Shale oil potential and depositional environment of the Lower Toarcian Posidonia Shale in NW Europe Von der Fakultät für Georessourcen und Materialtechnik der Rheinisch -Westfälischen Technischen Hochschule Aachen zur Erlangung des akademischen Grades einer Doktorin der Naturwissenschaften genehmigte Dissertation vorgelegt von M.Sc. Jinli Song aus Henan, China Berichter: Univ.-Prof. Dr. rer. nat. Ralf Littke Univ.-Prof. Dr. rer. nat. Detlev Leythaeuser Tag der mündlichen Prüfung: 29.10.2015 Diese Dissertation ist auf den Internetseiten der Hochschulbibliothek online verfügbar Acknowledgments The present study received financial support from China Scholarship Council (CSC), which is gratefully acknowledged. First of all, I would like to express my profound gratitude to Prof. Dr. Ralf Littke for giving me the opportunity to carry out my PhD studies at the Institute of Geology and Geochemistry of Petroleum and Coal of RWTH Aachen University and for his support throughout my studies. Furthermore, I thank Prof. Dr. Detlev Leythauser for taking the time to review and supervise my thesis. I would like to thank ExxonMobil Production Deutschland GmbH and Dr. Christian Ostertag-Henning for providing core samples from SW-Germany, Robert Maquil for providing core samples from Luxembourg and Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek (TNO) for providing core samples from the well LOZ-1, NL, and outcrops of Runswick Bay, UK. I sincerely thank Dr. Philipp Weniger for sharing his knowledge and experiences in geosciences. Without his help during my PhD study, I would not have been able to write this thesis. I am grateful to patience and friendly assistance from Donka Macherey for preparing high quality polished sections and introducing me to operation procedures of microscopy. Special thanks also go to Dannial Rippen who taught me how to do microscopic analysis. I am grateful to Johannes Böcker who taught me the rigorous procedures of doing organic geochemical experiments in order to get reliable results. Precision is the way to get people closer to the truth. I am greatly impressed by his professional performance in doing scientific research, which also became one of my principles for scientific research. Thanks go to my colleagues for their assistance for my lab work, Prof. Jan Schwarzbauer, Annette Schneiderwind and Yvonne Esser on organic geochemistry, Kerstin Windeck on elemental analysis, Susan Giffin and Bandar Ghassal on Rock-Eval pyrolysis and to Alexej Merkel for his assistance and driving for my sampling travel. Our master students, Michaela Christine Biela and Carlos Molina Martín, are greatly acknowledged for their excellent work. With deep appreciation and respect, I thank all great scientists who ever shed light on science with invaluable wisdom, knowledge and goodness, such as ‘Albert Einstein’. Their contributions to science and the world illuminated human life like a beacon light of hope. When it comes to my study, one of the most inspirational quotes for me is as follows: ‘To raise new questions, new possibilities, to regard old problems from a new angle, requires creative imagination and marks real advance in science.’_ By Albert Einstein. i Most of all, I would like to thank my family in China who always support me with love and goodness through internet from thousands of miles away. Without those people I love, life is dull and meaningless. Especially, my dearest friends, Songtao Wu, Donglin Hao, Feng Long, Xiufen Zhai and Jiangong Zhang, are highly acknowledged. Without their supports and trust, it would not be possible for me to pursue my PhD degree abroad. ii Abstract This doctoral thesis deals with a suite of drilling cores and outcrop samples of the Lower Toarcian Posidonia Shale (PS) collected from multiple locations covering a vast area including the Swabian Alb (SA) and Franconian Alb (FA) of Southwest-Germany, Wenzen well (WEN) of Hils syncline, northern Germany, Runswick Bay of UK, Loon op Zand well (LOZ-1) of the West Netherlands Basin (WNB) and the Esch-sur-Alzette, Luxembourg (LU). Based on a series of laboratory measurements, firstly, shale oil potential was assessed including thermal maturity. In order to quantify the petroleum generation potential of the rocks a large set of experimental analyses was conducted including elemental analysis, Rock-Eval pyrolysis, organic petrographic investigations and molecular hydrocarbon analyses. Secondly, three types of depositional environments of the Posidonia Shale from these six different sampling localities were deduced mainly based on organic geochemical characteristics. The Lower Toarcian Shale is more carbonate-rich (about 30 % on average) in SW-Germany, NW- Germany and Luxembourg, and is instead more silicate-rich in UK and NL with carbonate contents of about 15% on average. However, HI values are similar, approx. 