Advanced surface-wave analysis for 3D ocean bottom cable data to detect localized heterogeneity in shallow geological formation of a CO2 storage site. (August 2015)

• Record Type: Journal Article
• Authors: Ikeda, Tatsunori; Tsuji, Takeshi
• Is Part Of: International journal of greenhouse gas control. Volume 39(2015:Aug.)
• Page Start: 107
• Page End: 118
• Publication Date: 2015-08
• Subjects: Surface-wave analysis -- CO2 storage -- Scholte waves -- 3D Vs structure -- 3D attenuation structure -- Geological heterogeneity; Greenhouse gases -- Environmental aspects -- Periodicals; Air -- Purification -- Technological innovations -- Periodicals; Gaz à effet de serre -- Périodiques; Gaz à effet de serre -- Réduction -- Périodiques; Air -- Purification -- Technological innovations; Greenhouse gases -- Environmental aspects; Periodicals; 363.73874605
• DOI: 10.1016/j.ijggc.2015.04.020
• Languages: English
• ISSNs: 1750-5836

Abstract

Highlights: We propose a surface-wave analysis using 3D data to estimate subsurface heterogeneity. Pseudo-3D S-wave velocity model is obtained by multimode inversion of Scholte-wave. Horizontal component data analysis can contribute to robust surface-wave analysis. The lithology boundary across the survey area is identified from our proposed analyses. The heterogeneity identified from our proposed approach is vital in safe CO2 storage. Abstract: To characterize heterogeneous geological formation with high-resolution, we propose a surface-wave analysis method for estimation of the spatial variation of S-wave velocity and attenuation coefficients. We applied the proposed method to the 3D ocean bottom cable (OBC) seismic data acquired at the Tomakomai CO2 storage site in Japan. By inversion of the observed dispersion curves of surface-wave (Scholte-wave in offshore survey), we successfully estimated the high-resolution pseudo-3D S-wave velocity structure for the shallow geological formation. We observed the dominant higher modes of the surface-wave, generated by the complex velocity structure such as inclusions of low-velocity layers. The interpretation based on the dispersion curves (or inverted S-wave velocities) and attenuation coefficients identified the lithological boundary in shallow formation across the 3D seismic survey area, but no fractures were detected. Our proposed method to estimate pseudo-3D S-wave velocity and attenuation structure can provide vital information for the CO2 geological storage, as it provides useful data for evaluation of CO2 leakage paths and estimation of permeability heterogeneity used in reservoir simulation. Moreover, it improves the accuracy of reflection seismic profile for deep structural analysis, and enhances estimations of lithology strength used for geomechanical modeling.