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Application of Seismic Inversion Methods in Salt-exit Velocity Prediction
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 76th EAGE Conference and Exhibition 2014, Jun 2014, Volume 2014, p.1 - 5
Abstract
Summary
Recent improvements in data acquisition and imaging techniques have significantly enhanced our ability to identify subsalt structures in the deep-water Gulf of Mexico (GOM) and other offshore basins of the world. However, the estimation of sub-salt velocity remains challenging. Our focus here is on the salt-exit velocity—the velocity just below a thick impermeable salt body. The knowledge of salt-exit velocity is critical for predrill prediction of potential overpressure zones below salt and also in developing a velocity model that will correctly delineate the stratigraphic units comprising the reservoir. Previous attempts to predict salt-exit velocity and pore pressure have not fully exploited the benefits of seismic inversion technology. In this paper we apply three different seismic inversion methods to estimate the salt-exit acoustic impedance in a deep-water subsalt basin of GOM and compare the results with those of the available well-log data. The impedance is then converted into velocity using a transform function obtained from impedance and velocity relation from a different location. The salt-exit velocity and impedance then becomes the basis for building a final velocity model for subsalt imaging and pore-pressure prediction.
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