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TitleTime-lapse seismic performance of a sparse permanent array: experience from the Aquistore CO2 storage site
AuthorWhite, D J; Roach, L A N; Roberts, B
SourceGeophysics vol. 80, no. 2, 2015 p. WA35-WA48,
Alt SeriesEarth Sciences Sector, Contribution Series 20140198
PublisherSociety of Exploration Geophysicists
Mediapaper; on-line; digital
File formathtml; pdf
AreaEstevan; Aquistore CO2 storage site
Lat/Long WENS-103.1000 -103.0333 49.1333 49.0333
Subjectsgeophysics; analytical methods; seismic surveys; pipelines; modelling
ProgramCarbon Capture & Storage, Environmental Geoscience
AbstractA sparse areal permanent array of buried geophones was deployed at the Aquistore CO2 storage site in Saskatchewan, Canada. The purpose of this array is to facilitate 4D seismic monitoring of CO2 that is to be injected to the deep subsurface. Use of a sparse buried array is designed to improve the repeatability of time-lapse data and to economize the monitoring effort. Prior to the start of CO2 injection, two 3D dynamite seismic surveys were acquired in March 2012 and May 2013 using the permanent array. The objective of acquiring these data was to allow an assessment of the data repeatability and overall performance of the permanent array. A comparison of the raw data from these surveys and with a conventional high-resolution 3D vibroseis survey demonstrated that (1) the signal-to-noise ratio for the buried geophones was increased by 6--7 dB relative to surface-deployed geophones and by an additional 20 dB for dynamite relative to a vibroseis source, (2) the use of buried sensors and sources at this site did not appear to be significantly degraded by the effects of ghosting, (3) repeatability for the permanent array data was excellent with a mean normalized rootmean-square (nrms) value of 57% for the raw baseline-monitor difference, (4) the variance of nrms values was higher for shot gathers (18%) compared with receiver gathers (7%), and (5) the raw data repeatability was a factor of three improved over that of comparable surface-geophone data acquired at a nearby location. The use of a sparse buried permanent array at the Aquistore site has demonstrably achieved a reduction in ambient noise levels and overall enhanced data repeatability, both of which are keys to successful 4D seismic monitoring.
Summary(Plain Language Summary, not published)
This study demonstrates the technical feasibility of using a sparse array of seismic sensors for monitoring CO2 storage sites. This has the potential to substantially reduce the cost of time-lapse seismic monitoring and thus help enable deployment of CCS technology.