HR: 10:45h
AN: U42A-02    [Abstracts]
TI: 3C3D VSP Imaging of Salt Flanks Using Converted Waves in the Gulf of Mexico
AU: * Li, Y
EM: yingping.li@vsfusion.com
AF: VSFusion, A BAKER HUGHES - CGG Company, 16430 Park Ten Place, Suite 405, Houston, TX 77084 United States
AU: Doherty, F
EM: Fran.doherty@vsfusion.com
AF: VSFusion, A BAKER HUGHES - CGG Company, 16430 Park Ten Place, Suite 405, Houston, TX 77084 United States
AU: Jackson, J
EM: James.jackson@vsfsuion.com
AF: VSFusion, A BAKER HUGHES - CGG Company, 16430 Park Ten Place, Suite 405, Houston, TX 77084 United States
AB: Locating salt boundary and imaging updip sediment structures flanking the salt domes are very important tasks for exploration in the Gulf of Mexico since major petroleum reserves are often trapped underneath overhangs of diapiric salt domes. Although the top of salt and less steep structures can be well imaged using current surface seismic methods, the steep sides of a salt dome with irregularly shapes are hard to image with adequate accuracy. Thus, Vertical Seismic Profiling (VSP) surveys with three-component (3C) receivers in wells are usually requested for improving images of subsurface structures. Conventional multi-offset VSP (OVSP) and refraction salt proximity (SP) surveys are widely applied in the Gulf of Mexico to improve images of slat interfaces, sub-salt and salt flank structures using P waves. In this paper, we will focus on using converted waves to image the steep salt-sediment boundary. A VSP dataset, including multi-OVSP and a SP survey, acquired in the Gulf of Mexico was used in this study. We analyzed 3C OVSP data to identify and separate converted waves, such as PS, P-SP, P-SS, generated at a salt boundary. Then both PP wave and converted waves were 3C3D depth migrated to generate images of the steep salt-sediment interface. Both transmitted P-P and P-S converted waves from the SP survey were used to calculate 3D salt exit points which delineate the steep salt face. The VSP results derived from both methods are abundant and a suitable 3D visualization tool is required for visual integration and interpretation. The image volumes and other available geophysical and geological data were integrated using a 3D visualization tool specially designed for VSP solutions. The migrated images using PP and converted waves provides a precise and complete definition of the steep salt face and reservoir sands flanking the salt dome. This study indicates that both reflection and reflection surveys can result in a consistent location of the steep salt flank, demonstrating the strength of combining these advanced VSP techniques.
DE: 0935 Seismic methods (3025)
DE: 7200 SEISMOLOGY
SC: Union [U]
MN: 2005 Joint Assembly