Organophilic clays and drilling fluids containing them
AssigneeEvonik Corporation
InventorsSarah Smith, Gary Davis, Dennis Parrish, Miyako Hisamoto
Life of this patent
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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.
Claims20
A method for preparing an organophilic clay, comprising:
- a) homogenizing a mixture comprising:
- i) a smectite-type clay;
- ii) 0 to 15% by weight water and/or polar solvent;
- and
- iii) a quaternary ammonium salt comprising at least 75 mol-% bis-(2-hydroxypropyl)-dimethylammonium methylsulfate fatty acid ester;
- wherein the homogenizing is performed at a temperature above the melting point of the quaternary ammonium salt;
- and
- b) drying the resulting homogenized mixture;
- wherein the organophilic clay comprises the 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.
Dependencies are inferred from the claim text.