SOME EFFECTS OF CAPILLARITY ON OIL ACCUMU- 

 LATION" BY A. W. McCOY 1 



DISCUSSION BY 



C. W. WASHBURNE 



New York 



Students of petroleum are indebted to Mr. McCoy for the 

 three useful experiments in this paper. His first conclusion is that 

 oil may accumulate in the larger pores and other spaces of rock, 

 regardless of structure. This fact had been recorded previously in 

 the occurrence of oil in lenticular sands, and I had shown its theoret- 

 ical necessity. 2 The additional experimental evidence is most wel- 

 come. The main argument of the paper is an attempt to show that 

 capillary action possibly may lift the strata into anticlines. This 

 idea appears impossible for four reasons. 



First, the pressures created by capillarity are exerted by fluids 

 in open spaces which communicate, more or less deviously, with 

 the ground surface. The perfection of this communication through 

 shale is of the same order as the perfection of transmission of the 

 capillary pressures (assuming that these exist) that are transmitted 

 through shale into sandstone. Moreover, any pressures in the 

 fluids in sandstones are exerted through all spaces, laterally as well 

 as vertically, and would be so equalized through the entire bed of 

 sand that only a local hydraulic gradient would be left to deform 

 the sand. That such slight difference of pressure is unable to tilt a 

 sand need not be argued. Even if the capillary pressures could 

 deform a sand, they would not disturb lower sands along the same 

 axis or lift any of the underlying strata. 



Secondly, the amount of pressure available under Mr. McCoy's 

 assumed conditions (p. 802) would not be "the difference in the 



'Jour. GeoL, XXIV (19 16), 798-805. 



2 C. W. Washburne, Transactions A.I.M.E., L, 831. 



584 



