significantly dispersible into the aqueous mud if desired other additives such as water loss improving agents corrosion inhibitors bactericides etc can be introduced as part of the additive solvent package into the drilling mud suitable hydrocarbon solvents include mineral oils particularly those paraffin base oils of good oxidation stability with a boiling range of from 200 u00b0 c to 400 u00b0 c such as mentor 28 sold by exxon chemical americas houston tex diesel and gas oils and heavy aromatic naphtha preferred are those above referenced paraffin base oils the invention is further illustrated by the following examples which are not to be considered as limitative of its scope an oxazoline of octadecylthioglycolic acid and 2 amino 2 methyl 1 propanol hereinafter amp was prepared as follows a mixture of 68 8 g 0 2 mole of octadecylthioglycolic acid prepared by the free radical addition of thioglycolic acid to 1 octadecene 200 ml of xylene and 17 8 g 0 2 mole of amp was charged into a laboratory glass 1 liter reaction flask equipped with a thermometer nitrogen atmosphere and an overhead condenser with a dean stark water trap the mixture in the flask was heated to about 140 u00b0 145 u00b0.