Exxon Mobile's acquisition of XTO - a natural gas company - could speed up the flow of gas from Pennsylvania's piece of the Marcellus Shale formation.

Exxon Mobile's acquisition of XTO - a natural gas company - could speed up the flow of gas from Pennsylvania's piece of the Marcellus Shale formation. The formation runs from West Virginia to upstate New York. The $31 billion dollar deal will help Exxon tap into the growing supply of natural gas in the U.S.

Drilling in the Marcellus Shale has become somewhat of a boon for landowners in the state. Companies have spent billions of dollars paying them for the right to drill for gas on their property.

And the state more than doubled the rate of drilling permits it issued in the past year.

Now big oil has joined the game.

Steven Rhoads is president of Pennsylvania Oil and Gas Association.

Rhoads: Exxon like any other major company is going to be looking to see where its future may be headed. And analyze any prospects that come along. The fact that they would get into the unconventional gas play in the continental United States is a very significant event.

Environmentalists oppose more drilling for gas in the state. They say the process, known as fracking, could pollute drinking water. Efforts to impose a severance tax on the gas companies have stalled in Harrisburg.