ERA

Download the full-sized PDF of Applications of Seismic Interferometry in Microseismic MonitoringDownload the full-sized PDF

Analytics

Share

Permanent link (DOI): https://doi.org/10.7939/R39S1KQ9R

Download

Export to: EndNote  |  Zotero  |  Mendeley

Communities

This file is in the following communities:

Graduate Studies and Research, Faculty of

Collections

This file is in the following collections:

Theses and Dissertations

Applications of Seismic Interferometry in Microseismic Monitoring Open Access

Descriptions

Other title
Subject/Keyword
Seismic interferometry
Microseismic monitoring
Instrument self-noise
Coda wave interferometry
Passive image interferometry
Microseismic event detection
Geophone clamping quality
Type of item
Thesis
Degree grantor
University of Alberta
Author or creator
Vaezi, Yoones
Supervisor and department
van der Baan, Mirko (Physics)
Examining committee member and department
Leung, Juliana (Civil and Environmental Engineering)
Kravchinsky, Vadim (Physics)
Heimpel, Moritz (Physics)
Draganov, Deyan (Geoscience and Engineering - Delft University)
Department
Department of Physics
Specialization
Geophysics
Date accepted
2016-09-12T09:27:05Z
Graduation date
2016-06:Fall 2016
Degree
Doctor of Philosophy
Degree level
Doctoral
Abstract
Microseismic monitoring involves the acquisition of continuous seismic data for the purpose of locating and characterizing microseismicity induced mainly by oilfield completion and production processes. Since its inception, microseismic monitoring has proved to be an invaluable tool for understanding underground processes and monitoring subsurface changes associated with hydraulic fracturing, steam stimulation, geothermal energy production, underground deep mines, and CO2 storage and sequestration. Different existing and emerging new techniques are progressively being employed by the microseismic monitoring industry to provide an even more detailed and comprehensive analysis of the available data. This thesis focuses on potential applications of seismic interferometry in microseismic monitoring, a rather new method which has shown extensive applications in exploration geophysics and global seismology. Seismic interferometry mainly refers to a technique used for recovering the Green's function between two receivers by crosscorrelating their passive seismic noise recordings, thereby emphasizing the coherent part of noise which is deeply buried under local seemingly incoherent noise. We have used this property to obtain body waves propagating along borehole geophones deployed in downhole microseismic experiments, and therefore, obtain the associated seismic velocities at the neighboring formations surrounding the wellbore at the intervals between the geophons. Whether or not the coherent body waves appear clearly on the crosscorrelation functions depends on the instrument self-noise and clamping quality of borehole geophones. By obscuring the coherent noise of interest, instrument self-noise levels that are comparable with or above background noise levels can challenge seismic interferometry which aims at analysis of coherent features in ambient noise wavefelds to reveal subsurface structure. Such high levels of instrument self-noise can also act as a major constraint for the detection of weak microseismic events, in particular for borehole deployments in quiet environments such as below 1.5-2 km depths. Estimates of the instrument self-noise are commonly approximated by power spectral densities at the quiet times. The power spectral densities can also themselves be used as a tool for microseismic event detection as such events typically represent stronger spectral content over a frequency band than that of the background noise. This technique outperforms the common event detection method of short-time average/long-time average by detecting a higher number of weak events while keeping the number of false alarms at a reasonable level. It also has the benefit of providing suitable bandpass filters for better picking and further analysis of the events. On the other hand, the characteristics of the retrieved crosscorrelation waveforms can give insights about the coupling quality of the geophones to the wellbore wall as better coupled arrays result in body waves reconstructed up to a higher frequency range when compared with poorly clamped geophone arrays. We also study the potential application of coda wave interferometry for monitoring purposes in a surface microseismic monitoring setting, specifically for a wastewater disposal well. Significant changes in the fluid injection pressure into the underground reservoir can have direct impacts on the seismic velocity variations. The relative velocity variations are estimated by a recently developed version of the coda wave interferometry, known as passive image interferometry, using the time shifts between consecutive correlation functions.
Language
English
DOI
doi:10.7939/R39S1KQ9R
Rights
This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for the purpose of private, scholarly or scientific research. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
Citation for previous publication
Vaezi, Y., and van der Baan, M., 2014, Analysis of instrument self-noise and microseismic event detection using power spectral density estimates, Geophysical Journal International, 197(2), 1076-1089, doi: 10.1093/gji/ggu036.Vaezi, Y., and van der Baan, M., 2015, Comparison of the STA/LTA and power spectral density (PSD) methods for microseismic event detection, Geophysical Journal International, 203(3), 1896-1908, doi: 10.1093/gji/ggv419.Vaezi, Y., and van der Baan, M., 2015, Interferometric assessment of clamping quality of borehole geophones, Geophysics, 80(6), WC89-WC98, doi: 10.1190/geo2015-0193.1.

File Details

Date Uploaded
Date Modified
2016-09-12T15:27:06.675+00:00
Audit Status
Audits have not yet been run on this file.
Characterization
File format: pdf (PDF/A)
Mime type: application/pdf
File size: 38783311
Last modified: 2016:11:16 14:17:18-07:00
Filename: Vaezi_Yoones_201609_PhD.pdf
Original checksum: 8bbdf5c5f402e4bcd1793c10a1196aa7
Activity of users you follow
User Activity Date