Method for modifying well injection profile and enhanced oil recovery
AssigneeSaudi Arabian Oil Company
InventorsAli Abdullah Al-Taq, Zuhair AlYousif, Othman Alswaie
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Abstract
A method for treating a hydrocarbon-containing formation includes injecting an aqueous solution that contains an alkali nitrite, an ammonium halide, and a foaming agent into the formation, injecting supercritical carbon dioxide into the formation, allowing a portion of the carbon dioxide to dissolve in the aqueous solutions, causing the alkali nitrite and ammonium halide to react and generate nitrogen gas, and allowing a foam to form by the interaction of the nitrogen gas with the foaming agent.
Claims27
A method for treating a hydrocarbon-containing formation, comprising:
- pre-flushing the hydrocarbon-containing formation with a flushing solution comprising a foaming agent to form a pre-flushed hydrocarbon-containing formation;
- injecting an aqueous solution that contains an alkali nitrite, an ammonium halide, and the foaming agent into the pre-flushed hydrocarbon-containing formation;
- and
- injecting a supercritical carbon dioxide into the pre-flushed hydrocarbon-containing formation;
- where a portion of the supercritical carbon dioxide dissolves into the aqueous solution causing the alkali nitrite and the ammonium halide to react and generate a nitrogen gas;
- and
- where a foam forms by the interaction of the nitrogen gas with the foaming agent.
A method for enhanced oil recovery, comprising:
- pre-flushing the hydrocarbon-containing formation with a flushing solution comprising the foaming agent to form a pre-flushed hydrocarbon-containing formation;
- injecting a solution comprising an alkali nitrite, an ammonium halide, and the foaming agent into a high permeability zone of the pre-flushed hydrocarbon-containing formation;
- decreasing a pH of the solution by injecting a supercritical carbon dioxide into the high permeability zone of the pre-flushed hydrocarbon-containing formation such that the alkali nitrite and the ammonium halide react to generate a nitrogen gas that forms a foam with the foaming agent in the high permeability zone and such that wormholes form in a low permeability zone of the pre-flushed hydrocarbon-containing formation such that hydrocarbons in the low permeability zone of the pre-flushed hydrocarbon-bearing formation are stimulated;
- and
- producing hydrocarbons from the pre-flushed hydrocarbon-containing formation.
A method for treating a hydrocarbon-containing formation, comprising:
- pre-flushing the hydrocarbon-containing formation with a flushing solution comprising the foaming agent to form a pre-flushed hydrocarbon-containing formation;
- injecting an aqueous solution that contains an alkali nitrite, an ammonium halide, and the foaming agent into the pre-flushed hydrocarbon-containing formation, wherein the aqueous solution comprises a mixture of a first aqueous solution containing the ammonium halide in a concentration of a range of 0.5 to 13 M and a second aqueous solution containing the alkali nitrite in a concentration of a range of 1 to 15 M, and a molar ratio of the ammonium halide to the alkali nitrite of a range of 1:1 to 1:3;
- injecting a supercritical carbon dioxide into the pre-flushed hydrocarbon-containing formation such that a portion of the supercritical carbon dioxide dissolves in the aqueous solution and causes the alkali nitrite and the ammonium halide to react and generate a nitrogen gas,
- wherein the reaction between the alkali nitrite and the ammonium halide is triggered by a pH of the aqueous solutions decreasing to 5 or less;
- and such that a foam having a viscosity in a range of about 1 to 50 cP to forms by an interaction of the nitrogen gas with the foaming agent.
Dependencies are inferred from the claim text.