Steam drive oil recovery method utilizing a downhole steam generator

Claim 2

In a method of recovering viscous oil from a subterranean, permeable, viscous oil-containing formation, said formation being penetrated by at least one injection well and at least one spaced-apart production well, said wells in fluid communication with a substantial portion of the formation, comprising: (a) mixing a water-soluble fuel with water; (b) injecting said mixture of water-soluble fuel dissolved in water under pressure into a steam generation zone in said injection well; (c) concurrently with step (b), injecting substantially pure oxygen into said steam generation zone under pressure via said injection well which contacts the pressurized mixture of water-soluble fuel and water thereby effecting spontaneous combustion of said fuel to generate a mixture of steam and combustion gases that pass through the formation, displacing oil and reducing the oil's viscosity; and (d) recovering fluids including oil from the formation via the production well.

Claim 3

The method of claim 1 wherein the water-soluble fuel is selected from the group consisting of sugars and alcohols.

Claim 4

The method of claim 2 wherein the sugar comprises molasses.

Claim 5

The method of claim 2 wherein the sugar comprises raw sugar beet extract (juice).

Claim 6

The method of claim 1 wherein the water-soluble fuel is raw sugar beet extract (juice) and the raw sugar beet extract (juice) concentration is about 20 weight percent.

Claim 7

The method of claim 1 wherein the pressure in the steam generation zone is maintained within the range of 1000 to 3000 psi and the temperature is within the range of 550° F. to 700° F.

Claim 8

The method of claim 1 wherein the concentration of water-soluble fuel is within the range of about 10 to about 33 weight percent.

Claim 9

The method of claim 1 wherein the steam generation zone is located about midway the vertical distance of the oil-containing formation.

Claim 10

The method of claim 1 further including continuing step (d) until the fluids produced contain an unfavorable ratio of oil to water.

Claim 11

In a method for recovering oil from a subterranean, permeable, viscous oil-containing formation, said formation being penetrated by at least one well, said well in fluid communication with a substantial portion of the formation, comprising: (a) mixing a water-soluble fuel with water; (b) injecting said mixture of water-soluble fuel dissolved in water under pressure into a steam generation zone in said injection well; (c) injecting substantially pure oxygen into said steam generation zone under pressure via said well which contacts the pressurized mixture of water-soluble fuel and water thereby effecting spontaneous combustion of said fuel to generate a mixture of steam and hot combustion gases that pass through the formation, displacing oil and reducing the oil's viscosity; (d) continuing injecting said pressurized mixture of water-soluble fuel dissolved in water and substantially pure oxygen for a predetermined period of time; and (e) thereafter, discontinuing fluid injection of step (d) and opening said well to production so that fluids including oil are recovered from the formation.

Claim 12

In a method for recovering oil from a subterranean, permeable, viscous oil-containing formation, said formation being penetrated by at least one well, said well in fluid communication with a substantial portion of the formation, comprising: (a) mixing a water-soluble fuel with water; (b) injecting said mixture of water-soluble fuel dissolved in water under pressure into a steam generation zone in said injection well; (c) injecting substantially pure oxygen into said steam generation zone under pressure via said well which contacts the pressurized mixture of water-soluble fuel and water thereby effecting spontaneous combustion of said fuel to generate a mixture of steam and hot combustion gases that pass through the formation, displacing oil and reducing the oil's viscosity; (d) continuing injecting said pressurized mixture of water-soluble fuel dissolved in water and substantially pure oxygen for a predetermined period of time; and (e) thereafter, discontinuing fluid injection of step (d) and opening said well to production so that fluids including oil are recovered from the formation.

Claim 13

The method of claim 10 including repeating steps (b) through (e) for a plurality of cycles.

Claim 14

The method of claim 10 comrising the additional step of leaving the steam and hot combustion gases injected into the formation in step (c) in the formation for a soak period for a predetermined time interval prior to the fluid production in step (e).

Claim 15

The method of claim 10 wherein the water-soluble fuel is selected from the group consisting of sugars and alcohols.

Claim 16

The method of claim 13 wherein the sugar comprises molasses.

Claim 17

The method of claim 13 wherein the sugar comprises raw sugar beet extract (Juice).

Claim 18

The method of claim 10 wherein the water-soluble fuel is raw sugar beet extract (juice) and the raw sugar beet extract (juice) concentration is about 20 weight percent.

Claim 19

The method of claim 10 wherein the pressure in the steam generation zone is maintained within the range of 1000 to 3000 psi and the temperature is within the range of 550° F. to 700° F.

Claim 20

The method of claim 10 wherein the concentration of water-soluble fuel is within the range of about 10 to about 33 weight percent.

Claim 21

The method of claim 10 wherein the steam generation zone is located about midway the vertical distance of the oil-containing formation.