The U.S. natural gas industry is rapidly evolving, largely because of shifting supply dynamics. The Appalachian region in the Northeast is one of the main proponents of change, as its Marcellus shale could contain recoverable resources equal to almost half of the current proven natural gas reserves in the U.S. Exploration and production (E&P) companies have only just started to develop this resource, spurred by the increased use of specialized technological capabilities such as horizontal drilling and hydraulic fracturing. Yet the rapid increase in production has already affected long-standing gas flows, reducing the area's reliance on natural gas imports from other regions and cutting premiums that local producers could realize. Standard&Poor's Ratings Services believes many industry players will