts for 57% of the total thickness of the Reed Sandstone. They are characterised by good reservoir parameters: their effective porosity ranges from 8.22% to 21.68%, and only clayey sandstones shows a value of 4.66%. The permeability, both parallel and perpendicular to layers, varies from trace amounts to 69.0mD/42.5mD. Especially favourable reservoir properties have been found in the sandstones from a depth of m. The upper part of the Reed Sandstone is represented by mudstones with single sandstone interbeds and occasional anhydrite concentrations. The effective porosity ranges from 7.4% to 12.36%. During the formation test, the discharge rate of mineralized brine (67.5g/L) was 0.5 m3/h and the formation temperature was 86 o C. The level of the discharge rate is not representative of the entire reservoir. The estimated volumetric capacity of CO 2 storage in the Reed Sandstone (at the CO 2 storage efficiency coefficient of 10%) is 51.7 million tons. The Reed Sandstone reservoir is sealed by a 120-m thick series of the Upper Gypsum Beds drilled through only in the Marianowo 1 borehole at a depth of m. The Upper Gypsum Beds are represented by marly-dolomitic claystones with marly limestone interbeds, and subordinate sandstones and mudstones with interbeds and concentrations of anhydrite. Effective porosity in the anhydrites and marly limestones ranges from 1.5% to 2.92%, in the marls and claystones from 7.64% to 13.02%. The permeability values are 0.43 md/0.84 md. Like in the Chabowo Anticline, both the Upper Gypsum Beds and the overlying m thick Rhaetian claystone-mudstone series have good sealing properties. Although the Reed Sandstone reservoir was drilled only in the central part of the anticline (Marianowo 1), it is very likely that, as in the case with the Chabowo Anticline, it can play a role of a geological formation suitable for the storage of industrial gases. A disadvantage may be the considerable depth to the reservoir (over 2000 m) Stratigraphy and lithology Borehole section 4.1. Geological section of the Marianowo 1 borehole (59.0 m a.s.l.), year of drilling 1990

38 (230.0 m) Cenozoic ( m) Upper Cretaceous (67.5 m) Upper Jurassic, Oxfordian (36.5 m) Middle Jurassic Callovian, Bathonian, Kuiavian (396.0 m) Lower Jurassic, including: (45.0 m) Lower Toarcian Gryfice Beds (cap rocks): claystones and mudstones with interbeds of silty sandstones especially frequent at the top (138.5 m) Upper Pliensbachian Domerian Komorowo Beds (reservoir horizon I): sandstones (80%), subordinate interbeds of claystones and mudstones (28.5 m) Lower Pliensbachian Carixian obez Beds: claystone-mudstone complex with sandstone interbeds (43.0 m) reservoir horizon Upper Sinemurian Radowo Beds: sandstones, subordinate interbeds of claystones and mudstones (141.0 m) reservoir horizon Lower Sinemurian and Hettangian Mechowo Beds: claystone-mudstone bed, ~2 m thick, sandstones (264.0 m) (cap rocks) including: (144.0 m) Upper Triassic Rhaetian: claystones and mudstones (120.0 m) Upper Triassic Norian, Upper Keuper, Upper Gypsum Beds: marly-dolomitic claystones with marly limestone interbeds, subordinate sandstones and mudstones with interbeds and nests of anhydrites (82.0 m) Upper Triassic, Middle Keuper, Reed Sandstone (reservoir horizon II): upper unit (59.0 m) claystones and mudstones with single sandstone interbeds and rare anhydrite nests, sandstones (23 m) in the middle and bottom parts (109.0 m) Upper Triassic, Carnian, Lower Gypsum Beds (60.0 m) Middle Triassic Lower Keuper (260.0 m) Muschelkalk (356.0 m) Upper, Middle and Lower Buntsandstein, unpierced Borehole section Geological section of the Marianowo 2 borehole (52.3 m a.s.l.), year of drilling (128.0 m) Cenozoic ( m) Upper Cretaceous (79.0 m) Upper Jurassic, Oxfordian (75.0 m) Middle Jurassic (352.0 m) Lower Jurassic, including: (47.0 m) Lower Toarcian Gryfice Beds (cap rocks): claystones and mudstones with interbeds of silty sandstones especially frequent at the top (81.5 m) Upper Pliensbachian Domerian, Komorowo Beds (reservoir horizon I): sandstones (80%), subordinate interbeds of claystones and mudstones (18.5 m) Lower Pliensbachian Carixian obez Beds: claystone-mudstone complex with sandstone interbeds

39 (44.0 m) reservoir horizon Upper Sinemurian Radowo Beds: sandstones, subordinate interbeds of claystones and mudstones (161.0 m) reservoir horizon Lower Sinemurian and Hettangian Mechowo Beds: claystone-mudstone bed, ~2 m thick, sandstones (143.0 m) Upper Triassic Rhaetian: claystones and mudstones 39

40 5. Oœwino Anticline 5.1. Geological setting The Oœwino Anticline (Figs ) was explored by a semi-detailed seismic survey (Grzesik, Bia³ek 1986) and one borehole Oœwino IG1 (Jaskowiak-Schoeneichowa ed. 1966). According to Dadlez (2001, 2005), the Oœwino Anticline is built upon a salt diapir, in which Zechstein salts pierced through the Triassic and much of Lower Jurassic strata during inversion of the Mid-Polish Trough. Faults that bound the Oœwino salt stock from the SW and NE are observed in the lower part of the Zechstein-Mesozoic complex strata up to the Upper Jurassic and Lower Cretaceous. Krzywiec (2002) believes that the Oœwino Anticline formed without the participation of salt masses due to compression related to the uplift of the axial part of the Pomeranian Trough during its Late Cretaceous inversion. In a transverse section, the Oœwino Anticline is bordered on the SW by a reverse fault cutting Zechstein, Triassic, Jurassic and partly Lower Cretaceous deposits. In the Zechstein and Triassic strata, the vertical throw (displacement) is about m Reservoir horizons Assuming a diapiric origin of the Oœwino Anticline and the possibility that Zechstein salts pierced through up to the upper layers of the Lower Jurassic, the results of the Oœwino IG-1 borehole (Fig. 5.3, Borehole section 5.1) show that there are two reservoir horizons suitable for underground gas storage: the Mogilno Formation (Barremian Upper Albian) and the Borucice Formation (Upper Toarcian). According to the 1400 m contour line of the base of the Cretaceous (top of the Mogilno Formation), the anticline is elliptical in shape with the long axis of approximately 5 km and the short axis of about 3 km. Its acreage is approximately 15 km 2. According to the structural surface of the base of the Upper Cretaceous, the Oœwino Anticline is asymmetric in shape. The amplitude of its NE flank is about 400 m, and of its SW flank about 700 m. The anticline crest is delimited by the 1000 m contour line. The Mogilno Formation reservoir (Borehole section 5.1) occurs in the Oœwino IG- 1 borehole at a depth of m (61.0 m) (Raczyñska 1979). The formation consists of three lower-order lithological units:

