Static correctionSEISMIC DATA PROCESSING – ZGE 373

Course Summary

1- Mathematical Basis for Fourier transform 2- Sampling considerations of seismic time series 3- Main processing sequence 4- Velocity analysis 5- Deconvolution, convolution, filtering and migration in space

and time (prestack). 6- Acquisition of seismic data ( land and sea). 7- 3-D seismic data processing 8- Radon transform, tau-p processing, Hilbert transform and

AVO

Average percenage

70%

30%

Chart Title

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Do you remember our last lecture ?

Yes, It was about seismic refraction

Let’s refresh our memory

1• Acquistion

2• T-X graph Analysis

3• Modeling• Interpretation

• Experiment planning

• Instrumentations

• Data retrieval• Seismic section plot• Picking first arrivals• Plot T-X curve• Identifying T-X featurs

1. Estimating velocities and depths2. Interpreting the obtained model

parameters in terms of Geology.

So what is the relation of this with our course!!!

It is all about ….Static Correction

So what is the static correction do?

It corrects the seismic for the effect of altitude

(elevation) of the earth’s surface and remove the

effect of weathering layer

http://homepage.ufp.pt/biblioteca/Seismic/Pages/Page13.htm

Plate 93- On this seismic line, from the northern offshore Angola, located nearby the Congo river, the water-depth variation induces local pull-down of uniformly continuous reflectors. Indeed, seismic waves travel slower through water than through sediments. The pulldown of the reflectors directly below the Congo submarine canyon is evident. However, it does not have any geological meaning. In a depth section the reflectors keep the regional seaward dip recognized all along the profile.

http://homepage.ufp.pt/biblioteca/Seismic/Pages/Page13.htm

https://esd.halliburton.com/support/LSM/GGT/ProMAXSuite/ProMAX/5000/5000_8/Help/promax/elev_stat_ovr.pdf

https://esd.halliburton.com/support/LSM/GGT/ProMAXSuite/ProMAX/5000/5000_8/Help/promax/elev_stat_ovr.pdf

FIG 6. Nominal 12-fold CDP stacked seismic reflection sectionwith derived velocity and geologic and static information as wellas an approximate statics-correction diagram for conventionaldatum statics. (a) Seismic reflection section. (b) NMO velocityfunction. (c) Interpreted geologic cross-section. (d) Datum staticsderived from shallow-reflection data. (e) Approximate datumcorrection using estimated information available from aconventional data set only.

Steeples, D. W. , R. D. Miller*, and R. A. Black*, 1990. Static corrections from shallow-reflection surveys. GEOPHYSICS, VOL. 55, NO. 6 (JUNE 1990); P. 769-775

Wait!! Is there any problem with seismic refraction?

YES!!!

1. Velocity inversion or low velocity layer.

2. Blind Zone (thin bed)

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