Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
82 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 oxygen or ozone oxidized lignosulfonates in an amount effective for reducing the extent of adsorption of the surfactant by the formation matrix.
Claim 2
Dependent Claim
82 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 oxygen or ozone oxidized lignosulfonates in an amount effective for reducing the extent of adsorption of the surfactant by the formation matrix.
Claim 3
Dependent Claim
20 words
A method as in claim 1 wherein the lignosulfonates have a degree of sulfonation ranging from about 2.0 to saturation.
Claim 4
Dependent Claim
26 words
A method as in claim 1 wherein the cation of the lignosulfonate salts is selected from the group consisting of calcium, magnesium, sodium, potassium, and ammonium.
Claim 5
Dependent Claim
27 words
A method as in claim 1 wherein the lignosulfonate salts are present in amount sufficient to occupy substantially all of the active sites on the formation matrix.
Claim 6
Independent Claim
103 words
A method for recovering oil from a subterranean formation containing oil and having an injection well and a production well wherein flooding water is injected into the subterranean formation comprising: (a) injecting through the injection well into the formation an aqueous solution of oxidized lignosulfonates, (b) subsequently injecting into the formation via the injection well an aqueous surfactant solution also containing oxygen or ozone oxidized lignosulfonates said oxidized lignosulfonates of steps (a) and (b) being present in amounts effective for reducing the extent of adsorption of the surfactant by the formation matrix and (c) producing oil from the formation via the production well.
Claim 7
Independent Claim
103 words
A method for recovering oil from a subterranean formation containing oil and having an injection well and a production well wherein flooding water is injected into the subterranean formation comprising: (a) injecting through the injection well into the formation an aqueous solution of oxidized lignosulfonates, (b) subsequently injecting into the formation via the injection well an aqueous surfactant solution also containing oxygen or ozone oxidized lignosulfonates said oxidized lignosulfonates of steps (a) and (b) being present in amounts effective for reducing the extent of adsorption of the surfactant by the formation matrix and (c) producing oil from the formation via the production well.
Claim 8
Dependent Claim
16 words
A method as in claim 5 wherein the solution step (b) is followed by flooding water.
Claim 9
Dependent Claim
21 words
A method as in claim 5 wherein the oxidized lignosulfonates have a degree of sulfonation ranging from about 2.0 to saturation.