formation 12 the well 14 is perforated at 15 at the lower end of the injection well steam injected through the perforations 15 heats and partially distills the petroleum within the formation and creates a distillate bank 17 ahead of the steam zone 19 and behind the unheated petroleum after prolonged injection of steam through the injection well the steam and distillate bank eventually break through to the perforations 21 in production well 16 having pushed heated petroleum ahead of the steam in accord with the procedures described herein a combination of steam noncondensible gas and foam maximize the recovery of petroleum from the formation by improving the sweep efficiency of the steam and the heating of the formation after the steam and distillate bank break through to the producing well a combination of noncondensable gas foamable surfactant and steam is injected through the injection well 14 to produce a foam zone 23 in the depleted portion of the steam zone above the oil producing steam zone 19 the foam zone 23 inhibits the passage of steam directly into the producing well 16 and creates a flow resistance to force the steam and noncondensable gas to produce a continuing distillate bank 17 into the formation 12 thus encouraging an efficient sweep of the formation and production of the crude into the well 16 the novelty of the processes described in this disclosure lies mainly in the effect that vapor volume and temperature have on distillation of the crude oil the injection of high temperature steam enhances.