41 41 Fig Structural map of the base of the Upper Cretaceous in the Grzêzno-Oœwino-Iñsko region, Szczecin Trough (after Dadlez ed. 1998, complemented by the authors) Rys Mapa strukturalna sp¹gu kredy górnej w rejonie Grzêzno-Oœwino-Iñsko w niecce szczeciñskiej (na podstawie Dadlez red z uzupe³nieniami autorów)

42 42 Fig Structural sketch map of the top of the Borucice Formation in the Grzêzno-Oœwino-Iñsko region (Szczecin Trough) Rys Szkic strukturalny stropu formacji borucickiej (toars górny) w rejonie Grzêzno-Oœwino (niecka szczeciñska)

43 Rys Przekrój sejsmiczno-geologiczny przez strukturê Oœwina wzd³u linii sejsmicznej 20-III-85/86 (na podstawie Dadlez 2005 z uzupe³nieniami autorów) K2 kreda górna, K1 kreda dolna, J3 jura górna, J2 jura œrodkowa, J1 jura dolna, Tk kajper, Tm wapieñ muszlowy, Tp pstry piaskowiec, Pz cechsztyn Fig Seismo-geological cross-section across the Oœwino structure along seismic profile 20-III-85/86 (after Dadlez 2005, complemented by the authors) K2 Upper Cretaceous, K1 Lower Cretaceous, J3 Upper Jurassic, J2 Middle Jurassic, J1 Lower Jurassic, Tk Keuper, Tm Muschelkalk, Tp Buntsandstein, Pz Zechstein 43

44 44 1 Kruszwica Member, depth m (1.5 m) is represented by fine to medium-grained glauconitic sandstones with clay cement, containing siderite intercalations. 2 Gop³o Member, depth m (28.5 m) consists principally of dark grey and grey claystones and mudstones with glauconite and irregular sandy intercalations. 3 Pagórki Member, depth m (31.0 m) is composed of uniform facies of light grey sandstones with clay cement. The proportion of sandstones in the Mogilno Formation of the Oœwino IG-1 borehole is approximately 70% = ~ 42.5 m. Porosity of the sandstones is ~20% and their permeability is ~100 md. The Mogilno Formation reservoir is filled by chloride-calcium class I/II brines (Na + :Cl = ) with TDS of 94 g/dcm 3. Formation pressure gradient Gc = 0.98 x 10 3 hpa/100m (Bojarski ed. 1996). The estimated volumetric CO 2 storage capacity (at the CO 2 storage efficiency coefficient of 10%) is 29.4 million tons (Table 5.1). The Borucice Formation reservoir (Upper Toarcian) has not been fully explored by drilling. In the Oœwino IG-1 borehole, this formation was drilled at a depth of m (110.0 m). It is possible that in the upper part of the anticline, the Borucice Formation strata overlie directly the Zechstein salts and their thickness can vary from 150 to 290 m. The Oœwino Anticline, delineated by the m contour line of the top of the Borucice Formation, is elliptical in shape. It is ~5 km long and km wide. Its acreage is about km 2. According to the structural surface of the top of the Borucice Formation, the anticline culmination is delineated by the 1850 m contour line. The Borucice Formation is represented by fine-grained sandstones, occasionally medium-grained, with interbeds of sandy claystones. The 110-m thick section (unpierced) of the Borucice Formation in the Oœwino IG-1 borehole consists of about 80% of sandstones (= ~88.0 m). Their porosity is about 15% and the permeability is below 100 md. The volumetric CO 2 storage capacity (at the CO 2 storage efficiency coefficient of 10%) is 43.7 million tons (Tab. 5.1). This formation contains chloride-calcium brines (Na + :Cl = = 0.86) with TDS of 110 g/dcm 3. Reservoir pressure gradient Gc = 1.02 x10 3 hpa/100m. Detailed information is given in the table below (Tab. 5.1). In the Mesozoic section of the Oœwino Anticline, two reservoir horizons can be taken into consideration for underground gas storage: the Mogilno Formation (Barremian Middle Albian) and the Borucice Formation (Upper Toarcian). A negative assessment of the Oœwino Anticline for underground gas storage is due to the likelihood of its diapiric structure, where the salts have possibly pierced up to the upper layers of the Lower Jurassic (Borucice Formation), and due to strong faulting of Triassic, Jurassic, and possibly Lower Cretaceous strata. Finally, very important is also the small surface of the anticline km 2.

45 45 Geological and reservoir data on the Oœwino Anticline Reservoir horizons: 1. Mogilno Formation sandstones (Barremian Middle Albian) 2. Borucice Formation sandstones (Upper Toarcian) Dane geologiczne i z³o owe dotycz¹ce antykliny Oœwino Pioziomy zbiornikowe: 1) piaskowce formacji mogileñskiej (barrem alb œrodkowy) 2) piaskowce formacji borucickiej (toars górny) Table 5.1 Tabela 5.1 Name Oœwino Anticline Anticline acreage ~15 km 2 Reservoir horizon thickness CO 2 storage capacity of reservoir (CO 2 storage efficiency coefficient 10%) Depth to the top of reservoir Depth to the base of reservoir Formation temperature Percentage of sandstones in reservoir Lithology of reservoir Lithological studies 1. ~61.0 m 2. >110 m million tons million tons m (Oœwino IG-1) m (Oœwino IG-1) m (Oœwino IG-1) m (Oœwino IG-1) Geothermal gradient Gt = 2.8 o C/100 m 1. 70% 2. 80% 1. Sandstones (70%), claystones and mudstones (30%) 2. Sandstones (80%), claystones (20%) Physico-chemical studies Rectangular coordinates X Y Oœwino IG-1: Coordinate system Rectangular coordinate system 1942 Overburden Overburden lithology Faults Number of boreholes Depth of boreholes 1. Upper Cretaceous (Campanian-Upper Albian) 2. Middle Jurassic (Callovian-Upper Bajocian) 1. Limestones and marls, opoka, over 1000 m thick 2. Claystones and mudstones, ~200 m thick Faults cutting Zechstein, Triassic and Jurassic deposits 1 borehole: Oœwino IG-1 Oœwino IG-1: m

