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Imaging Seismic Data With High Resolution Gravity Data
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 8th Simposio Bolivariano - Exploracion Petrolera en las Cuencas Subandinas, Sep 2003, cp-33-00048
Abstract
Imaging land seismic data has always required a time or static correction to remove the effect of elevation and time distortions caused by velocity variations in the near surface geology. Elevation or datum corrections are straightforward, although, it will be shown that even elevation corrections can introduce statics that affect the seismic image. Historically, the seismic processors have relied on up-hole information or methods using the attributes of the seismic data itself to image the deeper reflectors. These methods include hand static corrections, auto correlation methods, refraction analysis, and turning wave tomography. This presentation will show how optimally acquired and processed gravity data can provide a very accurate, often superior, static correction which is computed independently of the seismic data by the invertion of the high frecuency residual gravity data into a surface consistent static correction. It will also be shown how gravity data can provide missing information in the refraction model, how gravity data resolves statics in areas of high velocity weathering over low velocity sub-weathering where the refraction model teoretically faults and how this technology automatically compensates for velocity variations in the weathering and sub-weathering layers including statics introduced by topography. This technology is known as GravStat and has been used for 2D and 3D seismic statics corrections.