1. A method of producing heavy oils from a reservoir by single well steam and gravity drainage (SW-SAGD), comprising:a) providing a single horizontal well having a length in a heavy oil reservoir, the entire length of said horizontal well consisting essentially of blank tubulars and a plurality of flow control devices (FCDs), each said FCD between blank tubulars;
b) said horizontal well having a production segment at a heel end fitted for production, and an injection segment at a toe end fitted for steam injection, with no vertical separation between said production segment and said injection segment, wherein said plurality of FCDs are more restrictive with a lower flow resistance rating in said injection segment than in said production segment;
c) injecting steam into said injection segment to mobilize heavy oil and simultaneously producing mobilized heavy oil at said production segment;
d) wherein said method has a lower cumulative steam to oil ratio (CSOR) than said reservoir developed using a similar SW-SAGD well but with slots instead of said plurality of FCDs.