Long-term implications of new U.S. gas estimates

The US Geological Survey's 1995 estimates of domestic undiscovered plus undeveloped natural gas nearly tripled quantifies estimated in its 1989 Assessment. Much of the increase came from selected unconventional resources assessed using the paradigm of continuous type accumulations. These include such seemingly unrelated "unconventional" gas occurrences as "tight gas", coalbed gas, gas in shales, and deep basin-center gas. Though only a small fraction of the assessed 352 trillion cubic feet is now economic, the quantity is nevertheless significant. Moreover, the lowest cost resources are close to major gas markets where competing conventional gas is modest. With continued technological improvements these resources can contribute significantly to future U.S. gas supply, even without subsidies. © 1997 International Association for Mathematical Geology.