US4964467A — Non-aqueous viscosified carbon dioxide and method…

Claim 1

Independent Claim 79 words

A method of treating a subterranean formation penetrated by a well bore comprising: solubilizing a polymer comprising N,N-dimethylacrylamide in a substantially anhydrous fluid to form a viscosified fluid; admixing said viscosified fluid with liquid carbon dioxide to form an admixture in which said carbon dioxide is present in an amount sufficient to comprise from about 0% to about 80% by volume of said admixture; introducing said admixture into said well bore; and treating said subterranean formation with said admixture.

Claim 2

Independent Claim 79 words

A method of treating a subterranean formation penetrated by a well bore comprising: solubilizing a polymer comprising N,N-dimethylacrylamide in a substantially anhydrous fluid to form a viscosified fluid; admixing said viscosified fluid with liquid carbon dioxide to form an admixture in which said carbon dioxide is present in an amount sufficient to comprise from about 0% to about 80% by volume of said admixture; introducing said admixture into said well bore; and treating said subterranean formation with said admixture.

Claim 3

Dependent Claim 19 words

The method of claim 1 wherein said substantially anhydrous fluid is selected from the group consisting of monohydric alcohols.

Claim 4

Dependent Claim 13 words

The method of claim 1 wherein said polymer is the homopolymer of N,N-dimethylacrylamide.

Claim 5

Dependent Claim 28 words

The method of claim 1 wherein said polymer is present in an amount of about 0.25% to about 2.5% based on the volume of the substantially anhydrous fluid.

Claim 6

Dependent Claim 33 words

The method of claim 1 wherein said substantially anhydrous fluid is admixed with liquid carbon dioxide in a ratio of from about 1 to 1 to a ratio of about 3 to 1.

Claim 7

Dependent Claim 54 words

The method of claim 1 wherein said polymer comprising N,N-dimethylacrylamide is selected from the group consisting of the homopolymer, copolymers with at least one of the following monomers: methacrylamidopropyltrimethyl ammonium chloride, dimethylaminopropyl methacrylamide, 2-acrylamido-2-methyl propane sulfonic acid (sodium salt), trimethylammoniumethyl methacrylic methyl sulfate, trimethylammoniumethyl methacrylic chloride, hydrophobic derivatives of said copolymers, and mixtures thereof.

Claim 8

Dependent Claim 19 words

The method of claim 1 wherein said polymer in said substantially anhydrous fluid is crosslinked with a crosslinking agent.

Claim 9

Independent Claim 126 words

A method of treating a subterranean formation penetrated by a well bore comprising: solubilizing a polymer comprising N,N-dimethylacrylamide in a substantially anhydrous fluid; admixing said substantially anhydrous fluid/polymer solution with a crosslinking agent; admixing said solution with a proppant material and liquid carbon dioxide in a ratio so as to maintain a single-phase, viscosified fluid; introducing said single-phase, viscosified fluid into said well bore and said subterranean formation at a temperature below the critical temperature of carbon dioxide and under sufficient pressure to maintain the carbon dioxide as a liquid; and maintaining said single-phase, viscosified fluid within said formation for a sufficient time to permit said fluid to be heated to a temperature above the critical temperature of carbon dioxide to form a stabilized supercritical fluid.

Claim 10

Independent Claim 126 words

A method of treating a subterranean formation penetrated by a well bore comprising: solubilizing a polymer comprising N,N-dimethylacrylamide in a substantially anhydrous fluid; admixing said substantially anhydrous fluid/polymer solution with a crosslinking agent; admixing said solution with a proppant material and liquid carbon dioxide in a ratio so as to maintain a single-phase, viscosified fluid; introducing said single-phase, viscosified fluid into said well bore and said subterranean formation at a temperature below the critical temperature of carbon dioxide and under sufficient pressure to maintain the carbon dioxide as a liquid; and maintaining said single-phase, viscosified fluid within said formation for a sufficient time to permit said fluid to be heated to a temperature above the critical temperature of carbon dioxide to form a stabilized supercritical fluid.

Claim 11

Dependent Claim 19 words

The method of claim 8 wherein said substantially anhydrous fluid is selected from the group consisting of monohydric alcohols.

