Texaco Inc.

George Kalfoglou

Kenoth H Flournoy

Grover S Paulett

Lawrence E Whittington

Mohan V Kudchadker

John Prieditis

The invention is a method for improving conformance during a carbon dioxide foam flood, which comprises injecting into the formation an aqueous solution of about 0.05% to about 5% by weight of a carbon dioxide foaming surfactant, and about 0.05% to about 5% by weight of a lignosulfonate-acrylic acid graft copolymer having about 2% to about 70% by weight of acrylic acid, and injecting into the formation carbon dioxide to sweep the hydrocarbons towards a production well for recovery.

Lignosulfonate-acrylic acid graft copolymers as sacrificial agents for carbon dioxide foaming agents

A method for reducing the permeability of a region of an underground formation by injecting a gelant solution that forms a stable gel into the region is disclosed. The gelant solution includes an aqueous solvent, about 2% to about 16% by weight of a lignosulfonate-acrylic acid graft copolymer and a sufficient concentration of a crosslinking agent to crosslink the copolymer. The lignosulfonate-acrylic acid copolymer used in the invention has an acrylic acid content of about 10% to about 50% by weight and the crosslinking agent is a complex of one or more positively charged chromium (III) species and one or more negatively charged carboxylate species. Preferably, the chromium (III) species used in the invention has a concentration of about 0.1% to about 8.0% by weight. In one preferred embodiment, the carboxylate species of the crosslinker may be selected from formate, acetate, propionate, lactate, oxalate and malonate. In another preferred embodiment the crosslinker may further comprise one or more species selected from hydroxide and oxygen.

Conformance improvement in hydrocarbon bearing underground strata using lignosulfonate-acrylic acid graft copolymer gels

A sacrificial agent method employing lignosulfonate-acrylic acid graft copolymers to reduce chemical loss to the formation during hydrocarbon recovery by surfactant system injection and sweep through an underground formation.

Method of using lignosulfonate-acrylic acid graft copolymers as

The invention is a method of moving hydrocarbons through an underground formation for later recovery which comprises injecting an aqueous surfactant system having about 0.5% to about 10% of one or more surfactants and about 0.5% to about 10% of an alkoxylated dialkylate having the formula:

Dialkylate additives for surfactant sytems

A sacrificial agent solution which is compatible with high molecular weight mobility control polymers for enhanced oil recovery, said solution comprising about 0.1% to about 5% by weight of a lignosulfonate and about 0.01% to about 5% by weight of a polyalkylene glycol having a relatively low molecular weight.

Method of using a combination lignosulfonate/polyalkylene glycol system

The invention is a method for lowering the oxygen content of an aqueous polymer solution below 100 ppb, which comprises recirculating an aqueous polymer solution through microporous hollow fibers grouped in a module having an air tight interior which surrounds the hollow fibers. A vacuum is applied to the interior of the fiber module to enhance transportation of oxygen through the walls of the hollow fibers and out of the module interior.

Deoxygenation of aqueous polymer solutions used in enhanced oil recovery

The disclosed sacrificial agent invention is a method of injecting a solution containing about 0.1% to about 10% by weight of a mixture of at least two sacrificial agents, wherein one sacrificial agent is a lignosulfonate and the second sacrificial agent is a carbohydrate, more specifically, a starch or cellulose derivative. The starch or cellulose derivative suitable for the second sacrificial agent can be found in the group comprising alkoxylated starch, esterified starch, oxidized starch, phosphated starch, alkoxylated cellulose, carboxyalkyl cellulose, carboxyalkylalkoxylated cellulose, alkylalkoxylated cellulose, cellulose sulfates and cellulose acetate sulfates.

Method of using a lignosulfonate/carbohydrate system as a sacrificial

A process for producing petroleum from subterranean formations is disclosed wherein production from the formation is obtained by driving a fluid from an injection well to a production well. The process involves injecting via the injection well into the formation an aqueous solution of modified lignosulfonate salt as a sacrificial agent to inhibit the deposition of surfactant and/or polymer on the reservoir matrix. The process may best be carried out by injecting the modified lignosulfonates into the formation through the injection well mixed with either a polymer, a surfactant solution and/or a micellar dispersion. This mixture would then be followed by a drive fluid such as water to push the chemicals to the production well. The lignosulfonates may be modified by any combination of any two or more of: reaction with chloroacetic acid, reaction with carbon dioxide, addition of the methylene sulfonate radical to the lignosulfonate molecule and oxidation with oxygen.

