UNIVERSITY OF OKLAHOMA GRADUATE COLLEGE INTEGRATED INTERPRETATION OF BOREHOLE MICROSEISMIC DATA FROM HYDRAULIC FRACTURING STIMULATION TREATMENTS A DISSERTATION SUBMITTED TO THE GRADUATE FACULTY in partial fulfillment of the requirements for the Degree of DOCTOR OF PHILOSOPHY By CARLOS LUIS CABARCAS BEJARANO Norman, Oklahoma 2014 INTEGRATED INTERPRETATION OF BOREHOLE MICROSEISMIC DATA FROM HYDRAULIC FRACTURING STIMULATION TREATMENTS A DISSERTATION APPROVED FOR THE CONOCOPHILLIPS SCHOOL OF GEOLOGY AND GEOPHYSICS BY ______________________________ Dr. Roger Slatt, Chair ______________________________ Dr. Kurt Marfurt ______________________________ Dr. Shankar Mitra ______________________________ Dr. Gloria Romero ______________________________ Dr. Jeffrey Callard © Copyright by CARLOS LUIS CABARCAS BEJARANO 2014 All Rights Reserved. In memory of Dora Bejarano, mi mama, una mujer virtuosa Acknowledgements God has given me multiple blessings such as a countless number of academic opportunities. Among these gifts (for which I am extremely grateful) was the chance to complete the dissertation work presented within this book. I pray God will allow me to make the most of these opportunities to better serve him. I would also like to thank everyone who contributed to this project. In particular, I would like to explicitly show my gratitude to my advisor, Dr. Roger Slatt, for his guidance and encouragement allowed me to pursue my goals and successfully reach the finish line. Special thanks also go to my advisory committee: Dr. Kurt Marfurt, Dr. Shankar Mitra, Dr. Jeffrey Callard and Dr. Gloria Romero, who kindly supported my aspirations since the very early stages of this dissertation. The entire staff of the ConocoPhillips School of Geology of Geophysics, the Mewbourne College of Earth and Energy, the Graduate College, and my alma mater, The University of Oklahoma, also deserves my sincere appreciation. Among such an extraordinary group of people, I have to expressly recognize the support of Donna Mullins, who always went above and beyond her job duties, not only on my behalf but—to the best of my knowledge—to serve the best interest of each and every student that has ever reached out to her for help. I would also like to state my praise and appreciation of Hilcorp Energy Company’s management for permission to publish this work, as well as its support of the application of new technologies. I must also thank the Society of Exploration Geophysicists, the American Association of Petroleum Geologists, and the Society of iv Petroleum Engineers, because these professional groups have played a key role on my intellectual growth, providing the venues, resources and tools to develop, share and discuss the ideas presented within this publication. Likewise, I would like to appreciate and recognize my gratitude to Dawn Henderson for proofreading numerous drafts of this manuscript, making it a more appealing piece of writing. On a more personal note, I would like to offer special thanks to all my OU friends and colleague students whom made this journey more enjoyable. In particular, I would like to recognize the explicit and implicit encouragement received from Dr. Oswaldo Davogustto, Dr. Paul McColgan, Dr. Roderick Perez and Dr. Norelis Rodriguez, for their words lifted me up on more than one occasion, while their actions kept pushing me back into the pathway to success. Richard Brito also deserves my gratitude as I could have not finished this project without his help. In the same spirit, I would like to express sincere gratitude to my family, a source of motivation and cheer to achieve my academic goals. Among all people whom I am proud to call family, Heather and Robert Grimm (Mom and Bob) deserve a very special recognition, for their love has always been given to me unconditionally and without them this work, and probably my whole life, would have been completely different. Similarly, I would like to acknowledge the encouragement received from my beloved son, Carlos Jesus, who arrived to this world on the later stages of this project, injecting me with the energy I needed to finish it. Finally, my greatest appreciation goes to the love of my life, Dr. Maricel Marquez. She is my better half, but she definitely deserves more than half of the credit for this dissertation. v Table of Contents Acknowledgements .............................................................................................................. iv List of Tables ........................................................................................................................ ix List of Figures ........................................................................................................................ x Abstract ............................................................................................................................xxxv CHAPTER 1: Introduction .................................................................................................... 1 1.1 Basics of hydraulic fracturing ............................................................................... 4 1.2 Borehole microseismic monitoring of hydraulic fracturing. ............................. 16 1.3 Fundamentals of Sequence Stratigraphy............................................................. 24 1.4 Eagle Ford geologic characteristics .................................................................... 38 1.4.1 Regional perspective ................................................................................... 39 1.4.2 Outcrop characteristics ............................................................................... 44 1.4.3 Reservoir characteristics ............................................................................. 46 1.4.4 Sample characteristics ................................................................................ 50 1.4.5 Eagle Ford sequence stratigraphic framework .......................................... 72 CHAPTER 2: Pitfalls locating microseismic events from borehole measurements – practical observations from field applications ....................................................... 78 2.1 Abstract ................................................................................................................. 78 2.2 Introduction .......................................................................................................... 79 2.3 A note on data acquisition and modeling ........................................................... 81 2.4 Velocity model, location algorithms, and their implications ............................ 83 2.5 In support of reprocessing efforts........................................................................ 88 vi 2.6 Final thoughts ....................................................................................................... 89 2.7 Acknowledgement................................................................................................ 90 CHAPTER 3: The impact of dipping velocity models on microseismic events locations ................................................................................................................... 98 3.1 Abstract ................................................................................................................. 98 3.2 Introduction .......................................................................................................... 99 3.3 Geologic Framework.......................................................................................... 100 3.4 Layout of the Monitoring System ..................................................................... 100 3.5 Velocity Model ................................................................................................... 102 3.5.1 Velocity Model Building .......................................................................... 102 3.5.2 Anisotropy Corrections ............................................................................ 104 3.6 Event Location ................................................................................................... 105 3.7 Real-time Editing and Geiger Relocation ......................................................... 106 3.8 Results and Discussion ...................................................................................... 107 3.9 Conclusions and Recommendations ................................................................. 110 3.10 Acknowledgments ............................................................................................ 110 CHAPTER 4: The Magnitude vs. Distance Plot, a tool for fault reactivation identification .......................................................................................................... 111 4.1 Abstract ............................................................................................................... 111 4.2 Introduction ........................................................................................................ 112 4.3 Fault reactivation identification – an integrated case study ............................ 118 4.4 Conclusions ........................................................................................................ 123 4.5 Acknowledgement.............................................................................................. 124 vii CHAPTER 5: Sequence stratigraphic principles applied to the analysis of borehole microseismic data .................................................................................................