High conformance enhanced oil recovery process

Claim 1

A method of recovering petroleum from a subterranean, petroleum-containing formation, said formation containing water whose salinity is from 5,000 to 220,000 parts per million total dissolved solids, said formation containing at least two distinct pertoleum-containing strata, the permeability of at least one of said strata being at least 50 percent greater than the permeability of the other stratum, said formation being penetrated by at least one injection well and by at least one production well, both wells being in fluid communication with substantially all of said formation, comprising (a) injecting a first aqueous oil-displacing fluid into the formation via the injection well, said fluid passing through at least one of the more permeable strata of said formation and displacing oil therein toward the production well, from which it is recovered to the surface of the earth; (b) after said first aqueous oil displacing fluid has passed through at least one of said more permeable strata to the production well, discontinuing injecting said fluid and injecting into said stratum at least one aqueous fluid containing an emulsifying surfactant mixture comprising (1) from 0.2 to 5 percent by weight of an organic sulfonate comprising an alkyl or alkylaryl sulfonate having the following formula: R--SO.sub.3 M wherein R is an alkyl group containing from 6 to 20 carbon atoms, or an alkylaryl group selected from the group consisting of benzene, toluene or xylene having attached thereto at least one alkyl containing from 6 to 20 carbon atoms, and M is ammonium, sodium, potassium, or lithium, or a sodium, potassium, lithium, or ammonium salt of petroleum sulfonate which is at least partially water soluble and has a median equivalent weight in the range of 350 to 420; (2) from 0.01 to 5.0 percent by weight of a dialkylarylpolyalkoxyalkylene sulfonate having the following formula: R.sub.a (OR.sub.a ').sub.na R.sub.a "SO.sub.3 M.sub.a wherein R a is a dialkylaryl group selected from the group consisting of benzene and toluene having attached thereto at least two alkyl groups, each having from 3 to 14 carbon atoms, R a ' is ethylene or a mixture of ethylene and higher alkylene with relatively more ethylene than higher alkylene, na is a number from 2 to 10, R a " is ethylene, propylene, hydroxypropylene or butylene, and M a is ammonium, sodium, potassium or lithium; and (3) from about 0.01 to about 10.0 percent by weight of an alkylpolyalkoxyalkylene sulfonate or alkylarylpolyalkoxyalkylene sulfonate having the following formula: R.sub.b --(OR.sub.b ').sub.nb --R.sub.b "SO.sub.3 M.sub.b wherein R b is an alkyl group having from 9 to 25 carbon atoms or an alkylaryl group selected from the group consisting of benzene, toluene or xylene having attached thereto one alkyl group, having from 9 to 15 carbon atoms; R b ' is ethylene or a mixture of ethylene and higher molecular weight alkylene with relatively more ethylene than higher molecular weight alkylene; nb is a number from 2 to 10, R b " is ethylene, propylene, hydroxy propylene, or butylene and M b is a monovalent cation selected from the group consisting of sodium, potassium lithium and ammonium, said emulsifying surfactant mixture forming a macro-emulsion in the flow channels of the most permeable strata of the formation, thereby reducing the permeability of the strata invaded by the emulsifying fluid; and (c) thereafter injecting a second aqueous oil displacing fluid into the formation, said oil displacing fluid invading at least one stratum not invaded by the oil displacing fluid of step (a) above, displacing petroleum therein toward the production well where it is recovered to the surface of the earth.

