372 ILLINOIS STATE ACADEMY OP SCIENCE 



OIL PRODUCTION IN ILLINOIS 



1) M. CoLLINGWOOD, STATE GEOLOGICAL SURVEY, UrBANA 



Object of the paper: A review of past results and a 

 consideration of the geological basis for guidance in 

 future oil development. 1 



The production of crude petroleum in Illinois for 1922 

 was nearly 10,000,000 barrels. The peak of Illinois pro- 

 duction occurred in 1908, when about 33,000,000 barrels 

 were produced, giving Illinois third place among the 

 states, with Oklahoma leading and California second. 

 These latter have retained their relative prior positions, 

 but newer gusher fields have been discovered in the south- 

 western and western states, and Illinois has now dropped 

 to eighth place. The decline curve for Illinois (Fig. 1) 

 shows the trend of the annual production from 1905 to 

 1922 for the whole State and from 1905 to 1918 for indi- 

 vidual pools. The decline in 1922 over the previous year 

 was about 6 per cent. The low decline rate is due in part 

 to the long life of the average Illinois oil well. 



The main oil fields of Illinois are situated in the south- 

 eastern part of the State in Edgar, Coles, Clark, Cumber- 

 land, Crawford, Lawrence, and Wabash counties, in 

 which the areal limits have been fairly well defined. 

 Lesser amounts are produced in a number of small fields 

 scattered over southwestern Illinois. These are mostly 

 younger fields and are still being extended. The total 

 actual producing acreage is only about 250 square miles, 

 or the equivalent of about seven townships. This seems 

 very small compared with the total area of the State. 

 The smallness of the actual producing areas is significant 

 and indicates the precariousness of drilling a well just 

 anywhere, even in a general area regarded as having 

 probabilities. 



It is absolutely essential to use every guide from geol- 

 ogy and from the study of production and drilling data 

 in neighboring or similar areas so that the larger, prob- 



1 Special acknowledgement is due to the State Geological Survey of 

 Illinois for the information and records on which this paper is based, and 

 to Miss H. Christensen in particular for her kind assistance in the compila- 

 tion of data and preparation of the accompanying map. 



