Distributed Acoustic Sensing in Geophysics

1 Cover

2 Series Page

3 Title Page Geophysical Monograph 268

4 Copyright Page

5 List of Contributors

6 List of Reviewers

7 Preface

8 Part I: Distributed Acoustic Sensing (DAS)Concept, Principle, and Measurements 1 High Definition Seismic and Microseismic Data Acquisition Using Distributed and Engineered Fiber Optic Acoustic Sensors 1.1. DISTRIBUTED ACOUSTIC SENSOR (DAS) PRINCIPLES AND MEASUREMENTS 1.2. DAS SYSTEM PARAMETERS AND COMPARISON WITH GEOPHONES 1.3. DAS WITH PRECISION ENGINEERED FIBER ACKNOWLEDGMENTS REFERENCES TABLE OF VARIABLES 2 Important Aspects of Acquiring Distributed Acoustic Sensing (DAS) Data for Geoscientists 2.1. INTRODUCTION 2.2. FIBER‐OPTIC SENSOR 2.3. INTERROGATOR UNIT 2.4. ACQUISITION PARAMETER SELECTION 2.5. PREPROCESSING ISSUES 2.6. PROCESSING ISSUES 2.7. DATA QUALITY: DAS VS. GEOPHONE COMPARISONS 2.8. SUMMARY REFERENCES Chapter 3: Distributed Microstructured Optical Fiber (DMOF) Based Ultrahigh Sensitive Distributed Acoustic Sensing (DAS) for Borehole Seismic Surveys 3.1. INTRODUCTION 3.2. PRINCIPLES AND METHODS OF DMOF‐DAS 3.3. BOREHOLE SEISMIC SURVEY TESTS AND RESULTS 3.4. DISCUSSIONS 3.5. CONCLUSIONS ACKNOWLEDGMENTS REFERENCES 4 Distributed Acoustic Sensing System Based on Phase‐Generated Carrier Demodulation Algorithm 4.1. INTRODUCTION 4.2. PRINCIPLE 4.3. EXPERIMENTS AND RESULTS 4.4. FIELD TRIAL OF NEAR‐SURFACE SEISMIC EXPERIMENT WITH PGC‐DAS SYSTEM 4.5. CONCLUSIONS ACKNOWLEDGMENTS REFERENCES

9 Part II: Distributed Acoustic Sensing (DAS) Applications in Oil and Gas, Geothermal, and Mining Industries 5 Field Trial of Distributed Acoustic Sensing in an Active Room‐and‐Pillar Mine 5.1. INTRODUCTION 5.2. EXPERIMENTAL METHODS 5.3. CABLE COUPLING COMPARISONS 5.4. DAS SENSITIVITY 5.5. LOCATING A SEISMIC SOURCE 5.6. SURFACE WAVE TRAVEL‐TIME TOMOGRAPHY 5.7. P ‐WAVE DIFFERENTIAL TRAVEL‐TIME TOMOGRAPHY 5.8. DISCUSSION AND CONCLUSIONS ACKNOWLEDGMENTS REFERENCES 6 On the Surmountable Limitations of Distributed Acoustic Sensing (DAS) Vertical Seismic Profiling (VSP) – Depth Calibration, Directionality, and Noise: Learnings From Field Trials 6.1. INTRODUCTION 6.2. DEPTH CALIBRATION 6.3. DIRECTIONALITY 6.4. NOISE 6.5. OVERCOMING THE FULL SUITE OF CHALLENGES – EXAMPLE FROM DEEP WATER 6.6. CONCLUSIONS ACKNOWLEDGMENTS REFERENCES 7 Denoising Analysis and Processing Methods of Distributed Acoustic Sensing (DAS) Vertical Seismic Profiling (VSP) Data 7.1. INTRODUCTION 7.2. FIBER DEPLOYMENT TYPES AND NOISE SOURCES 7.3. CABLE RESONANCE REMOVAL 7.4. RANDOM NOISE SUPPRESSION 7.5. SNR ENHANCEMENT 7.6. CONCLUSION REFERENCES 8 High‐Resolution Shallow Structure at Brady Hot Springs Using Ambient Noise Tomography (ANT) on a Trenched Distributed Acoustic Sensing (DAS) Array 8.1. INTRODUCTION 8.2. DATA AND METHODS 8.3. NCF RESULTS 8.4. DISPERSION MEASUREMENT RESULTS 8.5. SHEAR WAVE VELOCITY MODEL 8.6. CONCLUSIONS ACKNOWLEDGMENTS REFERENCES

