The Use of Distributed Acoustic Sensing for 4D Monitoring Using Vertical Seismic Profiles

175 Pages·2017·9.97 MB·English

by  Harris, Kyle

The Use of Distributed Acoustic Sensing for 4D Monitoring
Using Vertical Seismic Profiles: Results from the Aquistore
CO Storage Project
2

by

Kyle Harris

A thesis submitted to the
Faculty of Graduate and Postdoctoral Affairs
in partial fulfillment of the requirements for the degree of

Doctor of Philosophy in Earth Sciences

Department of Earth Sciences
Carleton University
Ottawa, Ontario
2017

©Copyright
Kyle Harris, 2017
1. Abstract
Distributed acoustic sensing (DAS) is a rapidly developing technology that
employs optical fibers to detect acoustic disturbances in the subsurface. The Aquistore
CO storage project uses time-lapse DAS VSP’s to monitor injected CO in a deep
2 2
geological reservoir (>3200 m) beneath the study site near Estevan, Saskatchewan,
Canada. Reservoir monitoring is a crucial component to any geological storage project,
and aims to ensure the safe and effective containment of the injected fluids, and evaluate
the integrity of the storage and sealing units.
An assessment of the ability of DAS VSP’s to detect the CO response has been
2
conducted for the Aquistore site. Prior to injection, fluid flow simulations were
performed to predict CO distributions in the reservoir. These simulations were used to
2
model the response of the CO plume in 2D time-lapse DAS VSP’s. The expected
2
responses were compared with estimates of time-lapse noise computed with field data
from the baseline survey, and it was demonstrated that the plume would be visible in the
reservoir after 27 kt of injection.
After 36 kt of CO injection, the first monitor dataset was acquired. 4D VSP
2
processing and imaging were applied to produce time-lapse difference volumes of the
reservoir. Acceptable repeatability was attained, with normalized root-mean-square
(nRMS) values less than 0.4 beneath the observation and injection wells. An anomaly in
the lower part of the reservoir near the observation and injection wells was attributed to
the replacement of brine with CO .
2
ii
Updated fluid flow simulations were obtained that better replicated the injection
parameters observed at the study site. Forward seismic modeling was then performed for
36 kt and 97 kt injection scenarios that reflected the 3D shot and receiver geometry in the
field acquisitions. These data were processed using the same sequence applied to the field
data to obtain comparable time-lapse difference volumes. Comparisons between the field
and synthetic 36 kt anomalies were used to refine interpretations of the CO distribution
2
in the reservoir. However, they also revealed the need to update the geological model to
better reproduce the laterally asymmetric plume expansion.

iii
Acknowledgements
Foremost, I thank my PhD co-supervisors Dr. Don White and Dr. Claire Samson.
Without their guidance, expertise, and encouragement this dissertation would not have
been possible. I would also like to thank everyone at (or formally at) the 3D Imaging and
Earth Modelling group at the Geological Survey of Canada, especially Gilles, Lisa, Brian,
and Dave. Their willingness to advise me throughout this research was always
appreciated, and their input was always valuable. I also appreciate the support from the
Earth Sciences department at Carleton University, and I am deeply grateful for the
Research Affiliate Program (RAP) bursaries made available by Natural Resources
Canada.
Finally, I would like to express my gratitude to my parents and to Carolyn for
providing encouragement and support throughout these four years.
iv
2. Preface
This document is an integrated thesis consisting of three articles published or
submitted to peer-reviewed scientific journals on the topic of distributed acoustic sensing
for 4D reservoir monitoring:
1. Harris, K., White, D. Melanson, D., Samson, C., and Daley, T., 2016, Feasibility of
time-lapse VSP monitoring at the Aquistore CO storage site using a distributed acoustic
2
sensing system: International Journal of Greenhouse Gas Control, 50, 248-260 (doi:
10.1016/j.ijggc.2016.04.016). Published [Chapter 5]
2. Harris, K., White, D., and Samson, C., 2017, Imaging the Aquistore reservoir after
36 kilotonnes of CO injection using distributed acoustic sensing: Geophysics, 82 (6),
2
M81-M96 (doi: 10.1190/geo2017-0174.1). Published [Chapter 6]
3. Harris, K., White, D., Samson, C., and Jiang, T., 201x, 4D vertical seismic profile
modeling of CO injection scenarios at Aquistore: submitted to the International Journal
2
of Greenhouse Gas Control. [Chapter 7]
Each article has been modified to comply with input from the thesis examination
committee. Table and figure numbers have been standardized and updated to be
consistent within the thesis, and a list of references has been compiled at the end.
In paper 1, K. Harris wrote the manuscript, developed the 2D migration software, and
performed the seismic processing and repeatability analysis. D. White planned the
seismic surveys, assisted in establishing the research objectives, advised on the software
development, and provided extensive comments on the article and response to reviewers’
v
comments. D. Melanson performed the fluid-replacement modeling and seismic
simulations used to estimate the CO plume response. C. Samson assisted in establishing
2
the research objectives and provided valuable comments on the manuscript. T. Daley
assisted in the DAS data acquisition and the preparation of the DAS data. The fluid flow
simulations were conducted by the Energy and Environmental Research Center (EERC),
as was the construction of the geostatic model.
In paper 2, K. Harris wrote the manuscript, developed and implemented the
processing flow, and characterized the plume response. D. White planned the seismic
surveys, advised on the development of the processing flow and plume response
characterization, and provided extensive comments on the article and response to
reviewers’ comments. C. Samson provided valuable comments on the manuscript.
In paper 3, K. Harris wrote the manuscript, performed fluid-replacement modeling
and seismic simulations, developed and implemented the processing flow, and
characterized the plume response. D. White assisted in establishing the research
objectives, planned the seismic surveys, advised on the development of the processing
flow and plume response characterization, and provided extensive comments on the
article. C. Samson provided valuable comments on the manuscript. T. Jiang (EERC)
performed the fluid flow simulations that were used to build the seismic models.
The thesis co-supervisors, Prof. Claire Samson and Dr. Don White, acknowledge the
above information as accurate.

