Geologic Overview and Activity Update for the Utica-Point Pleasant Shale Play in Ohio
The Ordovician Point Pleasant Formation-Utica Shale interval is shaping up to be the next stop of the “shale gale” in the United States and Ohio appears to be the primary focus of this play. Leasing activity ramped up in Ohio in late 2010 and still continues at a fevered pitch. The first horizontal exploration wells were drilled and completed in the Utica-Point Pleasant in early 2011.
Within Ohio, the Point Pleasant Formation lies directly above the Trenton Limestone and is, at least in part, equivalent with the thick deposits of the Trenton carbonate platform of northwestern Ohio, famous for the Lima-Indiana oil-and-gas trend, which was the first true giant field produced in North America starting in 1884. As the carbonate platform deposits of the Trenton thin, the interbedded organic-rich carbonates and shales of the Point Pleasant thicken, so that over much of Ohio the Trenton is only about 40-60 feet thick, while the Point Pleasant is 150-200 feet thick. The northwestern-Ohio Trenton carbonate platform represents a distal bulge of the ensuing Taconic Orogeny. As the orogenic activity and subsidence increased, the organic-rich Utica Shale proper transgressed the area from present day east-southeast to west-northwest, eventually overwhelming and drowning the carbonate environments. Thus, in the deeper portions of the present-day basin the Utica (and Antes) is, in part, laterally equivalent and overlies the Point Pleasant.
Analysis of source rock geochemistry and early
drilling results indicate the Utica-Point Pleasant to contain sufficient
hydrocarbons to sustain a major drilling play. Oil-source rock pairings
indicate the Utica-Point Pleasant has been the primary source for numerous
conventional reservoirs in the region. Also, analyses indicate much of the play
area in Ohio will be natural gas liquids and oil prone. In fact, a number of
historical wells have encountered large shows, and some have produced
substantial oil from this interval.
AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California