i ; ' Mobile and immobile migrated hydrocarbons in the Embla Field, i North Sea o 7 Faculty of Applied Earth Sc%#c8 anfl Petroleum Engineering The Norwegian University of Science and Technology Trondheim, Norway ^ NTNU I Dr. philos. thesis DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document. Mobile and immobile migrated hydrocarbons in the Embla Field, North Sea Sunil Bharat: a thesis accepted by The Faculty of Applied Earth Science and Petroleum Engineering Norwegian U niversity of Science and Technology (NTNU) Trondheim, Norway for public defense in partial fulfillment of the requirements for the Norwegian academic degree dr. philos December, 1997 ISBN 82-7861-089-4 © by Sunil Bharati March 1998. Printed in Norway by Tapir, Trondheim. To my mother and father, for always hoping and tomy wife, for keeping that hope alive. Contents i Contents Preface ........................................................................................................... v Executive Summary .............................................................................. vii Chapter 1: Introduction 1 Chapter 2 : Paper 1 Identifying diverse oil families in the Greater Ekofisk area, North Sea. Bharati, Hall and Bjor0y - under submission. 2.1 Abstract ........................................................................................ 7 2.2 Introduction .............................................................................. 8 2.3 Samples and methods ..................................................................... 8 2.4 Geological setting ..................................................................... 10 2.5 Maturity variations ..................................................................... 10 2.6 Source facies variations ............................................................ 15 2.7 The Greater Ekofisk oil families .................................................. 20 2.8 Conclusions .............................................................................. 22 2.9 Acknowledgments 23 2.10 References .............................................................................. 23 Chapter 3: Paper 2 Geochemical evaluation of the Embla field, Norwegian Continental Shelf - 1: Occurrence and compositional variations of migrated hydrocarbons. Bharati, Hall, Wagle and Bjorpy - under submission. 3.1 Abstract ........................................................................................ 25 3.2 Introduction .............................................................................. 26 3.3 Geological elements and field history ......................................... 27 3.4 Samples and methods ..................................................................... 31 3.5 Mineralogical composition of reservoir sandstones ...................... 33 3.6 Abundance of migrated hydrocarbons ......................................... 34 3.7 Variations in hydrocarbon composition across the field ............ 38 3.8 Molecular characteristics ............................................................ 40 3.9 Discussion ......................................................................................... 45 3.10 Summary and conclusions ............................................................. 52 3.11 Acknowledgments ...................................................................... 53 3.12 References......................................................................................... 53 Norwegian University of Science and Technology ii Mobile and immobile migrated hydrocarbons in the Embla Field, North Sea Chapter 4: Paper 3 Geochemical evaluation of the Embla field, Norwegian Continental Shelf - 2: Source, infilling , and intra-reservoir communication. Bharati, Hall, Wagle and Bjor0y - under submission. 4.1 Abstract ......................................................................................... 55 4.2 Introduction ................................................................................ 56 4.3 Geological background ............................................................. 56 4.4 Samples and methods ............................................................. 57 4.5 Maturity of the Embla oils ............................................................. 58 4.6 Source of the Embla oils ............................................................. 64 4.7 Possible filling directions ............................................................. 72 4.8 Trap boundaries and communication .......................................... 76 4.9 Field productivity: implications of OWC and bitumen occurrence .. 77 4.10 Summary and conclusions ............................................................. 78 4.11 Acknowledgments ...................................................................... 79 4.12 References ................................................................................ 80 Chapter 5: Paper 4 Solid reservoir bitumen in the Embla Field, Norwegian Continental Shelf -1: Occurrence, development and morphotypes. Bharati - under submission. 5.1 Abstract ........................................................................................ 83 5.2 Introduction .............................................................................. 84 5.3 Geological background ............................................................ 85 5.4 Reservoir bitumen: the less understood phase ..................... 87 5.5 Occurrence and types of bitumen in the Embla Field ............ 88 5.6 Morphotypes of Embla bitumen .................................................... 94 5.7 Minerals in inter-granular space .................................................. 100 5.8 Summary and conclusions 106 5.9 Acknowledgments ..................................................................... 106 5.10 References .............................................................................. 106 Chapter 6: Paper5 Solid reservoir bitumen in the Embla Field, Norwegian Continental Shelf -2: Chemistry, structure and origin. Bharati - under submission. 6.1 Abstract ......................................................................................... 109 6.2 Introduction ................................................................................ 110 6.3 Geological background ............................................................. 110 6.4 Samples and methods ............................................................. 110 6.5 Embla solid bitumen composition .......................................... Ill 6.6 The nature of carbon in the Embla bitumens ................................. 114 6.7 Internal structure of the bitumen phase 116 6.8 Timing of bitumen formation .................................................... 118 6.9 Causes of bitumen formation .................................................... 127 6.10 Paleo-oil emplacement and destruction in Embla: A hypothesis .... 131 6.11 Implications of solid bitumen in the Embla Field ....................... 132 Doctoral Dissertation by Sunil Bharati, 1997 Contents iii 6.12 Summary and conclusions 133 6.13 Acknowledgments 133 6.14 References ................................................................................ 134 Chapter 7: Paper 6 Calibration and standardization of Iatroscan (TLC-FTD) using standards derived from crude oils. Bharati, R0stum and L0berg -1994, Organic Geochemistry, v. 22, p. 835-862. 7.1 Abstract .......................................................................................... 141 7.2 Introduction ................................................................................. 142 7.3 Analytical procedures .............................................................. 144 7.4 Results and discussion .............................................................. 145 7.5 Summary and conclusions .............................................................. 167 7.6 Acknowledgments 168 7.7 References ................................................................................. 168 Chapter 8 : Paper 7 A new North Sea oil based standard for Iatroscan analysis. Bharati, Patience, Mills and Hanesand -1997, Organic Geochemistry, v. 26, p. 49-57. 8.1 Abstract ......................................................................................... 171 8.2 Introduction ................................................................................ 172 8.3 Analytical procedures ............................................................. 172 8.4 Results and discussion ............................................................. 173 8.5 Conclusions 179 8.6 References ................................................................................ 180 Chapter 9: Paper 8 Elucidation of the Alum Shale kerogen structure using a multi-disciplinary approach. Bharati, Patience, Latter, Standen and Poplett -1995, Organic Geochemistry, v. 23, p. 1043-1058. 9.1 Abstract .......................................................................................... 181 9.2 Introduction ................................................................................. 182 9.3 Samples and geology 182 9.4 Analytical methods 184 9.5 Results .......................................................................................... 185 9.6 Discussion ................................................................................. 193 9.7 Conclusions ................................................................................. 196 9.8 References