VELOCITY LOGS 



VELOCITY 8 10 Zt THOUSANDS FT/SEC. 8 10 29 



2 ' 3 —- 



6500 



2=37000 



7500 



Figure 21-9. Velocity log correlations, Arapahoe and Elbert Counties, Colorado. 



indicated by the horizontal bars. Absence of a sample is indicated by the 

 absence of a bar. It is believed that this application of velocity logging can be 

 refined to furnish quantitative porosity data, and, therefore, will be a major 

 contribution to well completion practices. Recent studies on the relationship 

 between porosity and velocity by Wyllie, Gregory and Gardner (1956), and 

 Hicks and Berry (1956), indicate that the porosity of a formation exerts great 

 influence on the apparent velocity through the formation. 



Velocity Logs Showing Geologic Correlations 



The next group of five illustrations is presented to demonstrate the good 

 correlative characteristics of the velocity log. Figure 21-9 shows velocity logs 

 of three wells in the Denver Basin, Arapahoe, and Elbert counties, Colorado. 



CONTINUOUS VELOCITY LOGS 

 3 2 



12.000 



12.500 



— BEND 



MISS 



WOODFORD 12.500, 



- DEVONIAN - 



.1 



11.000 



11.500 



12.000 



12.500 



ANDREWS COUNTY. 

 TEXAS 



Figure 21-10. Velocity log correlations, Andrews County, Texas. 



417 



