PRINCIPLES OF OIL ACCUMULATION 



259 



This experiment is cited to show that oil does not migrate up 

 the dip due to specific gravity differences, nor is it forced upward 

 by circulating water. 



On the outcrop the sands in the oil-bearing formations are not 

 continuous but lenticular. By careful study of sands from well 

 logs in different pools of the mid-continent field, the lenticular 

 property of the sands becomes more evident. Water analyses 



Fig. 5. — Diagram of apparatus for experiment showing no movement of oil in sand 



Fig. 6. — Photograph of apparatus used in Experiment 3, showing the oil 

 remaining in the sand where it was originally placed. 



also corroborate this fact. Results from four hundred water analy- 

 ses to date point to the fact that each sand lens carries a definite 

 water, uniform throughout and differing in some respect from 

 the water of another lens. These waters are probably connate 

 sea waters uncontaminated by surface water. In nearly pure silica 

 sands the water differs little from sea water. In limy members 

 or where other soluble minerals are noted the water is much higher 

 in total sohds than sea water. The present work seems to indi- 

 cate that the change from normal sea water can be accounted for 