vi
Table of Contents
1. Abstract ............................................................................................................. ii
Acknowledgements…………………………………………………………………………………...iv
2. Preface ................................................................................................................v
List of Tables………………………………………………………...………………………………….ix
List of Figures……………………………………………………………………………………………x
3. Introduction .......................................................................................................1
3.1. Aquistore carbon storage project ..........................................................................1
3.2. Weyburn-Midale ..................................................................................................4
3.3. CO injection ........................................................................................................5
2
3.4. Vertical Seismic Profiling ....................................................................................6
3.5. Distributed Acoustic Sensing ...............................................................................7
3.6. Time-lapse seismic ............................................................................................. 11
3.7. Aquistore seismic monitoring background.......................................................... 13
3.8. Research objectives ............................................................................................ 14
3.9. Originality of research........................................................................................ 15
4. Methods ............................................................................................................ 16
4.1. Overview ........................................................................................................... 16
4.2. VSP data processing........................................................................................... 17
4.3. VSP imaging ...................................................................................................... 18
4.4. Fluid-replacement modeling ............................................................................... 20
4.5. Seismic modeling with finite differences ............................................................ 22
5. Feasibility of Time-lapse VSP Monitoring at the Aquistore CO Storage Site
2
Using a Distributed Acoustic Sensing System ................................................. 24
5.1. Abstract ............................................................................................................. 24
vii
5.2. Introduction ....................................................................................................... 24
5.2.1. Geological setting .............................................................................................. 26
5.2.2. Distributed Acoustic Sensing (DAS) ................................................................... 28
5.3. Methods ............................................................................................................. 30
5.3.1. Data acquisition ................................................................................................. 30
5.3.2. Data processing ................................................................................................. 31
5.4. Seismic results ................................................................................................... 33
5.4.1. Traditional geophones versus DAS ..................................................................... 33
5.4.2. Seismic repeatability .......................................................................................... 39
5.4.3. Seismic modeling ............................................................................................... 42
5.5. Discussion.......................................................................................................... 54
5.6. Conclusions and Outlook ................................................................................... 57
5.7. Acknowledgements ............................................................................................ 58
6. Imaging the Aquistore Reservoir after 36 kilotonnes of CO Injection using
2
Distributed Acoustic Sensing ........................................................................... 59
6.1. Abstract ............................................................................................................. 59
6.2. Introduction ....................................................................................................... 60
6.2.1. Background ........................................................................................................ 61
6.2.2. The Aquistore CO storage site .......................................................................... 63
2
6.2.3. Distributed Acoustic Sensing .............................................................................. 65
6.3. Methods ............................................................................................................. 68
6.3.1. Data acquisition ................................................................................................. 68
6.3.2. Data processing ................................................................................................. 71
6.4. Results ............................................................................................................... 87
6.5. Discussion.......................................................................................................... 95
viii
6.6. Conclusions ..................................................................................................... 102
6.7. Acknowledgements .......................................................................................... 103
7. 4D Vertical Seismic Profile Modeling of CO Injection Scenarios at Aquistore
2
........................................................................................................................ 104
7.1. Abstract ........................................................................................................... 104
7.2. Introduction ..................................................................................................... 104
7.2.1. The Aquistore CO storage site ........................................................................ 106
2
7.2.2. Previous studies ............................................................................................... 107
7.3. Methods ........................................................................................................... 109
7.3.1. Geological model and fluid flow simulations .................................................... 109
7.3.2. Elastic properties and seismic modeling ........................................................... 111
7.3.3. Acquisition of DAS field data ........................................................................... 115
7.3.4. Processing of seismic data ............................................................................... 116
7.4. Results ............................................................................................................. 122
7.5. Discussion........................................................................................................ 134
7.6. Conclusions and Outlook ................................................................................. 143
7.7. Acknowledgements .......................................................................................... 144
8. Conclusions..................................................................................................... 145
8.1. Summary ......................................................................................................... 145
8.2. Future work ..................................................................................................... 146
9. References ...................................................................................................... 147

ix
List of Tables
Table 5-1: Petrophysical properties of reservoir units at Aquistore based on injection well
log measurements made in 2013 (EERC, 2014). ............................................................ 28
Table 5-2: Finite Difference Model Parameters (Modified from Melanson, 2015) .......... 46
Table 6-1: Acquisition parameters for baseline and monitor DAS surveys ..................... 69
Table 6-2: Processing steps and parameters ................................................................... 76
Table 7-1: Finite Difference Model Parameters ............................................................ 114
Table 7-2: Acquisition parameters for baseline and monitor DAS surveys ................... 116
Table 7-3: Processing steps and parameters. ................................................................ 117

x