162 E. W. Evans on the Action of Oil-Wells. 
There is a second class of wells, in general more productive, 
which exhibit the same phenomena at first, but as often as they 
are exhausted are replenished again, and repeat a certain series — 
of actions indefinitely, and with remarkable regularity of time. 
This is to be explained by supposing that they are connec 
with other reservoirs by slight channels of communication, 
hose capacity for replenishing is less than that of the tube for 
exhausting. Let C, fig. 2, be an oil cavity having connections 
with two other cavities, Band D. Suppose that a well A enters 
the oil in C. After this well has thrown out oil, and perhaps 
afterward water, by force of the condensed gas, it comes to @ 
stop. Then owing to the diminished tension of the gas in the 
passages, represented by the dotted lines, into C, until the gas in 
this cavity again becomes sufficiently compressed to raise oil and 
water successively; after which the well comes to another stop 
until it is replenished with oil and gas as before; and the same 
process is repeated an indefinite number of times. The Newton 
well, on a branch of the Little Muskingum, a few miles from 
Marietta, repeats this process (with some escape of gas) at regular 
intervals of about half an hour, expelling about a barrel of oil 
I A note-worthy fact connected with this well is that 
when it stops it is necessary to pump out a little water in order 
to start it again; then the oil issues spontaneously. This is to 
be explained as follows. ‘The pressure of the gas is not quite 
sufficient to raise the water to the surface; but the position of 
the mouth of the tube is such that a few strokes of the pump 
suffice to reduce the surface of the water in the cavity below that 
i Now a column of oil will be raised by a given pressure 
so much higher than a column of water as its specific gravity 
is less. In this case it is raised not far from a fourth higher (the 
specific gravity of the oil being ‘816); and the difference is sufli- 
cient to make it flow over the top of the tube. Examples 0! 
this kind are common. . 
ually 
numerous: the and oil, 
hike the water, i ir 
Way in through a multitude 
res and slight crevices, | 
l a state of equilibrium | 
or ap : se 
om ms BE Pee = een es ee 
it se : 
