Stacking Statics Residual statics in combination with the velocity analysis Muting Approximated zero offset section.

Stacking Statics Residual statics in combination with the

velocity analysis Muting

Approximated zero offset section

Delay-Time

GRM (“generalised reciprocal method”)

DRM (“diminishing residual matrices”)

Methods to determine the residual statics:

Statics (done before velocity analysis)

•Topographic Correction (elevation statics)

•“Uphole”-correction using shots in borehole

•Refraction statics: corrections for weathered layer

CMP Gathers with field statics applied

1. Velocity analysis

NMO-Correction

Compute Residual statics

NMO-Correction with new Velocities

Stacking

Apply Residual statics

2. Velocity analysis

Residual statics

NMO corrected data before and after residual corrections

Yilmaz, 1987

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Velocity spectra before (a) and after (b) residual stacking

CMP stacks without and with residual stacking

Yilmaz, 1987

Mean stack

Weighted Stack

Diversity Stack/Min-Max-exclude

Certain traces are muted and not included in the stacking procedure

n

itimeant w

ns

1,,

1

n

itiiedmeanweightt w

ns

1,,

1

Methods to Stack

stacked section

Velocity model

Velocity model

Stacking velocity field

Yilmaz, 1987

CMP stack

Yilmaz, 1987

CMP stack using gain function

Yilmaz, 1987

Migrated CMP stack