Editor's Note: Periodically, this blog will cover selected milestones in unconventional play development, chosen from IHS Energy Editorial coverage of industry activity. These Play Activity Alerts cover the milestone within the overall context of the play, focusing on technical details of interest to O&G exploration professionals.

One of the most active companies in the Marcellus Shale play has drilled what could be the first of many horizontal tests in a new shale gas play covering parts of eastern Kentucky and southwestern West Virginia.

Targeting the Rogersville Shale, a subsidiary of EQT Corp recently reached an estimated total depth of 15,000 ft at a horizontal exploratory test in eastern Kentucky's Johnson County. The Appalachian Basin venture - named the 572360 EQT Production Co - was drilled out of a vertical pilot hole. The horizontal lateral was expected to reach almost three-quarters of a mile to the northwest. Few other details are available on the deep horizontal test.

Part of the Conasauga Group, the Rogersville Shale is a deep shale generally encountered at depths of 8000-10,000 ft. By comparison, the shallower Marcellus Shale is found at depths of 5000-7000 ft.

EQT already has an active horizontal drilling program in Johnson and Lawrence counties, with wells targeting the much shallower Berea Sandstone. Offsetting the company's deeper test is a horizontal Berea well permitted in February. The proposed true vertical depth of the Berea test is 1600 ft. Extending several miles to the northeast are several other horizontal Berea tests permitted or drilled by EQT over the past year. The Berea is found at around 1100-1600 ft in eastern Kentucky.

EQT's venture may be the first horizontal Rogersville Shale test, but a handful of vertical wells targeting the formation have been drilled in recent years. Roughly 15 miles to the north of the EQT venture is a deep vertical test drilled by Cimarex Energy subsidiary Bruin Exploration in late 2013. The 1 Sylvia Young in Kentucky's Lawrence County, which was permitted to 15,000 ft, reached an unreported depth. Also in Lawrence County is Bruin Exploration's proposed 1 Walbridge Holdings. Permitted in March, the proposed total depth of the vertical test is 15,000 ft.

The shale play extends farther to the northeast into West Virginia. Late last year in Putnum County, West Virginia, Cabot Oil & Gas drilled the 50 Cabot, a vertical well. It was expected to reach a total depth of 14,000 ft. Cabot's venture is 70 miles northeast of EQT's horizontal test.

Although not permitted to target the Rogersville Shale, Exxon 40 years ago drilled a deep West Virginia test on trend with drilling occurring today. In 1975, Exxon's 1 Jay P. Smith in Wayne County reached a total depth of 14,625 ft. The top of the Conasauga Group was encountered from 8482 ft. to 14,548 ft.

Numerous deep tests have been permitted or drilled in the Kentucky/West Virginia play - but the true potential of the Rogersville Shale will not emerge until companies share completion details. And similar to other plays, low commodity prices make a rapid rise in development unlikely.

Opposition from landowners and public interest groups could also derail the play's growth. One newly formed group - called Frack Free Foothills - describes itself as "a community effort to keep the Appalachian foothills of eastern Kentucky safe from fracking." Other environmental groups will likely emerge should there be a ramp up in Rogersville Shale development.

By Jeff Gosmano June 9, 2015, Senior Editor Energy News On Demand

This article was published by S&P Global Commodity Insights and not by S&P Global Ratings, which is a separately managed division of S&P Global.