Abstract: A miscible flooding process for oil recovery employs a multiple contact miscible solvent such as carbon dioxide and an additive such as butane which lowers the minimum miscibility pressure of the oil/solvent system. The additive is injected in a slug with a solvent, preferably followed by a slug of water to improve sweep, after which solvent alone may be injected to extract residual additive and oil by miscible extraction. A number of slugs of solvent, either by itself or with the additive may be injected, with intervening slugs of water and finally, water injection may be made to termination.

Abstract: A thermal oil recovery process in which steam is injected into a heavy oil-bearing formation through a horizontally-drilled injection well and oil is produced through a horizontal production well parallel to the injection well.

Abstract: In a thermal method for the recovery of oil from a subterranean, viscous oil-containing formation, a predetermined amount of steam in an amount not greater than 1.0 pore volume and an injection rate of 4 to 7 barrels of steam (cold water equivalent) per day per acre-foot of formation is injected into the formation via an injection well and oil is produced from the formation via a production well. The injection well is then shut-in for a variable time to allow the injected steam to dissipate its heat throughout the formation and reduce oil viscosity while continuing production of oil. Thereafter, a predetermined amount of hot water or low quality steam in an amount not greater than 1.0 pore volume is injected into the formation with continued production but avoiding steam breakthrough. Thereafter, production is continued until there is an unfavorable amount of water or steam in the fluids recovered.

Abstract: A method for the recovery of viscous oil from a subterranean, viscous oil-containing formation by injecting steam into the formation via at least one well at a sufficient temperature, rate, and in a sufficient amount to effect maximum visbreaking of the oil in place, terminating injection of steam and producing fluids including oil through the same well used for injecting steam. The injection-production cycle may be repeated for a plurality of cycles until the ratio of oil/water in the produced fluids is unfavorable.

Abstract: A method for the recovery of oil from a subterranean, viscous oil-containing formation by injecting a predetermined amount of steam into the formation via a well completed in the middle portion of the oil-containing formation for a distance between 40 to 60 percent of the vertical thickness of the oil-containing formation, terminating injection of steam and producing fluids including oil through the same well used for the injection of steam. The steps of injecting steam and producing oil can be repeated for a plurality of cycles. Injecting steam through a selected completion interval in the middle of the formation induces maximum visbreaking of the viscous oil within the formation by controlling heat losses to the over and under strata.

Abstract: In a thermal method for the recovery of oil from a subterranean, viscous oil-containing formation, steam in an amount ranging from 0.3 to 0.5 pore volume and an injection rate within the range of 4.0 to 7.0 bbl/day/ac.-ft. is injected into the formation via an injection well completed in the lower 50% or less of the formation and fluids including oil are recovered via a spaced-apart production well completed in the upper 50% or less of the formation. The injection well is then shut-in for a variable time and thereafter a predetermined amount of hot water or low quality steam is injected into the formation via the injection well in an amount ranging from 0.03 to 0.10 pore volume and at an injection rate of 1 to 2.0 bbl/day/ac.-ft. The method is applied to viscous oil-containing formation in which either naturally occurring or induced communication exists between the injection well and the production well in the bottom zone of the formation.