Figures 6 and 7. Alberta normalized gas production profiles and US Lower 48 States vintaged gas production profiles. Alberta normalized gas production profiles and US Lower 48 States vintaged gas production profiles characterize changes in Alberta (Western Canadian Sedimentary Basin) and US onshore average annual gas well productivity for wells completed during four calendar (vintage) years 1990, 1994, 1998 and 1999. Average peak well production after one month is indicated by the end of the orange section; average well production at the end of the first producing year is indicated by the end of the yellow section; and average well production at the end of the second producing year is shown by the end of the green section. In Alberta, production from wells completed during each vintage year was summed as if all wells commenced production on January 1. In the US, production from all completions during a vintage year was tracked thereafter by reported month through the producing life of each completion. In both cases, annual average well production was calculated by dividing total production at the end of each producing year by the maximum number of completions in the initial vintage year. In Alberta, average decline rates over the first two years increased from 19% in 1990 to 49% in 1998, and average well peak production declined from 1,070 Mcf/d to 680 Mcf/d. In comparison, first year US average decline rates increased from 29% in 1990 to 41% in 1998, but average new well peak production increased from 461 Mcf/d in 1990 to 740 Mcf/d over this same period. The increase in US peak production is only partly explained by improved completion technologies. The 1990 number was abnormally low due to curtailed production and inclusion of low-volume Section 29 well completions.