# US 10,865,338 B2 · Organophilic clays and drilling fluids containing them

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- Number: US 10,865,338 B2
- Document ID: US10865338B2
- Status: Granted
- Kind: B2
- Application number: 15/831,152
- Filed: 2017-12-04
- Published: 2018-06-07
- Granted: 2020-12-15
- Earliest claimed: 2016-12-06
- Assignees: Evonik Corporation
- Applicants: Evonik Corporation
- Inventors: Sarah Smith; Gary Davis; Dennis Parrish; Miyako Hisamoto
- Web page: https://patentgrep.com/patent/US10865338B2

## CPC

- C09K 8/36: Water-in-oil emulsions
- C09K 8/03: Specific additives for general use in well-drilling compositions
- C09K 8/32: Non-aqueous well-drilling compositions, e.g. oil-based
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE

## Abstract

The organophilic clay comprises a smectite-type clay ion exchanged with quaternary ammonium ions, where at least 75 mol-% of said quaternary ammonium ions are bis-(2-hydroxypropyl)-dimethylammonium fatty acid esters and at least 90% of the fatty acid moieties of the bis-(2-hydroxypropyl)-dimethylammonium fatty acid esters have a structure RC(O) with group R being a linear alkyl or alkenyl group containing from 9 to 21 carbon atoms. The organophilic clay is useful for thickening oil based compositions, in particular drilling fluids for drilling oil or gas wells, comprising an oil phase.

## Claims

### Claim 1

An organophilic clay comprising a smectite-type clay ion exchanged with quaternary ammonium ions, wherein at least 75 mol-% of said quaternary ammonium ions are bis-(2-hydroxypropyl)-dimethylammonium fatty acid esters and at least 90% of the fatty acid moieties of said bis-(2-hydroxypropyl)-dimethylammonium fatty acid esters have a structure RC(O) with group R being a linear alkyl or alkenyl group containing from 9 to 21 carbon atoms;
wherein the organophilic clay, additionally comprises (2-hydroxypropyl)-(1-methyl-2-hydroxyethyl)-dimethylammonium fatty acid esters, wherein the molar ratio of bis-(2-hydroxypropyl)-dimethylammonium fatty acid esters to (2-hydroxypropyl)-(1-methyl-2-hydroxyethyl)-dimethylammonium fatty acid esters is from 4:1 to 20:1.

### Claim 2 (depends on 1)

The organophilic clay of claim 1, wherein at least 75 mol-% of the exchangeable cations of said smectite-type clay are ion exchanged with quaternary ammonium ions.

### Claim 3 (depends on 1)

The organophilic clay of claim 1, wherein the smectite-type clay comprises bentonite.

### Claim 4 (depends on 3)

The organophilic clay of claim 3, wherein the bentonite comprises at least 60% by weight montmorillonite.

### Claim 5 (depends on 1)

The organophilic clay of claim 1, wherein groups R have an average chain length of from 16 to 18 carbon atoms.

### Claim 6 (depends on 1)

The organophilic clay of claim 1, wherein groups R have an iodine value of from 0 to 120, calculated for the free fatty acid RCOOH.

### Claim 7 (depends on 1)

The organophilic clay of claim 1, wherein said bis-(2-hydroxypropyl)-dimethylammonium fatty acid esters on average have a molar ratio of fatty acid moieties to ammonium nitrogen of from 1.2 to 2.0.

### Claim 8 (depends on 1)

A drilling fluid for drilling oil or gas wells, comprising an oil phase and the organophilic clay of claim 1.

### Claim 9 (depends on 8)

The drilling fluid of claim 8, further comprising a dispersed aqueous phase.

### Claim 10 (depends on 9)

The drilling fluid of claim 9, wherein the weight ratio of oil phase to dispersed aqueous phase, excluding solids dispersed in the phases, is in the range from 95:5 to 50:50.

### Claim 11 (depends on 1)

The organophilic clay of claim 1, wherein the organophilic clay further comprises water and/or an alcohol.