| abstract |
A drilling fluid containing an aqueous phase and an oil phase and an ether carboxylic acid of the formula: n nRO(CH 2 CH 2 O) x (CH 2 CHR 1 O) y CH 2 —COOX n nwherein, R is a saturated or unsaturated, branched or unbranched alkyl or alkenyl group containing 6 to 22 carbon atoms, x is a number from 1 to 20 and y is 0 or a number from 1 to 20, provided that the sum of x and y is at least 1 and at most 25, R 1 is an alkyl group containing 1 to 4 carbon atoms and X comprises at least one member selected from the group consisting of a hydrogen atom, monovalent anions and polyvalent anions. |