46 Stratigraphy and lithology Borehole section Geological section of the Oœwino IG-1 borehole (90.0 m a.s.l.), year of drilling (149.0 m) Cenozoic ( m) Upper Cretaceous (Campanian-Upper Albian) limestones, marls and opoka (cap rocks) m (302.0 m) Lower Cretaceous (Middle Albian-Lower Berriasian) m (61.0 m) Middle Albian-Barremian (Mogilno Formation) - sandstones (70%) (reservoir horizon I) m (1.5 m) Kruszwica Member, sandstones m (28.5 m) Gop³o Member, mudstones and claystones m (31.0 m) Pagórki Member, sandstones m (241.0 m) Hauterivian-Valanginian-Berriasian (including Upper Volgian) m (353.5 m) Upper Jurassic (Tithonian-Oxfordian) m (95.5 m) Tithonian m (26.0 m) Kimmeridgian m (232.0 m) Oxfordian m (196.0 m) Middle Jurassic (Callovian-Upper Bajocian) alternating beds of claystones, mudstones and sandstones (cap rocks) m (110.0 m) Lower Jurassic (Upper Toarcian; Kamieñ Beds=Borucice Formation) sandstones (80%) with dlaystone and mudstone interbeds (reservoir horizon II).

47 6. Strzelno Anticline 6.1. Geological setting The Strzelno Anticline is located about 6 km to the SE of the town of Strzelno and about 12 km to the SW of the town of Kruszwica (Fig. 6.1). It is explored by three boreholes: Strzelno IG-1, depth m Muschelkalk (Raczyñska ed. 1973), M³yny 1, depth m Zechstein (Kicman, Wróbel 1970), M³yny 2, depth m Zechstein (Surmiak, Wróbel 1971), and by a regional and semi-detailed reflection seismic surveys (Bia³ek, Grzesik, Oniszk 1991; Bia³ek, Karpoluk, Mikosz 1975; Jurek et al. 1977; Œmiechowski et al. 1979). Subsurface geological structure of the Strzelno Anticline and its surroundings is depicted in the structural map of the base of the Upper Albian (Fig. 6.2) and geological cross-sections Strzelno IG-1 Cykowo IG-1 (Fig. 6.3) and M³yny 1 Strzelno IG-1 (Figs. 6.4; 6.5). The Strzelno Anticline was formed in an area of crossing tectonic zones. It is a salt stock party pierced through the Triassic overburden. The Zechstein rocks were drilled in the northern part of the anticline in the M³yny 1 and M³yny 2 boreholes. In the M³yny 2 borehole, they were encountered at a depth of m under the Keuper Lower Gypsum Beds (Carnian), in the M³yny 1 borehole at a depth of m under a 57.5-m thick fragment of red deposits of unknown age (probably Rhaetian-Norian), which are in turn overlain by Middle Jurassic rocks. These facts may indicate that there was a stage of upward displacement of salts from the Late Carnian (Keuper) to the early Early Jurassic. The geological situation was found in the M³yny region, where the two boreholes, drilled 1 km apart, show a 500-m difference in the elevation of the top of the salts. A more complete Triassic section in the M³yny 2 borehole may suggest a tectonic contact. Subsequent considerable activity of salts is confirmed by data from the Strzelno IG-1 borehole (Raczyñska ed. 1973). The lower part of the Middle Jurassic section is represented by conglomerates, whose composition proves that not only Lower Jurassic deposits but also Triassic (most probably Keuper and Muschelkalk) rocks occurred at the contemporary ground surface (Marek, ed. 1977). The conglomerates do not contain the characteristic Buntsandstein oolitic limestones, suggesting that salts did not pierced significantly through the overburden at that time (Maliszewska, ed. 1999). The analysis of thickness and facies development in the Early Jurassic and Early to Late Cretaceous indicates that the main phase of salt movements occurred in the late Late

48 48 Kruszwica J3t 52 Mogilno 40' BYCZYNA-1 MOGILNO Geo-1 WYLATOWO-1 MOGILNO Geo-2 MOGILNO Geo-15 M YNY 2 KRUSZWICA-2 (Rzepiszyn) CYKOWO IG-1 KRUSZWICA-I KRUSZWICA-1 Strzelno Radziejów K2k M YNY 1 RACICE 2 RACICE 1 STRZELNO IG-1 RACICE 3 WOLANY-1 RADZIEJÓW KUJAWSKI 3 WIENIEC-1 SZCZEB OTOWO TRZEM AL-2 KOŒCIESZKI-1 USZCZEWO-2 USZCZEWO ' TRZEM AL-1 WILCZYN IGH-1 GOP O Geo-5 GOP O Geo-6 GOP O Geo-2 GOP O Geo-1 GOP O Geo-3 GOP O Geo-8 GOP O Geo-4 GOP O IG-1 GOP O Geo-7 MORZYCZYN PM-28 PAGÓRKI IG-1 GOP O Geo-9 GOP O Geo-10 GOP O Geo-11 o 18 00' o 18 10' o 18 20' o 18 30' o 18 40' o o K2t K1h K2m K1ba-a2 K2k K2cn-s K1b K2a3-c K2t K2cn-s Fig. 6.3 Fig. 6.4 K2k K2m km K2k K2k K2k Boreholes reaching sub-cenozoic basement Faults Fig. 6.4 Geological cross-sections K2m Fig Geological map of the Strzelno region (without Cenozoic formations) K2 Upper Cretaceous, K2m Maastrichtian, K2k Campanian, K2cn-s Coniacian-Santonian, K2t Turonian, K2a3-c Upper Albian-Cenomanian, K1 Lower Cretaceous, K1b-a2 Berriasian-Middle Albian, K1h Hauterivian, K1b Berriasian, J3 Upper Jurassic, J3t Tithonian Rys Mapa geologiczna rejonu Strzelna (bez utworów kenozoiku) K2 kreda górna, K2m mastrycht, K2k kampan, K2cn-s santon, K2t turon, K2a3c alb górny cenoman, K1 kreda dolna, K1b-a2 berias alb œrodkowy, K1h hoteryw, K1b berias, J3 jura górna, J3t tyton