Claim 2

A method of recovering petroleum from a subterranean, petroleum-containing formation, said formation containing water whose salinity is from 5,000 to 220,000 parts per million total dissolved solids, said formation containing at least two distinct pertoleum-containing strata, the permeability of at least one of said strata being at least 50 percent greater than the permeability of the other stratum, said formation being penetrated by at least one injection well and by at least one production well, both wells being in fluid communication with substantially all of said formation, comprising (a) injecting a first aqueous oil-displacing fluid into the formation via the injection well, said fluid passing through at least one of the more permeable strata of said formation and displacing oil therein toward the production well, from which it is recovered to the surface of the earth; (b) after said first aqueous oil displacing fluid has passed through at least one of said more permeable strata to the production well, discontinuing injecting said fluid and injecting into said stratum at least one aqueous fluid containing an emulsifying surfactant mixture comprising (1) from 0.2 to 5 percent by weight of an organic sulfonate comprising an alkyl or alkylaryl sulfonate having the following formula: R--SO.sub.3 M wherein R is an alkyl group containing from 6 to 20 carbon atoms, or an alkylaryl group selected from the group consisting of benzene, toluene or xylene having attached thereto at least one alkyl containing from 6 to 20 carbon atoms, and M is ammonium, sodium, potassium, or lithium, or a sodium, potassium, lithium, or ammonium salt of petroleum sulfonate which is at least partially water soluble and has a median equivalent weight in the range of 350 to 420; (2) from 0.01 to 5.0 percent by weight of a dialkylarylpolyalkoxyalkylene sulfonate having the following formula: R.sub.a (OR.sub.a ').sub.na R.sub.a "SO.sub.3 M.sub.a wherein R a is a dialkylaryl group selected from the group consisting of benzene and toluene having attached thereto at least two alkyl groups, each having from 3 to 14 carbon atoms, R a ' is ethylene or a mixture of ethylene and higher alkylene with relatively more ethylene than higher alkylene, na is a number from 2 to 10, R a " is ethylene, propylene, hydroxypropylene or butylene, and M a is ammonium, sodium, potassium or lithium; and (3) from about 0.01 to about 10.0 percent by weight of an alkylpolyalkoxyalkylene sulfonate or alkylarylpolyalkoxyalkylene sulfonate having the following formula: R.sub.b --(OR.sub.b ').sub.nb --R.sub.b "SO.sub.3 M.sub.b wherein R b is an alkyl group having from 9 to 25 carbon atoms or an alkylaryl group selected from the group consisting of benzene, toluene or xylene having attached thereto one alkyl group, having from 9 to 15 carbon atoms; R b ' is ethylene or a mixture of ethylene and higher molecular weight alkylene with relatively more ethylene than higher molecular weight alkylene; nb is a number from 2 to 10, R b " is ethylene, propylene, hydroxy propylene, or butylene and M b is a monovalent cation selected from the group consisting of sodium, potassium lithium and ammonium, said emulsifying surfactant mixture forming a macro-emulsion in the flow channels of the most permeable strata of the formation, thereby reducing the permeability of the strata invaded by the emulsifying fluid; and (c) thereafter injecting a second aqueous oil displacing fluid into the formation, said oil displacing fluid invading at least one stratum not invaded by the oil displacing fluid of step (a) above, displacing petroleum therein toward the production well where it is recovered to the surface of the earth.

Claim 26

A method of recovering petroleum from a subterranean, petroleum-containing formation, said formation containing water whose salinity is from 5,000 to 220,000 parts per million total dissolved solids, said formation contaning at least two distinct petroleum-containing strata, the permeability of at least one of said strata being at least 50 percent greater than the permeability of the other stratum, and formation being penetrated by at least one injection well and by at least one production well, both wells being in fluid communication with said formation strata, comprising (a) injecting a first aqueous fluid comprising an oil-displacing fluid into the formation via the injection well, said fluid passing through at least one of the more permeable strata of said formation and displacing oil therein toward the production well, from which it is recovered to the surface of the earth; (b) after said first aqueous fluid has passed through at least one of said more permeable stratum to the production well, discontinuing injecting said fluid and injecting into said stratum a second aqueous fluid containing from 0.2 to 5.0 percent by weight of an organic sulfonate comprising an alkyl sulfonate or alkylaryl sulfonate having the following formula: R--SO.sub.3 M wherein R is an alkyl containing from 6 to 20 carbon atoms, or an alkylaryl selected from the group consisting of benzene, toluene or xylene having attached thereto at least one alkyl containing from 6 to 20 carbon atoms, and M is ammonium, sodium, potassium, or lithium, or a sodium, potassium, lithium, or ammonium salt or petroleum sulfonate which is at least partially water soluble and has a median equivalent weight in the range of 350 to 420; (c) injecting a third aqueous fluid containing from 0.01 to 5.0 percent by weight of a dialkylarylpolyalkoxyalkylene sulfonate having the following formula: R.sub.a (OR.sub.a ').sub.na R.sub.a "SO.sub.3 M.sub.a wherein R a is a dialkylaryl selected from the group consisting of benzene and toluene having attached thereto at least two alkyl groups each having from 3 to 14 carbon atoms, R a ' is ethylene or a mixture of ethylene and higher alkylene with relatively more ethylene than higher alkylene, na is a number from 2 to 10, R a " is ethylene, propylene, hydroxypropylene or butylene, and M a is ammonium, sodium, potassium or lithium; (d) injecting a fourth aqueous fluid containing from 0.01 to 10.0 percent by weight of an alkylpolyalkoxyalkylene sulfonate or alkylarylpolyalkoxyalkylene sulfonate having the following formula: R.sub.b --(OR.sub.b ').sub.nb --R.sub.b "SO.sub.3 M.sub.b wherein R b is an alkyl having from 9 to 25 carbon atoms or an alkylaryl selected from the group consisting of benzene, toluene or xylene having attached thereto one alkyl group having from 9 to 15 carbon atoms; R b ' is ethylene or a mixture of ethylene and higher molecular weight alkylene with relatively more ethylene than higher molecular weight alkylene; nb is a number from 2 to 10, R b " is ethylene, propylene, hydroxy propylene, or butylene and M b is a monovalent cation selected from the group consisting of sodium, potassium lithium and ammonium; (e) said second, third and fourth fluids being injected sequentially to mix in the stratum of the formation invaded by the first aqueous fluid, forming a macro-emulsion in the flow channels of said stratum, thereby reducing the permeability of said stratum invaded by the emulsifying fluid; and (f) thereafter injecting a fifth aqueous fluid comprising an aqueous oil displacing fluid into the formation, said oil displacing fluid invading at least one stratum not invaded by the oil displacing fluid of step (a) above, displacing petroleum therein toward the production well where it is recovered to the surface of the earth.

