This invention relates to a composition comprising: a mixture of a brine and a liquid oil, and (A) an emulsifying amount of (i) at least one reaction product of a hydrocarbyl-substituted succinic acylating agent, and at least one of (a) ammonia, (b) an alcohol, (c) an amine, (d) or mixtures thereof, or at least one salt of the reaction product; or (ii) at least one reaction product of a hydroxyaromatic compound, an aldehyde, and an amine. The compositions of the present invention have beneficial emulsification properties. These compositions are useful in drilling, working over and completing well-bore holes. The well-drilling compositions of the present invention have beneficial viscosity, pumping and suspension properties.