Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
126 words
In a method for recovering oil from a subterranean formation containing oil and having an injection well and a production well wherein an aqueous surfactant solution is injected into the injection well in order to drive the oil to the production well wherein it is produced the improvement which comprises: injecting into the injection well in admixture with the surfactant lignosulfonates alkoxylated with an amount of ethylene oxide or propylene oxide effective to reduce the extent of adsorption of the surfactant on the formation matrix below that of lignosulfonate not alkoxylated and to render any insoluble lignosulfonates soluble in the aqueous surfactant solution wherein the alkoxylated lignosulfonate is present in an amount effective for reducing the extent of adsorption of the surfactant by the formation matrix.
Claim 2
Dependent Claim
126 words
In a method for recovering oil from a subterranean formation containing oil and having an injection well and a production well wherein an aqueous surfactant solution is injected into the injection well in order to drive the oil to the production well wherein it is produced the improvement which comprises: injecting into the injection well in admixture with the surfactant lignosulfonates alkoxylated with an amount of ethylene oxide or propylene oxide effective to reduce the extent of adsorption of the surfactant on the formation matrix below that of lignosulfonate not alkoxylated and to render any insoluble lignosulfonates soluble in the aqueous surfactant solution wherein the alkoxylated lignosulfonate is present in an amount effective for reducing the extent of adsorption of the surfactant by the formation matrix.
Claim 3
Dependent Claim
14 words
A method as in claim 1 wherein the lignosulfonates are alkoxylated with ethylene oxide.
Claim 4
Dependent Claim
18 words
A method as in claim 2 wherein the ethoxylated lignosulfonate had been previously sulfomethylated and oxidized with oxygen.
Claim 5
Independent Claim
133 words
A method for recovering oil from a subterranean formation containing oil and having an injection well and a production employing an aqueous surfactant solution comprising: (a) injecting through the injection well into the formation an aqueous solution of lignosulfonates alkoxylated with an amount of ethylene oxide or propylene oxide effective to reduce the extent of adsorption of the surfactant on the formation matrix below that of lignosulfonate not alkoxylated and to render any insoluble lignosulfonates soluble in the aqueous solution wherein the lignosulfonate is present in an amount effective for reducing the extent of adsorption of the surfactant by the formation matrix, (b) subsequently injecting into the formation via the injection well an aqueous surfactant solution also containing alkoxylated lignosulfonates as above and (c) producing oil from the formation via the production well.
Claim 6
Independent Claim
133 words
A method for recovering oil from a subterranean formation containing oil and having an injection well and a production employing an aqueous surfactant solution comprising: (a) injecting through the injection well into the formation an aqueous solution of lignosulfonates alkoxylated with an amount of ethylene oxide or propylene oxide effective to reduce the extent of adsorption of the surfactant on the formation matrix below that of lignosulfonate not alkoxylated and to render any insoluble lignosulfonates soluble in the aqueous solution wherein the lignosulfonate is present in an amount effective for reducing the extent of adsorption of the surfactant by the formation matrix, (b) subsequently injecting into the formation via the injection well an aqueous surfactant solution also containing alkoxylated lignosulfonates as above and (c) producing oil from the formation via the production well.
Claim 7
Dependent Claim
14 words
A method as in claim 4 wherein the lignosulfonates are alkoxylated with ethylene oxide.
Claim 8
Dependent Claim
18 words
A method as in claim 5 wherein the ethoxylated lignosulfonate had been previously sulfomethylated and oxidized with oxygen.
Claim 9
Independent Claim
128 words
A method for recovering oil from a subterranean formation containing oil and having an injection well and a projection well employing an aqueous surfactant solution compressing: (a) injecting through the injection well into the formation an aqueous solution of lignosulfonates alkoxylated with an amount of ethylene oxide or propylene oxide effective to reduce the extent of adsorption of the surfactant on the formation matrix below that of lignosulfonate not alkoxylated and to render any insoluble lignosulfonates soluble in the aqueous solution wherein the lignosulfonate is present in an amount effective for reducing the extent of adsorption of the surfactant by the formation matrix, (b) subsequently injecting into the formation via the injection well an aqueous surfactant solution and (c) producing oil from the formation via the production well.
Claim 10
Independent Claim
128 words
A method for recovering oil from a subterranean formation containing oil and having an injection well and a projection well employing an aqueous surfactant solution compressing: (a) injecting through the injection well into the formation an aqueous solution of lignosulfonates alkoxylated with an amount of ethylene oxide or propylene oxide effective to reduce the extent of adsorption of the surfactant on the formation matrix below that of lignosulfonate not alkoxylated and to render any insoluble lignosulfonates soluble in the aqueous solution wherein the lignosulfonate is present in an amount effective for reducing the extent of adsorption of the surfactant by the formation matrix, (b) subsequently injecting into the formation via the injection well an aqueous surfactant solution and (c) producing oil from the formation via the production well.
Claim 11
Dependent Claim
14 words
A method as in claim 7 wherein the lignosulfonates are alkoxylated with ethylene oxide.
Claim 12
Dependent Claim
18 words
A method as in claim 8 wherein the ethoxylated lignosulfonate had been previously sulfomethylated and oxidized with oxygen.
Claim 13
Dependent Claim
26 words
A method as in claim 7 wherein the lignosulfonates are present in amount sufficient to occupy substantially all of the active sites on the formation matrix.