Claim 12

Dependent Claim 28 words

The method of claim 8 wherein said polymer is present in an amount of from about 0.25% to about 2.5% based upon the volume of substantially anhydrous fluid.

Claim 13

Dependent Claim 30 words

The method of claim 8 wherein said substantially anhydrous fluid is admixed with liquid carbon dioxide in a ratio of from about 1 to 1 to about 3 to 1.

Claim 14

Dependent Claim 20 words

The method of claim 8 wherein said crosslinking agent is selected from the group consisting of compounds providing zirconium ions.

Claim 15

Dependent Claim 53 words

The method of claim 8 wherein said polymer consisting of N,N-dimethylacrylamide is selected from the group consisting of the homopolymer, copolymers with at least one of the following monomers: methacrylamidopropyltrimethyl ammonium chloride, dimethylaminopropylmethacrylamide, 2-acrylamido-2-methylpropane sulfonic acid (sodium salt), trimethylammoniumethyl methacrylic methyl sulfate, trimethylammoniumethyl methacrylic chloride, hydrophobic derivatives of said copolymers, and mixtures thereof.

Claim 16

Independent Claim 120 words

A method of treating a subterranean formation penetrated by a well bore comprising: solubilizing a polymer comprising N,N-dimethylacrylamide in a substantially anhydrous monohydric alcohol to form a viscosified fluid; admixing said viscosified fluid with liquid carbon dioxide in a ratio so as to form a singlephase, viscosified fluid; introducing said single-phase, viscosified fluid into said well bore and said subterranean formation at a temperature below the critical temperature of liquid carbon dioxide and a sufficient pressure to maintain the carbon dioxide as a liquid; and maintaining said single-phase, viscosified fluid within said formation for a sufficient time to permit said fluid to be heated to a temperature above the critical temperature of carbon dioxide to form a stabilized supercritical fluid.

Claim 17

Independent Claim 120 words

A method of treating a subterranean formation penetrated by a well bore comprising: solubilizing a polymer comprising N,N-dimethylacrylamide in a substantially anhydrous monohydric alcohol to form a viscosified fluid; admixing said viscosified fluid with liquid carbon dioxide in a ratio so as to form a singlephase, viscosified fluid; introducing said single-phase, viscosified fluid into said well bore and said subterranean formation at a temperature below the critical temperature of liquid carbon dioxide and a sufficient pressure to maintain the carbon dioxide as a liquid; and maintaining said single-phase, viscosified fluid within said formation for a sufficient time to permit said fluid to be heated to a temperature above the critical temperature of carbon dioxide to form a stabilized supercritical fluid.

Claim 18

Dependent Claim 53 words

The method of claim 14 wherein said polymer consisting of N,N-dimethylacrylamide is selected from the group consisting of the homopolymer, copolymers with at least one of the following monomers: methacrylamidopropyltrimethyl ammonium chloride, dimethylaminopropylmethacrylamide, 2-acrylamido-2-methylpropane sulfonic acid (sodium salt), trimethylammoniumethyl methyacrylic methyl sulfate, trimethylammoniumethyl methacrylic chloride, hydrophobic derivatives of said copolymers, and mixtures thereof.

Claim 19

Dependent Claim 23 words

The method of claim 14 wherein said substantially anhydrous monohydric alcohol is selected from the group consisting of methanol, ethanol, propanol and butanol.

Claim 20

Dependent Claim 20 words

The method of claim 14 wherein said polymer is present in an amount of from about 0.25% to about 2.5%.

Claim 21

Dependent Claim 36 words

The method of claim 14 wherein said substantially anhydrous monohydric alcohol is admixed with said liquid carbon dioxide in a ratio of from about 1 to 1 to about 3 to 1 based on liquid volume.

Claim 22

Independent Claim 118 words

A method of treating a subterranean formation penetrated by a well bore comprising: solubilizing a polymer comprising N,N-dimethylacrylamide in substantially anhydrous methanol to form a viscosified fluid; admixing said viscosified fluid with liquid carbon dioxide in a ratio so as to form a single phase, viscosified fluid; introducing said single-phase, viscosified fluid into said well bore and said subterranean formation at a temperature below the critical temperature of liquid carbon dioxide and sufficient pressure to maintain the carbon dioxide as a liquid; and maintaining said single-phase, viscosified fluid within said formation for a sufficient time to permit said fluid to be heated to a temperature above the critical temperature of carbon dioxide to form a stabilized supercritical fluid.

