Abstract: A water-based fluid, containing: a non-ionic surfactant, which is stable in a temperature range from 10 to 90° C. and soluble in water; and a salt, wherein the non-ionic surfactant contains an alkyl polyglucoside selected from the group consisting of a C8 alkyl polyglucoside, a C10 alkyl polyglucoside, and mixtures thereof, and the salt is present, and is present in an amount up to 60%. In addition, a process for preventing the formation of a W/O inverse emulsion or resolving a W/O inverse emulsion that has already formed in an oil well in which an oil-based mud has been employed by injecting the water-based fluid into the oil well.

Abstract: The invention relates to a water-based fluid for applications in the oil field, comprising non-ionic surfactants, stable at temperatures ranging from 10 to 90° C., having an HLB ranging from 8 to 20 and soluble in water, with a saline content ranging from 0 to 60% by weight, and possibly salts. The fluid can be conveniently used as completion fluid for preventing the formation of inverse W/O emulsions or as a remedial fluid for resolving emulsions already formed in oil wells in which oil-based mud has been used.