Patent ID: 9488040
Filing Date: 2016-11-08
CPC Classification: E21B

Claim Text:
1. A cyclic solvent-dominated recovery process for recovering hydrocarbons from an underground reservoir, the cyclic solvent-dominated recovery process comprising: (a) injecting injected fluid comprising greater than 50 mass % of a viscosity-reducing solvent into an injection well completed in the underground reservoir; (b) halting injection into the injection well and subsequently producing at least a fraction of the injected fluid and the hydrocarbons from the underground reservoir through a production well; (c) halting production through the production well; and (d) repeating the cycle of steps (a) to (c); wherein step (a) comprises, in at least one cycle, contacting uncovered hydrocarbons between solvent fingers by (a1) alternating injection of the injected fluid and production of at least a fraction of the injected fluid and the hydrocarbons to create an advance-retreat movement of the injected fluid; and wherein (a1) is performed in a given injection (a) at some point after 25% of pore volume has been injected and production volume in (a1) is less than 25% of production volume in (c) in a given cycle (a) to (c).