Affiliation:
1. University of Saskatchewan, Department of Geological Sciences, Saskatoon, Saskatchewan, Canada..
Abstract
For seismic monitoring injected fluids during enhanced oil recovery or geologic [Formula: see text] sequestration, it is useful to measure time-lapse (TL) variations of acoustic impedance (AI). AI gives direct connections to the mechanical and fluid-related properties of the reservoir or [Formula: see text] storage site; however, evaluation of its subtle TL variations is complicated by the low-frequency and scaling uncertainties of this attribute. We have developed three enhancements of TL AI analysis to resolve these issues. First, following waveform calibration (cross-equalization) of the monitor seismic data sets to the baseline one, the reflectivity difference was evaluated from the attributes measured during the calibration. Second, a robust approach to AI inversion was applied to the baseline data set, based on calibration of the records by using the well-log data and spatially variant stacking and interval velocities derived during seismic data processing. This inversion method is straightforward and does not require subjective selections of parameterization and regularization schemes. Unlike joint or statistical inverse approaches, this method does not require prior models and produces accurate fitting of the observed reflectivity. Third, the TL AI difference is obtained directly from the baseline AI and reflectivity difference but without the uncertainty-prone subtraction of AI volumes from different seismic vintages. The above approaches are applied to TL data sets from the Weyburn [Formula: see text] sequestration project in southern Saskatchewan, Canada. High-quality baseline and TL AI-difference volumes are obtained. TL variations within the reservoir zone are observed in the calibration time-shift, reflectivity-difference, and AI-difference images, which are interpreted as being related to the [Formula: see text] injection.
Publisher
Society of Exploration Geophysicists
Subject
Geochemistry and Petrology,Geophysics
Reference44 articles.
1. Monitoring of CO2 injected at Sleipner using time-lapse seismic data
2. Baharvand Ahmadi, A., L. Gao, J. Ma, and I. B. Morozov, 2011, CO2 saturation vs. pressure effects from time-lapse 3-D P-S surface and VSP seismic data, http://seisweb.usask.ca/Reports/Weyburn_USask_Report_Apr2011.pdf, accessed 1 November 2018.
3. Anisotropic frequency-dependent spreading of seismic waves from first-arrival vertical seismic profile data analysis
4. Brown, L. T., 2002, Integration of rock physics and reservoir simulation for the interpretation of time-lapse seismic data at Weyburn Field, Saskatchewan: M.S. thesis, Colorado School of Mines.
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