National Fuel Gas Co. executives keep seeing more and more potential in drilling for natural gas on its vast land holdings in northwestern Pennsylvania.

The Amherst-based energy company is nearly doubling its estimates of how much natural gas lies beneath the nearly 750,000 acres it controls in the Marcellus Shale region in northwestern Pennsylvania. And the company is further ramping up its plans to drill new wells in the region to tap into that pool of gas.

The company now believes between 8 trillion and 15 trillion cubic feet of gas can be tapped on that land, and National Fuel executives said Friday that the new wells it plans to drill in the Marcellus Shale region will account for all of the projected 31 percent increase in its oil and gas production next year.

“Right now, National Fuel Gas is in a very good place,” said David Smith,

the company’s chairman and chief executive officer, during a conference call Friday.

National Fuel disclosed its more upbeat view of its Marcellus assets as the company reported that its third-quarter profits dipped by less than 1 percent as lower earnings from its pipeline business offset improvement at its utility and oil and natural gas drilling operations.

National Fuel’s profits, which matched analyst forecasts, slipped to $42.6 million, or 51 cents per share, from $42.9 million, or 53 cents per share, a year ago, when the company had about 2 million fewer shares in circulation.

National Fuel also said it expects profits to strengthen in the fiscal year that begins in October, rising from a projected $2.60 to $2.70 per share this year to an estimated $2.60 to $2.90 per share in the upcoming fiscal year. Those forecasts are in line with consensus analyst expectations that the company will earn $2.65 per share this year and $2.83 per share next year.

In the quarter that just ended, higher natural gas prices at the Niagara/Chippewa gateway, where the company’s Empire Pipeline connects with the TransCanada pipeline, caused some of National Fuel’s pipeline customers to reduce their imports of natural gas from Canada. That cut into the volume of gas transported on National Fuel’s pipelines and some unused capacity on the Empire Pipeline, leading to a 22 percent drop in earnings from its pipeline business.

Those reduced imports will cost the pipeline business about $4.5 million in revenues during the fiscal year that starts in October, and another $6 million in 2012. But the company expects those revenue losses to be more than offset in 2012 by added sales from new pipeline projects in the Marcellus region in Pennsylvania that will be coming on line in 2012, said Ronald Tanski, National Fuel’s president and chief operating officer.

Earnings at the company’s oil and natural gas drilling business grew by 3 percent as higher oil prices and a 15 percent jump in production helped offset the impact of a 3 percent dip in average natural gas prices.

As National Fuel steps up its drilling in the Marcellus Shale with the addition of a third drilling rig in the region — and plans to add three more by September 2011 — the company said it now expects its oil and natural gas production to jump by 31 percent next year to the equivalent of between 60 billion and 70 billion cubic feet of natural gas.

The company’s natural gas production in the Marcellus Shale region more than doubled during the third quarter, as many of the wells have been producing at high volumes for a longer period of time than is typical in that area, said Matthew D. Cabell, who runs National Fuel’s oil and gas drilling business. The company expects to drill 60 to 80 wells in the Marcellus region next year, along with about 40 through its joint venture with EOG Resources.

While drilling in the Marcellus Shale in New York is on hold while state regulators develop new regulations for the hydraulic fracturing techniques called “fracking” used to extract natural gas from the shale, drilling is expanding rapidly in Pennsylvania under rules that already are in place. Some environmentalists are concerned that the millions of gallons of water, mixed with sand and chemicals, used in hydraulic fracturing could contaminate ground water.

Earnings from the company’s utility business rose by 11 percent.

National Fuel, which is trying to sell some of its small, side businesses, sold its Pennsylvania saw mill and some of the land that was part of its timber business for $15 million. National Fuel will retain the drilling rights on that land, Smith said.

The company also is continuing to try to sell its landfill gas business.