10 Part III: Distributed Acoustic Sensing (DAS) Applications in Monitoring of Deformations, Earthquakes, and Microseisms by Fracturing 9 Introduction to Interferometry of Fiber‐Optic Strain Measurements 9.1. INTRODUCTION 9.2. SENSITIVITY OF DAS TO FAR‐FIELD SOURCES 9.3 Sensitivity of DAS Cross‐Correlations to Plane Wave Sources 9.4. THOUGHT EXPERIMENT DEMONSTRATING AMBIENT NOISE INTERFEROMETRY TRENDS 9.5. SIMULATED AMBIENT NOISE INTERFEROMETRY ALONG CABLES 9.6. CONCLUSIONS ACKNOWLEDGMENTS REFERENCES 10 Using Telecommunication Fiber Infrastructure for Earthquake Monitoring and Near‐Surface Characterization 10.1. INTRODUCTION 10.2. THE SFSO 10.3. CONTINUOUS MONITORING AND ANALYSIS OF LOCAL AND REGIONAL EARTHQUAKES 10.4. CONTINUOUS MONITORING OF NEAR‐SURFACE CONDITIONS BY INTEFEROMETRY 10.5. IS THE COUPLING BETWEEN CABLES AND THE GROUND THE LIMITING FACTOR? 10.6. PROCESSING CHALLENGES FOR LARGE DAS ARRAYS IN URBAN ENVIRONMENTS 10.7. CONCLUSIONS ACKNOWLEDGMENTS REFERENCES 11 Production Distributed Temperature Sensing versus Stimulation Distributed Acoustic Sensing for the Marcellus Shale 11.1. INTRODUCTION 11.2. METHODOLOGY 11.3. RESULTS AND DISCUSSIONS 11.4. CONCLUSIONS ACKNOWLEDGMENTS REFERENCES 12 Coalescence Microseismic Mapping for Distributed Acoustic Sensing (DAS) and Geophone Hybrid Array: A Model‐Based Feasibility Study 12.1. INTRODUCTION 12.2. DAS SYNTHETIC DATA FORMICROSEISMIC EVENTS 12.3. THE LOCATION ALGORITHM FORDAS-GEOPHONE HYBRID ARRAY 12.4. TESTS 12.5. DISCUSSION AND CONCLUSION REFERENCES

11 Part IV: Distributed Acoustic Sensing (DAS) Applications in Environmental and Shallow Geophysics 13 Continuous Downhole Seismic Monitoring Using Surface Orbital Vibrators and Distributed Acoustic Sensing at the CO2CRC Otway Project: Field Trial for Optimum Configuration 13.1. INTRODUCTION 13.2. PERMANENT MONITORING AT THECO2CRC OTWAY PROJECT 13.3. FIELD EXPERIMENTS WITH DAS AND SOV SOURCES AT THE CO2CRC OTWAY PROJECT 13.4. OFFSET VSP PROCESSING 13.5. MAY 2017 FIELD TRIAL: CONVENTIONAL SINGLE‐MODE FIBER VS. CONSTELLATION FIBER 13.6. NOVEMBER 2017 FIELD TRIAL: PERFORMANCE OF SMALL AND LARGE MOTORS 13.7. SUMMARY AND CONCLUSIONS ACKNOWLEDGMENTS REFERENCES 14 Introduction to Distributed Acoustic Sensing (DAS) Applications for Characterization of Near‐Surface Processes 14.1. INTRODUCTION 14.2. CONSIDERATIONS FOR DEPLOYMENTS 14.3. SPECIFIC TOPICS IN THIS CHAPTER 14.4. CONCLUSIONS REFERENCES 15 Surface Wave Imaging Using Distributed Acoustic Sensing Deployed on Dark Fiber: Moving Beyond High‐Frequency Noise 15.1. INTRODUCTION 15.2. DARK FIBER NETWORKS: THE ESNET DARK FIBER TESTBED 15.3. STUDY SITE AND DATA ACQUISITION 15.4. DATA CHARACTERISTICS AND ANALYSIS OF NOISE SOURCES 15.5. PROCESSING STRATEGY 15.6. RESULTS 15.7. DISCUSSION 15.8. CONCLUSIONS ACKNOWLEDGMENTS REFERENCES 16 Using Distributed Acoustic Sensing (DAS) for Multichannel Analysis of Surface Waves (MASW) 16.1. INTRODUCTION 16.2. DAS MEASUREMENT PRINCIPLES 16.3. STUDY AREA AND EQUIPMENT LAYOUT 16.4. LARGE SHAKER SEISMIC SOURCE 16.5. DAS AND GEOPHONE SENSORS 16.6. MULTICHANNEL ANALYSIS OF SURFACE WAVES (MASW) 16.7. SURFACE-WAVE DISPERSION ANALYSIS RESULTS 16.8. DISCUSSION 16.9. SUMMARY AND CONCLUSIONS ACKNOWLEDGMENTS REFERENCES 17 A Literature Review: Distributed Acoustic Sensing (DAS) Geophysical Applications Over the Past 20 Years 17.1. INTRODUCTION 17.2. FBG‐BASED QDAS GEOPHYSICAL APPLICATIONS 17.3. VARIOUS DAS GEOPHYSICAL APPLICATIONS 17.4. SOME THOUGHTS ON RECENT ADVANCES AND FUTURE APPLICATIONS 17.5. CONCLUSION ACKNOWLEDGMENTS REFERENCES

12 INDEX

13 End User License Agreement

1 Chapter 6Table 6.1 Fields Trials of Active‐Source DAS Seismic Applications by Shell ...

2 Chapter 9Table 9.1 Plane Wave Particle Displacements and Velocities.Table 9.2 Plane Wave Particle Velocity, , Point‐Wise Axial Strain Rate, , ...Table 9.3 Cross‐Correlations of Measurements at ( x 1, y 1, z 1) in the Direc...Table 9.4 Horizontal Particle Velocity and Point‐Wise Axial Strain Rate Res...

3 Chapter 10Table 10.1 Local Earthquake Recorded by the SFSO DAS Array.Table 10.2 Estimates of Relative Amplitudes of the Data Generated by Five L...

4 Chapter 12Table 12.1 Comparison of Specifications of Geophone and DAS Arrays.Table 12.2 CMM Algorithm Parameters Used in This Study.

5 Chapter 13Table 13.1 Acquisition Parameters for the May 2017 Field Trial.Table 13.2 Acquisition Parameters for the November 2017 Field Trial.Table 13.3 Offset VSP Processing Flow.