Method and apparatus for producing viscous hydrocarbons from a subterranean formation

Method for thermally enhanced production of a viscous hydrocarbon fluid from a productive layer of a formation in which the viscous hydrocarbon is releasably held, whereby to progressively heat discrete segments of the formation to decrease the viscosity of said hydrocarbon fluid, which method includes the steps of;

• forming in said formation a plurality of substantially parallel well completions which extend in a generally horizontal direction and which are vertically spaced apart one from the other to define a series of contiguous horizontal formation segments striated by the respective well completions,
• selectively introducing steam to the upper one of said contiguous horizontal formation segments whereby to release hydrocarbon fluid therefrom and to enhance the downward flow of a hot hydrocarbon emulsion, and
• producing said hydrocarbon emulsion from said horizontal well completion positioned at the lower side of said upper horizontal formation segment, and thereafter individually heating said discrete horizontal formation segments one at a time in descending order, and producing emulsion form each of said horizontal segments by way of the well completion immediately below the heated segment.