ORGANOPHILIC CLAYS AND DRILLING MUD CONTAINING THEM Russian patent published in 2021 - IPC C09K8/32 

FIELD: drilling of wells.

SUBSTANCE: present invention relates to organophilic clays which can be used for thickening oil-based compositions at high temperatures and for drilling mud, containing organophilic clays. Organophilic clay containing smectite clay subjected to ion exchange with quaternary ammonium ions. At least 75 mol % of said quaternary ammonium ions are represented by esters of bis-(2-hydroxypropyl)-dimethylammonium and fatty acids and at least 90 % of fatty acid fragments have structure RC(O), wherein the group R is a linear alkyl or alkenyl group containing from 9 to 21 carbon atoms. Method of producing said clay, where mixture containing smectite clay, 0 to 15 wt % water and/or polar solvent and quaternary ammonium salt, containing at least 75 mol % of ester of bis-(2-hydroxypropyl)-dimethylammonium methyl sulfate and fatty acid, homogenizing at temperature above melting point of quaternary ammonium salt and obtained mixture is dried. In another version, a method of producing said clay, where an aqueous suspension of smectite-type clay is mixed with a quaternary ammonium salt, containing at least 75 mol % of bis-(2-hydroxypropyl)-dimethylammonium methyl sulfate and fatty acid ester, at temperature higher than that of quaternary ammonium salt, solid substances are separated from obtained suspension and separated solid substances are dried. Use of said clay for thickening of oil-based composition. Drilling mud for drilling oil or gas wells contains oil phase and above described organophilic clay.

EFFECT: technical result is providing organophilic clay containing biodegradable quaternary ammonium ions, effective for thickening comparable to conventional organophilic clays, sufficiently stable in water-oil emulsions at high temperatures, for use in water-oil emulsion drilling muds.

19 cl, 4 tbl, 4 ex