Miscible flooding process

Claim 1

IN THE METHOD FOR RECOVERING PETROLEUM FROM A SUBSTERRANEAN RESERVOIR CONTAINING EXCESSIVE AMOUNTS OF METAL CATIONS IN WHICH A SOLUBLE OIL MISCIBLE WITH BOTH THE CONNATE RESERVOIR OIL AND WITH WATER IS INJECTED INTO THE RESERVOIR THROUGH AN INJECTION WELL, AND THEREAFTER AN AQUEUS FLOODING MEDIUM IS INJECTED TO DRIVE THE MISCIBLE DISPLACEMENT FLUID TOWARDS A SPACED PRODUCTION WELL FROM WHICH FLUIDS ARE RECOVERED, THE IMPROVEMENT WHICH COMPRISES EMPLOYING A SOLUBLE OIL COMPRISING AN ADMIXTURE OF A LIQUID HYDROCARBON, PREFERENTIALLY OIL-SOLUBLE SURFACE ACTIVE ALKYL ARYL SULFONATES, A LIQUID ORGANI STABILIZING AGENT, AND A SULFONATED SURFACTANT COMPRISING AN ADMIXTURE OF AMMONIUM LAURYL POLYETHOXY SULFATE HAVING 2 TO 6 ETHOXY GROUPS AND AN AMIDE BUILDER.

Claim 11

A method for recovering petroleum from a subterranean reservoir penetrated by an injection well and a production well spaced apart in the reservoir, which comprises: injectIng 0.01 to 0.15 reservoir pore volume of a soluble oil comprising a mixture of (1) about 35 to 90 volume percent of liquid hydrocarbon; (2) about 0.5 to 8 volume percent of an organic liquid stabilizing agent selected from the group consisting of monohydric aliphatic alconols having 3 to 5 carbon atoms, alcohols aliphatic alcohols having 2 to 3 carbon atoms, aliphatic ketones having 4 to 6 carbon atoms, glycol ethers having 4 to 10 carbon atoms, and dialkylene glycols having 4 to 6 carbon atoms; (3) about 4 to 30 volume percent of a mixture of preferentially oil-soluble and preferentially water-soluble surface active alkyl aryl sulfonates in the proportion of about 1 to 15 parts by weight of oil-soluble sulfonate per part of water-soluble sulfonate; (4) about 0.1 to 1.5 parts by weight of a sulfated surfactant per part of sulfonate, said sulfated surfactant comprising an admixture of ammonium lauryl polyethoxy sulfate having 2 to 6 ethoxy groups and an amide builder; and (5) from about 0 to 50 volume percent of water present in the form of a water-in-oil microemulsion; thereafter injecting an aqueous flooding medium to drive the soluble oil towards a spaced production well, at least an initial portion of said aqueous flooding medium being increased in viscosity by the addition of a thickening agent; and recovering petroleum from said production well.

Claim 12

A method for recovering petroleum from a subterranean reservoir penetrated by an injection well and a production well spaced apart in the reservoir, which comprises: injectIng 0.01 to 0.15 reservoir pore volume of a soluble oil comprising a mixture of (1) about 35 to 90 volume percent of liquid hydrocarbon; (2) about 0.5 to 8 volume percent of an organic liquid stabilizing agent selected from the group consisting of monohydric aliphatic alconols having 3 to 5 carbon atoms, alcohols aliphatic alcohols having 2 to 3 carbon atoms, aliphatic ketones having 4 to 6 carbon atoms, glycol ethers having 4 to 10 carbon atoms, and dialkylene glycols having 4 to 6 carbon atoms; (3) about 4 to 30 volume percent of a mixture of preferentially oil-soluble and preferentially water-soluble surface active alkyl aryl sulfonates in the proportion of about 1 to 15 parts by weight of oil-soluble sulfonate per part of water-soluble sulfonate; (4) about 0.1 to 1.5 parts by weight of a sulfated surfactant per part of sulfonate, said sulfated surfactant comprising an admixture of ammonium lauryl polyethoxy sulfate having 2 to 6 ethoxy groups and an amide builder; and (5) from about 0 to 50 volume percent of water present in the form of a water-in-oil microemulsion; thereafter injecting an aqueous flooding medium to drive the soluble oil towards a spaced production well, at least an initial portion of said aqueous flooding medium being increased in viscosity by the addition of a thickening agent; and recovering petroleum from said production well.

Claim 17

A method for recovering petroleum from a subterranean reservoir penetrated by an injection well and a production well spaced apart in the reservoir, which comprises: injecting 0.01 to 0.15 reservoir pore volume of a soluble oil comprising a mixture of (1) about 35 to 90 volume percent of crude petroleum; (2) about 0.5 to 8 volume percent of an organic liquid stabilizing agent selected from the group consisting of secondary butyl alcohol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol hexyl ether and ethylene glycol hexyl ether; (3) about 4 to 30 volume percent of a mixture of preferentially oil-soluble surface active alkyl aryl monosulfonates that in the form of their sodium salts have average molecular weight above about 400 and preferentially water-soluble surface active alkyl aryl monosulfonates that in the form of their sodium salts have average molecular weights below about 400 and/or preferentially water-soluble surface active alkyl aryl polysulfonates, said sulfonates being present in the proportional of about 1 to 15 parts by weight of oil-soluble sulfonate per part of water-soluble sulfonate; (4) about 0.1 to 1.5 parts by weight of a sulfated surfactant per part of sulfonate, said sulfated surfactant comprising an admixture of ammonium laurYl polyethoxy sulfate having 2 to 6 ethoxy groups and an amide builder; and (5) from about 0 to 50 volume percent water present in the form of a water-in-oil microemulsion; thereafter injecting an aqueous flooding medium to drive the soluble oil towards a spaced production well, at least an initial portion of said aqueous flooding medium being increased in viscosity by the addition of a thickening agent, and recovering petroleum from said production well.

Claim 18

A method for recovering petroleum from a subterranean reservoir penetrated by an injection well and a production well spaced apart in the reservoir, which comprises: injecting 0.01 to 0.15 reservoir pore volume of a soluble oil comprising a mixture of (1) about 35 to 90 volume percent of crude petroleum; (2) about 0.5 to 8 volume percent of an organic liquid stabilizing agent selected from the group consisting of secondary butyl alcohol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol hexyl ether and ethylene glycol hexyl ether; (3) about 4 to 30 volume percent of a mixture of preferentially oil-soluble surface active alkyl aryl monosulfonates that in the form of their sodium salts have average molecular weight above about 400 and preferentially water-soluble surface active alkyl aryl monosulfonates that in the form of their sodium salts have average molecular weights below about 400 and/or preferentially water-soluble surface active alkyl aryl polysulfonates, said sulfonates being present in the proportional of about 1 to 15 parts by weight of oil-soluble sulfonate per part of water-soluble sulfonate; (4) about 0.1 to 1.5 parts by weight of a sulfated surfactant per part of sulfonate, said sulfated surfactant comprising an admixture of ammonium laurYl polyethoxy sulfate having 2 to 6 ethoxy groups and an amide builder; and (5) from about 0 to 50 volume percent water present in the form of a water-in-oil microemulsion; thereafter injecting an aqueous flooding medium to drive the soluble oil towards a spaced production well, at least an initial portion of said aqueous flooding medium being increased in viscosity by the addition of a thickening agent, and recovering petroleum from said production well.