# US 10,308,858 B2 · Biodegradable anti-accretion additive for water-based drilling fluids > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,308,858 B2 - Document ID: US10308858B2 - Status: Granted - Kind: B2 - Application number: 14/406,701 - Filed: 2013-06-05 - Published: 2015-06-11 - Granted: 2019-06-04 - Earliest claimed: 2012-07-06 - Assignees: BASF SE - Applicants: BASF SE - Inventors: Andrea Assmann; Roland Reichenbach-Klinke; Jutta Karin Langlotz - Web page: https://patentgrep.com/patent/US10308858B2 ## CPC - C09K 8/08: containing natural organic compounds, e.g. polysaccharides, or derivatives thereof - C09K 8/528: inorganic depositions, e.g. sulfates or carbonates - E21B 7/00: Special methods or apparatus for drilling - 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 - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS ## Abstract The use of gelatin-based copolymers containing at least one grafted side chain formed from ethylenically unsaturated compounds as an anti-accretion additive is proposed for water-based drilling fluids in the development, exploitation and completion of underground mineral oil and natural gas deposits and in deep wells. These copolymers are water-soluble and have good biodegradability. ## Claims ### Claim 1 A method for drilling a well comprising: drilling a well through shale in an operation selected from the group consisting of development, exploitation and completion of underground mineral oil and natural gas deposits wells and drilling a deep well; and controlling the acretion of clay from the shale on a drill head and drill string by adding a water-based drilling fluid as an anti-accretion additive, wherein the water-based anti-accretion additive consists of: water; and a non-gelatable gelatin comprising at least one grafted side chain formed from an ethylenically unsaturated compound; wherein a content of the non-gelatable gelatin comprising at least one grafted side chain formed from an ethylenically unsaturated compound is from 1 to 15% by weight, based on the water-based drilling fluid. ### Claim 2 (depends on 1) The method according to claim 1, wherein a molar mass of the non-gelatable gelatin is from 500 to 25.000 g/mol. ### Claim 3 (depends on 1) The method according to claim 1, wherein the molar mass of the non-gelatable gelatin is from 1000 to 20,000 g/mol. ### Claim 4 (depends on 1) The method according to claim 1, wherein a molar mass of the grafted side chain is from 150 to 10,000 g/mol. ### Claim 5 (depends on 1) The method according to claim 1, wherein a molar mass of the grafted side chain is from 200 to 5,000 g/mol. ### Claim 6 (depends on 1) The method according to claim 1, wherein a molar mass of the non-gelatable gelatin comprising at least one grafted side chain is from 750 to 50,000 g/mol. ### Claim 7 (depends on 6) The method according to claim 6, wherein the molar mass of the non-gelatable gelatin comprising at least one grafted side chain is from 1,000 to 30,000 g/mol. ### Claim 8 (depends on 7) The method according to claim 7, wherein the molar mass of the non-gelatable gelatin comprising at least one grafted side chain is from 10,000 to 20,000 g/mol. ### Claim 9 (depends on 1) The method according to claim 1, wherein the non-gelatable gelatin comprising at least one grafted side chain comprises the non-gelatable gelatin component in a proportion of 10 to 90% by weight and the ethylenically unsaturated component in proportions of 10 to 90% by weight. ### Claim 10 (depends on 1) The method according to claim 1, wherein the non-gelatable gelatin comprising at least one grafted side chain comprises the non-gelatable gelatin component in a proportion of 25 to 75% by weight and the ethylenically unsaturated component in proportions of 25 to 75% by weight. ### Claim 11 (depends on 1) The method according to claim 1, wherein the ethylenically unsaturated component comprises a vinylic compound or a salt thereof. ### Claim 12 (depends on 11) The method according to claim 11, wherein the vinylic compound is at least one member selected from the group consisting of a vinyl ether, acrylic acid, methacrylic acid, 2-ethylacrylic acid, 2-propylacrylic acid, vinylacetic acid, crotonic acid, isocrotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid and a sulfonated vinyl compound. ### Claim 13 (depends on 12) The method according to claim 12, wherein the vinylic compound is a sulfonated vinyl compound which is a vinylic sulphonic acid. ### Claim 14 (depends on 13) The method according to claim 13, wherein the vinylic sulphonic acid is at least one member selected from the group consisting of from the group of 2-acrylamido-2-methylpropanesulphonic acid, vinylsulphonic acid, methallylsulphonic acid and styrenesulphonic acid, and monovalent salts thereof. ### Claim 15 (depends on 11) The method according to claim 11, wherein the ethylenically unsaturated component is salt of a vinylic compound which contains a cation selected from the group consisting of Na+, K+, Ca2+ and Mg2+. ### Claim 16 (depends on 11) The method according to claim 11, wherein the vinylic compound comprises a quaternized cation group. ### Claim 17 (depends on 16) The method according to claim 16, wherein the quaternized cation group is a salt and further comprises an anion selected from the group consisting of a carbonate, a sulfate, an hydroxide and a chloride. ### Claim 18 (depends on 1) A method according to claim 1, wherein the non-gelatable gelatin comprising at least one grafted side chain is obtained direct graft polymerization at a temperature between 10 and 150° C. ### Claim 19 (depends on 1) The method according to claim 1, wherein the non-gelatable gelatin comprising at least one grafted side chain is obtained direct graft polymerization at a temperature between 0 and 100° C. ### Claim 20 (depends on 18) The method according to claim 18, wherein the direct graft polymerization comprises a solvent. ### Claim 21 (depends on 20) The method according to claim 20, wherein the solvent is a polar solvent. ### Claim 22 (depends on 21) The method according to claim 21, wherein the polar solvent is selected from the group consisting of water and dimethyl sulfoxide. ### Claim 23 (depends on 1) The method according to claim 1, wherein the non-gelatable gelatin comprising at least one grafted side chain is obtained by a process comprising functionalizing the non-gelatable gelatin component with a double bond. ### Claim 24 (depends on 23) The method according to claim 23, wherein the functionalizing of the non-gelatable gelatin component with a double bond comprises reaction with a maximum of 10% by weight of a maleic anhydride compound or a (meth)acryl anhydride or of a glycidyl methacrylate, and a subsequent polymerization of the ethylenically unsaturated compound onto the double bond obtained. ### Claim 25 (depends on 1) The method according to claim 1, wherein the non-gelatable gelatin comprising at least one grafted side chain is water-soluble. ### Claim 26 (depends on 1) The method according to claim 1, wherein the non-gelatable gelatin comprising at least one grafted side chain is biodegradable.