Multiphase Fluid Flow through Porous Media Conductivity and Geomechanics by Nariman Mahabadi A Dissertation Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy Approved July 2016 by the Graduate Supervisory Committee: Jaewon Jang, Chair Claudia Zapata Edward Kavazanjian ARIZONA STATE UNIVERSITY August 2016 ABSTRACT The understanding of multiphase fluid flow in porous media is of great importance in many fields such as enhanced oil recovery, hydrology, CO2 sequestration, contaminants cleanup, and natural gas production from hydrate bearing sediments. In this study, first, the water retention curve (WRC) and relative permeability in hydrate bearing sediments are explored to obtain fitting parameters for semi-empirical equations. Second, immiscible fluid invasion into porous media is investigated to identify fluid displacement pattern and displacement efficiency that are affected by pore size distribution and connectivity. Finally, fluid flow through granular media is studied to obtain fluid-particle interaction. This study utilizes the combined techniques of discrete element method simulation, micro-focus X-ray computed tomography (CT), pore-network model simulation algorithms for gas invasion, gas expansion, and relative permeability calculation, transparent micromodels, and water retention curve measurement equipment modified for hydrate-bearing sediments. In addition, a photoelastic disk set-up is fabricated and the image processing technique to correlate the force chain to the applied contact forces is developed. The results show that the gas entry pressure and the capillary pressure increase with increasing hydrate saturation. Fitting parameters are suggested for different hydrate saturation conditions and morphologies. And, a new model for immiscible fluid invasion and displacement is suggested in which the boundaries of displacement patterns depend on the pore size distribution and connectivity. Finally, the fluid-particle interaction study shows that the fluid flow increases the contact forces between photoelastic disks in parallel direction with the fluid flow. i DEDICATION This dissertation is dedicated to my love, Golnoosh, who has always supported me and encouraged me to pursue my dreams. Thank you very much for your unconditional love and sincere support. This work is also dedicated to my parents. All I have and will accomplish are only possible due to their love and sacrifice. ii ACKNOWLEDGMENTS I would like to express my sincere gratitude to my advisor, Dr. Jaewon Jang for giving me such an excellent time in my life. It was really fortunate to work with him at ASU. I was always amazed by his endless curiosity, patience, excellent guidance, and generous support, which really motivated and helped me to pursue my Ph.D. I would like to thank my thesis committee members, Dr. Edward Kavazanjian and Dr. Claudia Zapata for their insightful comments and recommendations. Special thanks to Dr. Yongkoo Seol (DOE/NETL), Dr. Sheng Dai (Georgia Tech), Dr. William. F. Waite (USGS) and Xianglei Zheng for their generous support and great experience. Finally, I would like to acknowledge the support for this work that was funded by the U.S. Department of Energy gas hydrate project. I’m grateful to the funding source that made my Ph.D. work possible. iii TABLE OF CONTENTS Page LIST OF TABLES…………………………………………………….............………...viii LIST OF FIGURES……………………………………………………………………….ix CHAPTER 1 INTRODUCTION ......................................................................................................... 1 1.1 Motivation............................................................................................ 1 1.2 Thesis Organization ............................................................................. 2 2 RELATIVE WATER AND GAS PERMEABILITY FOR GAS PRODUCTION FROM HYDRATE-BEARING SEDIMENTS: DEM AND PORE NETWORK MODEL SIMULATION .............................................................................. 3 2.1 Introduction .......................................................................................... 3 2.2 Relative Permeability Equations for Gas Hydrate Production .............. 4 2.3 Numerical Method and Procedure ........................................................ 5 2.3.1 Pore Network Model Generation .............................................. 5 2.3.2 Initial hydrate distribution ........................................................ 7 2.3.3 Hydrate Dissociation by Depressurization ................................ 7 2.3.4 Gas Expansion .......................................................................... 7 2.3.5 Permeability Calculation .......................................................... 9 2.4 Numerical Results .............................................................................. 10 2.5 Analyses and Discussion .................................................................... 12 2.6 Conclusions ........................................................................................ 16 iv CHAPTER Page 3 THE WATER RETENTION CURVE AND RELATIVE PERMEABILITY FOR GAS PRODUCTION FROM HYDRATE BEARING SEDIMENTS: X-RAY CT SCANNING AND PORE-NETWORK SIMULATION ............................ 18 3.1 Introduction ........................................................................................ 18 3.2 Fundamentals: Water Retention Curve and Relative Permeability Models ........................................................................................................ 19 3.3 Methodology ...................................................................................... 21 3.3.1 X-ray CT Scanning and Pore-Network Extraction .................. 21 3.3.2 Hydrate Realization: Saturation and Morphology ................... 23 3.3.3 Water Retention Curves in Hydrate-Bearing sediments .......... 25 3.3.4 Relative Permeability after Hydrate Dissociation .................... 26 3.4 Simulation Results ............................................................................. 27 3.4.1 Computed Water Retention Curves ......................................... 27 3.4.2 Relative Permeability during Gas Expansion .......................... 28 3.5 Analyses and Discussions .................................................................. 32 3.5.1 Pore-Network Model Simulation—Relevance to Experimental Tests ………………………………………………………………...32 3.5.2 Flow in Hydrate-Bearing Sediments—Recommended Parameter Values ………………………………………………………………...32 3.6 Conclusions—Recommendations ...................................................... 35 v CHAPTER Page 4 THE EFFECT OF HYDRATE SATURATION ON WATER RETENTION CURVES IN HYDRATE-BEARING SEDIMENTS .................................................. 37 4.1 Introduction ........................................................................................ 37 4.2 Experimental Details .......................................................................... 38 4.2.1 THF Hydrates ......................................................................... 39 4.2.2 Micromodel Experiment ......................................................... 40 4.2.3 Water Retention Curve Measurement ..................................... 41 4.3 Results and Analyses ......................................................................... 44 4.4 Conclusions ........................................................................................ 52 5 IMMISCIBLE MULTIPHASE FLUID FLOW THROUGH POROUS MEDIA: DIMENSSIONLESS NUMBERS AND PHASE DIAGRAM ................... 54 5.1 Introduction ........................................................................................ 54 5.2 Numerical Method and Procedure ...................................................... 60 5.2.1 Pore-Network Model .............................................................. 60 5.2.2 Two-Phase Fluid Flow Simulation .......................................... 61 5.3 Results and Discussion ....................................................................... 64 5.4 Conclusion ......................................................................................... 73 6 PARTICLE-FLUID INTERACTION: PHOTOELASTIC DISK EXPERIMENT ....... 74 6.1 Introduction ........................................................................................ 74 6.2 Fundamentals of Photoelasticity ........................................................ 75 6.3 Experimental Details .......................................................................... 78 6.3.1 Equipment Set-up. .................................................................. 78 vi CHAPTER Page 6.3.2 Experimental Procedure ......................................................... 81 6.4 Image Analysis .................................................................................. 81 6.4.1 Particle Locations ................................................................... 82 6.4.2 Contact Detection ................................................................... 83 6.4.3 Contact Forces: Direction and Magnitude ............................... 84 6.5 Results and Analysis .......................................................................... 88 6.6 Conclusion ......................................................................................... 95 7 CONCLUSIONS…………………………………………………………..………..96 7.1 Conclusions-Suggestions…………………………………………..96 7.1 Recommendations for Future Study………………...……...…….100 REFERENCES………………………………………………………..………..………103 vii LIST OF TABLES Table Page 3.1 Fitting Parameters for Water Retention