Output for the period prior to 1960 is output minus flared or wasted gas. For 1961 on, series Q31-37 reports marketable production and values, after deduction of processing shrinkage and line loss. Provincial figures in series Q26-30 are 'net production withdrawal'. Those exclude flared or wasted gas but not processing shrinkage or line loss. Values, prior to 1950, include value of condensate and 'pentanes plus'.
Values are at wellhead or field gate, except in Ontario where an imputed wholesale price is used.
Condensate and 'pentanes plus' are also known as 'natural gasoline' and are usually used as feedstock or blending stock in refinery operations. This field was the only source of these products prior to the 1950s. Volumes were insignificant until large- scale gas exports from Alberta and British Columbia developed in the late 1950s. Trade figures include propane and butane from refineries as well as field processing plants. The latter source derives from the apparent crude consumption shown in series Q19-25, and is thus a secondary, not a primary, source of energy.