ABSTRACT Seismic interferometry (SI) has been recently employed to retrieve the reflection respon... more ABSTRACT Seismic interferometry (SI) has been recently employed to retrieve the reflection response from natural earthquakes. We perform experimental study to apply SI to Ocean Bottom Seismogram (OBS) records in the Nankai Trough, southwest Japan in order to reveal the relatively shallow geological boundaries including surface of oceanic crust. Although the local earthquakes with short raypath we use to retrieve reflection response are expected to contain the higher-frequency components to detect fine-scale structures by SI, they cannot be assumed as plane waves and are inhomogeneously distributed. Since the condition of inhomogeneous source distribution violates the assumption of SI, the conventional processing yields to the deteriorated subsurface images. Here we adopt the raypath calculation for stationary phase evaluation of SI in order to overcome this problem. To find stationary phase, we estimate the raypaths of two reflections: (1) sea-surface P-wave reflection and (2) sea-surface multiple P-wave reflection. From the estimated raypath, we choose the crosscorrelation traces which are expected to produce objective reflections considering the stationary phase points. We use the numerical-modeling data and field data with 6 localized earthquakes and show that choosing the crosscorrelation traces by stationary phase evaluation improves the quality of the reflections of the oceanic crust surface.
Proceedings of the 10th SEGJ International Symposium, 2011
ABSTRACT A map of ground surface deformations due to the geomechanical instability of the reservo... more ABSTRACT A map of ground surface deformations due to the geomechanical instability of the reservoir has been estimated by using a differential InSAR stacking technique. The surface deformations have valuable information about the dynamic reservoir and are most likely to occur in the production of hydrocarbon even if the reservoir is kilometers deep. In order to invert surface deformations obtained from InSAR data, we propose a two-step inversion approach based on a tensional rectangular dislocation model. The first step, we use genetic algorithms to estimate the depth and the geometry of reservoir deformation. However, this model provides a single dislocation with uniform deformation. This uniform deformation can not provide an adequate representation of the spatially varying deformation in the reservoir. Therefore, in the second step, we have applied the least square inversion with the penalty function and smoothing factor in order to efficiently invert the spatial distribution of reservoir deformations and volume changes from the surface deformation data. Through a synthetic model, we have examined our inversion approach by estimating the root mean square error and the relative error, then applied to real data. We conclude that the InSAR technology is useful to provide ground surface deformations and accurately monitor reservoir deformation using inversion techniques.
SEG Technical Program Expanded Abstracts 2013, 2013
ABSTRACT Monitoring and characterization of land subsidence of the Bandung basin, Indonesia has b... more ABSTRACT Monitoring and characterization of land subsidence of the Bandung basin, Indonesia has been carried out based on Synthetic Aperture Radar (SAR) data acquired by ALOSPALSAR satellite for the period of 1 January 2007 — 3 March 2011. Estimated subsidence continuously increased up to around 45 cm at a rate of about 12 cm/yr for this period. The land subsidence occurred in the industrial and dense-residential regions in the Bandung basin where large amounts of groundwater were consumed. Interestingly the subsidence patterns are uncorrelated to the distribution of groundwater production wells and the map of aquifer zonation in several areas. We concluded that the subsidence expansion not only depended on groundwater production but also was controlled by lithology over the Bandung basin. Read More: http://library.seg.org/doi/abs/10.1190/segam2013-0221.1
ABSTRACT Seismic interferometry (SI) has been recently employed to retrieve the reflection respon... more ABSTRACT Seismic interferometry (SI) has been recently employed to retrieve the reflection response from natural earthquakes. We perform experimental study to apply SI to Ocean Bottom Seismogram (OBS) records in the Nankai Trough, southwest Japan in order to reveal the relatively shallow geological boundaries including surface of oceanic crust. Although the local earthquakes with short raypath we use to retrieve reflection response are expected to contain the higher-frequency components to detect fine-scale structures by SI, they cannot be assumed as plane waves and are inhomogeneously distributed. Since the condition of inhomogeneous source distribution violates the assumption of SI, the conventional processing yields to the deteriorated subsurface images. Here we adopt the raypath calculation for stationary phase evaluation of SI in order to overcome this problem. To find stationary phase, we estimate the raypaths of two reflections: (1) sea-surface P-wave reflection and (2) sea-surface multiple P-wave reflection. From the estimated raypath, we choose the crosscorrelation traces which are expected to produce objective reflections considering the stationary phase points. We use the numerical-modeling data and field data with 6 localized earthquakes and show that choosing the crosscorrelation traces by stationary phase evaluation improves the quality of the reflections of the oceanic crust surface.
Proceedings of the 10th SEGJ International Symposium, 2011
ABSTRACT A map of ground surface deformations due to the geomechanical instability of the reservo... more ABSTRACT A map of ground surface deformations due to the geomechanical instability of the reservoir has been estimated by using a differential InSAR stacking technique. The surface deformations have valuable information about the dynamic reservoir and are most likely to occur in the production of hydrocarbon even if the reservoir is kilometers deep. In order to invert surface deformations obtained from InSAR data, we propose a two-step inversion approach based on a tensional rectangular dislocation model. The first step, we use genetic algorithms to estimate the depth and the geometry of reservoir deformation. However, this model provides a single dislocation with uniform deformation. This uniform deformation can not provide an adequate representation of the spatially varying deformation in the reservoir. Therefore, in the second step, we have applied the least square inversion with the penalty function and smoothing factor in order to efficiently invert the spatial distribution of reservoir deformations and volume changes from the surface deformation data. Through a synthetic model, we have examined our inversion approach by estimating the root mean square error and the relative error, then applied to real data. We conclude that the InSAR technology is useful to provide ground surface deformations and accurately monitor reservoir deformation using inversion techniques.
SEG Technical Program Expanded Abstracts 2013, 2013
ABSTRACT Monitoring and characterization of land subsidence of the Bandung basin, Indonesia has b... more ABSTRACT Monitoring and characterization of land subsidence of the Bandung basin, Indonesia has been carried out based on Synthetic Aperture Radar (SAR) data acquired by ALOSPALSAR satellite for the period of 1 January 2007 — 3 March 2011. Estimated subsidence continuously increased up to around 45 cm at a rate of about 12 cm/yr for this period. The land subsidence occurred in the industrial and dense-residential regions in the Bandung basin where large amounts of groundwater were consumed. Interestingly the subsidence patterns are uncorrelated to the distribution of groundwater production wells and the map of aquifer zonation in several areas. We concluded that the subsidence expansion not only depended on groundwater production but also was controlled by lithology over the Bandung basin. Read More: http://library.seg.org/doi/abs/10.1190/segam2013-0221.1
Uploads
Papers by Takeshi Tsuji