In addition to the above field methods, permeability and damage effect on 

 DST charts can also be qualitatively evaluated by visual inspection. Figure 

 37-6 shows the effect of permeability and damage on the actual appearance of 

 the flowing and shut-in curves. These charts are facsimiles based on earlier 

 analyzer studies of the process (Bruce, 1943; Dolan and Hill, 1955). The chief 



HIGH PERMEABILITY 

 NO DAMAGE EFFECT 



HIGH PERMEABILITY 

 STRONG DAMAGE EFFECT 



MEDIUM PERMEABILITY 

 NO DAMAGE EFFECT 



MEDIUM PERMEABILITY 

 STRONG DAMAGE EFFECT 



LOW PERMEABILITY 

 NO DAMAGE EFFECT 



LOW PERMEABILITY 

 STRONG DAMAGE EFFECT 



Figure 37-6. Typical DST charts illustrating effects of permeability and damage. 



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