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f Seismic imaging solutions by multi-geophysical measurements and joint inversion
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 72nd EAGE Conference and Exhibition - Workshops and Fieldtrips, Jun 2010, cp-162-00077
- ISBN: 978-90-73781-87-0
Abstract
A wide range of near surface geological features challenge seismic acquisition and processing in arid land environments: sand dunes, collapsed karsts, dry river beds, sabkas, outcropping refractors, high velocity near surface layers, velocity reversals, layered basalts and rough topography, to cite a few. These features introduce sharp velocity changes in the vertical and horizontal directions that are difficult to model by using seismic data alone (e.g. velocity inversions, karsts). As a consequence, their imprints remain in the seismic images from surface to reservoir depths. The type of problems introduced by unresolved near surface velocity anomalies range from lack of seismic image quality, to misidentification of prospective low-relief structures and to erroneous depth conversions. Conventional statics and seismic acquisition practices often fail in areas with complex near surface conditions. Therefore, new and even unconventional approaches should be considered to address the near surface challenge. Among these, non-seismic methods such as precision gravity, shallow electromagnetics (EM) and/or electrical resistivity techniques could be effective in reconstructing near surface features correlated to seismic velocity anomalies.