METHOD OF INJECTING SOLVENT INTO AN UNDERGROUND RESERVOIR TO AID RECOVERY OF HYDROCARBONS

摘要

Described is a method of operating a cyclic solvent-dominated recovery process (CSDRP) for recovering viscous oil from a subterranean reservoir of the viscous oil. The cyclic solvent process involves using an injection well to inject a viscosity- reducing solvent into a subterranean viscous oil reservoir. Reduced viscosity oil is produced to the surface using the same well used to inject solvent. The process of alternately injecting solvent and producing a solvent/viscous oil blend through the same wellbore continues in a series of cycles until additional cycles are no longer economical. To improve solvent efficiency, the injection includes at least one restriction duration, where injection is restricted, between two continuous injection periods.