Unconventional Offshore Petroleum-Extracting Oil from Active Source Rocks of the Kimmeridge Clay Formation of the North Sea
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Durham E-Theses Unconventional Oshore Petroleum-extracting oil from active source rocks of the Kimmeridge Clay Formation of the North Sea RAJI, MUNIRA How to cite: RAJI, MUNIRA (2018) Unconventional Oshore Petroleum-extracting oil from active source rocks of the Kimmeridge Clay Formation of the North Sea, Durham theses, Durham University. Available at Durham E-Theses Online: http://etheses.dur.ac.uk/12476/ Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in Durham E-Theses • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full Durham E-Theses policy for further details. Academic Support Oce, Durham University, University Oce, Old Elvet, Durham DH1 3HP e-mail: [email protected] Tel: +44 0191 334 6107 http://etheses.dur.ac.uk 2 University of Durham Doctoral Thesis Unconventional Offshore Petroleum-extracting oil from active source rocks of the Kimmeridge Clay Formation of the North Sea Munira Raji Thesis submitted in accordance with the regulations for the degree of Doctor of Philosophy in the University of Durham, Department of Earth Sciences. September, 2017 How to cite: Munira, Raji (2017) Unconventional Offshore Petroleum-extracting oil from active source rocks of the Kimmeridge Clay Formation of the North Sea. Department of Earth Science, Durham University, United Kingdom. Abstract The organic-rich Upper Jurassic Kimmeridge Clay Formation is the major source rock for conventional oil and gas in the North Sea with a maximum thickness of 1,100 m. TOC values range from 2 wt.%-10 wt.% and predominantly Type II (bacterially- degraded algal, and a mix of Type I (mainly algal) kerogens. The δ13Corg values for the investigated samples range from -29.73 ‰ to -26. 88 ‰, these values are characteristic of marine organic matter with terrestrial input. Sixteen billion barrels of commercial reserves have been discovered in conventional reservoirs in the UK Viking Graben area with 29 billion barrels discovered in the Norwegian sector of the North Sea. However, this principal UK conventional hydrocarbon province is reaching the maturity phase of field exploration, leading to a growing interest for unconventional hydrocarbons in the UK and some part of Europe. The purpose of this study is to evaluate the unconventional hydrocarbon potential of the Kimmeridge shale to identity sweet-spot areas using multidisciplinary analogues from successful unconventional resource plays in North American. Conventional and unconventional source rock analyses show that the Kimmeridge Clay Formation contains a significant amount of un-expelled residual oil both within the source rock and in the interbedded sandstone in the South Viking Graben area. As a consequence, this source rock and juxtaposed non-source lithofacies (sand interbeds) can form a hybrid shale resource system. Due to its high organic richness and favourable sweet- spot reservoir properties such as lithology, thickness, kerogen type, level of thermal maturity and hydrocarbon generative potential, the Kimmeridge Clay Formation could be the first offshore unconventional resource in the future. TOC, Rock-Eval S1, Tmax, mineralogical content and the formation of organic, interparticle and intraparticle porosities at peak oil maturity are all factors that have influenced the retention and drainage of the observed oil. The examination/analysis of their interrelationships provides a useful framework and signature for future prediction of sweet spot areas for viable unconventional resources. Contents Abstract ......................................................................................................................................... List of figures .............................................................................................................................. vii List of Tables ............................................................................................................................. xxi List of Abbreviations ............................................................................................................... xxiv Declaration and Copyright Statement ..................................................................................... xxv Preface and Acknowledgements ............................................................................................ xxvi Dedication ............................................................................................................................. xxviii Research Rationale ................................................................................................................. xxix Chapter 1: Introduction .............................................................................................................. 1 1.1: Introduction to the North Sea Petroleum System ........................................................... 1 1.2: Tectonic Evolution and Geological History of the North Sea ........................................... 3 1.2.1: The Caledonian Phase of the North Sea Evolution ................................................... 3 1.2.2: The Variscan Phase of the North Sea Evolution........................................................ 4 1.3: The South Viking Graben area of the North Sea .............................................................. 5 1.4: Kimmeridge Clay (Draupne) Formations.......................................................................... 7 1.5: Conventional and Unconventional Oil and Gas Resources .............................................. 9 1.5.1: Conventional Resources............................................................................................ 9 1.5.2: Unconventional Resources: An Overview ................................................................. 9 1.6: Previous work on Shale Reservoir Parameters for Identification of Sweet-spots ......... 16 1.6.1: Organic Matter Quantity ......................................................................................... 17 1.6.2: Kerogen Types ......................................................................................................... 18 1.6.3: Thermal Maturation ................................................................................................ 19 1.6.4: Mineralogy Composition ......................................................................................... 20 1.6.5: Porosity ................................................................................................................... 21 1.7: Assessment of Unconventional Reservoir Potential of the Kimmeridge Clay Formation .............................................................................................................................................. 22 i 1.8: Syntheses of Research, Aim and Structures .................................................................. 25 1.9: References ..................................................................................................................... 34 Chapter 2: Geochemical Database Sample Collection and Analytical Methods....................... 60 2.1: Literature Review ........................................................................................................... 61 2.2: Published and Public Database ...................................................................................... 62 2.3: Regional Geochemical Databases Used ......................................................................... 62 2.3.1: Criterial for Database Sample Selection………………………………………………………………….63 2.4: Sample Strategy and Sample Collection. ....................................................................... 64 2.4.1: Sample Strategy ...................................................................................................... 64 2.4.2: Sample Collection ................................................................................................... 64 2.4.3: Borehole Core Sampling: ........................................................................................ 65 2.4.4: Outcrop Sampling ................................................................................................... 69 2.4.5: Sample Preparation and Analytical Techniques ..................................................... 72 2.4.6: Powdered Sample Preparation and Analyses ......................................................... 72 2.5: Overview of the Analytical Techniques used for Evaluation of the Kimmeridge Clay Formation.............................................................................................................................. 72 2.5.1: Geochemical Techniques ........................................................................................ 73 2.5.2: Total Organic Carbon (TOC) Analysis ...................................................................... 74 2.5.3: Kerogen Isolation Analysis ...................................................................................... 75 2.5.4: Rock-Eval Pyrolysis analysis .................................................................................... 75 2.5.5: Carbon Isotopic Analysis ........................................................................................