SEAL QUALITY AND DISTRIBUTION IN THE SOUTHERN TARANAKI BASIN LATE CRETACEOUS TO EOCENE SECTION AND IMPLICATIONS FOR HYDROCARBON TRAPPING ________________________________________________________________ A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Science in Geology in the University of Canterbury by J. Coyle University of Canterbury 2018 ________________________________________________________________ Contents Abstract ................................................................................................................................................... V Acknowledgments .................................................................................................................................. VI 1. Introduction .................................................................................................................................... 1 1.1 Project Aims and Outline ........................................................................................................ 1 1.2 Geological Overview ............................................................................................................... 4 1.3 Seals ........................................................................................................................................ 5 1.4 Previous and Current Exploration ........................................................................................... 6 2. Overview of the Taranaki Basin ...................................................................................................... 9 2.1 Structural Overview ................................................................................................................ 9 2.2 Cretaceous Early Basin Development 103-82 Ma ................................................................. 10 2.3 Late Cretaceous - Paleocene; Syn Rift 82–56 Ma ................................................................. 11 2.4 Paleocene – Early Oligocene; Passive Margin 56-34 Ma ...................................................... 11 2.5 Oligocene – Early Miocene; Transitional Phase 34-19 Ma .................................................... 15 2.6 Miocene - Present; Convergence 19-0 Ma ........................................................................... 15 2.7 North Cape Formation .......................................................................................................... 16 2.8 Farewell Formation ............................................................................................................... 16 2.9 North Cape and E Shales ....................................................................................................... 19 2.10 Biostratigraphic Ages of North Cape and E Shale ................................................................. 19 2.11 Transgressive Depositional Model ........................................................................................ 21 3. Seal Rocks ...................................................................................................................................... 24 3.1 Introduction .......................................................................................................................... 24 3.2 Previous Research on the Influences on Seal Quality ........................................................... 25 3.2.1 Mercury Injection Capillary Testing and Capillary Pressure ......................................... 27 3.2.2 Clay Minerals and Their Effect on Seal Rocks ............................................................... 29 3.3 North Cape Shale Properties ................................................................................................. 31 3.4 E Shale Properties ................................................................................................................. 34 3.5 Results and Discussion .......................................................................................................... 36 4. Seal Quality Estimates from Petroleum Wells .............................................................................. 39 4.1 Introduction .......................................................................................................................... 39 4.2 Relevant Wells for Study ....................................................................................................... 39 4.3 Log Acquisition ...................................................................................................................... 40 4.4 Overview of Log Types .......................................................................................................... 42 4.5 Well Correlation Panel .......................................................................................................... 43 I 4.6 Volume of Clay (Vcl) .............................................................................................................. 46 4.7 Neutron / Density Cross-plots ............................................................................................... 47 4.8 Discussion and Conclusions .................................................................................................. 48 5. Seismic Reflection Interpretation ................................................................................................. 51 5.1 Introduction .......................................................................................................................... 51 5.2 Geological to Seismic Modelling ........................................................................................... 51 5.3 Data Utilised .......................................................................................................................... 51 5.4 Seismic to Well Ties............................................................................................................... 52 5.5 Seismic Interpretation Workflow .......................................................................................... 56 5.6 Interpreted Horizons ............................................................................................................. 59 5.6.1 T40 (base Oligocene) ..................................................................................................... 60 5.6.2 T15 top E Shale equivalent (early Eocene, Waipawan Stage) ....................................... 62 5.6.3 T11 top Farewell Formation (Paleocene, Teurian Stage) .............................................. 62 5.6.4 K95 top North Cape Shale (Latest Cretaceous, Latest Haumurian Stage) .................... 62 5.6.5 K91 near top North Cape Formation (Late Cretaceous, Latest Haumurian Stage) ....... 62 5.6.6 Basement ...................................................................................................................... 62 5.7 E Shale Interpretation (T15 – T11) ........................................................................................ 63 5.7.1 Discussion by Sub Regions ............................................................................................ 65 5.8 North Cape Shale Interpretation (K95 – K91) ....................................................................... 65 5.8.1 Discussion by Sub-Regions ............................................................................................ 66 5.9 Amplitude and Variance Seismic Extractions ........................................................................ 69 5.10 Faulting.................................................................................................................................. 71 6. Paleogeography ............................................................................................................................ 72 6.1 Introduction .......................................................................................................................... 72 6.2 Inputs from Previous Chapters ............................................................................................. 72 6.3 Paleoenvironments from Biostratigraphy............................................................................. 72 6.4 Modern Analogues for Interpretation of Paleoenvironments .............................................. 73 6.5 Results and Discussion .......................................................................................................... 76 6.5.1 E Shale Maximum Flooding Surface, Waipawan, 55 Ma .............................................. 76 6.5.2 North Cape Shale Max Flooding Surface, Latest Haumuraian (66 Ma) ........................ 79 6.6 Summary and Conclusions .................................................................................................... 82 7. Summary and Conclusions ............................................................................................................ 83 7.1 Project Outcomes ................................................................................................................. 83 7.2 Conclusions ........................................................................................................................... 83 7.3 Implications for Future Exploration in the Southern Taranaki Basin .................................... 84 7.4 Future Work .......................................................................................................................... 86 II References ...........................................................................................................................................