The Marcellus Shale is about to become the most productive natural gas field in the United States, according to new data from energy industry analysts and the federal government.
 
Though serious drilling only began five years ago, the sheer volume of Marcellus production suggests that in some ways there's no going back, even as New York debates whether to allow drilling in its portion of the shale, which also lies under large parts of Pennsylvania, West Virginia and Ohio.
 
In 2008, Marcellus production barely registered on national energy reports. In July, the combined output from Pennsylvania and West Virginia wells was about 7.4 billion cubic feet per day, according to Kyle Martinez, an analyst at Bentek Energy. That's more than double the 3.6 billion cubic feet from last April, and represents over 25 percent of national shale gas production.
 
That's neck-and-neck with production from the Haynesville region in Arkansas and Texas, but new drilling permits there have declined sharply.
 
The Powell Shale Digest, an industry newsletter based in Fort Worth, Texas, concluded that a recent report from the U.S. Energy Information Agency means "it is reasonable to assume" that the Marcellus has or will soon pass Haynesville as the top producer.