Water-in-oil emulsion drilling fluid

Claim 1

A STABLE WATER-IN-OIL EMULSION DRILLING FLUID COMPRISING AN OIL PHASE, A WATER PHASE AND, AS THE OIL-SOLUBLE, SURFACE-ACTIVE EMULSIFIER, A COMPOSITION OF MATTER FORMED BY THE STEPS OF CONDENSING A POLYHYDRIC ALCOHOL CONTAINING FROM THREE TO SIX HYDROXYL GROUPS PER MOLECULE WITH A REACTIVE EPIHALOHYDRIN, REACTING THE PRODUCT OF THE AFORESAID REACTION WITH A BASIC NITROGEN-CONTAINING COMPOUND SELECTED FROM THE GROUP CONSISTING OF AMMONIA, REACTIVE PRIMARY ALKYL MONOAMINE, REACTIVE PRIMARY HYDROXY LOWER ALKYL MONOAMINE, REACTIVE PRIMARY CYCLO ALKYL MONOAMINE, REACTIVE PRIMARY POLYHDROXY LOWER ALKYL MONOAMINE, AND ALKYLENE POLYAMINES CONTAINING FROM 2 TO 3 AMINO NITROGEN ATOMS AND AT LEAST 2 AMINO HYDROGEN ATOMS PER MOLECULE, LIBERATING THE ETHER CONDENSATION PRODUCTS WITH AN ALKALI AND THEREAFTER ACYLATING THE RESULTING MIXTURE TO FORM A FATTY AMIDE.