Claim 27

A method of recovering petroleum from a subterranean, petroleum-containing formation, said formation containing water whose salinity is from 5,000 to 220,000 parts per million total dissolved solids, said formation contaning at least two distinct petroleum-containing strata, the permeability of at least one of said strata being at least 50 percent greater than the permeability of the other stratum, and formation being penetrated by at least one injection well and by at least one production well, both wells being in fluid communication with said formation strata, comprising (a) injecting a first aqueous fluid comprising an oil-displacing fluid into the formation via the injection well, said fluid passing through at least one of the more permeable strata of said formation and displacing oil therein toward the production well, from which it is recovered to the surface of the earth; (b) after said first aqueous fluid has passed through at least one of said more permeable stratum to the production well, discontinuing injecting said fluid and injecting into said stratum a second aqueous fluid containing from 0.2 to 5.0 percent by weight of an organic sulfonate comprising an alkyl sulfonate or alkylaryl sulfonate having the following formula: R--SO.sub.3 M wherein R is an alkyl containing from 6 to 20 carbon atoms, or an alkylaryl selected from the group consisting of benzene, toluene or xylene having attached thereto at least one alkyl containing from 6 to 20 carbon atoms, and M is ammonium, sodium, potassium, or lithium, or a sodium, potassium, lithium, or ammonium salt or petroleum sulfonate which is at least partially water soluble and has a median equivalent weight in the range of 350 to 420; (c) injecting a third aqueous fluid containing from 0.01 to 5.0 percent by weight of a dialkylarylpolyalkoxyalkylene sulfonate having the following formula: R.sub.a (OR.sub.a ').sub.na R.sub.a "SO.sub.3 M.sub.a wherein R a is a dialkylaryl selected from the group consisting of benzene and toluene having attached thereto at least two alkyl groups each having from 3 to 14 carbon atoms, R a ' is ethylene or a mixture of ethylene and higher alkylene with relatively more ethylene than higher alkylene, na is a number from 2 to 10, R a " is ethylene, propylene, hydroxypropylene or butylene, and M a is ammonium, sodium, potassium or lithium; (d) injecting a fourth aqueous fluid containing from 0.01 to 10.0 percent by weight of an alkylpolyalkoxyalkylene sulfonate or alkylarylpolyalkoxyalkylene sulfonate having the following formula: R.sub.b --(OR.sub.b ').sub.nb --R.sub.b "SO.sub.3 M.sub.b wherein R b is an alkyl having from 9 to 25 carbon atoms or an alkylaryl selected from the group consisting of benzene, toluene or xylene having attached thereto one alkyl group having from 9 to 15 carbon atoms; R b ' is ethylene or a mixture of ethylene and higher molecular weight alkylene with relatively more ethylene than higher molecular weight alkylene; nb is a number from 2 to 10, R b " is ethylene, propylene, hydroxy propylene, or butylene and M b is a monovalent cation selected from the group consisting of sodium, potassium lithium and ammonium; (e) said second, third and fourth fluids being injected sequentially to mix in the stratum of the formation invaded by the first aqueous fluid, forming a macro-emulsion in the flow channels of said stratum, thereby reducing the permeability of said stratum invaded by the emulsifying fluid; and (f) thereafter injecting a fifth aqueous fluid comprising an aqueous oil displacing fluid into the formation, said oil displacing fluid invading at least one stratum not invaded by the oil displacing fluid of step (a) above, displacing petroleum therein toward the production well where it is recovered to the surface of the earth.