Abstract: Data useful to evaluate the effectiveness of or to design an enhanced recovery process (the recovery process involving mobilizing and moving hydrocarbons through a hydrocarbon-bearing subterranean formation from an injection well to a production well by injecting a mobilizing fluid into the injection well) are obtained by a process which comprises sequentially: determining hydrocarbon saturation in the formation in a volume in the formation near a well bore penetrating the formation, injecting sufficient of the mobilizing fluid to mobilize and move hydrocarbons from a volume in the formation near the well bore penetrating the formation, and determining by the single well tracer method a hydrocarbon saturation profile in a volume from which hydrocarbons are moved. The single well tracer method employed is disclosed by U.S. Pat. No. 3,623,842. The process is useful to evaluate surfactant floods, water floods, polymer floods, CO.sub.