Lab 6: Static Corrections

INTRODUCTION 
Static corrections are applied to seismic data in order to compensate for various effects on the data such as those related to near surface, variations in elevations, weathering and reference to a datum.

OBJECTIVE:

• ·     To apply static correction to the stacked data.
•       To adjust seismic traces in such a way that sources and receivers are present at one horizontal level.

PROCEDURE:

      1.     The NMO corrected seismic data and its header is loaded.

      2.     Static correction is applied.

      3.     The static corrected data is stacked.

      4.     Stacked data is loaded again.

      5.     Stacked and the static corrected stacked data is displaye

...load SeismicData_gain_bpf_sdecon_gain_sorted_nmo_corrected_stacked_A.mat cmp_num t Dstacked

%%

cmp_start=205;

cmp_end=205;

lags=20;

Dsort_static=scr_static(Dsort,Hsort,cmp_start,cmp_end,lags);

[Dstacked_static,t,cmp_num]=sstack(Dsort_static,Hsort);

%%

save SeismicData_gain_bpf_sdecon_gain_sorted_nmo_corrected_static Dsort Dsort_static Hsort Dstacked_static cmp_num t

%%

% Display Colored scale

scale=1;

figure(1);

simage_display(Dstacked,cmp_num,t,1)

xlabel(['CMP:',num2str(cmp_num),''],'FontSize',14)

ylabel('Time(s)','FontSize',14)

title ('Before Static Correction','FontSize',14)

% Display Colored scale

scale=1;

figure(2);

simage_display(Dstacked_static,cmp_num,t,1)

xlabel(['CMP:',num2str(cmp_num),''],'FontSize',14)

ylabel('Time(s)','FontSize',14)

title ('After Static Correction','FontSize',14)

..RESULTS 

DISCUSSION:

Both Figures are showing the stacked data before and after conducting the static correction. there are same  differences between these two figures. first Figure  is the original data. After applying the static corrections, the seismic section is getting better since the noise has been attenuated a bit and the background is much smoother than before as seen in second Figure due to  the elevation between sources and receivers has been corrected.

CONCLUSION:

Static corrections are applied to seismic data in order to compensate various effects on the data itself. There are two types of static corrections. The first type is the elevation static correction where it accounts for variable elevations of the sources and receivers meanwhile the second type is the residual static correction where it accounts for lateral variations in the velocity and thickness of the rock layers. Since the elevation between the sources and receivers are not in the vertical alignment, it causes some changes in travel time. By conducting the static correction, it will correct the alignment between these sources and receivers so that the seismic section will show a smoother result at the end of the analysis.