A Systems Approach to Identifying Exploration and Development Opportunities in the Illinois Basin: Digital Portfolio of Plays in Underexpored Lower Palezoic Rocks

Lower Paleozoic rocks of the Illinois Basin represent an important, yet under-explored target. Of the 4 billion barrels of oil produced from the Illinois Basin only 7.5 percent has been from lower Paleozoic rocks. Reservoirs deeper than 2,500 feet are rarely targeted. Lower Paleozoic units represent 50% of the rock volume of the Illinois Basin, yet only 2% of all exploratory wells drilled have penetrated deep enough to test these rocks. Potential for large reserves in Devonian, Silurian and Ordovician rocks have been demonstrated. Examples include highly prolific Middle Devonian Geneva Dolomite reservoirs in Illinois where a recent discovery has resulted in a gain in total production of over 1 million barrels per year from just 4 wells. The discovery well in this new field had sustained production of over 2,000 barrels per day. High volume Ordovician age Trenton/Black River reservoirs have been established in the Michigan and Appalachian Basins in fractured dolomites in structural lows. The Albion Scipio Field that borders the Illinois Basin in southern Michigan has produced 125 million barrels of oil. Exploration has not adequately examined the play in the Illinois Basin. Ordovician production in the Illinois Basin to date is from reservoirs on anticlinal closures, and most Trenton production was discovered by drilling deeper into structures with established shallower production. Geologic conditions exist in the Illinois Basin that are comparable to those that form the prolific reservoirs in the Michigan and Appalachian Basins. We propose the development of a digital play portfolio for Devonian and Deeper Paleozoic Strata that could improve exploration and development strategies in the Illinois Basin and lead to increased production in the Basin. The play analysis will be conducted by members of the Illinois Basin Consortium, using a) analytical techniques to visualize and image structural evolution of the basin b) innovative methods to mine, refine and update old data and create new databases, and c) proven, modem technology transfer methods to efficiently reach a wide audience at low cost. We will analyze the grid of existing seismic data grid to explore possible untapped play trends, develop ideas of re-mobilization of structures over geologic time, refine understanding of the role of offsetting of structures with depth, to better define the potential role of remobilization of structures in hydrocarbon migration, and to examine the role of deeply seated faults and other structural features. A website with an ArcIMS component will be used to disseminate the digital products developed for this project. This interactive website will offer users the ability to visualize unconformity pinchouts, stratigraphic trap potential and structural evolution, facilitating their ability to develop new play concepts in the under-explored Lower Paleozoic strata of the Illinois Basin. Presenting the data through a geographic information systems approach capitalizes upon the proven strengths of the state geological survey members of the Illinois Basin Consortium, who have exhibited leadership and innovation in this field.