Claim 23

Independent Claim 118 words

A method of treating a subterranean formation penetrated by a well bore comprising: solubilizing a polymer comprising N,N-dimethylacrylamide in substantially anhydrous methanol to form a viscosified fluid; admixing said viscosified fluid with liquid carbon dioxide in a ratio so as to form a single phase, viscosified fluid; introducing said single-phase, viscosified fluid into said well bore and said subterranean formation at a temperature below the critical temperature of liquid carbon dioxide and sufficient pressure to maintain the carbon dioxide as a liquid; and maintaining said single-phase, viscosified fluid within said formation for a sufficient time to permit said fluid to be heated to a temperature above the critical temperature of carbon dioxide to form a stabilized supercritical fluid.

Claim 24

Dependent Claim 53 words

The method of claim 19 wherein said polymer consisting of N,N-dimethylacrylamide is selected from the group consisting of the homopolymer, copolymers with at least one of the following monomers: methacrylamidopropyltrimethyl ammonium chloride, dimethylaminopropylmethacrylamide, 2-acrylamido-2methylpropane sulfonic acid (sodium salt), trimethylammoniumethyl methyacrylic methyl sulfate, trimethylammoniumethyl methacrylic chloride, hydrophobic derivatives of said copolymers, and mixtures thereof.

Claim 25

Independent Claim 127 words

A method of treating a subterranean formation penetrated by a well bore comprising: solubilizing a polymer comprising N,N-dimethylacrylamide in substantially anhydrous methanol to form a viscosified fluid; admixing said viscosified fluid with a crosslinking agent; admixing said viscosified fluid and liquid carbon dioxide in a ratio so as to maintain a single-phase, viscosified admixing said single-phase, viscosified fluid with a proppant material; introducing said single-phase, viscosified fluid into said well bore and said formation at a temperature below the critical temperature of carbon dioxide and a pressure to maintain the carbon dioxide as a liquid; and maintaining said single-phase, viscosified fluid within said formation to permit said fluid to be heated to a temperature above the critical temperature of carbon dioxide to form a stabilized supercritical fluid.

Claim 26

Independent Claim 127 words

A method of treating a subterranean formation penetrated by a well bore comprising: solubilizing a polymer comprising N,N-dimethylacrylamide in substantially anhydrous methanol to form a viscosified fluid; admixing said viscosified fluid with a crosslinking agent; admixing said viscosified fluid and liquid carbon dioxide in a ratio so as to maintain a single-phase, viscosified admixing said single-phase, viscosified fluid with a proppant material; introducing said single-phase, viscosified fluid into said well bore and said formation at a temperature below the critical temperature of carbon dioxide and a pressure to maintain the carbon dioxide as a liquid; and maintaining said single-phase, viscosified fluid within said formation to permit said fluid to be heated to a temperature above the critical temperature of carbon dioxide to form a stabilized supercritical fluid.

Claim 27

Dependent Claim 53 words

The method of claim 21 wherein said polymer consisting of N,N-dimethylacrylamide is selected from the group consisting of the homopolymer, copolymers with at least one of the following monomers: methacrylamidopropyltrimethyl ammonium chloride, dimethylaminopropylmethacrylamide, 2-acrylamido-2-methylpropane sulfonic acid (sodium salt), trimethylammoniumethyl methyacrylic methyl sulfate, trimethylammoniumethyl methacrylic chloride, hydrophobic derivatives of said copolymers, and mixtures thereof.

Claim 28

Dependent Claim 23 words

The method of claim 21 wherein said crosslinking agent is selected from the group consisting of zirconium oxychloride, zirconium lactate, and zirconium acetate.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1993-10-22	1994-04-23	1994-10-23	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1997-10-22	1998-04-23	1998-10-23	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2001-10-22	2002-04-23	2002-10-23	$7700.00	Window Closed / Lapsed

Non-aqueous viscosified carbon dioxide and method of use

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag