Abstract: An invert drilling fluid composition containing: (a) an oil phase; (b) a water phase; (c) at least one emulsifier; (d) at least one weighting agent; (e) at least one fluid loss additive; (e) at least one electrolyte component containing a mixture of calcium acetate and magnesium acetate; and (g) at least one thickening agent.

Abstract: The invention relates to a process for intensifying the surface stabilization of soil susceptible to erosion by introduction of water-based adhesion-promoting impregnating compounds based on esters of polyvinyl alcohol with C.sub.1-5 monocarboxylic acids and mixtures thereof with higher monocarboxylic acids (binders) using surface-active and biologiclly compatible wetting agents. The process is characterized in that impregnation of the soil is carried out in several stages and in that an aqueous preparation containing the wetting agents is used at least in the first impregnating stage. Binder is preferably used in a comparatively small quantity in this pre-impregnation stage.

Abstract: The invention describes the use of selected esters, fluid at room temperature and with flash points above 80.degree. C., from monocarboxylic acids of synthetic and/or natural origin with 6 to 11 carbon atoms and mono- and/or polyfunctional alcohols as the oil phase or a component of the oil phase of invert drilling muds, which are suitable for environment-friendly development of petroleum and natural gas deposits and in a continuous oil phase contain a dispersed aqueous phase together with emulsifiers, weighting agents, fluid-loss additives and preferably further conventional additives. In a further embodiment the invention relates to invert-drilling fluids of the types mentioned, which are characterized in that the oil phase contains esters of monocarboxylic acids of synthetic and/or natural origin with 6 to 11 carbon atoms and with mono- and/or polyfunctional alcohols preferably in admixture with other components from the class of ecologically acceptable compounds.

Abstract: The invention describes the use of selected esters, fluid at room temperature and with flash points above 80.degree. C., of C.sub.1-5 -monocarboxylic acids and mon- and/or polyfunctional alcohols as the oil phase, or a component of the oil phase of invert drilling muds which are suitable for environment-friendly development of petroleum or natural gas deposits and contain in a continuous oil phase a dispersed aqueous phase together with emulsifiers, weighting agents, fluid-loss additives and preferably further conventional additives. In a further embodiment the invention relates to invert drilling fluids of the type described, which are characterized in that the oil phase contains esters from C.sub.1-5 -monocarboxylic acids with mono- and/or polyfunctional alcohols preferably in admixture with other components from the class of ecologically acceptable compounds.