Regional Cross Section Program for Illinois Basin

Janis D. Treworgy, Stephen T. Whitaker

For the first time, the Illinois State Geological Survey will publish a network of regional cross sections portraying the structural and stratigraphic framework of the entire Illinois basin. The network of 16 structural cross sections radiating outward from the Union Oil 1 Cisne Community well (Sec. 3, T1N, 7E, Wayne County, Illinois) will consist of wireline logs showing formation boundaries and gross lithofacies of the entire stratigraphic column for over 140 wells. Indiana and Kentucky portions of the network will be prepared in conjunction with their respective state geological surveys.

Wireline logs are being digitized and stored to allow reproduction of log curves at different scales and in various combinations. Initial cross sections will be published at a vertical scale of 1 in. = 400 ft and a horizontal scale of 1 in. = 8 mi (1:500,000).

To assure the most accurate structural and lithologic portrayals possible, numerous wireline logs are being examined in addition to the 140 illustrated on the sections. Available seismic data, sample and core descriptions, and existing structure, isopach, and facies maps are also being used.

Text describing the sections will be included on each sheet. Topics will cover a brief history of deposition and structural evolution, distribution of source rocks, reservoir rocks and seals, and significant fields and plays.

AAPG Search and Discovery Article #91023©1989 AAPG Eastern Section, Sept. 10-13, 1989, Bloomington, Indiana.