Texaco Inc.

Jack F Tate

Jim Maddox, Jr

Russell D Shupe

Joseph C Allen

Thomas E Sample, Jr

James W Hughes

Significant improvement in the recovery of hydrocarbons from a subterranean hydrocarbon-bearing formation is accomplished by injecting into the formation via an injection well drilled into a formation communicating with an adjacent producing well and containing sandstone and clay components, and aqueous solution of an acid such as hydrochloric acid and a fluorine-containing acid or salt and having dissolved therein an oxyalkylated acrylamido alkanesulfonic acid polymer whereupon the acid solution reacts with the acid soluble components of the formation creating passageways thus facilitating the flow of fluids therein and thereby increasing the recovery of hydrocarbons from the formation through the adjacent production well.

Aqueous acid solution containing an acrylamido alkanesulfonic acid

The production of hydrocarbons from a subterranean hydrocarbon-bearing formation containing acid-soluble components, such as one composed at least in part of dolomite or limestone, is stimulated by injecting into the formation usually via casing and cement pack perforations a composition comprising an aqueous solution of a mineral acid having dissolved therein a small amount of a vinylpyrrolidone polymer or an alkoxylated vinylpyrrolidone polymer. The increase in the permeability and porosity of the formation achieved utilizing the method of invention results in a substantial improvement in hydrocarbon recovery. Optionally, the injected composition may be saturated with natural gas at the injection pressure. In another embodiment this invention relates to the oxyalkylated vinylpyrrolidone polymer compositions.

Terpolymer of N-vinyl pyrrolidone in alkoxylated form

The production of hydrocarbons from a subterranean hydrocarbon-bearing formation containing acid-soluble components, such as one composed at least in part of dolomite or limestone, is stimulated by injecting into the formation usually via casing and cement pack perforations a composition comprising an aqueous solution of a mineral acid having dissolved therein a small amount of a vinylpyrrolidone terpolymer. The increase in the permeability and porosity of the formation achieved utilizing the method of invention results in a substantial improvement in hydrocarbon recovery. Optionally, the injected composition may be saturated with natural gas at the injection pressure.

Composition and process for stimulating well production

Significant improvement in the recovery of hydrocarbons from a subterranean hydrocarbon-bearing calcareous formation is accomplished by injecting into the formation via an injection well drilled into a formation communicating with an adjacent producing well and containing acid-soluble components which may or may not have water-sensitive clays and shales included therein, a composition comprising an aqueous solution of a mineral acid having dissolved therein a small amount of a vinylpyrrolidone terpolymer solution whereupon the acid solution reacts with the acid-soluble components of the formation creating passageways or enlarging existing passageways thus facilitating the flow of fluids therein and thereby increasing the recovery of hydrocarbons from the formation through the adjacent producing well. Optionally, the injected composition may be saturated with natural gas at the injection pressure.

Secondary recovery process

The production of hydrocarbons from a subterranean hydrocarbon-bearing formation containing acid-soluble components, such as one composed at least in part of dolomite or limestone, is stimulated by injecting into the formation a composition comprising an aqueous solution of a mineral acid having dissolved therein an oxyalkylated acrylamido alkanesulfonic acid polymer. The increase in the permeability and porosity of the formation achieved utilizing the method of invention results in a substantial improvement in hydrocarbon recovery.

Method for stimulating well production

The production of hydrocarbons from a subterranean hydrocarbon-bearing formation containing acid-soluble components, such as one containing clays or siliceous minerals as exemplified by sandstone, shale, etc. is stimulated by injecting into the formation a composition comprising an aqueous solution of a mineral acid and a fluorine-containing acid or salt and having dissolved therein an oxyalkylated acrylamido alkanesulfonic acid polymer. The indepth increase in the permeability and porosity of the formation achieved utilizing the method of invention results in a substantial improvement in hydrocarbon recovery.

