# US 2018/0022985 A1 · Method of using cationic polymers comprising imidazolium groups for permanent clay stabilization

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- Number: US 2018/0022985 A1
- Document ID: US20180022985A1
- Status: Published application
- Kind: A1
- Application number: 15/536,599
- Filed: 2015-12-07
- Published: 2018-01-25
- Earliest claimed: 2014-12-17
- Assignees: BASF SE
- Applicants: BASF SE; BASF Corporation
- Inventors: Michael SIEMER; Jean-Pierre Berkan LINDNER; Shawn RIMASSA; Nikolas KAPRINIDIS
- Web page: https://patentgrep.com/patent/US20180022985A1

## CPC

- C09K 8/608: {Polymer compositions}
- C08G 73/0616: {with only two nitrogen atoms in the ring}
- C09K 8/035: Organic additives
- C09K 8/52: Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning
- C09K 8/588: characterised by the use of specific polymers {(polymeric surfactants C09K8/584)}
- C09K 8/62: Compositions for forming crevices or fractures
- C09K 8/703: {Foams}
- C09K 8/78: for preventing sealing
- C09K 2208/12: Swell inhibition, i.e. using additives to drilling or well treatment fluids for inhibiting clay or shale swelling or disintegrating
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

Method of inhibiting the swelling of clay in subterranean formations by introducing carrier fluid comprising at least one clay inhibitor into the formation, wherein at least one of the clay inhibitors is a cationic polymer comprising imidazolium groups having a high weight average

## Claims

### Claim at position 1

-18. (canceled)

### Claim 19

A method of inhibiting the swelling of clay in subterranean formations at least comprising introducing a carrier fluid comprising at least one clay inhibitor into the formation, wherein at least one of the clay inhibitors is a cationic polymer comprising repeating units (I) selected from the group of
wherein
R1, R2, and R3 are each, independently of one another, H or a saturated or unsaturated, branched or unbranched, aliphatic and/or aromatic hydrocarbon moiety having from 1 to 20 carbon atoms which optionally may be substituted with functional groups,
R4a, R4b, R4c are each, independently from one another, divalent, trivalent or tetravalent organic groups respectively comprising 2 to 50 carbon atoms, wherein the organic groups R4a, R4b, and R4c may optionally comprise functional groups and/or non-neighboring carbon atoms may be substituted by heteroatoms,
Ym− are each, independently of one another, anionic counter ions, wherein m is an integer from 1 to 4,
and wherein the cationic polymer has a weight average molecular weight Mw of at least 70,000 g/mol.

### Claim 20 (depends on 19)

The method according to claim 19, wherein the weight average molecular weight Mw is from 70,000 g/mol to 1,000,000 g/mol.

### Claim 21 (depends on 19)

The method according to claim 19, wherein the weight average molecular weight Mw is from 80,000 g/mol to 600,000 g/mol.

### Claim 22 (depends on 19)

The method according to claim 19, wherein R4a, R4b, R4c comprise 4 to 20 carbon atoms.

### Claim 23 (depends on 19)

The method according to claim 19, wherein R4a, R4b, R4c comprise at least one group selected from the group of ether groups, secondary amino groups or tertiary amino groups and apart from these no further functional groups.

### Claim 24 (depends on 19)

The method according to claim 19, wherein R4a, R4b, R4c are aliphatic groups.

### Claim 25 (depends on 19)

The method according to claim 19, wherein R4a is a C2 to C20 alkylene group.

### Claim 26 (depends on 19)

The method according to claim 19, wherein R4a is a C4 to C12 alkylene group.

### Claim 27 (depends on 19)

The method according to claim 19, wherein the cationic polymer comprises repeating units (Ia).

### Claim 28 (depends on 27)

The method according to claim 27, wherein the amount of repeating units (Ia) is at least 80 mol % relating to the total amount of all repeating units.

### Claim 29 (depends on 19)

The method according to claim 19, wherein Ym− is an anion of a mono- or polycarboxylic acid.

### Claim 30 (depends on 29)

The method according to claim 29, wherein Ym− is an acetate ion.

### Claim 31 (depends on 19)

The method according to claim 19, wherein the cationic polymer is available by reacting at least an α-dicarbonyl compound, an aldehyde, at least one amino compound having 2 to 4 primary amino groups, and a protic acid with one another.

### Claim 32 (depends on 19)

The method according to claim 19, wherein the concentration of the cationic polymers in the carrier fluid is from 0.001% to 1% by weight relating to the amount of all components of the carrier fluid.

### Claim 33 (depends on 19)

The method according to claim 19, wherein the carrier fluid is an aqueous fluid.

### Claim 34 (depends on 19)

The method according to claim 19, wherein the carrier fluid is selected from the group of drilling fluids, completion fluids, stimulation fluids, matrix acidizing fluids, production/remediation fluids, fluids for enhanced oil recovery (EOR), gravel packs, frac and pack fluids, and wellbore clean up fluids.

### Claim 35 (depends on 19)

The method according to claim 19, wherein the carrier fluid is selected from the group of drilling fluids, completion fluids, fracturing fluids, matrix acidizing fluids, production/remediation fluids, fluids for enhanced oil recovery (EOR), gravel packs, frac and pack fluids, and wellbore clean up fluids.

### Claim 36 (depends on 19)

The method according to claim 19, wherein the carrier fluid is acidic fracturing fluids, alkaline fracturing fluids or foamed fracturing fluids.

### Claim 37 (depends on 19)

The method according to claim 19, wherein the carrier fluid is a pre-flush fluid and the treatment with the pre-flush fluid is followed by the treatment of the formation with a treatment fluid.

### Claim 38 (depends on 19)

The method according to claim 19, wherein the carrier fluid is a hydraulic fracturing fluid comprising—besides the cationic polymer—at least a thickener and a proppant and the fluid is injected into the formation at a pressure sufficient to fracture the formation.