49 Strzelno RACICE 2 CYKOWO IG RACICE 1 RACICE ,1 513, Fig km Boreholes and depth to the base of the Upper Albian, in metres (b.s.l.) Contour lines of the base of the Upper Albian, in metres (b.s.l.) Faults Geological cross-sections 1200 Fig M YNY 2 M YNY ,0 1036, STRZELNO IG , KOŒCIESZKI Fig USZCZEWO-2 770,5 USZCZEWO Fig Structural map of the Strzelno Anticline according to the base of the Upper Albian (top of reservoir rocks) Rys Mapa strukturalna antykliny Strzelna wed³ug sp¹gu albu górnego (strop serii zbiornikowej)

50 50 Fig Geological cross-section Strzelno IG 1 Cykowo IG 1 along a seismic line Rys Przekrój geologiczny Strzelno IG-1 Cykowo IG-1 wzd³u linii sejsmicznej

51 51 Fig Geological cross-section M³yny 1 - Strzelno IG 1 along a seismic line Rys Przekrój geologiczny M³yny 1 Strzelno IG-1 wzd³u linii sejsmicznej

52 52 UPPER ALBIAN M YNY -1 STRZELNO IG-1 111,0 107,0 1147,5 1037,5 LOWER CRETACEOUS BARREMIAN-APTIAN - LOWER AND MIDDLE ALBIAN MOGILNO FORMATION KRUSZWICA MEMBER K.M. GOP O MEMBER G.M. PAGÓRKI MEMBER P.M. HAUTERIVIAN H. K.M. 1224,0 1250,0 G.M. 1265,0 P.M. K.M. 1140,5 G.M. 1167,0 H. 1189,0 P.M. H Fig Correlations of geological sections of the Mogilno Formation in the M³yny 1 and Strzelno IG 1 boreholes 1 fine-grained sandstones, 2 claystones and mudstones, 3 sandy mudstones, 4 variably grained sandstones with quartz gravel, 5 clay-muddy sandstones, 6 flora remains, 7 glauconite Rys Korelacja profili geologicznych formacji mogileñskiej w otworze M³yny-1 i Strzelno IG-1 1 piaskowce drobnoziarniste, 2 i³owce i mu³owce, 3 mu³owce piaszczyste, 4 piaskowce ró noziarniste ze wirkiem kwarcowym, 5 piaskowce ilasto-mu³owcowe, 6 szcz¹tki roœlinne, 7 glaukonit

53 53 Cretaceous. Significant facies and thickness changes observed in the Turonianian, Coniacian and Santonianian confirm the pre-campanian tectonic activity (Leszczyñski 2002a). The recorded degree of Campanian erosion suggests tectonic activity also in the Maastrichtian. Detailed analysis of drilling materials indicates that the salt structures were most active at the Cretaceous/Palaeoeogene transition. The Strzelno Anticline is marked on the sub-cenozoic surface by Campanian subcrops. Assuming conventionally that the outline of the Strzelno Anticline is delineated by the 1200-m (b.s.l.) contour line of the base of the Upper Albian structural surface, it is 6 km long and 4 km wide. According to all structural surfaces, the anticline shows a distinct asymmetry with the gently dipping NE flank and the clearly marked SW flank. The amplitude of the north-eastern flank in the Cretaceous structural surfaces is approximately 800 m, and in the Jurassic structural surfaces 1000 m. The amplitude of the south-western flank is 2000 and 3000 m, respectively. It should be stressed that the Zechstein-Mesozoic succession is more faulted in its deeper formations, and the amount of faults decreases upwards, fading away in the Lower Cretaceous (Fig. 6.1, Fig. 6.3, Fig. 6.4) Reservoir horizons Analysis of the geological and tectonic evolution of the Strzelno Anticline (salt stock) shows that the Barremian-Middle Albian Mogilno Formation displays the best reservoir properties for CO 2 underground storage. The formation is overlain by a 1000-m trick overburden of Upper Cretaceous limestones, marls and opoka. The thicknesses of this formation, dominated by sandstones and sandy mudstones (in the Gop³o Member), are as follows: m (Strzelno IG-1), m (M³yny 1) and m (M³yny 2) (Tab. 6.1, Tab. 6.2). The sandstones typically show high porosities ranging up to 30% (average 20%), and their permeability is up to 700 md. In the M³yny 1 borehole, the formation pressure at the top of the Kruszwica Member, at a depth of m, was 155 at. (for- Table 6.1 Geological data on the Strzelno Anticline Tabela 6.1 Dane geologiczne dotycz¹ce antykliny Strzelno Borehole Elevation above sea level [in metres] Depth to the top of Mogilno Formation [in metres] Mogilno Formation Thickness [m] Kruszwica Member Gop³o Member Pagórki Member Strzelno IG M³yny M³yny (?) (?)

54 54 Table 6.2 Geological and reservoir data on the Strzelno Anticline Reservoir horizon: Mogilno Formation (Barremian-Middle Albian) Tabela 6.2 Dane geologiczne i z³o owe dotycz¹ce antykliny Strzelno Poziom zbiornikowy: formacja mogileñska (barrem alb œrodkowy) Name Strzelno Anticline Anticline acreage 24 km 2 Reservoir horizon thickness CO 2 storage capacity of reservoir (CO 2 storage efficiency coefficient 10%) m (M³yny 1) to m (Strzelno IG-1) 45 million tons Depth to the top of reservoir m (Strzelno IG-1) to m (M³yny 1) Depth to the base of reservoir m (Strzelno IG-1) to m (M³yny 2) Percentage of sandstones in reservoir 85% Lithology of reservoir Sandstones (85%), claystones and mudstones (15%) Lithological studies Rectangular coordinates X Y Microscopic and physico-chemical investigations Strzelno IG-1: M³yny 1: M³yny 2: Coordinate system Rectangular coordinate system 1942 Overburden Overburden lithology Faults Upper Cretaceous: Upper Albian/Cenomanian-Campanian Limestones, marls, opoka, m thick High degree of faulting in deeper parts of the Zechstein-Mesozoic complex, faults fade out in the Jurassic/Cretaceous transition beds Number of boreholes 3 boreholes: Strzelno IG-1, M³yny 1, M³yny 2 Depth of boreholes Strzelno IG-1: M³yny 1: M³yny 2: m m m mation pressure gradient Gc = x 10 3 hpa/10 m). In the Strzelno IG-1 borehole, sandstones of the Kruszwica Member yielded inflow of chloride-calcium water with g/dcm 3 TDS and Na + :Cl ratio = (Bojarski ed. 1996; Górecki et al. 2010). The sandstone series of the Mogilno Formation is sealed by the overlying Upper Cretaceous marls and limestones attaining thicknesses of m (M³yny 1), m (M³yny 2) and m (Strzelno IG-1). Assuming that the average thickness of the Mogilno Formation reservoir is 130 m, the percentage of sandstones is 85%, average porosity is 20%, the volumetric capacity of CO 2

55 55 storage (at the CO 2 storage efficiency coefficient of 10%) is 45 million tons. Detailed characteristics of the Mogilno Formation are presented in the Table below (Tab.6.2) Stratigraphy and lithology Borehole section 6.1. Geological section of the M³yny 1 borehole (111.0 m a.s.l.), year of drilling (77.5 m) Quaternary ( m) Upper Cretaceous (349.5 m) Lower Cretaceous (117.5 m) Barremian-Middle Albian; Mogilno Formation; reservoir horizon (76.5 m) Kruszwica Member; sandstones (26.0 m) Gop³o Member; claystones, mudstones? and sandstones (15.0 m) Pagórki Member; sandstones? (232.0 m) Hauterivian-Valanginian-Berriasian (376.5 m) Upper Jurassic (52.5 m) Middle Jurassic (57.5 m) Upper Triassic ( m) Zechstein. Borehole section 6.2. Geological section of the M³yny 2 borehole (102.5 m a.s.l.), year of drilling (80.0 m) Quaternary ( m) Upper Cretaceous (including Upper Albian) (465.0 m) Campanian (295.0 m) Santonian (44.0 m) Coniacian (174.0 m) Turonian (82.0 m) Cenomanian (4.5 m) Upper Albian (398.0 m) Lower Cretaceous (?including Upper Volgian) (150.5 m) Barremian-Middle Albian; Mogilno Formation; reservoir horizon (96.5 m) Kruszwica Member sandstones (24.0 m) Gop³o Member; claystones, mudstones, sandstones (30.0 m) Pagórki Member (36.0 m) Hauterivian-Upper Valanginian; W³oc³awek Formation (31.0 m) Hauterivian (22.0 m) Upper Hauterivian; ychlin Member

56 (9.0 m) Lower Hauterivian; Gniewkowo Member (5.0 m) Upper Valanginian; Wierzchos³awice Member (138.0 m) Lower Valanginian-Upper Berriasian (Ryasanian) (50.0 m) LowerValanginian; Bodzanowo Formation (88.0 m) Lower Valanginian; RogoŸno Formation (122.5 m) Ryasanian; RogoŸno Formation Stratigraphic gap ? (295.5 m) Upper Jurassic (37.5 m) Calcareous-Marly Formation ? (258.0 m) Calcareous-Spongy Formation (104.0 m) Middle Jurassic (12.0 m) Callovian (63.0 m) Bathonian (+uppermost Bajocian) (29.0 m) Bajocian Stratigraphic gap (42.0 m) Lower Jurassic Upper Pliensbachian, Domerian; Komorowo Formation Stratigraphic gap (465.0 m) Upper Triassic; Rhaetian-Norian-Carnian (96.0 m) Rhaetian-Norian; Lower K³odawa Beds (369.0 m) Carnian (219.0 m) Upper Gypsum Beds (38.0 m) Reed Sandstone (112.0 m) Lower Gypsum Beds Stratigraphic gap (254.5 m) Zechstein Borehole section 6.3. Geological section of the Strzelno IG-1 borehole (107.0 m a.s.l.), year of drilling 1966, after Raczyñska (ed.) 1973, complemented by the authors (71.5 m) Quaternary (966.0 m) Upper Cretaceous (449.0 m) Lower Cretaceous (151.5 m) Barremian-Middle Albian; Mogilno Formation; reservoir horizon (103.0 m) Kruszwica Member sandstones (26.5 m) Gop³o Member silty sandstones, mudstones and claystones

57 (22.0 m) Pagórki Member sandstones (297.5 m) Hauterivian-Valanginian-Berriasian (514.5 m) Upper Jurassic (140.5 m) Middle Jurassic (30.0 m) Lower Jurassic (795.0 m) Upper Triassic (>37.0 m) Middle Triassic (>33.0 m) Muschelkalk 57

58 7. Turek Anticline 7.1. Geological setting The Turek Anticline is located about 5 km east of the town of Turek. The current knowledge on the geological structure of his area is derived mainly from regional seismic studies carried out in the Mogilno-Uniejów Trough in the second half of the 20 th century (e.g.: Bia³ek, Midura 1978; Brauer, Mikosz 1977; Winiarska 1975, 1987, 1989). The Turek Anticline region is also covered by a semi-detailed seismic survey recording predominantly Cretaceous and Jurassic reflectors (Izakowski 1954; Wiœniewski 1958). Gravimetric studies were also important for the reconstruction of the subsurface geometry of Zechstein-Mesozoic structures (Grzywacz, Niedzió³ka 1972; Dziewiñska 1974). Geological and drilling studies of the geometry and evolution of the sedimetary-palaeotectonic structure are based on the results of two boreholes: Turek 1 ( m Muschelkalk, Anisian) (Borehole section 7.1) and Turek 2 ( m Rhaetian/Norian) (Borehole section 7.2). At least ten-odd shallow boreholes were also drilled in the Turek Anticline, mainly for the purpose of the opencast lignnite mine. The Turek Anticline developed in a zone of sub-zechstein basement situated at a depth of m (Skorupa 1974; Skorupa, Dziewiñska 1976; Dadlez, Marek 1977). This is a zone of a very rapid regional increase in the thickness of Upper Cretaceous deposits (Leszczyñski 2002a; Jaskowiak-Schoeneichowa, Krassowska 1988) (Fig. 7.1). Due to the thickness gradient, the Turek Anticline is very asymmetric, and its north-eastern flank is steep whereas its south-western flank is relatively flat (Fig. 7.2, Fig. 7.3). According to the structural surface base of the Upper Cretaceous, the amplitude of the north-eastern flank is 1200 m, and of the south-western flank m. These figures are constants also for the older structural surfaces in the Zechstein-Mesozoic succession. The crest of the anticline is delineated by the 1100 m contour line of the base of the Upper Cretaceous, and is located km to the northeast of the town of Turek. In the period spanning the Triassic to the Early Cretaceous, local activity of the salt pillow was limited. Slight mobility of the anticline, expressed by a low variability in the thickness of sedimentary formations, especially Middle Jurassic (Bathonian) and Upper Jurassic (Kimmeridgian Tithonian) deposits, was probably associated with a lenticular stage (Dayczak- -Calikowska, Moryc 1988; Niemczycka, Brochwicz-Lewiñski 1988). Inversion processes

59 Ko³o Malanów ,5 Turek ,5 1106,5 Turek ,0 Dobrów IGH ,0 Ponêtów Przyby³ów ,5 1836,5 2083,5 Banachów IG Ponêtów , Ko³o IG3 1666, Uniejów IGH1 Uniejów PIG/AGH1 1804,0 Uniejów PIG/AGH2 1780,5 Poddêbice IG Ko³o IG4 1619,0 1100,0 Wartkowice , Turek Fig Uniejów Florentyna IG2 290,0 Zakrzyn IG1 652,0 1599,0 Uniejów 1 Fig Poddêbice Contour lines of the base of the Upper Cretaceous, in metres (b.s.l.) Faults km Uniejów ,0 Boreholes and elevation of the base of the Upper Cretaceous in borehole, in metres (b.s.l.) 2000 Fig. 7.2 Fig. 7.3 Seismo-geological cross-section across the Turek Anticline Geological cross-section across the Turek Anticline (reservoir horizons) Fig Structural map of the base of the Upper Cretaceous (including Upper Albian) in the Turek region (after Leszczyñski 2002a, complemented by the authors) Rys Mapa strukturalna sp¹gu kredy górnej (z albem górnym) w rejonie antykliny Turka (na podstawie Leszczyñski 2002a z uzupe³nieniami autorów)

60 60 SW MALANÓW 1 NE km km Borehole projected onto the profile Faults, certain Seismic boundaries Faults, presumed JANÓW Names of anticlines Fig Seismo-geological cross-section across the Turek Anticline along seismic profile 4-II-78 (Lubieñ line) (after Dziewiñska, Marek and JóŸwiak, 2001, complemented by the authors) K2 Upper Cretaceous, K1 Lower Cretaceous, J3 Upper Jurassic, J2 Middle Jurassic, J1 Lower Jurassic, T3 Upper Triassic, T2 Middle Triassic, T1 Lower Triassic, P2 Zechstein Rys Przekrój sejsmiczno-geologiczny przez antyklinê Turka wzd³u linii 4-II-78 (linia lubieñska) (na podstawie Dziewiñska, Marek, JóŸwiak 2001 z uzupe³nieniami autorów) K2 kreda górna, K1 kreda dolna, J3 jura górna, J2 jura œrodkowa, J1 jura dolna, T3 trias górny, T2 trias œrodkowy, T1 trias dolny, P2 cechsztyn km

61 61 Fig Geological cross-section across the Turek Anticline reservoir horizons Rys Przekrój geologiczny przez antyklinê Turka poziomy zbiornikowe took place in the latest Cretaceous in the Santonian and Campanian, and the main phase of tectonic inversion occurred at the Late Cretaceous/Early Paleocene transition (Leszczyñski 2002a). Assuming conventionally that the outline of the Turek Anticline is delineated by the 1300 m contour line of the base of the the Upper Cretaceous (including Upper Albian), the length of the anticline is about 12 km, its width is about 7 km, and its area is approximately 84 km 2. The faults controlling the evolution of the Turek Anticline are rooted in the sub-zechstein basement and fade out in the Lower Triassic formations. Seismic studies suggest that some of them could be rejuvenated during main inversion phase.

62 Reservoir horizons Results of exploration of the geological structure of the Turek Anticline show that it can be used as an underground CO 2 storage site. The main potential reservoir is the Kruszwica Member of the Mogilno Formation, which is supposed to be Lower-Middle Albian in age. The Kruszwica Member was examined in the Turek 1 borehole at a depth of m and in the Turek 2 borehole at a depth of m. The unit is represented predominantly by light-grey and grey-greenish sandstones, commonlu medium- and coarse-grained, locally gravelly and non-calcareous. Its middle part contains some interbeds of mudstones and claystones. The proportion of sandstones is approximately 90%, their porosity is 20 30% and permeability md. The thickness of the Kruszwica Member is m (average 75.0 m). The volumetric capacity of CO 2 storage (at the CO 2 storage efficiency coefficient of 10%) is million tons. The Kruszwica Member rocks are filled with bicarbonate-sodium brines with g/dcm 3 TDS and the Na + :Cl ratio= (Bojarski ed. 1996). Formation pressure gradient Gc = 1.02 x 10 3 hpa/10 m. Formation temperature is approximately 60 o C, geothermal gradient Gt = o C/100 m (Górecki et al. 2010). The Kruszwica Member reservoir is sealed by Upper Cretaceous limestones, marls and opoka (Upper Albian-Maastrichtian), m in thickness. The other potential reservoir for underground CO 2 storage in the Turek Anticlineis the Upper Pliensbachian (Domerian) reservoir of the Komorowo Formation drilled in the Turek 1 borehole at a depth of m and in the Turek 2 borehole at a depth of m. The Komorowo Formation reservoir is represented by grey sandstones, commonly fineand medium-grained, with claystone and mudstone interbeds which are more frequent in the upper part of the section. The percentage of sandstones in the section is about 85%, their porosity is approximately 20% and permeability md. The thickness of the Komorowo Formation ranges from 42.0 to 48.0 m, 45.0 m on average. The volumetric capacity of CO 2 storage (at the CO 2 storage efficiency coefficient of 10%) is 49.4 million tons. The reservoir contains chloride-calcium class II brines, with 58 g/dcm 3 TDS and the Na + :Cl ratio = Formation pressure gradient Gc = x 10 3 hpa/10 m. The Komorowo Formation reservoir is sealed by the unconformably overlying (at a high angle and stratigraphic gap) Bajocian, Bathonian and Callovian deposits attaining a thickness of m (average 140 m) and represented by alternating claystones, mudstones and sandstones (up to 40% of the total thickness). Detailed information on the reservoirs is given in Tab. 7.1 and in Stratigraphy and lithology (Borehole section 7.1, Borehole section 7.2). Geological and geophysical exploration of the Turek Anticline shows that the best reservoir properties for CO 2 storage have been found in the Kruszwica Member.

63 63 Geological and reservoir data on the Turek Anticline Reservoir horizons: 1 Kruszwica Member of the Mogilno Formation (Lower and Middle Albian) 2 Komorowo Formation (Upper Pliensbachian, Domerian) Dane geologiczne i z³o owe dotycz¹ce antykliny Turek Poziomy zbiornikowe: 1) ogniwo kruszwickie formacji mogileñskiej (alb dolny i œrodkowy) 2) formacja komarowska (pliensbach dolny, domar) Name Anticline acreage 84 km 2 Reservoir horizon thickness CO 2 storage capacity of reservoir (CO 2 storage efficiency coefficient 10%) Depth to the top of reservoir Depth to the base of reservoir Formation temperature Percentage of sandstones in reservoir Lithology of reservoir Lithological studies Rectangular coordinates X Y 1. average 75.0 m 2. average 45.0 m million tons million tons Turek Anticline m (Turek 2) to m (Turek 1) m (Turek 2) to m (Turek 1) m (Turek 2) to m (Turek 1) m (Turek 2) to m (Turek 1) 1, 2. Gt = o C/100 m 1. 90% 2. 85% Table 7.1 Tabela Variously grained sandstones, locally gravelly, in the middle part with thin intercalations of claystones and mudstones (90%) 2. Fine and medium-grained sandstones with relatively frequent intercalations of claystones and mudstones in the upper part (85%) 1, 2. Microscopic and physico-chemical investigations Turek 1: Turek 2: Coordinate system Rectangular coordinate system 1942 Overburden Overburden lithology Faults 1. Upper Cretaceous (Upper Albian/Cenomanian-Maastrichtian) 2. Middle Jurassic (Upper Bajocian -Callovian) 1. Limestones, marls, opoka (~1200 ~1250) Number of boreholes 2 boreholes: Turek 1, Turek 2 Depth of boreholes 2. Alternating claystones, mudstones and sandstones (30-40%) Rooted in the sub-zechstein basement, fade out in the Lower Triassic, in the NE flank probably reach up to the base-upper Cretaceous Turek 1: m Turek 2: m

64 64 The Komorowo Formation reservoir is also positively assessed. Some doubts are raised about the sealing quality Stratigraphy and lithology Borehole section 7.1. Geological section of the Turek 1 borehole (112.5 m a.s.l.), year of drilling (9.0 m) Quaternary ( m) Upper Cretaceous (including Upper Albian); (101.0 m) Maastrichtian; gaizes, subordinate opoka (500.0 m) Campanian; opoka grading to marls and marly limestones (300.0 m) Santonian; opoka with interbeds of marls and marly limestones (107.0 m) Coniacian; silty opoka (196.0 m) Turonian; units: lower=marly-carbonate, upper=carbonate-opoka (47.0 m) Cenomanian; marly limestones and marls (3.0 m) Upper Albian; calcareous sandstones with phosphorites (89.0 m) Lower Cretaceous; Barremian-Middle Albian; Mogilno Formation; (77.0 m) Kruszwica Member (Lower and Middle Albian); reservoir horizon I; variously grained sandstones, subordinate mudstones; proportion of sandstones is 85 90%; (12.0 m) Gop³o Member (Aptian); claystones and mudstones with interbeds of sandstones Stratigraphic gap (652.0 m) Upper Jurassic; Tithonian-Oxfordian; (102.0 m) Tithonian-Upper Kimmeridgian; Pa³uki Formation (58.0 m) Tithonian (44.0 m) Upper Kimmeridgian (115.0 m) Lower Kimmeridgian; Calcareous-Marly-Siltstone Formation (435.0 m) Oxfordian ~ (~156.0 m) Oolitic Formation ~ ~ (~131.0 m) Calcareous-Marly-Coralliferous Formation ~ (~148.0 m) Calcareous-Spongy Formation (146.0 m) Middle Jurassic; (20.0 m) Callovian; dolomitic sandstones with flints, Nodular Bed at the top

65 (56.0 m) Bathonian; sandstones, mudstones at the bottom (70.0 m) Upper Bajocian ~ (~20.0 m) Upper Kuiavian; claystones, mudstones with siderite interbeds ~ (~50.0 m) Middle Kuiavian; alternating claystones, mudstones and sandstones Stratigraphic gap (48.0 m) Lower Jurassic; (48.0 m) Pliensbachian, Domerian; Komorowo Formation; Reservoir horizon II; dominant sandstones (85%). Stratigraphic gap (805.5 m) Upper and Middle Triassic; (142.0 m) Rhaetian-Norian; Lower K³odawa Beds; nodular claystones and clay conglomerates Stratigraphic gap (505.0 m) Carnian-Ladinian; Lower Keuper and?lowermost Upper Keuper; interbedding claystones, mudstones and sandstones, sandstones predominant in the lower part (158.0 m) Middle/LowerMuschelkalk; Schaumkalk Limestones Borehole section 7.2. Geological section of the Turek 2 borehole (109.5 m a.s.l.), year of drilling (13.0 m) Quaternary Stratigraphic gap ( m) Upper Cretaceous (including Upper Albian); (30.0 m) Maastrichtian; gaizes (522.0 m) Campanian; opoka grading to marls and marly limestones (292.0 m) Santonian; opoka with interbeds of marls and marly limestones (105.0 m) Coniacian; silty opoka (201.0 m) Turonian; units: lower=marly-carbonate, upper=carbonate-opoka (50.0 m) Cenomanian; marly limestones and marls (3.0 m) Upper Albian; calcareous sandstones with phosphorites (90.0 m) Lower Cretaceous (?Aptian-Middle Albian); Mogilno Formation; (73.0 m) Lower and Middle Albian; Kruszwica Member; reservoir horizon I; variously grained sandstones with gravelly horizons, interbeds of silty sandstones in the middle part; percentage of sandstones 85 90%,

