An analysis of 1945-1957 gas-production statistics gave a quantitative correlation between cumulated production, P, and cumulated discoveries, D, of the form P = KDⁿ, where K and n are constants. The recent trend of life index, L, with time, t, was represented adequately by the equation of a hyperbola, [EQUATION], where t₀ is a base year, A is a life-index asymptote, and t_s and C are constants. Combination of these correlations with the definition of the rate of gas production, _p = R/L, where R is proved reserves, formulates mathematical equations which closely fit the past yearly production data. This approach can be extended for computing future production rates mathematically. One significant result is the prediction of 1,500 trillion cu ft ultimate discoveries, for which the production-rate forecast, under conditions of a 15-yr life-index asymptote, shows a 16.4 trillion cu ft a year peak in 1980. Calculated effects on the rate forecasts can be explored over an illustrative 1,500-2,500 trillion cu ft range of ultimate discoveries, and 0-, 15-, and 20-yr life-index asymptotes.