Subsurface Laboratory Methods 



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The practice of breaking up the core into small pieces to smell and 

 taste for the presence of hydrocarbons should be avoided. The use of 

 an ultraviolet light will detect the presence of liquid hydrocarbons, and 

 a portable gas analyzer will detect even minute quantities of gas. Smell- 

 ing or tasting cores for the presence of gas is fallible because sweet gases 

 have no apparent odor or taste, and many gas sands have been condemned 

 as water productive because of the inability physically to detect gas. 



Figure 124. Gas- and water-permeability relationships for well A. Results of these 

 tests show that sand is clean and relatively free from hydratable materials. Sand 

 of this type would respond to injection of gas, salt water, or fresh water. 