Modified lignosulfonates as additives in oil recovery processes

Disclosed is a novel surfactant, a method for making the surfactant and an aqueous fluid containing the surfactant which is effective for recovering petroleum from a high temperature formation containing high salinity water. The surfactant fluid is an aqueous fluid containing an organic sulfonate such as petroleum sulfonate and a solubilizing cosurfactant which is a sulfated or sulfonated, polyethoxylated alkylthiol, or a sulfated or sulfonated, polyethoxylated alkylarylthiol.

Surfactant fluid suitable for use in waterflood oil recovery method

Disclosed is a novel surfactant fluid and an oil recovery method using the fluid for recovering oil from subterranean formations thereof by surfactant waterflooding process. The fluid comprises water and at least one surfactant, preferably including an alkylpolyalkoxyalkylene sulfonate or an alkylarylpolyalkoxyalkylene sulfonate and as an additive for reducing the rigidity of the interfacial film, a silica-polydialkylsiloxane such as a silica-polydimethylsiloxane. Reduction in rididity of the interfacial film occupied by surfactant molecules of which the hydrophobic portion is dissolved in the oil phase and the hydrophilic portion is dissolved in the aqueous phase, improves the effectiveness of the surfactant fluid for recovering oil from subterranean formations.

Surfacant waterflooding oil recovery method

An improved surfactant waterflood method for the recovery of oil from a subterranean reservoir utilizing an anionic surface-active agent wherein an aqueous postflush slug containing a nonionic solubilizer is employed to minimize retention of the surface-active agent in the reservoir matrix.

Surfactant waterflood method for the recovery of oil

A process for producing petroleum from subterranean formations is disclosed wherein production from the formation is obtained by driving a fluid from an injection well to a production well. The process involves injecting via the injection well into the formation an aqueous solution of sulfomethylated lignosulfonate salt as a sacrificial agent to inhibit the deposition of surfactant and/or polymer on the reservoir matrix. The process may best be carried out by injecting the sulfomethylated lignosulfonates into the formation through the injection well mixed with either a polymer, a surfactant solution and/or a micellar dispersion. This mixture would then be followed by a drive fluid such as water to push the chemicals to the production well.

Sulfomethylated lignosulfonates as additives in oil recovery processes

A process for producing petroleum from subterranean formations is disclosed wherein production from the formation is obtained by driving a fluid from an injection well to a production well. The process involves injecting via the injection well into the formation an aqueous solution of lignosulfonates carboxylated with chloroacetic acid as a sacrificial agent to inhibit the deposition of surfactant and/or polymer on the reservoir matrix. The process may best be carried out by injecting the lignosulfonates carboxylated with chloroacetic acid into the formation through the injection well mixed with either a polymer, a surfactant solution and/or a micellar dispersion. This mixture would then be followed by a drive fluid such as water to push the chemicals to the production well.

Lignosulfonates carboxylated with chloroacetic acid as additives in oil

A process for producing petroleum from subterranean formations is disclosed wherein production from the formation is obtained by driving a fluid from an injection well to a production well. The process involves injecting via the injection well into the formation an aqueous solution of lignosulfonate salt carboxylated with carbon dioxide as a sacrificial agent to inhibit the deposition of surfactant and/or polymer on the reservoir matrix. The process may best be carried out by injecting the lignosulfonates carboxylated with carbon dioxide into the formation through the injection well mixed with either a polymer, a surfactant solution and/or a micellar dispersion. This mixture would then be followed by a drive fluid such as water to push the chemicals to the production well.

Lignosulfonates carboxylated with carbon dioxide as additives in oil

A process for producing petroleum from subterranean formations is disclosed wherein production from the formation is obtained by driving a fluid from an injection well to a production well. The process involves injecting via the injection well into the formation an aqueous solution of lignosulfonate salt modified by alkoxylation as a sacrificial agent to inhibit the deposition of surfactant and/or polymer on the reservoir matrix. The process may best be carried out by injecting the lignosulfonates modified by alkoxylation into the formation through the injection well mixed with either a polymer, a surfactant solution and/or a micellar dispersion. This mixture would then be followed by a drive fluid such as water to push the chemicals to the production well.

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Houston, TX, United States of America

George Kalfoglou