Wave‐equation‐based residual moveout inversion in the subsurface angle domain for sub salt velocity model building

Gerritsen, Sijmen; Roozemond, Leen; Daalen, Diederik van; Bakker, P. M.

doi:10.1190/1.3628033

Cited by 4 publications

References 12 publications

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Sensitivity-kernel-based tomographic migration velocity analysis using reverse time migration angle-image gathers

2015

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Sensitivity-kernel-based tomographic migration velocity analysis (TMVA) provides a means to better update the migration velocity model in complex media. For actual seismic data with finite-frequency bandwidth, migration velocity updated from wave-equation-based tomography is more suitable and robust than ray-based tomography for images obtained from reverse time migration (RTM). Depth residuals in the RTM-extracted angle-image gathers offer a reliable source of velocity information. We have developed cost-effective means of calculating the angle-domain sensitivity kernel and incorporated it into the TMVA approach using RTM angle-image gathers. The angle-domain sensitivity kernels are used to convert the depth residuals from RTM angle-image gathers into velocity perturbations, which were then used to refine the velocity model. We derived an approximate analytical residual moveout function for measuring depth residuals of the RTM angle-image gather in isotropic media and also devised a workflow for sensitivity-kernel-based TMVA. The workflow maintains the simplicity of ray-based tomography by replacing the rays with the more accurate angle-domain sensitivity kernels. We determined the capability of this method in updating migration velocity with the 2D Sigsbee2 model and the 3D SEAM model. Our method significantly improved the quality of the migrated depth image and flattened the RTM angle-image gathers.

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Sensitivity-kernel-based tomographic migration velocity analysis using reverse time migration angle-image gathers

2015

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Full-waveform event location and moment tensor inversion for induced seismicity

et al. 2019

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Locating microearthquake events below complex heterogeneous overburden requires robust location methodologies that can honor multipathing in the seismic wavefield. We have developed two full-waveform event location methods that form a complementary solution for locating earthquakes and simultaneously deriving focal mechanisms via moment tensor inversion. The methods are based on the application of 3D elastic wavefield modeling, which is used to generate waveforms and extract wavefield attributes, for comparison to the observed field data. Events are located and focal mechanisms are derived via a multiparameter inversion, which minimizes the differences between synthetic and observed data. The results have been applied to the induced seismicity observed within the giant Groningen gas field, onshore Netherlands, where recorded earthquakes are triggered by stress changes, induced in the reservoir through pressure depletion. Locating events below the field is compounded by the presence of strong guided waves, which are trapped in the lower velocity reservoir interval. This complex multivalued wavefield is problematic for traditional event location methods, which assume a single traveltime arrival. We overcome this limitation by using all event arrivals in a wave-based solution to improve the accuracy of locating earthquakes and overcome the ambiguity of solving for location and the focal mechanism simultaneously. The event location methods have been applied to shallow and deep monitoring networks, and 150 events have been located with high accuracy. The interpretation of the earthquake activity indicates that the events studied originate from the movement of larger graben bounding faults, which are oriented in a north-northwest–south-southeast direction.

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3D RTM-based wave-path tomography: theory and applications to synthetic and field data

Bakker

Gerritsen²,

Cao

et al. 2015

SEG Technical Program Expanded Abstracts 2015

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Wave‐equation‐based residual moveout inversion in the subsurface angle domain for sub salt velocity model building

Cited by 4 publications

References 12 publications

Sensitivity-kernel-based tomographic migration velocity analysis using reverse time migration angle-image gathers

Sensitivity-kernel-based tomographic migration velocity analysis using reverse time migration angle-image gathers

Full-waveform event location and moment tensor inversion for induced seismicity

3D RTM-based wave-path tomography: theory and applications to synthetic and field data

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