Louisiana State University LSU Digital Commons LSU Historical Dissertations and Theses Graduate School 1995 Effects of Salt Dome Dissolution on Sediment Diagenesis: An Experimental and Field Study. William Lee Esch Louisiana State University and Agricultural & Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_disstheses Recommended Citation Esch, William Lee, "Effects of Salt Dome Dissolution on Sediment Diagenesis: An Experimental and Field Study." (1995). LSU Historical Dissertations and Theses. 6095. https://digitalcommons.lsu.edu/gradschool_disstheses/6095 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Historical Dissertations and Theses by an authorized administrator of LSU Digital Commons. For more information, please contact [email protected]. INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand corner and continuing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book. Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6" x 9" black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. UMI A Bell & Howell Information Company 300 North Zeeb Road, Ann Arbor MI 48106-1346 USA 313/761-4700 800/521-0600 EFFECTS OF SALT DOME DISSOLUTION ON SEDIMENT DIAGENESIS: AN EXPERIMENTAL AND FIELD STUDY A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The Department of Geology and Geophysics by William Lee Esch B.A., University of Colorado, 1990 December 1995 UMI Number: 9618285 Copyright 1996 by Esch, William Lee All rights reserved. UMI Microform 9618285 Copyright 1996, by UMI Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. UMI 300 North Zeeb Road Ann Arbor, MI 48103 ACKNOWLEDGEMENTS I would like to extend my appreciation and thanks to Jeff Hanor, Darrell Henry, Gary Byerly, Jeff Nunn, and Oscar Huh for serving as members of my dissertation committee. I am especially grateful to Jeff Hanor, my major advisor, for his constant interest and support for this research. Jeffs tireless encouragement, wise tutelage, and patient reviews of my work are greatly appreciated and have given me a far greater knowledge of the diverse chemical processes that operate in sedimentary environments. Discussions with Darrell Henry concerning experimental geochemistry were particularly helpful in developing the experiments in Chapter 2, as well as in understanding the general challenges and problems encountered in laboratory experimentation. Gary Byerly's enthusiastic guidance on sample preparation and analytical work with SEM-EDS and ICP-AES gave me a greater appreciation for the power of these techniques and the potential difficulties encountered in their use. I would also like to thank Barbara Dutrow for her careful review and helpful comments on the text, and Chad McCabe who served as an early member of the committee. I was supported in part by an LSU Board of Regents Fellowship and grants from the Gulf Coast Association of Geological Societies Financial-Aid-to-Students program, and Sigma Xi, The Scientific Research Society. I am grateful to the Shell Development Company for the funds that supported the analytical work in this dissertation, the purchase of equipment, and travel support. I would like to thank Shell Offshore, Inc. for its support which included numerous ii sidewall core samples, fluid analyses, and well logs from the Eugene Island 128A field. I would like to thank Texaco, Inc. for providing sediment cuttings from the Iberia field, as well as Audrey Workman and Dan Snow for collecting the fluid samples used in the Iberia study. Thanks also to Xiaogang Xie who was instrumental in teaching me the operation of the SEM and microprobe, and to Wanda LeBlanc who acquainted me with the XRD equipment and preparation of clays. The patient support of my wife, Toni, and my children, Andrea and Orion will not be forgotten. To them I am deeply grateful for the chance to pursue a dream. iii TABLE OF CONTENTS ACKNOWLEDGEMENTS ii LIST OF TABLES ix LIST OF FIGURES x ABSTRACT xvi CHAPTER 1) INTRODUCTION 1 BACKGROUND 1 Flank sediments, dissolved salt, and diagenesis 2 Fluid flow in flank sediments 2 OVERVIEW OF RESEARCH 3 CHAPTER 2) THE EXPERIMENTAL REACTION OF NaCl SOLUTIONS WITH SILICICLASTIC AND MIXED SILICICLASTIC-CARBONATE SEDIMENTS 6 INTRODUCTION 6 EXPERIMENTAL TECHNIQUES 8 Sediments 8 NaCl Solutions 11 ANALYTICAL TECHNIQUES 13 ICP Analyses 13 pH, Alkalinity, and Chloride 16 Cation