Illinois Annual Oil Field Reports

Oil field production figures are derived from information supplied by commercial scouting services and have not been verified by the Illinois State Geological Survey.



During the month of December in 2004 and the first 8 months of 2005 one oil gatherer did not report the majority of their oil purchases to commercial information gathering services. To account for the unreported volumes, production estimates were made by ISGS Oil and Gas Section staff member Bryan Huff on a lease by lease basis based on production histories before and after the non-reported period.

The total unreported volume for 2005 in Illinois is estimated at 1.2 million barrels. The total unreported volume for 2004 in Illinois is estimated at 157,350 barrels.


Explanation of Abbreviations and Symbols


  • N, North;
  • S, South;
  • E, East;
  • W, West;
  • C, Consolidated;
  • Cen, Central.
  • Fields located in two or more counties have county names listed in order of oil discovery.


  • PC, Precambrian;
  • CAM, Cambrian;
  • ORD, Ordovician;
  • SHK, Shakopee;
  • STP, St. Peter;
  • TRN, Trenton;
  • SIL, Silurian;
  • DEV, Devonian;
  • DVS, Devonian-Silurian;
  • MIS, Mississippian;
  • PEN, Pennsylvanian.

Kind of rock

  • D, dolomite;
  • DS, sandy dolomite;
  • L, limestone;
  • LS, sandy limestone;
  • OL, oolitic limestone;
  • s, sandstone

ABD Field abandoned

  • REV Field rivived


  • A, anticline;
  • C, stratigraphic trap;
  • D, dome;
  • F, faulting;
  • H, strata horizontal or nearly horizontal;
  • L, lens;
  • M, monocline;
  • N, nose;
  • R, reef;
  • T, terrace;
  • U, unconformity.
  • Combinations of the letters are used when more than one factor applies.


  • Correct entry not determinable