Two parallel Jackfork trends have emerged in southeast Oklahoma since the serendipitous discovery of Jackfork production in 1992 at a well targeted for Pennsylvanian (Atokan) Spiro sandstone.

Jackfork Group rocks were deposited as deepwater turbidites and related deposits in the Ouachita Basin during the Late Mississippian (?), early Pennsylvanian (Morrowan) time. Jackfork deposits include 4000-6000' of shale, siltstone, and fine-to-medium grained sandstone with occasional channel-type intervals of coarser sand (Montgomery, 1996). It is believed these sediments were derived primarily from the Appalachians and the Illinois Basin and formed an elongate submarine fan complex that prograded westward across Arkansas into southeastern Oklahoma. Recent investigations by Slatt, et al., 1997, have revealed three common hydrocarbon-bearing architectural elements of deepwater (turbidite) systems, channel-fill complexes, sheet deposits, and levee/over bank deposits.

The submarine fan that formed the Jackfork Group was incorporated into the northward advancing allochthon to form the Ouachita thrust front, creating an extremely complex structural setting. The Ouachita thrust front is the result of a thick prism of sediment being thrust northward over the shelf rock during early Desmoinesian time. The event also marked the end of Ouachita deposition.

The northern most Jackfork trend is located in southern Latimer County, Oklahoma between the Ti Valley and Windingstair thrust faults. Gas production in this play comes from fine-grained, fractured channel-type sands with low matrix porosity/permeability (Montgomery, 1996). Wells are thought to produce from fractures in highly quartz-cemented brittle sandstones.

The southern Jackfork trend is located in extreme southern Latimer and northern Pushmataha Counties in the Potato Hills. Jackfork production was discovered in the Potato Hills field in 1997. The field had previously been productive from the Big Fork Chert. The southern trend is much more prolific than the northern trend. Through October 2001, 27 wells in the region had recovered almost 90 billion cubic feet of gas and 22 of the wells are still active.