Oil Recovery (Patent No: 692073)

Inventor: Doscher, Todd M.

Location: Edmonton

Comments: N/A

Description:


THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. The process of recovering hydrocarbons from a subterranean, bituminous, or tar sand formation which is penetrated by at least two spaced wells, one of which is adapted for use as an injection and the other as a production well, which process comprises the steps of fracturing said formation to create fractures which extend substantially horizontally through said formation between said wells, introducing into said formation through said injection well an aqueous alkaline solution containing between about 0.0025 weight percent and about 1 weight percent of an alkaline metal hydroxide, causing said aqueous alkaline solution to flow substantially along the fractures toward the production well, thereby extracting hydrocarbons from the sands and producing a hydrocarbon in-water emulsion and injecting steam through said injection well and through the formation, thereby causing the flow of the emulsion through said formation to the production well.

2. The process of recovering oil from a subterranean, bituminous or tar sand formation which is penetrated by two spaced wells, respectively, for use as an injection well and as a production well, which process comprises the steps of hydraulically fracturing said formation to create fractures which extend substantially horizontally through said formation between said wells, introducing into said formation through said injection well an aqueous alkaline solution containing between about 0.05 weight percent and about 1 weight percent of an alkaline metal hydroxide, causing said aqueous alkaline solution to flow substantially along the fractures toward the production well, thereby extracting the oil from the sands and producing an oil-in-water emulsion, and injecting steam through said injection well and through the formation, thereby causing the flow of the emulsion -through said formation to the production well.

3. The process according to claim 2, wherein the steps of injecting the aqueous alkaline solution and of injecting steam are alternated to cause heating of the formation and the emulsification of the oil in the aqueous solution.

4. The process of recovering oil from a subterranean, bituminous, or tar sand formation which is penetrated by two spaced wells adapted, respectively, for use as an injection well and as a production well, which process comprises the steps of hydraulically fracturing said formation to create fractures which extend substantially horizontally, through said formation (for a substantial part of the distance) between said wells, introducing into said formation through said injection well an aqueous alkaline solution containing between about 0.05 weight percent and about 1 weight percent of sodium hydroxide, said solution being substantially free from any free polyvalent metal ions, causing said aqueous sodium hydroxide solution to flow substantially along the fractures toward the production well, thereby extracting the oil from the sands and producing an oil-in-water emulsion, injecting steam through said injection well, forcing said steam through the formation to the production well, thereby causing the flow of the emulsion through said formation to the production well and recovering said emulsion from the production well.

5. The process of recovering oil from a subterranean, bituminous, or tar sand formation which is penetrated by two spaced wells of substantially similar depth adapted, respectively, for use as an injection well and as a production well, which process comprises the steps of hydraulically fracturing said formation to create fractures which extend substantially horizontally through said formation between said wells, introducing into said formation through said injection well an aqueous alkaline solution containing between about 0.05 weight percent and about 1 weight percent of sodium hydroxide, said solution being substantially free from any unsequestered polyvalent metal ions, causing said aqueous sodium hydroxide solution to flow substantially along the fractures toward the production well, thereby extracting the oil from the sands and producing an oil-in-water emulsion, injecting steam through said injection well, alternating the injections of the aqueous sodium hydroxide solution and of steam, thereby heating the formation and causing the flow of the emulsion therethrough to the production well, and recovering said emulsion from the production well.

6. The process of recovering oil from a subterranean, bituminous, or tar sand formation which is penetrated by two spaced wells of substantially similar depth adapted, respectively, for use as an injection well and as a production well, which process comprises the steps of hydraulically fracturing said formation to create fractures which extend substantially horizontally through said formation for a substantial part of the distance between said wells, said fractures being located near the bottom of said input and production wells, introducing into said formation through said injection well an aqueous solution containing between about 0.05 weight percent and about 1 weight percent of sodium hydroxide solution to flow substantially along the fractures toward the production well, thereby extracting the oil from the sands and producing an oil-in-water emulsion, injecting steam through said injection well, forcing said steam through the formation to the production well, alternating said alkali and steam injections, thereby causing the flow of the emulsion through said formation to the production well, recovering said emulsion from the production well, and separating the oil from said emulsion.

7. The process of recovering oil from a subterranean tar sand formation penetrated by two spaced wells of substantially similar depth and adapted, respectively, for use as in injection well and as a production well, which process comprises the steps of introducing through said injection well a dilute aqueous alkaline solution, containing between about 0.05 weight percent and about 1 weight percent of sodium hydroxide under a pressure sufficient to hydraulically fracture said tar sand formation to create fractures which extend substantially horizontally through said formation between said wells, said fractures being located near the bottom of said input and production wells, continuing the introduction of said dilute aqueous sodium hydroxide solution, thereby causing it to flow through the fractures, to extract the oil from the sands and to produce an oil-in-water emulsion, interrupting said injection of the sodium hydroxide solution, injecting steam during said interruption, thereby causing the flow of the emulsion through the formation to the production well, recovering said emulsion from the production well and separating the oil from said emulsion.

8. The process according to claim 1 wherein the aqueous sodium hydroxide used is substantially free from any unsequestered polyvalent metal ions.