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Sponsored by: United States Department of Agriculture via
Argonne National Laboratory
     

Frankfort, Kansas

            

Hubbard, Nebraska

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Ceresco, Nebraska

Milford, Nebraska
  Seismic Data Processing 
  at Milford, Nebraska, 1999

Area Overview

Seismic Recording

VSP Recording

Data Processing

VSP Recording:

S-wave vertical seismic profiles were recorded by ESRI-University of South Carolina at five locations in Milford. All of the VSPs were recorded using Argonne National Laboratory's cone penetrometer (CPT) truck. Measurements were made at 2 ft increments as the rods were pushed into the Earth using a three geophone CPT sonde (1 vertical, 2 horizontal) and a hydraulic piston hammer seismic source attached to the cross member of the CPT jacks. Hammer hits were recorded four times from each side of the truck, alternating between sides for each level. These records were recorded separately for further processing. The data were recorded on an OYO DAS-1 24 bit seismograph. The weight of the CPT truck on the jacks resulted in excellent source coupling with the ground surface, which greatly enhanced the propagation of the shear waves.

S-wave CPT-VSP SB-1T. 
Upgoing waves at TWT and corridor stack.

Interval and average S-wave velocity 
profile SB-1T.

VSP Data Processing:

All the CPT-VSPs were processed in the field on laptop computers concurrent with seismic profiling, borehole drilling, chemical sampling, and CPT pushes.

Processing flow:

  • Reformat SEG-D to SEG-Y

 

 
  • Sort field records / Reverse & sum shear wave records

 

 
  • Write depth info to headers

 

 
  • Display / Trace edits / Bandpass filter

 

 
  • Pick first breaks

 

 
  • Correct times for source offset (TVT) / Calculate velocity profile

 

 
  • Time align downward travelling energy / Mean amplitude scaling

 

 
  • Spatial median filter 5 pt - enhance downgoing wavefield

 

 
  • Wavefield separation (subtract median filtered data from input)

 

(Downgoing waves)

<--------------------------------->

(Upgoing waves)
  • Spiking decon operator found

 
  • Spiking deconvolution
  • Bandpass filter / Scaling

 
  • Bandpass filter / Scaling
  • Display

 
  • Display

 

 
  • Align at two-way reflection time

 

 
  • Spatial median filter (5 pt)

 

 
  • Display

 

 
  • Mute / Front corridor stack

 

 
  • Bandpass filter / Scaling

 

 
  • Display

Page maintained by: Mark Evans, Last update: April 10, 2008
Copy right @ 2001 University of South Carolina Board of Trustees