E. ORTON — ROCK PRESSURE OF NATURAL GAS. 



per day; and more than 200,000 barrels of total production are already to 

 be credited to single wells of the new field, while a considerable number 

 have passed the 100,000-barrel mark. 



'I'm: Rock Pressure. 



The rock pressure of the gas is a vital factor in all this production. To 

 its energy is due the propulsion of the volatile fuel from the wells where it 

 i- released, through twenty, thirty, fifty miles of buried pipes, to the cities 

 which it supplies with the unspeakable advantages of gaseous fuel. It is the 

 Bame cause that lifts the oil from the rock in all flowing wells. 



By ruck pressure is meant the pressure which a gauge shows in a well 

 that is locked in after the drill has reached the gas reservoir. The iron 

 tubing of the well becomes by this means a pari of the reservoir, and the 

 Bame conditions as to pressure are supposed to pertain to it that arc found 

 in the porous rock helow. 



The rock pressure of gas varies greatly in different fields and to a less, 

 but Still an important, extent indifferent portion- of the same field. The 

 highest rock pressure recorded in the Trenton limestone is about 650 pounds 

 to the square inch, while there are considerahle sections of the gas territory 

 that never reach 300 pounds pressure per square inch. The original pressure 

 in the Findlay field was 150 pounds, varying somewhat in wells of differenl 

 depths. In the Wood county field, from which the largest amount of gas is 

 now being conveyed to Ohio cities, the original pressure ranged from 120 to 

 l v 'i pounds, the general pressure being counted 160 pounds to the square 

 inch. There were occasional records made of still higher pressure in single 

 well-, hut of such cases the number is very small, ami the existence of th 

 anomalous pressures was short-lived. 



Passing to the westward, the gas wells of A.uglaize and Mercer counties 

 -how a decided reduction in original rock pressure as compared with Find- 

 lay, though the depths of the wells remain the Bame as in that lield. The 

 highest pressure recorded in Mercer county is :!!)(» pounds t.> the square 

 inch, but ii" gauge was applied to the wells until they had been allowed t ■ » 

 discharge without restrainl for several months, while 375 and 350 pound- 

 mark the extreme limit of Other portion- of this district. 



In the Indiana field a >till further reduction of rock pressure is to he 

 noted. The range of the principal Indiana wells is between 250 and 325 

 pounds to the Bquare inch. The Indiana L r a- wells, as compared with Ohio 



- wells, are marked by a reduction in total depth, a- well a- in rock 

 pressure, the figures for depth in the productive territory seldom or never 

 passing one t bousand feet. 



II w can these variation- be accounted for? Back of this ipie.-tioii is a 



larger one, viz: What ii the origin of the rock pressure of natural gas? 



