Covering portions of Illinois, Indiana, and western Kentucky, the New Albany Shale attracts operators with its wide coverage and shallow depths, but the longtime-producing formation has taken a back seat to more prolific prospects.

According to "Modern Shale Gas Development in the United States: A Primer," prepared for Department of Energy agencies by the Ground Water Protection Council and ALL Consulting, the New Albany Shale covers approximately 43,500 sq miles, second only to the 93,000 sq miles in the Marcellus among major US shale plays.

The New Albany is the ...