Rockies gas production is projected to grow by 2.5 billion cubic feet (Bcf) per day between now and 2012. That's the conclusion of a report issued by Calgary-based Ziff Energy Group. The region is one of the few traditional producing areas in North America that can deliver growth. The Rocky Mountain region holds remaining gas reserves of 55 trillion cubic feet (Tcf), and undiscovered potential of 115 Tcf. At present, some 13.5 billion cubic feet of gas per day is produced from Rockies basins, and Ziff expects that to rise to 16 Bcf during the next seven years. Most of this production growth will come from tight-gas reservoirs, which have become increasingly attractive to operators given higher commodity prices and the attractive flow rates and recoveries that today's technology can deliver. Although tight-gas reservoirs occur throughout the world, economic development has occurred almost exclusively in North America. Estimates of the volumes of recoverable tight-gas resources vary widely, with the U.S. considered to contain between 200 and 550 Tcf. The grouping of resources into either the conventional or tight-gas category can vary with the price of gas, distance to markets, and the application of appropriate drilling and completion technologies.