PWi, 



sMi 





UNTREATED 



TREATED 



Figure 400. Kansas Arbuckle core. Dense core with permeable streak 

 obliquely. Appearance of core and treating response indicate uniform 

 within permeable section. (From Chamberlain, Oil Weekly.) 



running 

 structure 



UNTREATED 



TREATED 



Figure 401. Niagara dolomite treated with 15-percent hydrochloric acid containing 

 a surface-tension-lowering agent. Uniform structure, moderate channeling. (From 

 Chamberlain, Oil Weekly.) 



4rit%.-^t^i^ - 



UNTREATED 



TREATED 



Figure 402. Viola limestone treated with 15-percent hydrochloric acid plus an 

 aromatic penetrating agent. High resistance to acid until acid channels through 

 core. Small crystals dislodge from walls and plug pores. (From Chamberlain, 

 Oil Weekly.) 



