IL Basin

Rex Energy Basin Area
Rex Energy Basin Area

The Illinois Basin covers approximately 60,000 square miles in Illinois, Indiana and Kentucky. Since the initial discovery of oil in the basin in 1886, approximately 4 billion barrels of oil and an estimated 4 trillion cubic feet of natural gas have been produced in the basin. Most of the basin’s hydrocarbons have been produced from Late Mississippian and Pennsylvanian sandstones. Oil and source rock analyses indicate that the New Albany Shale (Upper Devonian – lowermost Mississippian) was the primary source of hydrocarbons in the Illinois Basin.


Rex Energy produces approximately 2,500 gross bbls/day of oil and is one of the largest producers in the Illinois Basin. Being a high volume producer enables us to realize a premium over the basin posted prices and also gives us a cost competitive advantage with economies of scale.


Rex Energy is implementing Alkaline-Surfactant-Polymer (ASP) flood operations in our Lawrence field acreage in Lawrence County, Illinois. The Lawrence field is believed to have produced more than 400 million barrels of oil, representing approximately 40% of the estimated one billion barrels of original oil-in-place, since its discovery in 1906. We currently own and operate 21.2 square miles of the Lawrence field and our properties account for approximately 85% of the current total gross production from the field. The Cypress (Mississippian) and the Bridgeport (Pennsylvanian) sandstones are the major producing horizons in the field. During the 1960s, 1970s and 1980s, surfactant polymer flood projects implemented in the Lawrence field by a previous operator demonstrated incremental oil recovery over secondary flooding.

In an ASP flood, surfactant mobilizes residual oil to water by decreasing the interfacial tension between oil and water, polymer provides mobility control to push the already mobilized oil by surfactant, and alkali is added to make the surfactant more efficient. Based on the performance of our pilot flood in the Lawrence field, Rex plans to implement larger field scale projects in the future. The goal of the pilot ASP flood is to understand the physics of this technology and learn about any challenges faced during the operation of the project while making it economical as we go forward.