66 (17.0 m) Aptian(?); Gop³o Member; claystones and mudstones, subordinate sandstones Stratigraphic gap (649.0 m) Upper Jurassic; Tithonian-Oxfordian; (114.0 m) Tithonian-Upper Kimmeridgian; Pa³uki Formation (59.0 m) Tithonian (55.0 m) Upper Kimmeridgian (96.0 m) Lower Kimmeridgian (439.0 m) Oxfordian (148.0 m) Oolitic Formation (206.0 m) Calcareous-Marly-Coralliferous Formation (85.0 m) Calcareous-Spongy Formation Stratigraphic gap (135.0 m) Middle Jurassic; (6.5 m) Callovian (81.0 m) Bathonian (45.5 m) Upper Bajocian Stratigraphic gap (42.0 m) Lower Jurassic; Pliensbachian, Domerian; Komorowo Formation; Reservoir horizon II: sandstones (85%) Stratigraphic gap (73.5 m) Upper Triassic; Rhaetian; Lower K³odawa Beds

67 8. Tuszyn Anticline 8.1. Geological setting The subsurface geological structure of the anticline is depicted in the structural map of the base of the Upper Albian (Fig. 8.1) and of the top of the Pliensbachian (Fig. 8.2), in the seismic-geological cross-section along the Je ów line (8.3) and geological cross-sections with correlations of the Lower Cretaceous sections (Fig. 8.4, Fig. 8.5) and Lower Jurassic sections (Fig. 8.6). The Tuszyn Anticline, being a salt-cored pillow with thickened Zechstein salts to m, has been recorded by seismic studies (Bia³ek, Rowiñski, Krynicki 1972; obaziewicz, Misiewicz, Majewski 1976; Winiarska 1977) as an elongate, NNW-SSE-trending anticlinal form (Dadlez, Marek 1969; Dziewiñska 1974). It has developed in the neighbourhood of faults deeply rooted in the basement and observed in the lower part of the Zechstein- -Mesozoic complex up to the Jurassic structural surfaces (Dziewiñska, Marek, JóŸwiak 2001). Comparison of structural surfaces of the top of the Pliensbachian and the base of the Upper Albian shows that, in the younger surfaces, the culmination of the anticline shifts toward the northeast. This anticline shows a marked asymmetry. Its southwest flank is much steeper than the north-eastern. The amplitude of the south-western flank, estimated based on the top surface of the Pliensbachian and the base of the Upper Albian, is in the range of m, and the amplitude of the north-eastern flank, which is about m for the top of the Pliensbachian, decreases to about m at the base of the Upper Albian. The smaller amplitude of the north-eastern flank is mainly due to increase in the thickness of the Jurassic succession (especially Lower and Middle Jurassic deposits) and the Lower Cretaceous succession toward the Kujawy Swell. Analysis of the results of drilling and seismic data suggests that the Tuszyn Anticline salt pillow showed an uplifting trend at the Late Triassic/Early Jurassic transition. Increased mobility of the anticline was probably due to a general tectonic restructuring of the entire Gniezno- ask Block (Dadlez, Marek 1974; Marek, Znosko 1972a and b; Dadlez, Franczyk 1976). These events resulted in a stratigraphic gap spanning the Rhaetian, Hettangian, Sinemurian and Lower Pliensbachian. The next period of presumed rise of the Tuszyn Anticline salt pillow is the Jurassic/Early Cretaceous transition. It is inferred from a stratigraphic gap spanning the Berriasian and Lower Valanginian.

68 Tuszyn 715,5 TUSZYN 3 Fig TUSZYN III TUSZYN 2 5-XII-75K 19-XII-75K Fig km 612 TUSZYN 9 4-XII-75K TUSZYN Fig. 8.5, Fig. 8.3 Fig XII-75K Boreholes Depth to the base of the Upper Albian in metres (b.s.l.) Contour lines of the base of the Upper Albian, in metres (b.s.l.) Seismo-geological cross-section Geological cross-sections Seismic sections Fig Structural map of the Tuszyn Anticline according to the base of the Upper Albian (top of the Mogilno Formation reservoir) Rys Mapa strukturalna antykliny Tuszyna wed³ug sp¹gu albu górnego (strop poziomu zbiornikowego formacji mogileñskiej)

69 Tuszyn? TUSZYN Fig XII-75K 19-III TUSZYN 1 TUSZYN Fig XII-75K km TUSZYN XII-75K 2500? Fig. 8.3 Fig. 8.5, Fig XII-75K Boreholes Depth to the top of the Pliensbachian, in metres (b.s.l.) Contour lines of the top of the Pliensbachian, in metres (b.s.l.) Faults Seismo-geological cross-section Geological cross-sections Seismic sections TUSZYN Fig Structural map of the Tuszyn Anticline according to the top of the Pliensbachian (top of the Komorowo = Drzewica Formation reservoir) Rys Mapa strukturalna antykliny Tuszyna wed³ug stropu pliensbachu (strop poziomu zbiornikowego formacji komorowskiej = drzewickiej)

70 70 Fig Seismo-geological cross-section along the Je ów line (after Dziewiñska, Marek and JóŸwiak, 2001, complemented by the authors) K2 Upper Cretaceous, K1 Lower Cretaceous, J3 Upper Jurassic, J2 Middle Jurassic, J1 Lower Jurassic, T3 Upper Triassic, T2 Middle Triassic, T3 Lower Triassic, P2 Zechstein, P1/C Rotliegend/Carboniferous Rys Przekrój sejsmiczno-geologiczny wzd³u linii je owskiej (na podstawie Dziewiñska, Marek, JóŸwiak, 2001 z uzupe³nieniami autorów) K2 kreda górna, K1 kreda dolna, J3 jura górna, J2 jura œrodkowa, J1 jura dolna, T3 trias górny, T2 trias œrodkowy, T3 trias dolny, P2 cechsztyn, P1/C czerwony sp¹gowiec/karbon