Gregory Lee Loumos

US Patent:

51576384, Oct 20, 1992

Filed:

Jan 13, 1992

Appl. No.:

7/819894

Inventors:

Gregory L. Loumos - Ponca City OK
Shein S. Wang - Ponca City OK
Thomas R. Stoeckley - Ponca City OK

Assignee:

Conoco Inc. - Ponca City OK

International Classification:

G01V 136

US Classification:

367 54

Abstract:

A method for static correction includes a three step process which eliminates the problems of assuming hyperbolic moveout curves and forming base traces from common midpoint gathers while addressing long spatial wavelength variations. First, after calculating and applying an approximate high-frequency static correction to the individual shot and receivers (using traditional automatic methods), depth migration iterations are employed to coarsely tune the near-surface velocity layer. Second, after applying this correction, the remaining statics are incorporated into the model by tomography, which accounts for the velocity and thickness of the weathering layer and buried anomalies. Third, any residual misalignments are addressed using a multi-windowed statics adjustment within the common image point (CIP) gathers.

US Patent:

53072685, Apr 26, 1994

Filed:

Jun 7, 1991

Appl. No.:

7/711823

Inventors:

Shein S. Wang - Ponca City OK
David W. Bell - Ponca City OK
Stephen J. Hill - Ponca City OK
Gregory L. Loumos - Ponca City OK

Assignee:

Conoco Inc. - Ponca City OK

International Classification:

G01V 136

US Classification:

364420

Abstract:

A hybrid velocity model is used to image the subsalt reflector. A method for imaging subsalt reflectors includes receiving seismic data and depth migrating the raw data. Generated seismic P-waves are assigned a first P-wave velocity for travel outside a salt wedge. Prior to entering the salt wedge, the wave is treated as a compressional wave. Upon entering the salt wedge, the P-wave is treated as a converted S-wave and a corresponding S-wave velocity is assigned to the converted wave. When the converted S-wave exits the salt wedge, it is again converted, this time back to a P-wave. As this wave travels through the subsalt layer to a reflector interface, it is assigned a P-wave velocity. Thus, a velocity model which includes both P-wave and S-wave velocities is used to image reflectors below salt wedges.