A Texas-based company is pleased with its initial results in drilling horizontal wells for oil in the often-drilled Clinton Sandstone in Stark and two other counties.

The results from the shallow rock formation look promising, although EnerVest Operating LLC is still fine-tuning the drilling, said Barry Lay, senior vice president and general manager of the company’s Appalachian North Asset Team.

The company has completed seven smaller experimental wells in the Clinton Sandstone, he said on Thursday at the Ohio Oil and Gas Association’s three-day winter meeting in Columbus. Five of the wells are in Stark County, and one each in Carroll and Tuscarawas counties.

Those horizontal wells are producing more than vertical-only wells, and that’s good news, he said.

Serious drilling in the Clinton Sandstone is unlikely until commodity prices rise, he said. Company executives, however, “still believe that Clinton drilling is a good option,” he said.

The new wells, with 2,000-foot laterals, each cost about $1.8 million and each could produce an estimated $7 million to $10 million in revenue, Lay said. The $1.8 million cost is far more than the $400,000 it costs to drill a vertical-only well, he said.

That revenue is a huge increase from the $1 million typically derived from vertical-only wells in the Clinton Sandstone, he said in the company’s most-detailed report about the drilling that was announced in 2014.

Some see the Clinton Sandstone as being a new source of income for Ohio drillers and landowners. The new horizontal wells could help small drillers unable to fund expensive Utica Shale drilling to tap into a new Ohio energy source.

Clinton sandstone is found under 25 counties in eastern Ohio including those in the Akron-Canton-Cleveland area and it has been drilled for 100 years. The wells have been straight vertical holes into the formation that is 3,000 to 4,600 feet below the surface.

Ohio already has about 63,000 producing wells, more than half tapping Clinton sandstone. Three-fourths of the oil and gas produced in Ohio from 1985-2009 came from Clinton, according to the Ohio Oil and Gas Association.

EnerVest Operating, part of Houston-based EnerVest Ltd., saw the horizontal wells as a new way to tap into the Clinton Sandstone and decided to test its plan in what’s called the East Canton Well Field where large quantities of oil remain underground, despite heavy drilling.

The field was discovered in 1947 and has about 3,000 active wells on 214,000 acres. The area is believed to be home to 1.5 billion barrels of oil. An estimated 105 million barrels of oil have been recovered but estimates are that 93 percent of the oil remains underground.

The East Canton Well Field covers eastern Stark County and extends into Carroll, Tuscarawas and Harrison counties. EnerVest has about 115,000 leased acres and 1,700 vertical wells in the area.

The shallow horizontal wells can be drilled in 20 to 25 days, although his company has encountered problems in drilling its seven wells, Lay said. The rock is especially hard and has broken countless bits during drilling, he said.

That $1.8 million drilling cost is far less than it would cost to drill a larger horizontal well in the Utica Shale in eastern Ohio where such wells cost from $6 million to $10 million.