500-700 mg HC/g TOC on average at all sampling localities, exhibiting typical type II kerogen with excellent hydrocarbon generation potential. Samples from outcrops of the Lower Toarcian Shale from Runswick Bay, UK, have reached the early stage of the oil window, with quite uniform Tmax values (425-438°C, avg. 433 °C) and a narrow range of PI (production index) values (0.10-0.19), substantiated by mature fluorescing characteristics of telalginite and lamalginite and vitrinite reflectance values of 0.6-0.7%. Wider ranges of Tmax values (421-443°C, avg. 427°C), vitrinite reflectance (0.4-0.8%) and production indices (0.06-0.29) suggest more variable thermal maturation ranging from immature to almost peak oil generation at the LOZ-1 well, NL, although only some intervals indicate advanced thermal maturity there. Non-indigenous light hydrocarbons occur at the LOZ-1 well, NL, evidenced by unexpectedly high production indices and abundant low molecular weight, short-chain n-alkanes extending from n-C10 to n-C16 together with a sharp decrease of n-alkanes concentration towards the heavier, long-chain components (>n-C20). In contrast, the Lower Toarcian marlstones from the Swabian and Franconian Alb of SW-Germany are clearly immature, similar to the samples from Luxembourg. In NW-Germany, the Posidonia Shale covers a wide spectrum of maturity ranging from immature to overmature. Organic geochemical characteristics were comprehensively analyzed and compared for these six different sampling localities on a series of sterane, hopane and aromatic biomarkers. Results indicate that highest thermal maturity occurs in the PS of Runswick Bay, UK, equivalent to ca. 0.7% VRr, whereas samples from other sampling localities did not exceed the early stage of oil generation or are immature with merely slight variations. Comparable, immature to marginally mature source rocks make it possible to compare iii their depositional environments based on biomarker characteristics. Accordingly, three different types of redox conditions are established on the basis of biomarker indicators for these six sampling localities during deposition of the PS in NW Europe. (1) Ferruginous conditions are discriminated by low dibenzothiophene/ phenanthrene (<0.2) and gammacerane index (<0.1) values in Runswick Bay, UK, and possibly also LOZ-1, NL, especially when accompanied by high sulfur content and abundant tiny pyrites (>95% of < 7 µm in diameter) which are postulated to be partly generated within the water column due to 2+ immediate reaction of Fe and H2S derived from bacterial sulfate reduction. (2) In contrast to the iron- rich, low-sulfidic conditions, sulfidic (euxinic) bottom waters possibly with enhanced water salinity and stratified water column prevailed due to restricted iron supply in the Esch-sur-Alzette of LU. Similar but slightly less reducing and less sulfidic conditions occurred in the FA of SW-Germany as well as WEN of northern Germany which was also probably less saline. (3) For the PS of SA, a more oxygenated (dysoxic) water column associated with anoxic sediments (anoxic/dysoxic boundary close to the sediment/water interface) is indicated. iv Zusammenfassung Im Rahmen dieser Dissertation wurden eine Vielzahl von Bohrkern- und Aufschlussproben aus dem Posidonienschiefer (PS) des Unteren Toarciums untersucht. Die Probenlokationen umfassen die Schwäbische- (SA) und die Fränkische Alb (FA) Südwest-Deutschlands, die Wenzen Bohrung (WEN) in der Hils Synkline Norddeutschlands, die Runswick Bay des Vereinigten Königreichs, die Loon op Zand Bohrung (LOZ-1) im West-Niederländischen Becken (WNB) sowie die Esch-sur-Alzette Bohrung in Luxembourg (LU). Zunächst wurden anhand unterschiedlicher Messungen das Shale Oil Potential und die thermische Reife der Proben bestimmt. Zur Quantifizierung des Ölgenesepotentials wurde umfangreiche Analysemethoden angewandt. Neben der elementaren Zusammensetzung der Ton- und Mergelsteine wurden Rock-Eval Pyrolyse, organisch-petrographische Untersuchungen sowie molekulare Analysen der Kohlenwasserstoffe durchgeführt. Basierend auf den organisch-geochemischen Charakteristika konnten die Posidonienschiefer der sechs Herkunftsgebiete unterschiedlichen Ablagerungsmilieus zugeordnet werden. In Südwest- und Nordwestdeutschland, ebenso wie in Luxembourg, weist der untersuchte Posidonienschiefer höhere Karbonatgehalte auf (durchschnittlich 30 %) als im Vereinigten Königreich und in den Niederlanden. Hier enthält der silikatreiche Schiefer durchschnittlich 15 % Karbonat. Die HI- Werte aller Lokationen hingegen sind mit durchschnittlich 500-700 mg HC/g TOC durchaus ähnlich und weisen auf ein typisches Typ II Kerogen mit ausgezeichnetem