James Van Blaricum
There are a myriad of different industry participants that formulate their own estimates regarding natural gas supplies, such as production companies, independent geologists, the government, and environmental groups, to name a few. While this leads to a wealth of information, it also leads to a number of difficulties. Each estimate is based on a different set of assumptions, completed with different tools, and even referred to with different language. It is thus difficult to get a definitive answer to the question of how much natural gas exists. In addition, since these are all essentially educated guesses as to the amount of natural gas in the earth, there are constant revisions being made. New technology, combined with increased knowledge of particular areas and reservoirs mean that these estimates are in a constant state of flux. Further complicating the scenario is the fact that there are no universally accepted definitions for the terms that are used differently by geologists, engineers, accountants, and others.
Historical Proved Natural Gas Reserves
The graph below shows the change in proved natural gas reserves in the United States from 1990 to 2000, as recorded by the EIA. As can be seen, the levels of proved reserves in the United States have not changed significantly over the past 10 years. If the additions to proved reserves in a given year are larger than the subtractions from production, then proved reserves will increase, and vice versa. Usually, however, the additions are close enough to the subtractions to maintain a relatively constant level of proved reserves.