REPORT OF THE DIRECTOR, 1922 15 
region in northwestern Pennsylvania and southwestern New York 
where the ‘ water drive’ is now employed to obtain oil from the 
Bradford sand, which was supposed to be largely exhausted. Under 
the peculiar conditions there the use of this method will result in the 
recovery of a large quantity of oil that can not be recovered by ordi- 
nary methods of production.” The purpose of the survey has been 
to determine the best scientific methods for the employment of the 
flood for the recovery of oil. This practice of obtaining oil by 
flooding or restored pressure is still in its infancy and has its possi- 
bilities of good as well as danger. It is important that a scientific 
study of the process be continued in order that the greatest per- 
centage of recoverable oil can be obtained. An important item in 
obtaining the petroleum from the oil sands is the cost of drilling the 
wells which must be closely spaced when flooding is employed. At 
the present time there are over 14,000 producing wells in the south- 
western New York field and it is estimated that ten to fifteen times 
this number will have to be drilled before the fields can all be flooded. 
By means of a flood the life of the oil field will be extended at least 
50 years and perhaps longer, depending on the rate at which opera- 
tions are carried on. The area that can be flooded comprises some 
60,000 acres and as the floods travel only at the rate of between 50 
and 200 feet a year, the flooding will take a long period unless many 
floods are started in many parts of the field. The location and the 
number of floods which should be used in the oil region is a problem 
to which attention should be given. The oil leases are in the hands 
of very many persons and companies and only by cooperation can 
the best results be obtained as floods will pass from one lease bound- 
ary to another and as a result of this the owner of a lease must be 
familiar with activities of adjoining leases. : | 
What “ flooding” is. When the pressure of the gas in an oil well 
becomes so low that ‘ Sail no longer force a sufficient amount of oil 
into the bottom of the well to make pumping profitable, the method 
of flooding is employed. Flooding is really a process of restoring 
pressure and, in an indirect way, takes the place of the exhausted 
natural gas in forcing oil from the sands to the wells so that the oil 
can be pumped. When it is desired to start a flood, water is intro- 
duced into an oil well, and as a result of the hydrostatic pressure thus 
established the oil is slowly forced away from the bottom of the 
oil well. The oil well into which water has been introduced no longer 
produces any oil but serves only as a flood or pressure well. The 
oil which is forced away from the pressure or flood well and in 
