ABSTRACT: Case History of a Petroleum Prospect Generated by a Remote Sensing Study of Dewitt County, Illinois

Robert K. Vincent, John D. Herman

Images of Landsat MSS (Multispectral Scanner) data, gravity data, and aeromagnetic data were processed and interpreted for clues to subsurface structures in central Illinois in late 1985. A residual Bouguer gravity high in the gravity image of the study area was found to occur within a circular feature mapped from a Landsat color composite image of MSS bands 4, 5, and 7. In late 1985, this prospect area, located in the southeastern part of Dewitt County, was leased by a client company, which then proceeded to pay for the collection and interpretation of two short seismic lines (2.5 and 1.5 mi, respectively) that intersected in the lease block. The seismic sections showed evidence of a subsurface structural dome and possible evidence of a Silurian reef. The nearest three p oducing oil fields are the Deland, Parnell, and Wapella East fields. The Deland field produces from Silurian reef dolomite at a depth of 1100 ft over a dome that has approximately 100 ft of closure. The Parnell field produces from Mississippian sandstone and Devonian limestone at depths of 670 and 1100 ft, respectively, with a structural trapping mechanism along a northwest-southeast-trending dome. The Dewitt County prospect was judged to have production potential in the Devonian sandy limestones and sandstones and the Silurian dolomites or limestones, with production from the deeper Ordovician and Cambrian formations and the shallower Mississippian formations also a possibility. A wildcat well was being drilled on this prospect to a target depth of 4000 ft as of October, 1989.

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990