Exchange Characteristics 17 Thermodynamic Modeling 17 XRD and SEM Analysis 18 RESULTS 19 Exchangeable Cations 19 Variations in Fluid Composition, Carbonate-Free Systems 20 Charge balance problems 20 pH 22 Anions 23 Dissolved Silica 25 Major Cations 27 Minor Species 27 Variations in Fluid Composition, Systems With Carbonate 32 pH and alkalinity 32 Dissolved silica 32 Major species 33 Minor species 33 XRD Results 33 IV SEM Results 36 Thermodynamic Modeling 39 DISCUSSION 44 Exchange reactions versus mineral hydrolysis reactions 46 Dissolution-Precipitation Reactions 48 CONCLUSIONS 51 Recommendations for future experiments 53 CHAPTER 3) SEDIMENT DIAGENESIS NEAR THE SALT-SEDIMENT INTERFACE AT THE EUGENE ISLAND 128 SALT DOME 56 INTRODUCTION 56 PURPOSE OF STUDY 57 EUGENE ISLAND 128A FIELD 58 MATERIALS AND METHODS 59 Sidewall cores 59 Electron microscopy 62 Thin-section and grain-mount preparation 62 RESULTS 63 Diagenetic minerals and textures 63 Identification of drilling mud contamination 65 Clastic sediments 68 Grain size, distribution, shape, and related modification of detrital grains by diagenesis 68 Mineralogy 73 Porosity and permeability 74 Secondary porosity 75 Mechanical deformation 79 Halite 81 Crystal size 81 Composition 81 Porosity in halite 82 Anhydrite, celestite, and barite 85 Morphology 85 Composition 89 Textural relations of sulfate minerals with surrounding sediments 91 Anhydrite dissolution 93 Barite dissolution 93 Sulfides 94 Pyrite 94 Sphalerite 96 Galena, chalcopyrite, and pyrrhotite 97 Carbonates 98 Analcime 98 Other diagenetic phases 99 Formation water compositions 99 v Ca 100 Mg 101 Alkalinity 103 Ba and sulfate 105 DISCUSSION 106 Mechanical controls on diagenesis 107 Effect of crushing on reaction rates 107 Effect of crushing on stability of geochemical system 108 Further aspects of mechanical diagenesis 111 Diagenesis within the evaporites and salt-sediment interface 112 Chemical diagenesis 112 Diagenesis within the flank sediments 115 Calcite cements 115 Redox reactions 116 Sulfates 119 Silicates and aluminosilicates 119 Sulfides 121 Diagenetic sequence 121 Diagenetic zones around the EI 128 salt-sediment interface 122 CONCLUSIONS 125 CHAPTER 4) FAULT AND FRACTURE CONTROL OF FLUID FLOW AND DIAGENESIS AROUND THE IBERIA SALT DOME, IBERIA PARISH, LOUISIANA 129 INTRODUCTION 129 IBERIA FIELD 131 METHODS 133 Flow path identification 133 Formation water analysis 134 Drill-cutting analysis 136 Well logs 137 Thermodynamic modeling 138 RESULTS 139 Formation waters 139 Spatial distribution of dissolved solutes at the Iberia field 139 Dissolved solutes versus chloride for the Iberia field and seven offshore Louisiana fields 145 Diagenetic minerals 151 Faults 157 Fractures and fracture dilation 158 Thermodynamic modeling 158 DISCUSSION 161 Fault influence on the concentration of dissolved species 161 High angle fault acting as a barrier to lateral fluid migration 164 High angle fault open to lateral fluid migration 164 vi High angle fault acting as a barrier to vertical fluid migration 165 High angle fault acting as a conduit for vertical fluid migration 165 Fault influence on flow paths and dissolved species in the Iberia field 165 Fractures and fracture dilation 167 Accommodation of fluid flow in intergranular porosity 170 Fluid-mineral equilibria in the presence of dissolved NaCl 170 CONCLUSIONS 171 CHAPTER 5) SUMMARY 173 EXPERIMENTAL WORK 173 Analcime and carbonate minerals 173 Salinity, kaolinite,and analcime 174 Spatial distribution of diagenetic minerals 175 EI 128 SALT DOME 176 Crushing, dissolution rates, and stability of geochemical system 176 Salt dome dissolution and sulfate minerals 176 Redox reactions 177 IBERIA SALT DOME 178 Slopes on log cation-log chloride plots: A measure of equilibrium 179 FUTURE RESEARCH 179 BIBLIOGRAPHY 181 APPENDICES 191 A.l. pH ANALYSES 192 A.2. TOTAL ALKALINITY as mg(HC03')/L 193 A.3. CI" ANALYSES (mg/L) 194 A.4. Ca ANALYSES (mg/L) 195 A.5. K ANALYSES (mg/L) 196 A.6. Mg ANALYSES (mg/L) 197 A.7. Na ANALYSES (mg/L) 198 A.8. DISSOLVED Si02 (mg/L) 199 A.9. Ba ANALYSES (mg/L) 200 A.10. Fe ANALYSES (mg/L) 201 A.ll. Mn ANALYSES (mg/L) 202 A.12. Sr ANALYSES (mg/L) 203 A.13. XRD PEAK-HEIGHT RATIOS 204 A.14a. CALCULATED ACTIVITY DATA 205 A.14b. CALCULATED ACTIVITY DATA 206 A.15. CARBONATE SATURATION INDICES 207 A.16. SILICA SATURATION INDICES 208 B.l.