Slip-slidin' away—some practical implications of seismic velocity anisotropy on depth imaging

2001 ◽  
Vol 20 (1) ◽  
pp. 70-73 ◽  
Author(s):  
Don C. Lawton ◽  
J. Helen Isaac ◽  
Robert W. Vestrum ◽  
Jennifer M. Leslie
Keyword(s):  
Seismic Velocity ◽  
Depth Imaging ◽  
Velocity Anisotropy ◽  
Seismic Velocity Anisotropy ◽  
Practical Implications

On Correlation Between Seismic Velocity Anisotropy and Stresses In Situ

1977 ◽  
pp. 259-265
Author(s):  
I. A. Turchaninov ◽  
V. I. Panin ◽  
G. A. Markov ◽  
V. I. Pavlovskii ◽  
N. V. Sharov ◽  
...  
Keyword(s):  
Seismic Velocity ◽  
Velocity Anisotropy ◽  
Seismic Velocity Anisotropy

Image mispositioning due to dipping TI media: A physical seismic modeling study

Geophysics ◽  
1999 ◽  
Vol 64 (4) ◽  
pp. 1230-1238 ◽  
Author(s):  
J. Helen Isaac ◽  
Don C. Lawton
Keyword(s):  
Seismic Velocity ◽  
Transversely Isotropic ◽  
Step Function ◽  
Depth Migration ◽  
Velocity Anisotropy ◽  
Depth Images ◽  
Thrust Belts ◽  
Migration Velocity Analysis ◽  
Seismic Velocity Anisotropy ◽  
Zero Offset

A scaled physical model was constructed to investigate the magnitudes of imaging errors incurred by the use of isotropic processing code when there is seismic velocity anisotropy present in the dipping overburden. The model consists of a block of transversely isotropic (TI) phenolic material with the TI axis of symmetry dipping at an angle of 45°. Its scaled thickness is 1500 m, and it is intended to simulate the dipping clastic sequences found in many fold‐thrust belts. A piece of isotropic Plexiglas, affixed to the underside of the anisotropic block, has a step function in it to simulate a target reef edge or fault. The anisotropy parameters of the material are δ = 0.1 and ε = 0.24. On zero‐offset data the imaged position of the target is shifted laterally 320 m in the updip direction of the beds, whereas on time‐ and depth‐migrated multichannel sections the shift is 300 m. The lateral shift is offset dependent, with the amount of shift in any common‐midpoint gather decreasing from 320 m on the near offsets to 280 m on the far offsets. Prestack depth‐migration velocity analysis based upon obtaining consistent depth images in the common‐offset domain results in the base of the anisotropic section being imaged 50 m (about 3%) too deep.

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