Master Thesis, Department of Geosciences Geochemical Comparison of Oils and Source Rocks from Barents Sea Correlation between crude oils and source rock core samples from the western Barents Sea by GC-FID and GC-MS techniques Dimitrios Rallakis Geochemical Comparison of Oils and Source Rocks from Barents Sea Correlation between crude oils and source rock core samples from the western Barents Sea by GC-FID and GC-MS techniques Dimitrios Rallakis Master Thesis in Geosciences Discipline: Petroleum Geology and Petroleum Geophysics Department of Geosciences Faculty of Mathematics and Natural Sciences University of Oslo June, 2015 © Dimitrios Rallakis, 2015 This work is published digitally through DUO – Digitale Utgivelser ved UiO http://www.duo.uio.no It is also catalogued in BIBSYS (http://www.bibsys.no/english) All rights reserved. No part of this publication may be reproduced or transmitted, in any form or by any means, without permission. “Patience is bitter, but its fruit is sweet.” Aristotle (384–322 B.C.E.) Abstract This project is part of the qualification for M.Sc. at Department of Geosciences, University of Oslo, in the direction of "Petroleum Geology and Petroleum Geophysics". The initial notion that the Barents Sea was a dry gas region proved to be incorrect since commercially valuable oil fields were also discovered. Examples of such fields include the wells 7125/4-1 (Nucula discovery), 7122/7-1 (Goliat field), 7222/6-1 S, and the most recent Lundin discovery in well 7220/11-1 (Gotha and Alta fields), NW of 7121/4-1 (Snøhvit field). The Barents Sea exploration campaign has had, and continues to have a high drilling success rate since most of the exploration wells of the 68 in total, until 2008, discovered sedimentary strata containing in some cases petroleum. However, most of the reservoirs discovered contain gaseous hydrocarbons and/or thin oil legs or residual oils i.e "shows" and this seems to be related mainly to uplift and remigration (Ohm et al., 2008). The main objective of this study is to attempt to correlate twelve (12) core and (1) one outcrop source rock samples, recovered from the Hammerfest Basin, the Nyslepp/Måsøy Fault Complex, the Finnmark Platform, the Nordkapp Basin, the Svalis Dome, the Bjarmeland Platform and the outcrop sample from the Trehøgdene on Svalbard, with ten (10) oil samples from the Hammerfest Basin, the Nyslepp/Måsøy Fault Complex, the Bjarmeland Platform, the Loppa High and the Nordkapp Basin in western Barents Sea, for the purpose of understanding better the source and maturity aspects of the petroleums. The oil samples represent liquid hydrocarbons from exploration oil wells. Eight of them were produced from reservoir rocks that are of Triassic-Jurassic age i.e. from the Kapp Toscana Group, one is from the Middle Triassic of the Sassendalen Group, and one is of Permo-Carboniferous age and from the Gipsdalen Group. This study aims to evaluate if the source rock (SR) samples are reasonable analogues for the SR of any of the oils and also as a help in overviewing the maturity of the oils. 3 Furthermore, it attempts to address the aspects of secondary processes like biodegradation, organofacies or in-reservoir mixing. As a matter of fact it is not easy to address the potential source of petroleum accumulations in the Barents Sea due to dysmigration, tilting and spill phenomena, as a result of several uplift episodes. Furthermore, the fact that Barents Sea is a multi-SR basin (Ohm et al., 2008; Faleide et al., 2010) means that oils may have mixed in the reservoirs. 4 Acknowledgements I would like to express my sincere gratitude to my supervisor Dr. Dag Arild Karlsen for giving me the opportunity of walking together with this thesis. I am grateful to Dr. Karlsen for assigning to me the topic that was my first priority and for guiding me with his fruitful comments and observations that led to the completion of the present study. Additionally, I am truly indebted to the PhD candidates Tesfamariam Berhane Abay and Benedikt Lerch for trusting me with their gas chromatogram database, part of their PhDs. I also thank the PhD candidate Zagros Matapour for his feedback and recommendations on previous studies. I take this opportunity to acknowledge all the Professors of the Petroleum Geology and Petroleum Geophysics master program for pursuing to transform us into professionals. These two years notably enriched my knowledge as I obtained various new skills. In the long run I would like to thank my family Athanasios, Vasiliki, Stavros, Artemis, and Lydia who supported and encouraged me all these years. Dimitrios Rallakis Oslo, 2015 5 Table of Contents Abstract ..................................................................................................................................... 3 Acknowledgements ................................................................................................................... 5 Chapter 1 ................................................................................................................................... 9 Introduction ............................................................................................................................... 9 Chapter 2 ................................................................................................................................. 13 Geological Setting .................................................................................................................... 13 2.1 Architectural Elements of the Geology ......................................................................... 14 2.2 Structure ........................................................................................................................ 17 2.3 Stratigraphy and Geological Evolution .......................................................................... 18 2.3.1 Upper Paleozoic ...................................................................................................... 21 2.3.2 Mesozoic ................................................................................................................. 21 2.3.3 Cenozoic ................................................................................................................. 22 2.4 The western Barents Sea petroleum system ................................................................. 23 Chapter 3 ................................................................................................................................. 25 Sample database ..................................................................................................................... 25 3.1 Oil dataset ..................................................................................................................... 25 3.1.1 Well 7120/2-1 (1944 m) ......................................................................................... 27 3.1.2 Well 7120/6-1 (2432 m) ......................................................................................... 29 3.1.3 Well 7121/5-2 (2328 m) ......................................................................................... 31 3.1.4 Well 7122/7-3 (1195.6 m & 1812) .......................................................................... 32 3.1.5 Well 7123/4-1 A (2165.9 m) ................................................................................... 34 3.1.6 Well 7124/3-1 (1298 m) ......................................................................................... 36 3.1.7 Well 7125/1-1 (1403.8 m) ...................................................................................... 38 3.1.8 Well 7222/6-1 S (1633.8 m) .................................................................................... 39 3.1.9 Well 7228/7-1 A (2091.1 m) ................................................................................... 41 3.1.10 NSO-1 standard .................................................................................................... 42 3.2 Source rock dataset ....................................................................................................... 43 3.2.1 Well 7122/6-1 (1156.60 & 2061.50 m) ................................................................... 46 3.2.2 Well 7124/3-1 (1367.50 m) .................................................................................... 48 3.2.3 Well 7128/6-1 (1738.50 m) .................................................................................... 49 3.2.4 Well 7230/5-U-5 (43.85 m) ..................................................................................... 50 3.2.5 Well 7231/1-U-1 (70.90 & 76.20 m) ....................................................................... 51 3.2.6 Well 7231/4-U-1 (84.70 m) ..................................................................................... 52 6 3.2.7 Well 7323/7-U-3 (100.30 m) ................................................................................... 53 3.2.8 Well 7323/7-U-9 (106.00 m) ................................................................................... 54 3.2.9 Well 7430/7-U-1 (38.80 & 64.70 m) ....................................................................... 55 3.2.10 De Geerdalen/Svalbard (outcrop) ........................................................................ 56 Chapter 4 ................................................................................................................................. 59 Analytical techniques .............................................................................................................