INCISED VALLEY-FILL SYSTEM DEVELOPMENT AND STRATIGRAPHIC ANALYSIS OF THE LOWER CRETACEOUS KOOTENAI FORMATION, NORTHWEST MONTANA by Casey Ryan Reid A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Earth Sciences MONTANA STATE UNIVERSITY Bozeman, Montana April 2015 ©COPYRIGHT by Casey Ryan Reid 2015 All Rights Reserved ii ACKNOWLEDGEMENTS I would like to thank the Big Sky Carbon Sequestration Partnership and Vecta Oil and Gas for the financial and technical support received during this project. I would also like to thank my committee Dr. Jim Schmitt, Dr. Dave Bowen and Dr. Dave Lageson for their support and guidance throughout the duration of this thesis. Montana State University and the American Association of Petroleum Geologists are also acknowledged for financial support received and continued excellence in the geosciences. Without the support of my family and friends this project would surely never have been completed. While I am indebted to numerous people a number of specific words of thanks are necessary: to my parents whose love, guidance, and unwavering encouragement has never yielded, to my sisters who always supplied a welcome break from work and to my fellow geoscientists Jack Borksi, Nick Atwood, Nate Corbin, Ryan Hillier, and Colter Anderson. iii TABLE OF CONTENTS 1. INTRODUCTION, OBJECTIVES, & SIGNIFICANCE OF STUDY ...........................1 Introduction ......................................................................................................................1 Objectives ........................................................................................................................5 Significance of study ........................................................................................................5 2. REGIONAL SETTING ...................................................................................................7 Introduction ......................................................................................................................7 Study Area .......................................................................................................................7 Tectonic Setting .............................................................................................................10 North American Cordilleran Orogeny and Foreland Basin System ......................10 Sweetgrass Arch .....................................................................................................15 Sweetgrass Hills .....................................................................................................16 Pendroy Fault Zone ................................................................................................17 Lithostratigraphy ............................................................................................................19 Introduction ............................................................................................................19 Ellis Group (Je) ......................................................................................................19 Sawtooth Formation (Jswt) ....................................................................................19 Rierdon Formation (Jr) ..........................................................................................21 Swift Formation (Jsw) ...........................................................................................22 Morrison Formation (Jmr) .....................................................................................22 Kootenai Formation (Kk) .......................................................................................23 Blackleaf Formation (Kbl) .....................................................................................25 Oil and Gas Fields ..........................................................................................................26 Fred & George Creek Oil and Gas Field ...............................................................26 Kevin-Sunburst Oil and Gas Field .........................................................................28 3. DATA AND METHODS ..............................................................................................30 Introduction ....................................................................................................................30 Geophysical Well Logs ..........................................................................................30 Drill Core ...............................................................................................................34 Outcrop ..................................................................................................................36 Thin Sections .........................................................................................................36 Portable X-ray Fluorescence ..................................................................................37 Data Assumptions ..................................................................................................39 iv TABLE OF CONTENTS - CONTINUED 4. LITHOFACIES, FACIES ASSOCIATIONS, AND ELECTROFACIES .....................41 Introduction ....................................................................................................................41 Lithofacies ......................................................................................................................42 Facies F1: (Cglm.) .................................................................................................42 Hydrodynamic Interpretation .................................................................................46 Facies F2: (St) ........................................................................................................46 Hydrodynamic Interpretation .................................................................................46 Facies F3: (Sp) .......................................................................................................48 Hydrodynamic Interpretation .................................................................................48 Facies F4: (Sr) ........................................................................................................48 Hydrodynamic Interpretation .................................................................................51 Facies F5: (Sh) .......................................................................................................51 Hydrodynamic Interpretation .................................................................................51 Facies F6: (Sm) ......................................................................................................53 Hydrodynamic Interpretation .................................................................................53 Facies F7: (SFh) .....................................................................................................53 Hydrodynamic Interpretation .................................................................................55 Facies F8: (Fm) ......................................................................................................55 Hydrodynamic Interpretation .................................................................................55 Facies F9: (P) .........................................................................................................58 Hydrodynamic Interpretation .................................................................................58 Facies Associations, Depositional Processes, and Interpretation ..................................58 Facies Association FA1: (Shoreface lower to middle) ..........................................58 Interpretation ..........................................................................................................60 Facies Association FA2: (Fluvial Channel Fill) ....................................................60 Interpretation ..........................................................................................................64 Estuarine System ............................................................................................................64 Facies Association FA3: (Bayhead Delta) .............................................................66 Interpretation ..........................................................................................................66 Facies Association FA4: (Central Basin Mud) ......................................................67 Interpretation ..........................................................................................................67 Facies Association FA5: (Mouth Sand Bodies) .....................................................67 Interpretation ..........................................................................................................68 Facies Association FA6: (Tidal Flat) .....................................................................68 Interpretation ..........................................................................................................70 Alluvial Plain System ....................................................................................................70 Facies Association FA7: (Flood Plain Deposits) ...................................................70 Interpretation ..........................................................................................................72 Facies Association FA8: (Channel