PETROLEUM AND NATURAL GAS IN NEW YORK 



473 



the column was found to be equal to 286 pounds to the square 

 inch, the specific gravity of the brine being about 1.1. 



Al Mamie, Ind., the gas rock was found to be at tide level. 

 The gas ought, therefore, to show a pressure of 286 pounds, if 

 this explanation is correct. The testimony of experienced oil 

 operators who observed the facts at the time the first wells were 

 drilled was to the effect that the rock pressure was between 280 

 and 300 pounds. It is to be noted that only when the first wells 

 of a field are drilled can the facts as to the original rock pressure 

 be accurately found. New adjustments of the contents of the 

 porous rocks become necessary when the equilibrium is once 

 interfered with, and a great many circumstances come in to 

 affect the rock pressure when drilling in a field has once got 

 fairly under way. In default of exact information, therefore, it 

 is safe to say that in this case the correspondence between the 

 observed facts and the theoretic calculation of what the rock 

 pressure should be is sufficiently close. 



In Marion, Ind., the gas rock was found at a depth of 78 feet 

 below tide. To the 286 pounds of pressure due at tide level there 

 must be added the weight of the 78 feet of salt water below the 

 level named. The amount of the true pressure was 323 pounds. 

 Visiting the field when the first well was completed I found 

 that the gage read 323 pounds. This fact was recorded before 

 any theory whatever had been formed in regard to the cause of 

 the rock pressure of gas. 



A well at St Henry, in Darke CO., O., found the gas at 200 

 feet below tide. After being allowed to blow into the air for 

 three months its pressure was found to be 375 pounds. The 800 

 feet of salt water found here would exert a pressure of 385 

 pounds. It seems altogether probable that at least 10 pounds 

 of pressure were lost in the three months of unrestricted flow. 



In well no. 1, Upper Sandusky, gas was struck at 470 feet 

 below tide, which would necessitate a rock pressure measured 

 by a column of salt water of 1075 feet in hight. This would 

 make the theoretic rock pressure of the gas 513 pounds. The 

 actual pressure as reported by Dr A. Bilhardt, a careful and 

 conscientious observer, was 515 pounds. Finally, at Tiffin, in 

 the Loomis and Nyman well, gas was found at a depth of 

 747 feet below tide. The salt water column on the gas must 