Composition and method for stimulating well production

Significant improvement in the recovery of hydrocarbons from a subterranean hydrocarbon-bearing calcareous formation is accomplished by injecting into the formation via an injection well drilled into a formation communicating with an adjacent producing well and containing acid-soluble components which may or may not have water-sensitive clays and shales included therein, an acidic aqueous oxyalkylated acrylamido alkanesulfonic acid polymer solution whereupon the acid solution reacts with the acid-soluble components of the formation creating passageways or enlarging existing passageways thus facilitating the flow of fluids therein and thereby increasing the recovery of hydrocarbons from the formation through the adjacent producing well.

Secondary recovery process utilizing an acrylamido alkanesulfonic acid

A fluid containing a dual surfactant system and a process using the fluid for recovering petroleum from petroleum formations containing high salinity water, e.g. from 50,000 to 225,000 parts per million which may include from about 200 to about 14,000 parts per million polyvalent ions such as calcium and/or magnesium dissolved therein and a method of using said fluid in a surfactant flooding oil recovery process. The surfactant system comprises a water-soluble salt of petroleum sulfonate or an alkyl or alkylaryl sulfonate wherein the alkyl chain may have from 5 to 25 carbon atoms, plus a phosphate ester surfactant with an average molecular weight not to exceed 1000. The surfactant combination is stable up to at least 225.degree. F and resistant to bacterial attack and inhibits scale formation.

Oil recovery process usable in high temperature formations containing

The production of hydrocarbons from a subterranean hydrocarbon-bearing formation containing acid-soluble components, such as one containing clays or siliceous minerals as exemplified by sandstone, shale, etc. is stimulated by injecting into the formation a composition comprising an aqueous solution of a mineral acid and a fluorine-containing acid or salt and having dissolved therein a vinylpyrrolidone polymer and, if desired, a small amount of a water-soluble acrylic acid-type polymer. The in-depth increase in the permeability and porosity of the formation achieved utilizing the method of invention results in a substantial improvement in hydrocarbon recovery.

Composition containing a polyvinylpyrrolidone and method for stimulating

This invention concerns methods of imparting properties of scale resistance to surfaces upon which adherent scale is normally prone to form during contact with mineralized waters through the use of novel; polyurethane-type resins, characterized by containing pendant polyoxyalkylene chains attached to a basic polyurethane skeletal network.

Scale control

A three surfactant system usable in high temperature petroleum formations containing water having from about 200 to about 14,000 parts per million polyvalent ions such as calcium and/or magnesium dissolved therein and a pH of from 5 to 9, and a method of using said surfactant system for recovering petroleum from high temperature subterranean petroleum-containing formations. The three component surfactant system comprises (1) water-soluble salt of an alkyl or alkylaryl sulfonate wherein the alkyl chain may have from 5 to 25 carbon atoms, (2) a phosphate ester surfactant with an average molecular weight not to exceed 1000, and (3) a surfactant having the following betaine related structure: ##STR1## wherein R is an alkyl group having from 12 to 24 carbon atoms, and n is an integer from one to five. The surfactant combination is stable up to at least 225.degree. F and resistant to bacterial attack and inhibits scale formation.

Surfactant oil recovery process usable in high temperature formations

Composition and method for the treatment of inorganic mineral scale, using a treating composition consisting of a water soluble substituted taurine of prescribed formula in an amount of from 0.0005% to about 0.005%, on a weight basis.

Composition and method for treating scale

Composition and method for the treatment of inorganic mineral scale, particularly calcium and/or barium sulfate scale, using a treating composition consisting of a water-soluble sulfonated ethoxylated alkylphenol of prescribed formula in an amount of from about 0.0005 to about 0.005%, on a weight basis.

Method for treating scale

Composition and method for the treatment of inorganic mineral scale particularly calcium and/or barium sulfate scale, using a treating composition consisting of a water-soluble sulfonated ethoxylated alcohol of prescribed formula in an amount of from about 0.0005% to about 0.005%, on a weight basis.

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Houston, TX, United States of America

Jack F Tate