Abstract: Subsurface conditions get very complicated in heavy oil reservoirs after steam huff and puff operation. A set of logging interpretation standards for identification of watered - out zones are established based on the conventional logging responses of watered - out zones at various levels in cored wells. They are used to identify watered - out zones in infill wells. Field application shows that it is viable to identify the watered - out degree of heavy oil reservoirs during thermal recovery through analysis of the conventional logging data.