paul sava


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© 2007 PC Sava

Page updated on
January 21, 2017

Patents


Wave-equation migration velocity analysis using image warping
Sava P.C., Perrone F., Andreoletti C., Bienati N.

An objective function is disclosed that extracts the velocity error information directly in the image domain without computing common-image gathers. Because of the dimensionality of the problem, gradient-based methods (such as the conjugate- gradient algorithm) are used in the optimization procedure. In order to include the full complexity of the wavefield in the velocity estimation algorithm, a two-way (as opposed to one-way) wave operator is considered, where the imaging operator is not linearized with respect to the model parameters (as in linearized wave-equation migration velocity analysis), and the gradient of the objective function is determined using the adjoint-state method. The velocity estimation methodology is illustrated with a few synthetic examples.
[WO 2013009944 A1,EP 2732312 A1]


Virtual electrode current injection using seismic focusing and seismoelectric conversion
Sava P.C., Revil A.

The present invention relates to acoustic wavefields produced using sources appropriately delayed in time and focused at known positions and times in a heterogeneous medium. Seismoelectric conversion occurs if the acoustic focus point coincides with a discontinuity in electrical and hydrological medium properties, thus generating a current density. The current generates a potential difference, which can be observed at a distance by an array of monitoring electrodes. Since the acoustic wavefield is precisely located at a position and time, this electrical source behaves like a controlled virtual electrode whose properties depend on the strength of the acoustic wavefield and on the medium properties. This procedure can be used to increase the robustness and resolutions of electrical resistivity tomography and to identify hydrological parameters at various points in the medium by scanning the medium by changing the position of the acoustic focus.
[WO 2013009944 A1]